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* [patch v21 0/4] JTAG driver introduction
@ 2018-05-15 14:21 Oleksandr Shamray
  2018-05-15 14:21 ` [patch v21 1/4] drivers: jtag: Add JTAG core driver Oleksandr Shamray
                   ` (3 more replies)
  0 siblings, 4 replies; 12+ messages in thread
From: Oleksandr Shamray @ 2018-05-15 14:21 UTC (permalink / raw)
  To: gregkh, arnd
  Cc: linux-kernel, linux-arm-kernel, devicetree, openbmc, joel, jiri,
	tklauser, linux-serial, vadimp, system-sw-low-level, robh+dt,
	openocd-devel-owner, linux-api, davem, mchehab,
	Oleksandr Shamray

When a need raise up to use JTAG interface for system's devices
programming or CPU debugging, usually the user layer
application implements jtag protocol by bit-bang or using a 
proprietary connection to vendor hardware.
This method can be slow and not generic.
 
We propose to implement general JTAG interface and infrastructure
to communicate with user layer application. In such way, we can
have the standard JTAG interface core part and separation from
specific HW implementation.
This allow new capability to debug the CPU or program system's 
device via BMC without additional devices nor cost. 

This patch purpose is to add JTAG master core infrastructure by 
defining new JTAG class and provide generic JTAG interface
to allow hardware specific drivers to connect this interface.
This will enable all JTAG drivers to use the common interface
part and will have separate for hardware implementation.

The JTAG (Joint Test Action Group) core driver provides minimal generic
JTAG interface, which can be used by hardware specific JTAG master
controllers. By providing common interface for the JTAG controllers,
user space device programing is hardware independent.
 
Modern SoC which in use for embedded system' equipped with
internal JTAG master interface.
This interface is used for programming and debugging system's
hardware components, like CPLD, FPGA, CPU, voltage and
industrial controllers.
Firmware for such devices can be upgraded through JTAG interface during
Runtime. The JTAG standard support for multiple devices programming,
is in case their lines are daisy-chained together.

For example, systems which equipped with host CPU, BMC SoC or/and 
number of programmable devices are capable to connect a pin and
select system components dynamically for programming and debugging,
This is using by the BMC which is equipped with internal SoC master
controller.
For example:

BMC JTAG master --> pin selected to CPLDs chain for programming (filed
upgrade, production) 
BMC JTAG master --> pin selected to voltage monitors for programming 
(field upgrade, production) 
BMC JTAG master --> pin selected to host CPU (on-site debugging 
and developers debugging)

For example, we can have application in user space which using calls
to JTAG driver executes CPLD programming directly from SVF file
 
The JTAG standard (IEEE 1149.1) defines the next connector pins:
- TDI (Test Data In);
- TDO (Test Data Out);
- TCK (Test Clock);
- TMS (Test Mode Select);
- TRST (Test Reset) (Optional);

The SoC equipped with JTAG master controller, performs
device programming on command or vector level. For example
a file in a standard SVF (Serial Vector Format) that contains
boundary scan vectors, can be used by sending each vector
to the JTAG interface and the JTAG controller will execute
the programming.

Initial version provides the system calls set for:
- SIR (Scan Instruction Register, IEEE 1149.1 Instruction Register scan);
- SDR (Scan Data Register, IEEE 1149.1 Data Register scan);
- RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
  number of clocks.

SoC which are not equipped with JTAG master interface, can be built
on top of JTAG core driver infrastructure, by applying bit-banging of
TDI, TDO, TCK and TMS pins within the hardware specific driver.

Oleksandr Shamray (4):
  drivers: jtag: Add JTAG core driver
  drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master
    driver
  Documentation: jtag: Add bindings for Aspeed SoC 24xx and 25xx
    families     JTAG master driver
  Documentation: jtag: Add ABI documentation

 Documentation/ABI/testing/jtag-dev                 |   27 +
 .../devicetree/bindings/jtag/aspeed-jtag.txt       |   22 +
 Documentation/ioctl/ioctl-number.txt               |    2 +
 Documentation/jtag/overview                        |   28 +
 Documentation/jtag/transactions                    |  109 +++
 MAINTAINERS                                        |   10 +
 drivers/Kconfig                                    |    2 +
 drivers/Makefile                                   |    1 +
 drivers/jtag/Kconfig                               |   32 +
 drivers/jtag/Makefile                              |    2 +
 drivers/jtag/jtag-aspeed.c                         |  786 ++++++++++++++++++++
 drivers/jtag/jtag.c                                |  274 +++++++
 include/linux/jtag.h                               |   41 +
 include/uapi/linux/jtag.h                          |  105 +++
 14 files changed, 1441 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/ABI/testing/jtag-dev
 create mode 100644 Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
 create mode 100644 Documentation/jtag/overview
 create mode 100644 Documentation/jtag/transactions
 create mode 100644 drivers/jtag/Kconfig
 create mode 100644 drivers/jtag/Makefile
 create mode 100644 drivers/jtag/jtag-aspeed.c
 create mode 100644 drivers/jtag/jtag.c
 create mode 100644 include/linux/jtag.h
 create mode 100644 include/uapi/linux/jtag.h


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [patch v21 1/4] drivers: jtag: Add JTAG core driver
  2018-05-15 14:21 [patch v21 0/4] JTAG driver introduction Oleksandr Shamray
@ 2018-05-15 14:21 ` Oleksandr Shamray
  2018-05-15 21:21   ` Andy Shevchenko
  2018-05-15 14:21 ` [patch v21 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver Oleksandr Shamray
                   ` (2 subsequent siblings)
  3 siblings, 1 reply; 12+ messages in thread
From: Oleksandr Shamray @ 2018-05-15 14:21 UTC (permalink / raw)
  To: gregkh, arnd
  Cc: linux-kernel, linux-arm-kernel, devicetree, openbmc, joel, jiri,
	tklauser, linux-serial, vadimp, system-sw-low-level, robh+dt,
	openocd-devel-owner, linux-api, davem, mchehab,
	Oleksandr Shamray, Jiri Pirko

Initial patch for JTAG driver
JTAG class driver provide infrastructure to support hardware/software
JTAG platform drivers. It provide user layer API interface for flashing
and debugging external devices which equipped with JTAG interface
using standard transactions.

Driver exposes set of IOCTL to user space for:
- XFER:
- SIR (Scan Instruction Register, IEEE 1149.1 Data Register scan);
- SDR (Scan Data Register, IEEE 1149.1 Instruction Register scan);
- RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
  number of clocks).
- SIOCFREQ/GIOCFREQ for setting and reading JTAG frequency.

Driver core provides set of internal APIs for allocation and
registration:
- jtag_register;
- jtag_unregister;
- jtag_alloc;
- jtag_free;

Platform driver on registration with jtag-core creates the next
entry in dev folder:
/dev/jtagX

Signed-off-by: Oleksandr Shamray <oleksandrs@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
---
v20->v21
Comments pointed by Randy Dunlap <rdunlap@infradead.org>
- Fix JTAG dirver help in Kconfig

v19->v20
Comments pointed by Randy Dunlap <rdunlap@infradead.org>
- Fix JTAG dirver help in Kconfig

Notifications from kbuild test robot <lkp@intel.com>
- fix incompatible type casts

v18->v19
Comments pointed by Julia Cartwright <juliac@eso.teric.us>
- Fix memory leak on jtag_alloc exit

v17->v18
Comments pointed by Julia Cartwright <juliac@eso.teric.us>
- Change to return -EOPNOTSUPP in case of error in JTAG_GIOCFREQ
- Add ops callbacks check to jtag_alloc
- Add err check for copy_to_user
- Move the kfree() above the if (err) in JTAG_IOCXFER
- remove unnecessary check for error after put_user
- add padding to struct jtag_xfer

v16->v17
Comments pointed by Julia Cartwright <juliac@eso.teric.us>
- Fix memory allocation on jtag alloc
- Move out unnecessary form lock on jtag open
- Rework jtag register behavior

v15->v16
Commen ts pointed by Florian Fainelli <f.fainelli@gmail.com>
- move check jtag->ops->* in ioctl before get_user()
- change error type -EINVAL --> -EBUSY on open already opened jtag
- remove unnecessary ARCH_DMA_MINALIGN flag from kzalloc
- remove define ARCH_DMA_MINALIGN

v14->v15
v13->v14
Comments pointed by Philippe Ombredanne <pombredanne@nexb.com>
- Change style of head block comment from /**/ to //

v12->v13
Comments pointed by Philippe Ombredanne <pombredanne@nexb.com>
- Change jtag.c licence type to
  SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
  and reorder line with license in description
v11->v12
Comments pointed by Greg KH <gregkh@linuxfoundation.org>
- Change jtag.h licence type to
  SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
  and reorder line with license in description

Chip Bilbrey <chip@bilbrey.org>
- Remove Apeed reference from uapi jtag.h header
- Remove access mode from xfer and idle transactions
- Add new ioctl JTAG_SIOCMODE for set hw mode
- Add only one open per JTAG port blocking with mutex blocking

v10->v11
Notifications from kbuild test robot <lkp@intel.com>
- include types.h headeri to jtag.h
- fix incompatible type of xfer callback
- remove rdundant class defination
- Fix return order in case of xfer error

V9->v10
Comments pointed by Greg KH <gregkh@linuxfoundation.org>
- remove unnecessary alignment for pirv data
- move jtag_copy_to_user and jtag_copy_from_user code just to ioctl
- move int jtag_run_test_idle_op and jtag_xfer_op code
  just to ioctl
- change return error codes to more applicable
- add missing error checks
- fix error check order in ioctl
- remove unnecessary blank lines
- add param validation to ioctl
- remove compat_ioctl
- remove only one open per JTAG port blocking.
  User will care about this.
- Fix idr memory leak on jtag_exit
- change cdev device type to misc

V8->v9
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- use get_user() instead of __get_user().
- change jtag->open type from int to atomic_t
- remove spinlock on jtg_open
- remove mutex on jtag_register
- add unregister_chrdev_region on jtag_init err
- add unregister_chrdev_region on jtag_exit
- remove unnecessary pointer casts
- add *data parameter to xfer function prototype

v7->v8
Comments pointed by Moritz Fischer <moritz.fischer@ettus.com>
- Fix misspelling s/friver/driver

v6->v7
Notifications from kbuild test robot <lkp@intel.com>
- Remove include asm/types.h from jtag.h
- Add include <linux/types.h> to jtag.c

v5->v6
v4->v5

v3->v4
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- change transaction pointer tdio type  to __u64
- change internal status type from enum to __u32
- reorder jtag_xfer members to avoid the implied padding
- add __packed attribute to jtag_xfer and jtag_run_test_idle

v2->v3
Notifications from kbuild test robot <lkp@intel.com>
- Change include path to <linux/types.h> in jtag.h

v1->v2
Comments pointed by Greg KH <gregkh@linuxfoundation.org>
- Change license type from GPLv2/BSD to GPLv2
- Change type of variables which crossed user/kernel to __type
- Remove "default n" from Kconfig

Comments pointed by Andrew Lunn <andrew@lunn.ch>
- Change list_add_tail in jtag_unregister to list_del

Comments pointed by Neil Armstrong <narmstrong@baylibre.com>
- Add SPDX-License-Identifier instead of license text

Comments pointed by Arnd Bergmann <arnd@arndb.de>
- Change __copy_to_user to memdup_user
- Change __put_user to put_user
- Change type of variables to __type for compatible 32 and 64-bit systems
- Add check for maximum xfer data size
- Change lookup data mechanism to get jtag data from inode
- Add .compat_ioctl to file ops
- Add mem alignment for jtag priv data

Comments pointed by Tobias Klauser <tklauser@distanz.ch>
- Change function names to avoid match with variable types
- Fix description for jtag_ru_test_idle in uapi jtag.h
- Fix misprints IDEL/IDLE, trough/through
---
 Documentation/ioctl/ioctl-number.txt |    2 +
 MAINTAINERS                          |   10 ++
 drivers/Kconfig                      |    2 +
 drivers/Makefile                     |    1 +
 drivers/jtag/Kconfig                 |   18 +++
 drivers/jtag/Makefile                |    1 +
 drivers/jtag/jtag.c                  |  274 ++++++++++++++++++++++++++++++++++
 include/linux/jtag.h                 |   41 +++++
 include/uapi/linux/jtag.h            |  105 +++++++++++++
 9 files changed, 454 insertions(+), 0 deletions(-)
 create mode 100644 drivers/jtag/Kconfig
 create mode 100644 drivers/jtag/Makefile
 create mode 100644 drivers/jtag/jtag.c
 create mode 100644 include/linux/jtag.h
 create mode 100644 include/uapi/linux/jtag.h

diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index 7f7413e..c5548b5 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -318,6 +318,8 @@ Code  Seq#(hex)	Include File		Comments
 0xB0	all	RATIO devices		in development:
 					<mailto:vgo@ratio.de>
 0xB1	00-1F	PPPoX			<mailto:mostrows@styx.uwaterloo.ca>
+0xB2	00-0f	linux/jtag.h		JTAG driver
+					<mailto:oleksandrs@mellanox.com>
 0xB3	00	linux/mmc/ioctl.h
 0xB4	00-0F	linux/gpio.h		<mailto:linux-gpio@vger.kernel.org>
 0xB5	00-0F	uapi/linux/rpmsg.h	<mailto:linux-remoteproc@vger.kernel.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 79bb02f..2fd22d6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7610,6 +7610,16 @@ L:	linux-serial@vger.kernel.org
 S:	Maintained
 F:	drivers/tty/serial/jsm/
 
+JTAG SUBSYSTEM
+M:	Oleksandr Shamray <oleksandrs@mellanox.com>
+M:	Vadim Pasternak <vadimp@mellanox.com>
+S:	Maintained
+F:	include/linux/jtag.h
+F:	include/uapi/linux/jtag.h
+F:	drivers/jtag/
+F:	Documentation/devicetree/bindings/jtag/
+F:	Documentation/ABI/testing/jtag-cdev
+
 K10TEMP HARDWARE MONITORING DRIVER
 M:	Clemens Ladisch <clemens@ladisch.de>
 L:	linux-hwmon@vger.kernel.org
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 95b9ccc..bb71e48 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -217,4 +217,6 @@ source "drivers/siox/Kconfig"
 
 source "drivers/slimbus/Kconfig"
 
+source "drivers/jtag/Kconfig"
+
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 24cd470..c92636b 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -185,3 +185,4 @@ obj-$(CONFIG_TEE)		+= tee/
 obj-$(CONFIG_MULTIPLEXER)	+= mux/
 obj-$(CONFIG_UNISYS_VISORBUS)	+= visorbus/
 obj-$(CONFIG_SIOX)		+= siox/
+obj-$(CONFIG_JTAG)		+= jtag/
diff --git a/drivers/jtag/Kconfig b/drivers/jtag/Kconfig
new file mode 100644
index 0000000..43eb9a4
--- /dev/null
+++ b/drivers/jtag/Kconfig
@@ -0,0 +1,18 @@
+menuconfig JTAG
+	tristate "JTAG support"
+	help
+	  This provides basic core functionality support for JTAG class devices.
+	  Hardware that is equipped with a JTAG microcontroller can be
+	  supported by using this driver's interfaces.
+	  This driver exposes a set of IOCTLs to the user space for
+	  the following commands:
+	  SDR: (Scan Data Register) Performs an IEEE 1149.1 Data Register scan
+	  SIR: (Scan Instruction Register) Performs an IEEE 1149.1 Instruction
+	  Register scan.
+	  RUNTEST: Forces the IEEE 1149.1 bus to a run state for a specified
+	  number of clocks or a specified time period.
+
+	  If you want this support, you should say Y here.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called jtag.
diff --git a/drivers/jtag/Makefile b/drivers/jtag/Makefile
new file mode 100644
index 0000000..af37493
--- /dev/null
+++ b/drivers/jtag/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_JTAG)		+= jtag.o
diff --git a/drivers/jtag/jtag.c b/drivers/jtag/jtag.c
new file mode 100644
index 0000000..84c29c8
--- /dev/null
+++ b/drivers/jtag/jtag.c
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// drivers/jtag/jtag.c
+//
+// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2018 Oleksandr Shamray <oleksandrs@mellanox.com>
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/jtag.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/rtnetlink.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <uapi/linux/jtag.h>
+
+#define JTAG_NAME	"jtag0"
+#define MAX_JTAG_NAME_LEN (sizeof("jtag") + 5)
+
+struct jtag {
+	struct miscdevice miscdev;
+	struct device *dev;
+	const struct jtag_ops *ops;
+	int id;
+	bool opened;
+	struct mutex open_lock;
+	unsigned long priv[0];
+};
+
+static DEFINE_IDA(jtag_ida);
+
+void *jtag_priv(struct jtag *jtag)
+{
+	return jtag->priv;
+}
+EXPORT_SYMBOL_GPL(jtag_priv);
+
+static long jtag_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct jtag *jtag = file->private_data;
+	struct jtag_run_test_idle idle;
+	struct jtag_xfer xfer;
+	u8 *xfer_data;
+	u32 data_size;
+	u32 value;
+	int err;
+
+	if (!arg)
+		return -EINVAL;
+
+	switch (cmd) {
+	case JTAG_GIOCFREQ:
+		if (!jtag->ops->freq_get)
+			return -EOPNOTSUPP;
+
+		err = jtag->ops->freq_get(jtag, &value);
+		if (err)
+			break;
+
+		if (put_user(value, (__u32 __user *)arg))
+			err = -EFAULT;
+		break;
+
+	case JTAG_SIOCFREQ:
+		if (!jtag->ops->freq_set)
+			return -EOPNOTSUPP;
+
+		if (get_user(value, (__u32 __user *)arg))
+			return -EFAULT;
+		if (value == 0)
+			return -EINVAL;
+
+		err = jtag->ops->freq_set(jtag, value);
+		break;
+
+	case JTAG_IOCRUNTEST:
+		if (copy_from_user(&idle, (const void __user *)arg,
+				   sizeof(struct jtag_run_test_idle)))
+			return -EFAULT;
+
+		if (idle.endstate > JTAG_STATE_PAUSEDR)
+			return -EINVAL;
+
+		err = jtag->ops->idle(jtag, &idle);
+		break;
+
+	case JTAG_IOCXFER:
+		if (copy_from_user(&xfer, (const void __user *)arg,
+				   sizeof(struct jtag_xfer)))
+			return -EFAULT;
+
+		if (xfer.length >= JTAG_MAX_XFER_DATA_LEN)
+			return -EINVAL;
+
+		if (xfer.type > JTAG_SDR_XFER)
+			return -EINVAL;
+
+		if (xfer.direction > JTAG_WRITE_XFER)
+			return -EINVAL;
+
+		if (xfer.endstate > JTAG_STATE_PAUSEDR)
+			return -EINVAL;
+
+		data_size = DIV_ROUND_UP(xfer.length, BITS_PER_BYTE);
+		xfer_data = memdup_user(u64_to_user_ptr(xfer.tdio), data_size);
+
+		if (IS_ERR(xfer_data))
+			return -EFAULT;
+
+		err = jtag->ops->xfer(jtag, &xfer, xfer_data);
+		if (err) {
+			kfree(xfer_data);
+			return -EFAULT;
+		}
+
+		err = copy_to_user(u64_to_user_ptr(xfer.tdio),
+				   (void *)(xfer_data), data_size);
+		kfree(xfer_data);
+		if (err)
+			return -EFAULT;
+
+		if (copy_to_user((void __user *)arg, (void *)&xfer,
+				 sizeof(struct jtag_xfer)))
+			return -EFAULT;
+		break;
+
+	case JTAG_GIOCSTATUS:
+		err = jtag->ops->status_get(jtag, &value);
+		if (err)
+			break;
+
+		err = put_user(value, (__u32 __user *)arg);
+		break;
+	case JTAG_SIOCMODE:
+		if (get_user(value, (__u32 __user *)arg))
+			return -EFAULT;
+		if (value == 0)
+			return -EINVAL;
+
+		err = jtag->ops->mode_set(jtag, value);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+	return err;
+}
+
+static int jtag_open(struct inode *inode, struct file *file)
+{
+	struct jtag *jtag = container_of(file->private_data, struct jtag,
+					 miscdev);
+
+	if (mutex_lock_interruptible(&jtag->open_lock))
+		return -ERESTARTSYS;
+
+	if (jtag->opened) {
+		mutex_unlock(&jtag->open_lock);
+		return -EBUSY;
+	}
+	jtag->opened = true;
+	mutex_unlock(&jtag->open_lock);
+
+	nonseekable_open(inode, file);
+	file->private_data = jtag;
+	return 0;
+}
+
+static int jtag_release(struct inode *inode, struct file *file)
+{
+	struct jtag *jtag = file->private_data;
+
+	mutex_lock(&jtag->open_lock);
+	jtag->opened = false;
+	mutex_unlock(&jtag->open_lock);
+	return 0;
+}
+
+static const struct file_operations jtag_fops = {
+	.owner		= THIS_MODULE,
+	.open		= jtag_open,
+	.release	= jtag_release,
+	.llseek		= noop_llseek,
+	.unlocked_ioctl = jtag_ioctl,
+};
+
+struct jtag *jtag_alloc(size_t priv_size, const struct jtag_ops *ops)
+{
+	struct jtag *jtag;
+
+	if (!ops)
+		return NULL;
+
+	if (!ops->idle || !ops->mode_set || !ops->status_get || !ops->xfer)
+		return NULL;
+
+	jtag = kzalloc(sizeof(*jtag) + priv_size, GFP_KERNEL);
+	if (!jtag)
+		return NULL;
+
+	jtag->ops = ops;
+	return jtag;
+}
+EXPORT_SYMBOL_GPL(jtag_alloc);
+
+void jtag_free(struct jtag *jtag)
+{
+	kfree(jtag);
+}
+EXPORT_SYMBOL_GPL(jtag_free);
+
+int jtag_register(struct jtag *jtag)
+{
+	char *name;
+	int err;
+	int id;
+
+	id = ida_simple_get(&jtag_ida, 0, 0, GFP_KERNEL);
+	if (id < 0)
+		return id;
+
+	jtag->id = id;
+	jtag->opened = false;
+
+	name = kzalloc(MAX_JTAG_NAME_LEN, GFP_KERNEL);
+	if (!name) {
+		err = -ENOMEM;
+		goto err_jtag_alloc;
+	}
+
+	err = snprintf(name, MAX_JTAG_NAME_LEN, "jtag%d", id);
+	if (err < 0)
+		goto err_jtag_name;
+
+	mutex_init(&jtag->open_lock);
+	jtag->miscdev.fops =  &jtag_fops;
+	jtag->miscdev.minor = MISC_DYNAMIC_MINOR;
+	jtag->miscdev.name = name;
+
+	err = misc_register(&jtag->miscdev);
+	if (err) {
+		dev_err(jtag->dev, "Unable to register device\n");
+		goto err_jtag_name;
+	}
+	return 0;
+
+err_jtag_name:
+	kfree(name);
+err_jtag_alloc:
+	ida_simple_remove(&jtag_ida, id);
+	return err;
+}
+EXPORT_SYMBOL_GPL(jtag_register);
+
+void jtag_unregister(struct jtag *jtag)
+{
+	misc_deregister(&jtag->miscdev);
+	kfree(jtag->miscdev.name);
+	ida_simple_remove(&jtag_ida, jtag->id);
+}
+EXPORT_SYMBOL_GPL(jtag_unregister);
+
+static void __exit jtag_exit(void)
+{
+	ida_destroy(&jtag_ida);
+}
+
+module_exit(jtag_exit);
+
+MODULE_AUTHOR("Oleksandr Shamray <oleksandrs@mellanox.com>");
+MODULE_DESCRIPTION("Generic jtag support");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/jtag.h b/include/linux/jtag.h
new file mode 100644
index 0000000..80a887f
--- /dev/null
+++ b/include/linux/jtag.h
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0
+// include/linux/jtag.h - JTAG class driver
+//
+// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2018 Oleksandr Shamray <oleksandrs@mellanox.com>
+
+#ifndef __JTAG_H
+#define __JTAG_H
+
+#include <uapi/linux/jtag.h>
+
+#define jtag_u64_to_ptr(arg) ((void *)(uintptr_t)arg)
+
+#define JTAG_MAX_XFER_DATA_LEN 65535
+
+struct jtag;
+/**
+ * struct jtag_ops - callbacks for jtag control functions:
+ *
+ * @freq_get: get frequency function. Filled by device driver
+ * @freq_set: set frequency function. Filled by device driver
+ * @status_get: set status function. Filled by device driver
+ * @idle: set JTAG to idle state function. Filled by device driver
+ * @xfer: send JTAG xfer function. Filled by device driver
+ */
+struct jtag_ops {
+	int (*freq_get)(struct jtag *jtag, u32 *freq);
+	int (*freq_set)(struct jtag *jtag, u32 freq);
+	int (*status_get)(struct jtag *jtag, u32 *state);
+	int (*idle)(struct jtag *jtag, struct jtag_run_test_idle *idle);
+	int (*xfer)(struct jtag *jtag, struct jtag_xfer *xfer, u8 *xfer_data);
+	int (*mode_set)(struct jtag *jtag, u32 mode_mask);
+};
+
+void *jtag_priv(struct jtag *jtag);
+int jtag_register(struct jtag *jtag);
+void jtag_unregister(struct jtag *jtag);
+struct jtag *jtag_alloc(size_t priv_size, const struct jtag_ops *ops);
+void jtag_free(struct jtag *jtag);
+
+#endif /* __JTAG_H */
diff --git a/include/uapi/linux/jtag.h b/include/uapi/linux/jtag.h
new file mode 100644
index 0000000..ecd02a0
--- /dev/null
+++ b/include/uapi/linux/jtag.h
@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: GPL-2.0
+// include/uapi/linux/jtag.h - JTAG class driver uapi
+//
+// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2018 Oleksandr Shamray <oleksandrs@mellanox.com>
+
+#ifndef __UAPI_LINUX_JTAG_H
+#define __UAPI_LINUX_JTAG_H
+
+#include <linux/types.h>
+/*
+ * JTAG_XFER_HW_MODE: JTAG hardware mode. Used to set HW drived or bitbang
+ * mode. This is bitmask param of ioctl JTAG_SIOCMODE command
+ */
+#define  JTAG_XFER_HW_MODE 1
+
+/**
+ * enum jtag_endstate:
+ *
+ * @JTAG_STATE_IDLE: JTAG state machine IDLE state
+ * @JTAG_STATE_PAUSEIR: JTAG state machine PAUSE_IR state
+ * @JTAG_STATE_PAUSEDR: JTAG state machine PAUSE_DR state
+ */
+enum jtag_endstate {
+	JTAG_STATE_IDLE,
+	JTAG_STATE_PAUSEIR,
+	JTAG_STATE_PAUSEDR,
+};
+
+/**
+ * enum jtag_xfer_type:
+ *
+ * @JTAG_SIR_XFER: SIR transfer
+ * @JTAG_SDR_XFER: SDR transfer
+ */
+enum jtag_xfer_type {
+	JTAG_SIR_XFER,
+	JTAG_SDR_XFER,
+};
+
+/**
+ * enum jtag_xfer_direction:
+ *
+ * @JTAG_READ_XFER: read transfer
+ * @JTAG_WRITE_XFER: write transfer
+ */
+enum jtag_xfer_direction {
+	JTAG_READ_XFER,
+	JTAG_WRITE_XFER,
+};
+
+/**
+ * struct jtag_run_test_idle - forces JTAG state machine to
+ * RUN_TEST/IDLE state
+ *
+ * @reset: 0 - run IDLE/PAUSE from current state
+ *         1 - go through TEST_LOGIC/RESET state before  IDLE/PAUSE
+ * @end: completion flag
+ * @tck: clock counter
+ *
+ * Structure represents interface to JTAG device for jtag idle
+ * execution.
+ */
+struct jtag_run_test_idle {
+	__u8	reset;
+	__u8	endstate;
+	__u8	tck;
+};
+
+/**
+ * struct jtag_xfer - jtag xfer:
+ *
+ * @type: transfer type
+ * @direction: xfer direction
+ * @length: xfer bits len
+ * @tdio : xfer data array
+ * @endir: xfer end state
+ *
+ * Structure represents interface to JTAG device for jtag sdr xfer
+ * execution.
+ */
+struct jtag_xfer {
+	__u8	type;
+	__u8	direction;
+	__u8	endstate;
+	__u8	padding;
+	__u32	length;
+	__u64	tdio;
+};
+
+/* ioctl interface */
+#define __JTAG_IOCTL_MAGIC	0xb2
+
+#define JTAG_IOCRUNTEST	_IOW(__JTAG_IOCTL_MAGIC, 0,\
+			     struct jtag_run_test_idle)
+#define JTAG_SIOCFREQ	_IOW(__JTAG_IOCTL_MAGIC, 1, unsigned int)
+#define JTAG_GIOCFREQ	_IOR(__JTAG_IOCTL_MAGIC, 2, unsigned int)
+#define JTAG_IOCXFER	_IOWR(__JTAG_IOCTL_MAGIC, 3, struct jtag_xfer)
+#define JTAG_GIOCSTATUS _IOWR(__JTAG_IOCTL_MAGIC, 4, enum jtag_endstate)
+#define JTAG_SIOCMODE	_IOW(__JTAG_IOCTL_MAGIC, 5, unsigned int)
+
+#define JTAG_FIRST_MINOR 0
+#define JTAG_MAX_DEVICES 32
+
+#endif /* __UAPI_LINUX_JTAG_H */
-- 
1.7.1


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [patch v21 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver
  2018-05-15 14:21 [patch v21 0/4] JTAG driver introduction Oleksandr Shamray
  2018-05-15 14:21 ` [patch v21 1/4] drivers: jtag: Add JTAG core driver Oleksandr Shamray
@ 2018-05-15 14:21 ` Oleksandr Shamray
  2018-05-15 21:00   ` Andy Shevchenko
  2018-05-15 14:21 ` [patch v21 3/4] Documentation: jtag: Add bindings for " Oleksandr Shamray
  2018-05-15 14:21 ` [patch v21 4/4] Documentation: jtag: Add ABI documentation Oleksandr Shamray
  3 siblings, 1 reply; 12+ messages in thread
From: Oleksandr Shamray @ 2018-05-15 14:21 UTC (permalink / raw)
  To: gregkh, arnd
  Cc: linux-kernel, linux-arm-kernel, devicetree, openbmc, joel, jiri,
	tklauser, linux-serial, vadimp, system-sw-low-level, robh+dt,
	openocd-devel-owner, linux-api, davem, mchehab,
	Oleksandr Shamray, Jiri Pirko

Driver adds support of Aspeed 2500/2400 series SOC JTAG master controller.

Driver implements the following jtag ops:
- freq_get;
- freq_set;
- status_get;
- idle;
- xfer;

It has been tested on Mellanox system with BMC equipped with
Aspeed 2520 SoC for programming CPLD devices.

Signed-off-by: Oleksandr Shamray <oleksandrs@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
Acked-by: Joel Stanley <joel@jms.id.au>
---
v19->v20
Notifications from kbuild test robot <lkp@intel.com>
- add static declaration to 'aspeed_jtag_init' and
  'aspeed_jtag_deinit' functions

v18->v19
v17->v18
v16->v17
v15->v16
Comments pointed by Joel Stanley <joel.stan@gmail.com>
- Add reset_control on Jtag init/deinit

v14->v15
Comments pointed by Joel Stanley <joel.stan@gmail.com>
- Add ARCH_ASPEED || COMPILE_TEST to Kconfig
- remove unused offset variable
- remove "aspeed_jtag" from dev_err and dev_dbg messages
- change clk_prepare_enable initialisation order

v13->v14
Comments pointed by Philippe Ombredanne <pombredanne@nexb.com>
- Change style of head block comment from /**/ to //

v12->v13
Comments pointed by Philippe Ombredanne <pombredanne@nexb.com>
- Change jtag-aspeed.c licence type to
  SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
  and reorder line with license in description
Comments pointed by Kun Yi <kunyi@google.com>
- Changed capability check for aspeed,ast2400-jtag/ast200-jtag

v11->v12
Comments pointed by Chip Bilbrey <chip@bilbrey.org>
- Remove access mode from xfer and idle transactions
- Add new ioctl JTAG_SIOCMODE for set hw mode

v10->v11
v9->v10
V8->v9
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- add *data parameter to xfer function prototype

v7->v8
Comments pointed by Joel Stanley <joel.stan@gmail.com>
- aspeed_jtag_init replace goto to return;
- change input variables type from __u32 to u32
  in functios freq_get, freq_set, status_get
- change sm_ variables type from char to u8
- in jatg_init add disable clocks on error case
- remove release_mem_region on error case
- remove devm_free_irq on jtag_deinit
- Fix misspelling Disabe/Disable
- Change compatible string to ast2400 and ast2000

v6->v7
Notifications from kbuild test robot <lkp@intel.com>
- Add include <linux/types.h> to jtag-asapeed.c

v5->v6
v4->v5
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- Added HAS_IOMEM dependence in Kconfig to avoid
  "undefined reference to `devm_ioremap_resource'" error,
  because in some arch this not supported

v3->v4
Comments pointed by Arnd Bergmann <arnd@arndb.de>
- change transaction pointer tdio type  to __u64
- change internal status type from enum to __u32

v2->v3

v1->v2
Comments pointed by Greg KH <gregkh@linuxfoundation.org>
- change license type from GPLv2/BSD to GPLv2

Comments pointed by Neil Armstrong <narmstrong@baylibre.com>
- Add clk_prepare_enable/clk_disable_unprepare in clock init/deinit
- Change .compatible to soc-specific compatible names
  aspeed,aspeed4000-jtag/aspeed5000-jtag
- Added dt-bindings

Comments pointed by Arnd Bergmann <arnd@arndb.de>
- Reorder functions and removed the forward declarations
- Add static const qualifier to state machine states transitions
- Change .compatible to soc-specific compatible names
  aspeed,aspeed4000-jtag/aspeed5000-jtag
- Add dt-bindings

Comments pointed by Randy Dunlap <rdunlap@infradead.org>
- Change module name jtag-aspeed in description in Kconfig

Comments pointed by kbuild test robot <lkp@intel.com>
- Remove invalid include <asm/mach-types.h>
- add resource_size instead of calculation
---
 drivers/jtag/Kconfig       |   14 +
 drivers/jtag/Makefile      |    1 +
 drivers/jtag/jtag-aspeed.c |  786 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 801 insertions(+), 0 deletions(-)
 create mode 100644 drivers/jtag/jtag-aspeed.c

diff --git a/drivers/jtag/Kconfig b/drivers/jtag/Kconfig
index 43eb9a4..6b43ac8 100644
--- a/drivers/jtag/Kconfig
+++ b/drivers/jtag/Kconfig
@@ -16,3 +16,17 @@ menuconfig JTAG
 
 	  To compile this driver as a module, choose M here: the module will
 	  be called jtag.
+
+menuconfig JTAG_ASPEED
+	tristate "Aspeed SoC JTAG controller support"
+	depends on JTAG && HAS_IOMEM
+	depends on ARCH_ASPEED || COMPILE_TEST
+	help
+	  This provides a support for Aspeed JTAG device, equipped on
+	  Aspeed SoC 24xx and 25xx families. Drivers allows programming
+	  of hardware devices, connected to SoC through the JTAG interface.
+
+	  If you want this support, you should say Y here.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called jtag-aspeed.
diff --git a/drivers/jtag/Makefile b/drivers/jtag/Makefile
index af37493..04a855e 100644
--- a/drivers/jtag/Makefile
+++ b/drivers/jtag/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_JTAG)		+= jtag.o
+obj-$(CONFIG_JTAG_ASPEED)	+= jtag-aspeed.o
diff --git a/drivers/jtag/jtag-aspeed.c b/drivers/jtag/jtag-aspeed.c
new file mode 100644
index 0000000..2d22de0
--- /dev/null
+++ b/drivers/jtag/jtag-aspeed.c
@@ -0,0 +1,786 @@
+// SPDX-License-Identifier: GPL-2.0
+// drivers/jtag/aspeed-jtag.c
+//
+// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2018 Oleksandr Shamray <oleksandrs@mellanox.com>
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/jtag.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <uapi/linux/jtag.h>
+
+#define ASPEED_JTAG_DATA		0x00
+#define ASPEED_JTAG_INST		0x04
+#define ASPEED_JTAG_CTRL		0x08
+#define ASPEED_JTAG_ISR			0x0C
+#define ASPEED_JTAG_SW			0x10
+#define ASPEED_JTAG_TCK			0x14
+#define ASPEED_JTAG_EC			0x18
+
+#define ASPEED_JTAG_DATA_MSB		0x01
+#define ASPEED_JTAG_DATA_CHUNK_SIZE	0x20
+
+/* ASPEED_JTAG_CTRL: Engine Control */
+#define ASPEED_JTAG_CTL_ENG_EN		BIT(31)
+#define ASPEED_JTAG_CTL_ENG_OUT_EN	BIT(30)
+#define ASPEED_JTAG_CTL_FORCE_TMS	BIT(29)
+#define ASPEED_JTAG_CTL_INST_LEN(x)	((x) << 20)
+#define ASPEED_JTAG_CTL_LASPEED_INST	BIT(17)
+#define ASPEED_JTAG_CTL_INST_EN		BIT(16)
+#define ASPEED_JTAG_CTL_DR_UPDATE	BIT(10)
+#define ASPEED_JTAG_CTL_DATA_LEN(x)	((x) << 4)
+#define ASPEED_JTAG_CTL_LASPEED_DATA	BIT(1)
+#define ASPEED_JTAG_CTL_DATA_EN		BIT(0)
+
+/* ASPEED_JTAG_ISR : Interrupt status and enable */
+#define ASPEED_JTAG_ISR_INST_PAUSE	BIT(19)
+#define ASPEED_JTAG_ISR_INST_COMPLETE	BIT(18)
+#define ASPEED_JTAG_ISR_DATA_PAUSE	BIT(17)
+#define ASPEED_JTAG_ISR_DATA_COMPLETE	BIT(16)
+#define ASPEED_JTAG_ISR_INST_PAUSE_EN	BIT(3)
+#define ASPEED_JTAG_ISR_INST_COMPLETE_EN BIT(2)
+#define ASPEED_JTAG_ISR_DATA_PAUSE_EN	BIT(1)
+#define ASPEED_JTAG_ISR_DATA_COMPLETE_EN BIT(0)
+#define ASPEED_JTAG_ISR_INT_EN_MASK	GENMASK(3, 0)
+#define ASPEED_JTAG_ISR_INT_MASK	GENMASK(19, 16)
+
+/* ASPEED_JTAG_SW : Software Mode and Status */
+#define ASPEED_JTAG_SW_MODE_EN		BIT(19)
+#define ASPEED_JTAG_SW_MODE_TCK		BIT(18)
+#define ASPEED_JTAG_SW_MODE_TMS		BIT(17)
+#define ASPEED_JTAG_SW_MODE_TDIO	BIT(16)
+
+/* ASPEED_JTAG_TCK : TCK Control */
+#define ASPEED_JTAG_TCK_DIVISOR_MASK	GENMASK(10, 0)
+#define ASPEED_JTAG_TCK_GET_DIV(x)	((x) & ASPEED_JTAG_TCK_DIVISOR_MASK)
+
+/* ASPEED_JTAG_EC : Controller set for go to IDLE */
+#define ASPEED_JTAG_EC_GO_IDLE		BIT(0)
+
+#define ASPEED_JTAG_IOUT_LEN(len)	(ASPEED_JTAG_CTL_ENG_EN |\
+					 ASPEED_JTAG_CTL_ENG_OUT_EN |\
+					 ASPEED_JTAG_CTL_INST_LEN(len))
+
+#define ASPEED_JTAG_DOUT_LEN(len)	(ASPEED_JTAG_CTL_ENG_EN |\
+					 ASPEED_JTAG_CTL_ENG_OUT_EN |\
+					 ASPEED_JTAG_CTL_DATA_LEN(len))
+
+#define ASPEED_JTAG_TCK_WAIT		10
+#define ASPEED_JTAG_RESET_CNTR		10
+
+#define ASPEED_JTAG_NAME		"jtag-aspeed"
+
+struct aspeed_jtag {
+	void __iomem			*reg_base;
+	struct device			*dev;
+	struct clk			*pclk;
+	enum jtag_endstate		status;
+	int				irq;
+	struct reset_control		*rst;
+	u32				flag;
+	wait_queue_head_t		jtag_wq;
+	u32				mode;
+};
+
+static char *end_status_str[] = {"idle", "ir pause", "drpause"};
+
+static u32 aspeed_jtag_read(struct aspeed_jtag *aspeed_jtag, u32 reg)
+{
+	return readl(aspeed_jtag->reg_base + reg);
+}
+
+static void
+aspeed_jtag_write(struct aspeed_jtag *aspeed_jtag, u32 val, u32 reg)
+{
+	writel(val, aspeed_jtag->reg_base + reg);
+}
+
+static int aspeed_jtag_freq_set(struct jtag *jtag, u32 freq)
+{
+	struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+	unsigned long apb_frq;
+	u32 tck_val;
+	u16 div;
+
+	apb_frq = clk_get_rate(aspeed_jtag->pclk);
+	div = (apb_frq % freq == 0) ? (apb_frq / freq) - 1 : (apb_frq / freq);
+	tck_val = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_TCK);
+	aspeed_jtag_write(aspeed_jtag,
+			  (tck_val & ASPEED_JTAG_TCK_DIVISOR_MASK) | div,
+			  ASPEED_JTAG_TCK);
+	return 0;
+}
+
+static int aspeed_jtag_freq_get(struct jtag *jtag, u32 *frq)
+{
+	struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+	u32 pclk;
+	u32 tck;
+
+	pclk = clk_get_rate(aspeed_jtag->pclk);
+	tck = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_TCK);
+	*frq = pclk / (ASPEED_JTAG_TCK_GET_DIV(tck) + 1);
+
+	return 0;
+}
+
+static int aspeed_jtag_mode_set(struct jtag *jtag, u32 mode)
+{
+	struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+
+	aspeed_jtag->mode = mode;
+	return 0;
+}
+
+static void aspeed_jtag_sw_delay(struct aspeed_jtag *aspeed_jtag, int cnt)
+{
+	int i;
+
+	for (i = 0; i < cnt; i++)
+		aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_SW);
+}
+
+static char aspeed_jtag_tck_cycle(struct aspeed_jtag *aspeed_jtag,
+				  u8 tms, u8 tdi)
+{
+	char tdo = 0;
+
+	/* TCK = 0 */
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+			  (tms * ASPEED_JTAG_SW_MODE_TMS) |
+			  (tdi * ASPEED_JTAG_SW_MODE_TDIO), ASPEED_JTAG_SW);
+
+	aspeed_jtag_sw_delay(aspeed_jtag, ASPEED_JTAG_TCK_WAIT);
+
+	/* TCK = 1 */
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+			  ASPEED_JTAG_SW_MODE_TCK |
+			  (tms * ASPEED_JTAG_SW_MODE_TMS) |
+			  (tdi * ASPEED_JTAG_SW_MODE_TDIO), ASPEED_JTAG_SW);
+
+	if (aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_SW) &
+	    ASPEED_JTAG_SW_MODE_TDIO)
+		tdo = 1;
+
+	aspeed_jtag_sw_delay(aspeed_jtag, ASPEED_JTAG_TCK_WAIT);
+
+	/* TCK = 0 */
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+			  (tms * ASPEED_JTAG_SW_MODE_TMS) |
+			  (tdi * ASPEED_JTAG_SW_MODE_TDIO), ASPEED_JTAG_SW);
+	return tdo;
+}
+
+static void aspeed_jtag_wait_instruction_pause(struct aspeed_jtag *aspeed_jtag)
+{
+	wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
+				 ASPEED_JTAG_ISR_INST_PAUSE);
+	aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_INST_PAUSE;
+}
+
+static void
+aspeed_jtag_wait_instruction_complete(struct aspeed_jtag *aspeed_jtag)
+{
+	wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
+				 ASPEED_JTAG_ISR_INST_COMPLETE);
+	aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_INST_COMPLETE;
+}
+
+static void
+aspeed_jtag_wait_data_pause_complete(struct aspeed_jtag *aspeed_jtag)
+{
+	wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
+				 ASPEED_JTAG_ISR_DATA_PAUSE);
+	aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_DATA_PAUSE;
+}
+
+static void aspeed_jtag_wait_data_complete(struct aspeed_jtag *aspeed_jtag)
+{
+	wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
+				 ASPEED_JTAG_ISR_DATA_COMPLETE);
+	aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_DATA_COMPLETE;
+}
+
+static void aspeed_jtag_sm_cycle(struct aspeed_jtag *aspeed_jtag, const u8 *tms,
+				 int len)
+{
+	int i;
+
+	for (i = 0; i < len; i++)
+		aspeed_jtag_tck_cycle(aspeed_jtag, tms[i], 0);
+}
+
+static void aspeed_jtag_run_test_idle_sw(struct aspeed_jtag *aspeed_jtag,
+					 struct jtag_run_test_idle *runtest)
+{
+	static const u8 sm_pause_irpause[] = {1, 1, 1, 1, 0, 1, 0};
+	static const u8 sm_pause_drpause[] = {1, 1, 1, 0, 1, 0};
+	static const u8 sm_idle_irpause[] = {1, 1, 0, 1, 0};
+	static const u8 sm_idle_drpause[] = {1, 0, 1, 0};
+	static const u8 sm_pause_idle[] = {1, 1, 0};
+	int i;
+
+	/* SW mode from idle/pause-> to pause/idle */
+	if (runtest->reset) {
+		for (i = 0; i < ASPEED_JTAG_RESET_CNTR; i++)
+			aspeed_jtag_tck_cycle(aspeed_jtag, 1, 0);
+	}
+
+	switch (aspeed_jtag->status) {
+	case JTAG_STATE_IDLE:
+		switch (runtest->endstate) {
+		case JTAG_STATE_PAUSEIR:
+			/* ->DRSCan->IRSCan->IRCap->IRExit1->PauseIR */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_idle_irpause,
+					     sizeof(sm_idle_irpause));
+
+			aspeed_jtag->status = JTAG_STATE_PAUSEIR;
+			break;
+		case JTAG_STATE_PAUSEDR:
+			/* ->DRSCan->DRCap->DRExit1->PauseDR */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_idle_drpause,
+					     sizeof(sm_idle_drpause));
+
+			aspeed_jtag->status = JTAG_STATE_PAUSEDR;
+			break;
+		case JTAG_STATE_IDLE:
+			/* IDLE */
+			aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0);
+			aspeed_jtag->status = JTAG_STATE_IDLE;
+			break;
+		default:
+			break;
+		}
+		break;
+
+	case JTAG_STATE_PAUSEIR:
+	/* Fall-through */
+	case JTAG_STATE_PAUSEDR:
+		/* From IR/DR Pause */
+		switch (runtest->endstate) {
+		case JTAG_STATE_PAUSEIR:
+			/*
+			 * to Exit2 IR/DR->Updt IR/DR->DRSCan->IRSCan->IRCap->
+			 * IRExit1->PauseIR
+			 */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_irpause,
+					     sizeof(sm_pause_irpause));
+
+			aspeed_jtag->status = JTAG_STATE_PAUSEIR;
+			break;
+		case JTAG_STATE_PAUSEDR:
+			/*
+			 * to Exit2 IR/DR->Updt IR/DR->DRSCan->DRCap->
+			 * DRExit1->PauseDR
+			 */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_drpause,
+					     sizeof(sm_pause_drpause));
+			aspeed_jtag->status = JTAG_STATE_PAUSEDR;
+			break;
+		case JTAG_STATE_IDLE:
+			/* to Exit2 IR/DR->Updt IR/DR->IDLE */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_idle,
+					     sizeof(sm_pause_idle));
+			aspeed_jtag->status = JTAG_STATE_IDLE;
+			break;
+		default:
+			break;
+		}
+		break;
+
+	default:
+		dev_err(aspeed_jtag->dev, "aspeed_jtag_run_test_idle error\n");
+		break;
+	}
+
+	/* Stay on IDLE for at least  TCK cycle */
+	for (i = 0; i < runtest->tck; i++)
+		aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0);
+}
+
+/**
+ * aspeed_jtag_run_test_idle:
+ * JTAG reset: generates at least 9 TMS high and 1 TMS low to force
+ * devices into Run-Test/Idle State.
+ */
+static int aspeed_jtag_idle(struct jtag *jtag,
+			    struct jtag_run_test_idle *runtest)
+{
+	struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+
+	dev_dbg(aspeed_jtag->dev, "runtest, status:%d, mode:%s, state:%s, reset:%d, tck:%d\n",
+		aspeed_jtag->status,
+		aspeed_jtag->mode & JTAG_XFER_HW_MODE ? "HW" : "SW",
+		end_status_str[runtest->endstate], runtest->reset,
+		runtest->tck);
+
+	if (!(aspeed_jtag->mode & JTAG_XFER_HW_MODE)) {
+		aspeed_jtag_run_test_idle_sw(aspeed_jtag, runtest);
+		return 0;
+	}
+
+	/* Disable sw mode */
+	aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_SW);
+	/* x TMS high + 1 TMS low */
+	if (runtest->reset)
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_CTL_ENG_EN |
+				  ASPEED_JTAG_CTL_ENG_OUT_EN |
+				  ASPEED_JTAG_CTL_FORCE_TMS, ASPEED_JTAG_CTRL);
+	else
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_EC_GO_IDLE,
+				  ASPEED_JTAG_EC);
+
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+			  ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
+
+	aspeed_jtag->status = JTAG_STATE_IDLE;
+	return 0;
+}
+
+static void aspeed_jtag_xfer_sw(struct aspeed_jtag *aspeed_jtag,
+				struct jtag_xfer *xfer, unsigned long *data)
+{
+	unsigned long remain_xfer = xfer->length;
+	unsigned long shift_bits = 0;
+	unsigned long index = 0;
+	unsigned long tdi;
+	char          tdo;
+
+	if (xfer->direction == JTAG_READ_XFER)
+		tdi = UINT_MAX;
+	else
+		tdi = data[index];
+
+	while (remain_xfer > 1) {
+		tdo = aspeed_jtag_tck_cycle(aspeed_jtag, 0,
+					    tdi & ASPEED_JTAG_DATA_MSB);
+		data[index] |= tdo << (shift_bits %
+					    ASPEED_JTAG_DATA_CHUNK_SIZE);
+
+		tdi >>= 1;
+		shift_bits++;
+		remain_xfer--;
+
+		if (shift_bits % ASPEED_JTAG_DATA_CHUNK_SIZE == 0) {
+			dev_dbg(aspeed_jtag->dev, "R/W data[%lu]:%lx\n",
+				index, data[index]);
+
+			tdo = 0;
+			index++;
+
+			if (xfer->direction == JTAG_READ_XFER)
+				tdi = UINT_MAX;
+			else
+				tdi = data[index];
+		}
+	}
+
+	tdo = aspeed_jtag_tck_cycle(aspeed_jtag, 1, tdi & ASPEED_JTAG_DATA_MSB);
+	data[index] |= tdo << (shift_bits % ASPEED_JTAG_DATA_CHUNK_SIZE);
+}
+
+static void aspeed_jtag_xfer_push_data(struct aspeed_jtag *aspeed_jtag,
+				       enum jtag_xfer_type type, u32 bits_len)
+{
+	dev_dbg(aspeed_jtag->dev, "shift bits %d\n", bits_len);
+
+	if (type == JTAG_SIR_XFER) {
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_IOUT_LEN(bits_len),
+				  ASPEED_JTAG_CTRL);
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_DOUT_LEN(bits_len) |
+				  ASPEED_JTAG_CTL_INST_EN, ASPEED_JTAG_CTRL);
+	} else {
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_DOUT_LEN(bits_len),
+				  ASPEED_JTAG_CTRL);
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_DOUT_LEN(bits_len) |
+				  ASPEED_JTAG_CTL_DATA_EN, ASPEED_JTAG_CTRL);
+	}
+}
+
+static void aspeed_jtag_xfer_push_data_last(struct aspeed_jtag *aspeed_jtag,
+					    enum jtag_xfer_type type,
+					    u32 shift_bits,
+					    enum jtag_endstate endstate)
+{
+	if (endstate != JTAG_STATE_IDLE) {
+		if (type == JTAG_SIR_XFER) {
+			dev_dbg(aspeed_jtag->dev, "IR Keep Pause\n");
+
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_IOUT_LEN(shift_bits),
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_IOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_INST_EN,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_wait_instruction_pause(aspeed_jtag);
+		} else {
+			dev_dbg(aspeed_jtag->dev, "DR Keep Pause\n");
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_DOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_DR_UPDATE,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_DOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_DR_UPDATE |
+					  ASPEED_JTAG_CTL_DATA_EN,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_wait_data_pause_complete(aspeed_jtag);
+		}
+	} else {
+		if (type == JTAG_SIR_XFER) {
+			dev_dbg(aspeed_jtag->dev, "IR go IDLE\n");
+
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_IOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_LASPEED_INST,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_IOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_LASPEED_INST |
+					  ASPEED_JTAG_CTL_INST_EN,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_wait_instruction_complete(aspeed_jtag);
+		} else {
+			dev_dbg(aspeed_jtag->dev, "DR go IDLE\n");
+
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_DOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_LASPEED_DATA,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_write(aspeed_jtag,
+					  ASPEED_JTAG_DOUT_LEN(shift_bits) |
+					  ASPEED_JTAG_CTL_LASPEED_DATA |
+					  ASPEED_JTAG_CTL_DATA_EN,
+					  ASPEED_JTAG_CTRL);
+			aspeed_jtag_wait_data_complete(aspeed_jtag);
+		}
+	}
+}
+
+static void aspeed_jtag_xfer_hw(struct aspeed_jtag *aspeed_jtag,
+				struct jtag_xfer *xfer, unsigned long *data)
+{
+	unsigned long remain_xfer = xfer->length;
+	unsigned long index = 0;
+	char shift_bits;
+	u32 data_reg;
+
+	data_reg = xfer->type == JTAG_SIR_XFER ?
+		   ASPEED_JTAG_INST : ASPEED_JTAG_DATA;
+	while (remain_xfer) {
+		if (xfer->direction == JTAG_WRITE_XFER) {
+			dev_dbg(aspeed_jtag->dev, "W dr->dr_data[%lu]:%lx\n",
+				index, data[index]);
+
+			aspeed_jtag_write(aspeed_jtag, data[index], data_reg);
+		} else {
+			aspeed_jtag_write(aspeed_jtag, 0, data_reg);
+		}
+
+		if (remain_xfer > ASPEED_JTAG_DATA_CHUNK_SIZE) {
+			shift_bits = ASPEED_JTAG_DATA_CHUNK_SIZE;
+
+			/*
+			 * Read bytes were not equals to column length
+			 * and go to Pause-DR
+			 */
+			aspeed_jtag_xfer_push_data(aspeed_jtag, xfer->type,
+						   shift_bits);
+		} else {
+			/*
+			 * Read bytes equals to column length =>
+			 * Update-DR
+			 */
+			shift_bits = remain_xfer;
+			aspeed_jtag_xfer_push_data_last(aspeed_jtag, xfer->type,
+							shift_bits,
+							xfer->endstate);
+		}
+
+		if (xfer->direction == JTAG_READ_XFER) {
+			if (shift_bits < ASPEED_JTAG_DATA_CHUNK_SIZE) {
+				data[index] = aspeed_jtag_read(aspeed_jtag,
+							       data_reg);
+
+				data[index] >>= ASPEED_JTAG_DATA_CHUNK_SIZE -
+								shift_bits;
+			} else {
+				data[index] = aspeed_jtag_read(aspeed_jtag,
+							       data_reg);
+			}
+			dev_dbg(aspeed_jtag->dev, "R dr->dr_data[%lu]:%lx\n",
+				index, data[index]);
+		}
+
+		remain_xfer = remain_xfer - shift_bits;
+		index++;
+		dev_dbg(aspeed_jtag->dev, "remain_xfer %lu\n", remain_xfer);
+	}
+}
+
+static int aspeed_jtag_xfer(struct jtag *jtag, struct jtag_xfer *xfer,
+			    u8 *xfer_data)
+{
+	static const u8 sm_update_shiftir[] = {1, 1, 0, 0};
+	static const u8 sm_update_shiftdr[] = {1, 0, 0};
+	static const u8 sm_pause_idle[] = {1, 1, 0};
+	static const u8 sm_pause_update[] = {1, 1};
+	struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+	unsigned long *data = (unsigned long *)xfer_data;
+	unsigned long remain_xfer = xfer->length;
+	char dbg_str[256];
+	int pos = 0;
+	int i;
+
+	for (i = 0; i <= xfer->length / BITS_PER_BYTE; i++) {
+		pos += snprintf(&dbg_str[pos], sizeof(dbg_str) - pos,
+				"0x%02x ", xfer_data[i]);
+	}
+
+	dev_dbg(aspeed_jtag->dev, " %s %s xfer, mode:%s, END:%d, len:%lu, TDI[%s]\n",
+		xfer->type == JTAG_SIR_XFER ? "SIR" : "SDR",
+		xfer->direction == JTAG_READ_XFER ? "READ" : "WRITE",
+		aspeed_jtag->mode & JTAG_XFER_HW_MODE ? "HW" : "SW",
+		xfer->endstate, remain_xfer, dbg_str);
+
+	if (!(aspeed_jtag->mode & JTAG_XFER_HW_MODE)) {
+		/* SW mode */
+		aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+				  ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
+
+		if (aspeed_jtag->status != JTAG_STATE_IDLE) {
+			/*IR/DR Pause->Exit2 IR / DR->Update IR /DR */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_update,
+					     sizeof(sm_pause_update));
+		}
+
+		if (xfer->type == JTAG_SIR_XFER)
+			/* ->IRSCan->CapIR->ShiftIR */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_update_shiftir,
+					     sizeof(sm_update_shiftir));
+		else
+			/* ->DRScan->DRCap->DRShift */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_update_shiftdr,
+					     sizeof(sm_update_shiftdr));
+
+		aspeed_jtag_xfer_sw(aspeed_jtag, xfer, data);
+
+		/* DIPause/DRPause */
+		aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0);
+
+		if (xfer->endstate == JTAG_STATE_IDLE) {
+			/* ->DRExit2->DRUpdate->IDLE */
+			aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_idle,
+					     sizeof(sm_pause_idle));
+		}
+	} else {
+		/* hw mode */
+		aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_SW);
+		aspeed_jtag_xfer_hw(aspeed_jtag, xfer, data);
+	}
+
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+			  ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
+	aspeed_jtag->status = xfer->endstate;
+	return 0;
+}
+
+static int aspeed_jtag_status_get(struct jtag *jtag, u32 *status)
+{
+	struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+
+	*status = aspeed_jtag->status;
+	return 0;
+}
+
+static irqreturn_t aspeed_jtag_interrupt(s32 this_irq, void *dev_id)
+{
+	struct aspeed_jtag *aspeed_jtag = dev_id;
+	irqreturn_t ret;
+	u32 status;
+
+	status = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_ISR);
+	dev_dbg(aspeed_jtag->dev, "status %x\n", status);
+
+	if (status & ASPEED_JTAG_ISR_INT_MASK) {
+		aspeed_jtag_write(aspeed_jtag,
+				  (status & ASPEED_JTAG_ISR_INT_MASK)
+				  | (status & ASPEED_JTAG_ISR_INT_EN_MASK),
+				  ASPEED_JTAG_ISR);
+		aspeed_jtag->flag |= status & ASPEED_JTAG_ISR_INT_MASK;
+	}
+
+	if (aspeed_jtag->flag) {
+		wake_up_interruptible(&aspeed_jtag->jtag_wq);
+		ret = IRQ_HANDLED;
+	} else {
+		dev_err(aspeed_jtag->dev, "irq status:%x\n",
+			status);
+		ret = IRQ_NONE;
+	}
+	return ret;
+}
+
+static int aspeed_jtag_init(struct platform_device *pdev,
+			    struct aspeed_jtag *aspeed_jtag)
+{
+	struct resource *res;
+	int err;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	aspeed_jtag->reg_base = devm_ioremap_resource(aspeed_jtag->dev, res);
+	if (IS_ERR(aspeed_jtag->reg_base))
+		return -ENOMEM;
+
+	aspeed_jtag->pclk = devm_clk_get(aspeed_jtag->dev, NULL);
+	if (IS_ERR(aspeed_jtag->pclk)) {
+		dev_err(aspeed_jtag->dev, "devm_clk_get failed\n");
+		return PTR_ERR(aspeed_jtag->pclk);
+	}
+
+	aspeed_jtag->irq = platform_get_irq(pdev, 0);
+	if (aspeed_jtag->irq < 0) {
+		dev_err(aspeed_jtag->dev, "no irq specified\n");
+		return -ENOENT;
+	}
+
+	clk_prepare_enable(aspeed_jtag->pclk);
+
+	aspeed_jtag->rst = devm_reset_control_get_shared(aspeed_jtag->dev,
+							 NULL);
+	if (IS_ERR(aspeed_jtag->rst)) {
+		dev_err(aspeed_jtag->dev,
+			"missing or invalid reset controller device tree entry");
+		return PTR_ERR(aspeed_jtag->rst);
+	}
+	reset_control_deassert(aspeed_jtag->rst);
+
+	/* Enable clock */
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_CTL_ENG_EN |
+			  ASPEED_JTAG_CTL_ENG_OUT_EN, ASPEED_JTAG_CTRL);
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+			  ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
+
+	err = devm_request_irq(aspeed_jtag->dev, aspeed_jtag->irq,
+			       aspeed_jtag_interrupt, 0,
+			       "aspeed-jtag", aspeed_jtag);
+	if (err) {
+		dev_err(aspeed_jtag->dev, "unable to get IRQ");
+		goto clk_unprep;
+	}
+	dev_dbg(&pdev->dev, "IRQ %d.\n", aspeed_jtag->irq);
+
+	aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_ISR_INST_PAUSE |
+			  ASPEED_JTAG_ISR_INST_COMPLETE |
+			  ASPEED_JTAG_ISR_DATA_PAUSE |
+			  ASPEED_JTAG_ISR_DATA_COMPLETE |
+			  ASPEED_JTAG_ISR_INST_PAUSE_EN |
+			  ASPEED_JTAG_ISR_INST_COMPLETE_EN |
+			  ASPEED_JTAG_ISR_DATA_PAUSE_EN |
+			  ASPEED_JTAG_ISR_DATA_COMPLETE_EN,
+			  ASPEED_JTAG_ISR);
+
+	aspeed_jtag->flag = 0;
+	aspeed_jtag->mode = 0;
+	init_waitqueue_head(&aspeed_jtag->jtag_wq);
+	return 0;
+
+clk_unprep:
+	clk_disable_unprepare(aspeed_jtag->pclk);
+	return err;
+}
+
+static int aspeed_jtag_deinit(struct platform_device *pdev,
+			      struct aspeed_jtag *aspeed_jtag)
+{
+	aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_ISR);
+	/* Disable clock */
+	aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_CTRL);
+	reset_control_assert(aspeed_jtag->rst);
+	clk_disable_unprepare(aspeed_jtag->pclk);
+	return 0;
+}
+
+static const struct jtag_ops aspeed_jtag_ops = {
+	.freq_get = aspeed_jtag_freq_get,
+	.freq_set = aspeed_jtag_freq_set,
+	.status_get = aspeed_jtag_status_get,
+	.idle = aspeed_jtag_idle,
+	.xfer = aspeed_jtag_xfer,
+	.mode_set = aspeed_jtag_mode_set
+};
+
+static int aspeed_jtag_probe(struct platform_device *pdev)
+{
+	struct aspeed_jtag *aspeed_jtag;
+	struct device *dev;
+	struct jtag *jtag;
+	int err;
+
+	dev = &pdev->dev;
+	jtag = jtag_alloc(sizeof(*aspeed_jtag), &aspeed_jtag_ops);
+	if (!jtag)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, jtag);
+	aspeed_jtag = jtag_priv(jtag);
+	aspeed_jtag->dev = &pdev->dev;
+
+	/* Initialize device*/
+	err = aspeed_jtag_init(pdev, aspeed_jtag);
+	if (err)
+		goto err_jtag_init;
+
+	/* Initialize JTAG core structure*/
+	err = jtag_register(jtag);
+	if (err)
+		goto err_jtag_register;
+
+	return 0;
+
+err_jtag_register:
+	aspeed_jtag_deinit(pdev, aspeed_jtag);
+err_jtag_init:
+	jtag_free(jtag);
+	return err;
+}
+
+static int aspeed_jtag_remove(struct platform_device *pdev)
+{
+	struct jtag *jtag;
+
+	jtag = platform_get_drvdata(pdev);
+	aspeed_jtag_deinit(pdev, jtag_priv(jtag));
+	jtag_unregister(jtag);
+	jtag_free(jtag);
+	return 0;
+}
+
+static const struct of_device_id aspeed_jtag_of_match[] = {
+	{ .compatible = "aspeed,ast2400-jtag", },
+	{ .compatible = "aspeed,ast2500-jtag", },
+	{}
+};
+
+static struct platform_driver aspeed_jtag_driver = {
+	.probe = aspeed_jtag_probe,
+	.remove = aspeed_jtag_remove,
+	.driver = {
+		.name = ASPEED_JTAG_NAME,
+		.of_match_table = aspeed_jtag_of_match,
+	},
+};
+module_platform_driver(aspeed_jtag_driver);
+
+MODULE_AUTHOR("Oleksandr Shamray <oleksandrs@mellanox.com>");
+MODULE_DESCRIPTION("ASPEED JTAG driver");
+MODULE_LICENSE("GPL v2");
-- 
1.7.1


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [patch v21 3/4] Documentation: jtag: Add bindings for Aspeed SoC 24xx and 25xx families JTAG master driver
  2018-05-15 14:21 [patch v21 0/4] JTAG driver introduction Oleksandr Shamray
  2018-05-15 14:21 ` [patch v21 1/4] drivers: jtag: Add JTAG core driver Oleksandr Shamray
  2018-05-15 14:21 ` [patch v21 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver Oleksandr Shamray
@ 2018-05-15 14:21 ` Oleksandr Shamray
  2018-05-15 14:21 ` [patch v21 4/4] Documentation: jtag: Add ABI documentation Oleksandr Shamray
  3 siblings, 0 replies; 12+ messages in thread
From: Oleksandr Shamray @ 2018-05-15 14:21 UTC (permalink / raw)
  To: gregkh, arnd
  Cc: linux-kernel, linux-arm-kernel, devicetree, openbmc, joel, jiri,
	tklauser, linux-serial, vadimp, system-sw-low-level, robh+dt,
	openocd-devel-owner, linux-api, davem, mchehab,
	Oleksandr Shamray, Jiri Pirko

It has been tested on Mellanox system with BMC equipped with
Aspeed 2520 SoC for programming CPLD devices.

Signed-off-by: Oleksandr Shamray <oleksandrs@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Rob Herring <robh@kernel.org>
---
v19->v20
v18->v19
v17->v18
v16->v17
v15->v16
Comments pointed by Joel Stanley <joel.stan@gmail.com>
- change clocks = <&clk_apb> to proper clocks = <&syscon ASPEED_CLK_APB>
- add reset descriptions in bndings file

v14->v15
v13->v14
v12->v13
v11->v12
v10->v11
v9->v10
v8->v9
v7->v8
Comments pointed by pointed by Joel Stanley <joel.stan@gmail.com>
- Change compatible string to ast2400 and ast2000

V6->v7
Comments pointed by Tobias Klauser <tklauser@distanz.ch>
 - Fix spell "Doccumentation" -> "Documentation"

v5->v6
Comments pointed by Tobias Klauser <tklauser@distanz.ch>
- Small nit: s/documentation/Documentation/

v4->v5

V3->v4
Comments pointed by Rob Herring <robh@kernel.org>
- delete unnecessary "status" and "reg-shift" descriptions in
  bndings file

v2->v3
Comments pointed by Rob Herring <robh@kernel.org>
- split Aspeed jtag driver and binding to sepatrate patches
- delete unnecessary "status" and "reg-shift" descriptions in
  bndings file
---
 .../devicetree/bindings/jtag/aspeed-jtag.txt       |   22 ++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/jtag/aspeed-jtag.txt

diff --git a/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt b/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
new file mode 100644
index 0000000..7c36eb6
--- /dev/null
+++ b/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
@@ -0,0 +1,22 @@
+Aspeed JTAG driver for ast2400 and ast2500 SoC
+
+Required properties:
+- compatible:		Should be one of
+      - "aspeed,ast2400-jtag"
+      - "aspeed,ast2500-jtag"
+- reg			contains the offset and length of the JTAG memory
+			region
+- clocks		root clock of bus, should reference the APB
+			clock in the second cell
+- resets		phandle to reset controller with the reset number in
+			the second cell
+- interrupts		should contain JTAG controller interrupt
+
+Example:
+jtag: jtag@1e6e4000 {
+	compatible = "aspeed,ast2500-jtag";
+	reg = <0x1e6e4000 0x1c>;
+	clocks = <&syscon ASPEED_CLK_APB>;
+	resets = <&syscon ASPEED_RESET_JTAG_MASTER>;
+	interrupts = <43>;
+};
-- 
1.7.1


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [patch v21 4/4] Documentation: jtag: Add ABI documentation
  2018-05-15 14:21 [patch v21 0/4] JTAG driver introduction Oleksandr Shamray
                   ` (2 preceding siblings ...)
  2018-05-15 14:21 ` [patch v21 3/4] Documentation: jtag: Add bindings for " Oleksandr Shamray
@ 2018-05-15 14:21 ` Oleksandr Shamray
  2018-05-16 18:16   ` Randy Dunlap
  3 siblings, 1 reply; 12+ messages in thread
From: Oleksandr Shamray @ 2018-05-15 14:21 UTC (permalink / raw)
  To: gregkh, arnd
  Cc: linux-kernel, linux-arm-kernel, devicetree, openbmc, joel, jiri,
	tklauser, linux-serial, vadimp, system-sw-low-level, robh+dt,
	openocd-devel-owner, linux-api, davem, mchehab,
	Oleksandr Shamray

Added document that describe the ABI for JTAG class drivrer

Signed-off-by: Oleksandr Shamray <oleksandrs@mellanox.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
v19->v20
Comments pointed by Randy Dunlap <rdunlap@infradead.org>
- Fix JTAG doccumentation

v18->v19
Pavel Machek <pavel@ucw.cz>
- Added JTAG doccumentation to Documentation/jtag

v17->v18
v16->v17
v15->v16
v14->v15
v13->v14
v12->v13
v11->v12
Tobias Klauser <tklauser@distanz.ch>
- rename /Documentation/ABI/testing/jatg-dev -> jtag-dev
- Typo: s/interfase/interface
v10->v11
v9->v10
Fixes added by Oleksandr:
- change jtag-cdev to jtag-dev in documentation
- update Kernel Version and Date in jtag-dev documentation;
v8->v9
v7->v8
v6->v7
Comments pointed by Pavel Machek <pavel@ucw.cz>
- Added jtag-cdev documentation to Documentation/ABI/testing folder
---
 Documentation/ABI/testing/jtag-dev |   27 +++++++++
 Documentation/jtag/overview        |   28 +++++++++
 Documentation/jtag/transactions    |  109 ++++++++++++++++++++++++++++++++++++
 3 files changed, 164 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/ABI/testing/jtag-dev
 create mode 100644 Documentation/jtag/overview
 create mode 100644 Documentation/jtag/transactions

diff --git a/Documentation/ABI/testing/jtag-dev b/Documentation/ABI/testing/jtag-dev
new file mode 100644
index 0000000..4325316
--- /dev/null
+++ b/Documentation/ABI/testing/jtag-dev
@@ -0,0 +1,27 @@
+What:		/dev/jtag[0-9]+
+Date:		May 2018
+KernelVersion:	4.18
+Contact:	oleksandrs@mellanox.com
+Description:
+		The misc device files /dev/jtag* are the interface
+		between JTAG master interface and userspace.
+
+		The ioctl(2)-based ABI is defined and documented in
+		[include/uapi]<linux/jtag.h>.
+
+		The following file operations are supported:
+
+		open(2)
+		The argument flag currently support only one access
+		mode O_RDWR.
+
+		ioctl(2)
+		Initiate various actions.
+		See the inline documentation in [include/uapi]<linux/jtag.h>
+		for descriptions of all ioctls.
+
+		close(2)
+		Stops and free up the I/O contexts that was associated
+		with the file descriptor.
+
+Users:		TBD
diff --git a/Documentation/jtag/overview b/Documentation/jtag/overview
new file mode 100644
index 0000000..a86f188
--- /dev/null
+++ b/Documentation/jtag/overview
@@ -0,0 +1,28 @@
+Linux kernel JTAG support
+=========================
+
+The JTAG is an industry standard for verifying hardware
+JTAG provides access to many logic signals of a complex integrated circuit,
+including the device pins.
+
+A JTAG interface is a special interface added to a chip.
+Depending on the version of JTAG, two, four, or five pins are added.
+
+The connector pins are:
+	TDI (Test Data In)
+	TDO (Test Data Out)
+	TCK (Test Clock)
+	TMS (Test Mode Select)
+	TRST (Test Reset) optional.
+
+JTAG interface is designed to have two parts - basic core driver and
+hardware specific driver. The basic driver introduces a general interface
+which is not dependent of specific hardware. It provides communication
+between user space and hardware specific driver.
+Each JTAG device is represented as a char device from (jtag0, jtag1, ...).
+Access to a JTAG device is performed through IOCTL calls.
+
+Call flow example:
+User: open  -> /dev/jatgX
+User: ioctl -> /dev/jtagX -> JTAG core driver -> JTAG hw specific driver
+User: close -> /dev/jatgX
diff --git a/Documentation/jtag/transactions b/Documentation/jtag/transactions
new file mode 100644
index 0000000..6a857c8
--- /dev/null
+++ b/Documentation/jtag/transactions
@@ -0,0 +1,109 @@
+The JTAG API
+=============
+
+JTAG master devices can be accessed through a character misc-device.
+Each JTAG master interface can be accessed by using /dev/jtagN
+
+JTAG system calls set:
+- SIR (Scan Instruction Register, IEEE 1149.1 Instruction Register scan);
+- SDR (Scan Data Register, IEEE 1149.1 Data Register scan);
+- RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
+number of clocks.
+
+open(), close()
+-------
+open() opens JTAG device. Only one open operation per JTAG device
+can be performed. Two or more open for one device will return error
+
+Open/Close  device:
+- open("/dev/jtag0", O_RDWR);
+- close(jtag_fd');
+
+ioctl()
+-------
+All access operations to JTAG devices performed through ioctl interface.
+The IOCTL interface supports this requests:
+	JTAG_IOCRUNTEST - Force JTAG state machine to RUN_TEST/IDLE state
+	JTAG_SIOCFREQ - Set JTAG TCK frequency
+	JTAG_GIOCFREQ - Get JTAG TCK frequency
+	JTAG_IOCXFER - send JTAG data Xfer
+	JTAG_GIOCSTATUS - get current JTAG TAP status
+	JTAG_SIOCMODE - set JTAG mode flags.
+
+JTAG_SIOCFREQ, JTAG_GIOCFREQ
+------
+Set/Get JTAG clock speed:
+
+	unsigned int jtag_fd;
+	ioctl(jtag_fd, JTAG_SIOCFREQ, &frq);
+	ioctl(jtag_fd, JTAG_GIOCFREQ, &frq);
+
+JTAG_IOCRUNTEST
+------
+Force JTAG state machine to RUN_TEST/IDLE state
+
+struct jtag_run_test_idle {
+	__u8	reset;
+	__u8	endstate;
+	__u8	tck;
+};
+
+reset: 0 - run IDLE/PAUSE from current state
+	   1 - go through TEST_LOGIC/RESET state before  IDLE/PAUSE
+endstate: completion flag
+tck: clock counter
+
+Example:
+	struct jtag_run_test_idle runtest;
+
+	runtest.endstate = JTAG_STATE_IDLE;
+	runtest.reset = 0;
+	runtest.tck = data_p->tck;
+	usleep(25 * 1000);
+	ioctl(jtag_fd, JTAG_IOCRUNTEST, &runtest);
+
+JTAG_IOCXFER
+------
+Send SDR/SIR transaction
+
+struct jtag_xfer {
+	__u8	type;
+	__u8	direction;
+	__u8	endstate;
+	__u8	padding;
+	__u32	length;
+	__u64	tdio;
+};
+
+type: transfer type - JTAG_SIR_XFER/JTAG_SDR_XFER
+direction: xfer direction - JTAG_SIR_XFER/JTAG_SDR_XFER,
+length: xfer data len in bits
+tdio : xfer data array
+endstate: xfer end state after transaction finish
+	   can be: JTAG_STATE_IDLE/JTAG_STATE_PAUSEIR/JTAG_STATE_PAUSEDR
+
+Example:
+	struct jtag_xfer xfer;
+	static char buf[64];
+	static unsigned int buf_len = 0;
+	[...]
+	xfer.type = JTAG_SDR_XFER;
+	xfer.tdio = (__u64)buf;
+	xfer.length = buf_len;
+	xfer.endstate = JTAG_STATE_IDLE;
+
+	if (is_read)
+		xfer.direction = JTAG_READ_XFER;
+	else
+		xfer.direction = JTAG_WRITE_XFER;
+
+	ioctl(jtag_fd, JTAG_IOCXFER, &xfer);
+
+JTAG_SIOCMODE
+------
+If hw driver can support different running modes you can change it.
+
+Example:
+	unsigned int mode;
+	mode = JTAG_XFER_HW_MODE;
+	ioctl(jtag_fd, JTAG_SIOCMODE, &mode);
-- 
1.7.1


^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [patch v21 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver
  2018-05-15 14:21 ` [patch v21 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver Oleksandr Shamray
@ 2018-05-15 21:00   ` Andy Shevchenko
  2018-05-22 15:00     ` Oleksandr Shamray
  0 siblings, 1 reply; 12+ messages in thread
From: Andy Shevchenko @ 2018-05-15 21:00 UTC (permalink / raw)
  To: Oleksandr Shamray
  Cc: Greg Kroah-Hartman, Arnd Bergmann, Linux Kernel Mailing List,
	linux-arm Mailing List, devicetree, openbmc, Joel Stanley,
	Jiří Pírko, Tobias Klauser,
	open list:SERIAL DRIVERS, Vadim Pasternak, system-sw-low-level,
	Rob Herring, openocd-devel-owner, linux-api, David S. Miller,
	Mauro Carvalho Chehab, Jiri Pirko

On Tue, May 15, 2018 at 5:21 PM, Oleksandr Shamray
<oleksandrs@mellanox.com> wrote:
> Driver adds support of Aspeed 2500/2400 series SOC JTAG master controller.
>
> Driver implements the following jtag ops:
> - freq_get;
> - freq_set;
> - status_get;
> - idle;
> - xfer;
>
> It has been tested on Mellanox system with BMC equipped with
> Aspeed 2520 SoC for programming CPLD devices.

> +#define ASPEED_JTAG_DATA               0x00
> +#define ASPEED_JTAG_INST               0x04
> +#define ASPEED_JTAG_CTRL               0x08
> +#define ASPEED_JTAG_ISR                        0x0C
> +#define ASPEED_JTAG_SW                 0x10
> +#define ASPEED_JTAG_TCK                        0x14
> +#define ASPEED_JTAG_EC                 0x18
> +
> +#define ASPEED_JTAG_DATA_MSB           0x01
> +#define ASPEED_JTAG_DATA_CHUNK_SIZE    0x20


> +#define ASPEED_JTAG_IOUT_LEN(len)      (ASPEED_JTAG_CTL_ENG_EN |\
> +                                        ASPEED_JTAG_CTL_ENG_OUT_EN |\
> +                                        ASPEED_JTAG_CTL_INST_LEN(len))

Better to read

#define MY_COOL_CONST_OR_MACRO(xxx) \
 ...

> +#define ASPEED_JTAG_DOUT_LEN(len)      (ASPEED_JTAG_CTL_ENG_EN |\
> +                                        ASPEED_JTAG_CTL_ENG_OUT_EN |\
> +                                        ASPEED_JTAG_CTL_DATA_LEN(len))

Ditto.

> +static char *end_status_str[] = {"idle", "ir pause", "drpause"};

> +static int aspeed_jtag_freq_set(struct jtag *jtag, u32 freq)
> +{
> +       struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
> +       unsigned long apb_frq;
> +       u32 tck_val;
> +       u16 div;
> +
> +       apb_frq = clk_get_rate(aspeed_jtag->pclk);

> +       div = (apb_frq % freq == 0) ? (apb_frq / freq) - 1 : (apb_frq / freq);

Isn't it the same as

div = (apb_frq - 1) / freq;

?

> +       tck_val = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_TCK);
> +       aspeed_jtag_write(aspeed_jtag,
> +                         (tck_val & ASPEED_JTAG_TCK_DIVISOR_MASK) | div,
> +                         ASPEED_JTAG_TCK);
> +       return 0;
> +}

> +static void aspeed_jtag_sw_delay(struct aspeed_jtag *aspeed_jtag, int cnt)
> +{
> +       int i;
> +
> +       for (i = 0; i < cnt; i++)
> +               aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_SW);

Isn't it readsl() (or how it's called, I don't remember).

> +}

> +static void aspeed_jtag_wait_instruction_pause(struct aspeed_jtag *aspeed_jtag)
> +{
> +       wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
> +                                ASPEED_JTAG_ISR_INST_PAUSE);

In such cases I prefer to see a new line with a parameter in full.
Check all places.

> +       aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_INST_PAUSE;
> +}

> +static void aspeed_jtag_sm_cycle(struct aspeed_jtag *aspeed_jtag, const u8 *tms,
> +                                int len)
> +{
> +       int i;
> +
> +       for (i = 0; i < len; i++)
> +               aspeed_jtag_tck_cycle(aspeed_jtag, tms[i], 0);
> +}
> +
> +static void aspeed_jtag_run_test_idle_sw(struct aspeed_jtag *aspeed_jtag,
> +                                        struct jtag_run_test_idle *runtest)
> +{
> +       static const u8 sm_pause_irpause[] = {1, 1, 1, 1, 0, 1, 0};
> +       static const u8 sm_pause_drpause[] = {1, 1, 1, 0, 1, 0};
> +       static const u8 sm_idle_irpause[] = {1, 1, 0, 1, 0};
> +       static const u8 sm_idle_drpause[] = {1, 0, 1, 0};
> +       static const u8 sm_pause_idle[] = {1, 1, 0};
> +       int i;
> +
> +       /* SW mode from idle/pause-> to pause/idle */
> +       if (runtest->reset) {
> +               for (i = 0; i < ASPEED_JTAG_RESET_CNTR; i++)
> +                       aspeed_jtag_tck_cycle(aspeed_jtag, 1, 0);
> +       }

I would rather split this big switch to a few helper functions per
each status of surrounding switch.

> +
> +       /* Stay on IDLE for at least  TCK cycle */
> +       for (i = 0; i < runtest->tck; i++)
> +               aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0);
> +}


> +/**
> + * aspeed_jtag_run_test_idle:
> + * JTAG reset: generates at least 9 TMS high and 1 TMS low to force
> + * devices into Run-Test/Idle State.
> + */

It's rather broken kernel doc.

> +               aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_CTL_ENG_EN |
> +                                 ASPEED_JTAG_CTL_ENG_OUT_EN |
> +                                 ASPEED_JTAG_CTL_FORCE_TMS, ASPEED_JTAG_CTRL);

> +               aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_EC_GO_IDLE,
> +                                 ASPEED_JTAG_EC);

> +       aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
> +                         ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);

Here you have permutations of flag some of which are repeatetive in
the code. Perhaps make additional definitions instead.
Check other similar places.


> +       char          tdo;

Indentation.

> +       if (xfer->direction == JTAG_READ_XFER)
> +               tdi = UINT_MAX;
> +       else
> +               tdi = data[index];

> +                       if (xfer->direction == JTAG_READ_XFER)
> +                               tdi = UINT_MAX;
> +                       else
> +                               tdi = data[index];

Take your time to think how the above duplication can be avoided.

> +               }
> +       }
> +
> +       tdo = aspeed_jtag_tck_cycle(aspeed_jtag, 1, tdi & ASPEED_JTAG_DATA_MSB);
> +       data[index] |= tdo << (shift_bits % ASPEED_JTAG_DATA_CHUNK_SIZE);
> +}


> +       if (endstate != JTAG_STATE_IDLE) {

Why not to use positive check?

> +       int i;
> +
> +       for (i = 0; i <= xfer->length / BITS_PER_BYTE; i++) {
> +               pos += snprintf(&dbg_str[pos], sizeof(dbg_str) - pos,
> +                               "0x%02x ", xfer_data[i]);
> +       }

Oh, NO! Consider reading printk-formats (for %*ph) and other
documentation about available APIs.

> +       if (!(aspeed_jtag->mode & JTAG_XFER_HW_MODE)) {
> +               /* SW mode */

This is rather too complex to be in one function.

> +       } else {

> +               /* hw mode */
> +               aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_SW);
> +               aspeed_jtag_xfer_hw(aspeed_jtag, xfer, data);

For symmetry it might be another function.

> +       }

> +       dev_dbg(aspeed_jtag->dev, "status %x\n", status);

Perhaps someone should become familiar with tracepoints?

> +               dev_err(aspeed_jtag->dev, "irq status:%x\n",
> +                       status);


Huh, really?! SPAM.

(I would drop it completely, though you may use ratelimited variant)

> +               ret = IRQ_NONE;
> +       }
> +       return ret;
> +}

> +       clk_prepare_enable(aspeed_jtag->pclk);

This might fail.

> +       dev_dbg(&pdev->dev, "IRQ %d.\n", aspeed_jtag->irq);

Noise even for debug.

> +       err = jtag_register(jtag);

Perhaps we might have devm_ variant of this. Check how SPI framework
deal with a such.

> +static int aspeed_jtag_remove(struct platform_device *pdev)
> +{

> +       struct jtag *jtag;
> +
> +       jtag = platform_get_drvdata(pdev);

Usually we put this on one line

> +       aspeed_jtag_deinit(pdev, jtag_priv(jtag));
> +       jtag_unregister(jtag);
> +       jtag_free(jtag);
> +       return 0;
> +}


-- 
With Best Regards,
Andy Shevchenko

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [patch v21 1/4] drivers: jtag: Add JTAG core driver
  2018-05-15 14:21 ` [patch v21 1/4] drivers: jtag: Add JTAG core driver Oleksandr Shamray
@ 2018-05-15 21:21   ` Andy Shevchenko
  2018-05-22 15:00     ` Oleksandr Shamray
  0 siblings, 1 reply; 12+ messages in thread
From: Andy Shevchenko @ 2018-05-15 21:21 UTC (permalink / raw)
  To: Oleksandr Shamray
  Cc: Greg Kroah-Hartman, Arnd Bergmann, Linux Kernel Mailing List,
	linux-arm Mailing List, devicetree, openbmc, Joel Stanley,
	Jiří Pírko, Tobias Klauser,
	open list:SERIAL DRIVERS, Vadim Pasternak, system-sw-low-level,
	Rob Herring, openocd-devel-owner, linux-api, David S. Miller,
	Mauro Carvalho Chehab, Jiri Pirko

On Tue, May 15, 2018 at 5:21 PM, Oleksandr Shamray
<oleksandrs@mellanox.com> wrote:
> Initial patch for JTAG driver
> JTAG class driver provide infrastructure to support hardware/software
> JTAG platform drivers. It provide user layer API interface for flashing
> and debugging external devices which equipped with JTAG interface
> using standard transactions.
>
> Driver exposes set of IOCTL to user space for:
> - XFER:
> - SIR (Scan Instruction Register, IEEE 1149.1 Data Register scan);
> - SDR (Scan Data Register, IEEE 1149.1 Instruction Register scan);
> - RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
>   number of clocks).
> - SIOCFREQ/GIOCFREQ for setting and reading JTAG frequency.
>
> Driver core provides set of internal APIs for allocation and
> registration:
> - jtag_register;
> - jtag_unregister;
> - jtag_alloc;
> - jtag_free;
>
> Platform driver on registration with jtag-core creates the next
> entry in dev folder:
> /dev/jtagX

>  0xB0   all     RATIO devices           in development:
>                                         <mailto:vgo@ratio.de>
>  0xB1   00-1F   PPPoX                   <mailto:mostrows@styx.uwaterloo.ca>
> +0xB2   00-0f   linux/jtag.h            JTAG driver
> +                                       <mailto:oleksandrs@mellanox.com>

Consider to preserve style (upper vs. lower).

> +         This provides basic core functionality support for JTAG class devices.
> +         Hardware that is equipped with a JTAG microcontroller can be
> +         supported by using this driver's interfaces.
> +         This driver exposes a set of IOCTLs to the user space for
> +         the following commands:
> +         SDR: (Scan Data Register) Performs an IEEE 1149.1 Data Register scan
> +         SIR: (Scan Instruction Register) Performs an IEEE 1149.1 Instruction
> +         Register scan.
> +         RUNTEST: Forces the IEEE 1149.1 bus to a run state for a specified
> +         number of clocks or a specified time period.

Something feels wrong with formatting here.

> +#define MAX_JTAG_NAME_LEN (sizeof("jtag") + 5)

Interesting definition. Why not to set to 10 explicitly? And why 10?
(16 sounds better)

> +struct jtag {
> +       struct miscdevice miscdev;

> +       struct device *dev;

Doesn't miscdev parent contain exactly this one?

> +       const struct jtag_ops *ops;
> +       int id;
> +       bool opened;
> +       struct mutex open_lock;
> +       unsigned long priv[0];
> +};

> +               err = copy_to_user(u64_to_user_ptr(xfer.tdio),
> +                                  (void *)(xfer_data), data_size);

Redundant parens in one case. Check the rest similar places.

> +static int jtag_open(struct inode *inode, struct file *file)
> +{

> +       struct jtag *jtag = container_of(file->private_data, struct jtag,
> +                                        miscdev);

I would don't care about length and put it on one line.

> +       if (jtag->opened) {
> +       jtag->opened = true;
> +       jtag->opened = false;

Can it be opened non exclusively several times? If so, this needs to
be a ref counter instead.

> +       if (!ops->idle || !ops->mode_set || !ops->status_get || !ops->xfer)
> +               return NULL;

Are all of them mandatory?

> +int jtag_register(struct jtag *jtag)

Perhaps devm_ variant.

> +#define jtag_u64_to_ptr(arg) ((void *)(uintptr_t)arg)

Where is this used or supposed to be used?

> +#define JTAG_MAX_XFER_DATA_LEN 65535

Is this limitation from some spec?
Otherwise why not to allow 64K?

> +/**
> + * struct jtag_ops - callbacks for jtag control functions:
> + *
> + * @freq_get: get frequency function. Filled by device driver
> + * @freq_set: set frequency function. Filled by device driver
> + * @status_get: set status function. Filled by device driver
> + * @idle: set JTAG to idle state function. Filled by device driver
> + * @xfer: send JTAG xfer function. Filled by device driver
> + */

Perhaps you need to describe which of them are _really_ mandatory and
which are optional.

-- 
With Best Regards,
Andy Shevchenko

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [patch v21 4/4] Documentation: jtag: Add ABI documentation
  2018-05-15 14:21 ` [patch v21 4/4] Documentation: jtag: Add ABI documentation Oleksandr Shamray
@ 2018-05-16 18:16   ` Randy Dunlap
  0 siblings, 0 replies; 12+ messages in thread
From: Randy Dunlap @ 2018-05-16 18:16 UTC (permalink / raw)
  To: Oleksandr Shamray, gregkh, arnd
  Cc: linux-kernel, linux-arm-kernel, devicetree, openbmc, joel, jiri,
	tklauser, linux-serial, vadimp, system-sw-low-level, robh+dt,
	openocd-devel-owner, linux-api, davem, mchehab

On 05/15/2018 07:21 AM, Oleksandr Shamray wrote:
> Added document that describe the ABI for JTAG class drivrer
> 
> ---
>  Documentation/ABI/testing/jtag-dev |   27 +++++++++
>  Documentation/jtag/overview        |   28 +++++++++
>  Documentation/jtag/transactions    |  109 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 164 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/ABI/testing/jtag-dev
>  create mode 100644 Documentation/jtag/overview
>  create mode 100644 Documentation/jtag/transactions
> 

> diff --git a/Documentation/jtag/overview b/Documentation/jtag/overview
> new file mode 100644
> index 0000000..a86f188
> --- /dev/null
> +++ b/Documentation/jtag/overview
> @@ -0,0 +1,28 @@
> +Linux kernel JTAG support
> +=========================
> +
> +The JTAG is an industry standard for verifying hardware

   JTAG is an industry standard for verifying hardware.

> +JTAG provides access to many logic signals of a complex integrated circuit,
> +including the device pins.
> +
> +A JTAG interface is a special interface added to a chip.
> +Depending on the version of JTAG, two, four, or five pins are added.
> +
> +The connector pins are:
> +	TDI (Test Data In)
> +	TDO (Test Data Out)
> +	TCK (Test Clock)
> +	TMS (Test Mode Select)
> +	TRST (Test Reset) optional.
> +
> +JTAG interface is designed to have two parts - basic core driver and
> +hardware specific driver. The basic driver introduces a general interface
> +which is not dependent of specific hardware. It provides communication
> +between user space and hardware specific driver.
> +Each JTAG device is represented as a char device from (jtag0, jtag1, ...).
> +Access to a JTAG device is performed through IOCTL calls.
> +
> +Call flow example:
> +User: open  -> /dev/jatgX
> +User: ioctl -> /dev/jtagX -> JTAG core driver -> JTAG hw specific driver

                                                    JTAG hardware specific driver

> +User: close -> /dev/jatgX
> diff --git a/Documentation/jtag/transactions b/Documentation/jtag/transactions
> new file mode 100644
> index 0000000..6a857c8
> --- /dev/null
> +++ b/Documentation/jtag/transactions
> @@ -0,0 +1,109 @@
> +The JTAG API
> +=============
> +
> +JTAG master devices can be accessed through a character misc-device.
> +Each JTAG master interface can be accessed by using /dev/jtagN

                                                       /dev/jtagN.

> +
> +JTAG system calls set:
> +- SIR (Scan Instruction Register, IEEE 1149.1 Instruction Register scan);
> +- SDR (Scan Data Register, IEEE 1149.1 Data Register scan);
> +- RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
> +number of clocks.
> +
> +open(), close()
> +-------
> +open() opens JTAG device. Only one open operation per JTAG device
> +can be performed. Two or more open for one device will return error

                                                     will return error.

> +
> +Open/Close  device:
> +- open("/dev/jtag0", O_RDWR);
> +- close(jtag_fd');

     close(jtag_fd);

> +
> +ioctl()
> +-------
> +All access operations to JTAG devices performed through ioctl interface.
> +The IOCTL interface supports this requests:

                                these requests:

> +	JTAG_IOCRUNTEST - Force JTAG state machine to RUN_TEST/IDLE state
> +	JTAG_SIOCFREQ - Set JTAG TCK frequency
> +	JTAG_GIOCFREQ - Get JTAG TCK frequency
> +	JTAG_IOCXFER - send JTAG data Xfer
> +	JTAG_GIOCSTATUS - get current JTAG TAP status
> +	JTAG_SIOCMODE - set JTAG mode flags.
> +
> +JTAG_SIOCFREQ, JTAG_GIOCFREQ
> +------
> +Set/Get JTAG clock speed:
> +
> +	unsigned int jtag_fd;
> +	ioctl(jtag_fd, JTAG_SIOCFREQ, &frq);
> +	ioctl(jtag_fd, JTAG_GIOCFREQ, &frq);
> +
> +JTAG_IOCRUNTEST
> +------
> +Force JTAG state machine to RUN_TEST/IDLE state
> +
> +struct jtag_run_test_idle {
> +	__u8	reset;
> +	__u8	endstate;
> +	__u8	tck;
> +};
> +
> +reset: 0 - run IDLE/PAUSE from current state
> +	   1 - go through TEST_LOGIC/RESET state before  IDLE/PAUSE
> +endstate: completion flag
> +tck: clock counter
> +
> +Example:
> +	struct jtag_run_test_idle runtest;
> +
> +	runtest.endstate = JTAG_STATE_IDLE;
> +	runtest.reset = 0;
> +	runtest.tck = data_p->tck;
> +	usleep(25 * 1000);
> +	ioctl(jtag_fd, JTAG_IOCRUNTEST, &runtest);
> +
> +JTAG_IOCXFER
> +------
> +Send SDR/SIR transaction
> +
> +struct jtag_xfer {
> +	__u8	type;
> +	__u8	direction;
> +	__u8	endstate;
> +	__u8	padding;
> +	__u32	length;
> +	__u64	tdio;
> +};
> +
> +type: transfer type - JTAG_SIR_XFER/JTAG_SDR_XFER
> +direction: xfer direction - JTAG_SIR_XFER/JTAG_SDR_XFER,
> +length: xfer data len in bits
> +tdio : xfer data array
> +endstate: xfer end state after transaction finish
> +	   can be: JTAG_STATE_IDLE/JTAG_STATE_PAUSEIR/JTAG_STATE_PAUSEDR
> +
> +Example:
> +	struct jtag_xfer xfer;
> +	static char buf[64];
> +	static unsigned int buf_len = 0;
> +	[...]
> +	xfer.type = JTAG_SDR_XFER;
> +	xfer.tdio = (__u64)buf;
> +	xfer.length = buf_len;
> +	xfer.endstate = JTAG_STATE_IDLE;
> +
> +	if (is_read)
> +		xfer.direction = JTAG_READ_XFER;
> +	else
> +		xfer.direction = JTAG_WRITE_XFER;
> +
> +	ioctl(jtag_fd, JTAG_IOCXFER, &xfer);
> +
> +JTAG_SIOCMODE
> +------
> +If hw driver can support different running modes you can change it.

   If hardware driver

> +
> +Example:
> +	unsigned int mode;
> +	mode = JTAG_XFER_HW_MODE;
> +	ioctl(jtag_fd, JTAG_SIOCMODE, &mode);
> 


-- 
~Randy

^ permalink raw reply	[flat|nested] 12+ messages in thread

* RE: [patch v21 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver
  2018-05-15 21:00   ` Andy Shevchenko
@ 2018-05-22 15:00     ` Oleksandr Shamray
  2018-05-22 20:21       ` Andy Shevchenko
  0 siblings, 1 reply; 12+ messages in thread
From: Oleksandr Shamray @ 2018-05-22 15:00 UTC (permalink / raw)
  To: Andy Shevchenko
  Cc: Greg Kroah-Hartman, Arnd Bergmann, Linux Kernel Mailing List,
	linux-arm Mailing List, devicetree, openbmc, Joel Stanley,
	Jiří Pírko, Tobias Klauser,
	open list:SERIAL DRIVERS, Vadim Pasternak, system-sw-low-level,
	Rob Herring, openocd-devel-owner, linux-api, David S. Miller,
	Mauro Carvalho Chehab, Jiri Pirko

Hi Andy. 
Thanks for review.

Please read my answers inline.

> -----Original Message-----
> From: Andy Shevchenko [mailto:andy.shevchenko@gmail.com]
> Sent: 16 мая 2018 г. 0:00
> To: Oleksandr Shamray <oleksandrs@mellanox.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Arnd Bergmann 
> <arnd@arndb.de>; Linux Kernel Mailing List 
> <linux-kernel@vger.kernel.org>; linux-arm Mailing List 
> <linux-arm-kernel@lists.infradead.org>; devicetree 
> <devicetree@vger.kernel.org>; openbmc@lists.ozlabs.org; Joel Stanley 
> <joel@jms.id.au>; Jiří Pírko <jiri@resnulli.us>; Tobias Klauser 
> <tklauser@distanz.ch>; open list:SERIAL DRIVERS <linux- 
> serial@vger.kernel.org>; Vadim Pasternak <vadimp@mellanox.com>; 
> system-sw-low-level <system-sw-low-level@mellanox.com>; Rob Herring 
> <robh+dt@kernel.org>; openocd-devel-owner@lists.sourceforge.net; 
> linux- api@vger.kernel.org; David S. Miller <davem@davemloft.net>; 
> Mauro Carvalho Chehab <mchehab@kernel.org>; Jiri Pirko 
> <jiri@mellanox.com>
> Subject: Re: [patch v21 2/4] drivers: jtag: Add Aspeed SoC 24xx and 
> 25xx families JTAG master driver
> 
> On Tue, May 15, 2018 at 5:21 PM, Oleksandr Shamray 
> <oleksandrs@mellanox.com> wrote:
> > Driver adds support of Aspeed 2500/2400 series SOC JTAG master
> controller.
> >
> > Driver implements the following jtag ops:
> > - freq_get;
> > - freq_set;
> > - status_get;
> > - idle;
> > - xfer;
> >
> > It has been tested on Mellanox system with BMC equipped with Aspeed
> > 2520 SoC for programming CPLD devices.
> 
> > +#define ASPEED_JTAG_DATA               0x00
> > +#define ASPEED_JTAG_INST               0x04
> > +#define ASPEED_JTAG_CTRL               0x08
> > +#define ASPEED_JTAG_ISR                        0x0C
> > +#define ASPEED_JTAG_SW                 0x10
> > +#define ASPEED_JTAG_TCK                        0x14
> > +#define ASPEED_JTAG_EC                 0x18
> > +
> > +#define ASPEED_JTAG_DATA_MSB           0x01
> > +#define ASPEED_JTAG_DATA_CHUNK_SIZE    0x20
> 
> 
> > +#define ASPEED_JTAG_IOUT_LEN(len)      (ASPEED_JTAG_CTL_ENG_EN |\
> > +                                        ASPEED_JTAG_CTL_ENG_OUT_EN 
> > +|\
> > +
> > +ASPEED_JTAG_CTL_INST_LEN(len))
> 
> Better to read
> 
> #define MY_COOL_CONST_OR_MACRO(xxx) \
>  ...
> 
> > +#define ASPEED_JTAG_DOUT_LEN(len)      (ASPEED_JTAG_CTL_ENG_EN
> |\
> > +                                        ASPEED_JTAG_CTL_ENG_OUT_EN 
> > + |\
> > +
> > +ASPEED_JTAG_CTL_DATA_LEN(len))
> 
> Ditto.

Ok. Changed to:
#define ASPEED_JTAG_IOUT_LEN(len) \
                               (ASPEED_JTAG_CTL_ENG_EN | \
                               ASPEED_JTAG_CTL_ENG_OUT_EN | \
                               ASPEED_JTAG_CTL_INST_LEN(len))

#define ASPEED_JTAG_DOUT_LEN(len) \
                               (ASPEED_JTAG_CTL_ENG_EN | \
                               ASPEED_JTAG_CTL_ENG_OUT_EN | \
                               ASPEED_JTAG_CTL_DATA_LEN(len))


> 
> > +static char *end_status_str[] = {"idle", "ir pause", "drpause"};
> 
> > +static int aspeed_jtag_freq_set(struct jtag *jtag, u32 freq) {
> > +       struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
> > +       unsigned long apb_frq;
> > +       u32 tck_val;
> > +       u16 div;
> > +
> > +       apb_frq = clk_get_rate(aspeed_jtag->pclk);
> 
> > +       div = (apb_frq % freq == 0) ? (apb_frq / freq) - 1 : 
> > + (apb_frq / freq);
> 
> Isn't it the same as
> 
> div = (apb_frq - 1) / freq;
> 
> ?
> 

Seems it is same. Thanks.

> > +       tck_val = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_TCK);
> > +       aspeed_jtag_write(aspeed_jtag,
> > +                         (tck_val & ASPEED_JTAG_TCK_DIVISOR_MASK) | div,
> > +                         ASPEED_JTAG_TCK);
> > +       return 0;
> > +}
> 
> > +static void aspeed_jtag_sw_delay(struct aspeed_jtag *aspeed_jtag, 
> > +int
> > +cnt) {
> > +       int i;
> > +
> > +       for (i = 0; i < cnt; i++)
> > +               aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_SW);
> 
> Isn't it readsl() (or how it's called, I don't remember).
> 

No, readsl reads data into buffer. But in this place read used for make 
software delay. 
Aspeed jtag driver supports 2 modes:
1 - hw mode with the hardware controlled JTAG states
and pins
2 - with software controlled pins. 
This part of code used in sw-mode and generates delay for JTAG bit-bang .
I will change it to ndelay().

> > +}
> 
> > +static void aspeed_jtag_wait_instruction_pause(struct aspeed_jtag
> > +*aspeed_jtag) {
> > +       wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &
> > +                                ASPEED_JTAG_ISR_INST_PAUSE);
> 
> In such cases I prefer to see a new line with a parameter in full.
> Check all places.
> 
> > +       aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_INST_PAUSE; }
> 
> > +static void aspeed_jtag_sm_cycle(struct aspeed_jtag *aspeed_jtag, 
> > +const
> u8 *tms,
> > +                                int len) {
> > +       int i;
> > +
> > +       for (i = 0; i < len; i++)
> > +               aspeed_jtag_tck_cycle(aspeed_jtag, tms[i], 0); }
> > +
> > +static void aspeed_jtag_run_test_idle_sw(struct aspeed_jtag
> *aspeed_jtag,
> > +                                        struct jtag_run_test_idle
> > +*runtest) {
> > +       static const u8 sm_pause_irpause[] = {1, 1, 1, 1, 0, 1, 0};
> > +       static const u8 sm_pause_drpause[] = {1, 1, 1, 0, 1, 0};
> > +       static const u8 sm_idle_irpause[] = {1, 1, 0, 1, 0};
> > +       static const u8 sm_idle_drpause[] = {1, 0, 1, 0};
> > +       static const u8 sm_pause_idle[] = {1, 1, 0};
> > +       int i;
> > +
> > +       /* SW mode from idle/pause-> to pause/idle */
> > +       if (runtest->reset) {
> > +               for (i = 0; i < ASPEED_JTAG_RESET_CNTR; i++)
> > +                       aspeed_jtag_tck_cycle(aspeed_jtag, 1, 0);
> > +       }
> 
> I would rather split this big switch to a few helper functions per 
> each status of surrounding switch.
> 

Ok.
Will do it.


> > +
> > +       /* Stay on IDLE for at least  TCK cycle */
> > +       for (i = 0; i < runtest->tck; i++)
> > +               aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0); }
> 
> 
> > +/**
> > + * aspeed_jtag_run_test_idle:
> > + * JTAG reset: generates at least 9 TMS high and 1 TMS low to force
> > + * devices into Run-Test/Idle State.
> > + */
> 
> It's rather broken kernel doc.

Deleted.

> 
> > +               aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_CTL_ENG_EN |
> > +                                 ASPEED_JTAG_CTL_ENG_OUT_EN |
> > +                                 ASPEED_JTAG_CTL_FORCE_TMS, 
> > + ASPEED_JTAG_CTRL);
> 
> > +               aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_EC_GO_IDLE,
> > +                                 ASPEED_JTAG_EC);
> 
> > +       aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
> > +                         ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
> 
> Here you have permutations of flag some of which are repeatetive in 
> the code. Perhaps make additional definitions instead.
> Check other similar places.
> 

Ok. Will add defined for repeated flags

> 
> > +       char          tdo;
> 
> Indentation.

Ok.

> 
> > +       if (xfer->direction == JTAG_READ_XFER)
> > +               tdi = UINT_MAX;
> > +       else
> > +               tdi = data[index];
> 
> > +                       if (xfer->direction == JTAG_READ_XFER)
> > +                               tdi = UINT_MAX;
> > +                       else
> > +                               tdi = data[index];
> 
> Take your time to think how the above duplication can be avoided.
> 

In both cases data[] is different, so I should check it twice, but I will 
change it to, macro like:

#define ASPEED_JTAG_GET_TDI(direction, data) \
                              (direction == JTAG_READ_XFER) ? UNIT_MAX : data

> > +               }
> > +       }
> > +
> > +       tdo = aspeed_jtag_tck_cycle(aspeed_jtag, 1, tdi &
> ASPEED_JTAG_DATA_MSB);
> > +       data[index] |= tdo << (shift_bits % 
> > +ASPEED_JTAG_DATA_CHUNK_SIZE); }
> 
> 
> > +       if (endstate != JTAG_STATE_IDLE) {
> 
> Why not to use positive check?
> 

Will restructure to have positive check
if (endstate == JTAG_STATE_IDLE) {
...
} else {
...
} 

> > +       int i;
> > +
> > +       for (i = 0; i <= xfer->length / BITS_PER_BYTE; i++) {
> > +               pos += snprintf(&dbg_str[pos], sizeof(dbg_str) - pos,
> > +                               "0x%02x ", xfer_data[i]);
> > +       }
> 
> Oh, NO! Consider reading printk-formats (for %*ph) and other 
> documentation about available APIs.

Ok.

> 
> > +       if (!(aspeed_jtag->mode & JTAG_XFER_HW_MODE)) {
> > +               /* SW mode */
> 
> This is rather too complex to be in one function.
> 

Will split to separate functions.

> > +       } else {
> 
> > +               /* hw mode */
> > +               aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_SW);
> > +               aspeed_jtag_xfer_hw(aspeed_jtag, xfer, data);
> 
> For symmetry it might be another function.
> 
> > +       }
> 
> > +       dev_dbg(aspeed_jtag->dev, "status %x\n", status);
> 
> Perhaps someone should become familiar with tracepoints?
> 
> > +               dev_err(aspeed_jtag->dev, "irq status:%x\n",
> > +                       status);
> 
> 
> Huh, really?! SPAM.


I will review and delete redundant debug messages.

> 
> (I would drop it completely, though you may use ratelimited variant)
> 
> > +               ret = IRQ_NONE;
> > +       }
> > +       return ret;
> > +}
> 
> > +       clk_prepare_enable(aspeed_jtag->pclk);
> 
> This might fail.

Will add error check

> 
> > +       dev_dbg(&pdev->dev, "IRQ %d.\n", aspeed_jtag->irq);
> 
> Noise even for debug.

Agree.

> 
> > +       err = jtag_register(jtag);
> 
> Perhaps we might have devm_ variant of this. Check how SPI framework 
> deal with a such.
> 

Jtag driver uses miscdevice and related  misc_register and misc_deregister 
calls for creation and destruction. There is no device object prior 
to call to misc_register, which could be used in devm_jtag_register.

> > +static int aspeed_jtag_remove(struct platform_device *pdev) {
> 
> > +       struct jtag *jtag;
> > +
> > +       jtag = platform_get_drvdata(pdev);
> 
> Usually we put this on one line

+

> 
> > +       aspeed_jtag_deinit(pdev, jtag_priv(jtag));
> > +       jtag_unregister(jtag);
> > +       jtag_free(jtag);
> > +       return 0;
> > +}
> 
> 
> --
> With Best Regards,
> Andy Shevchenko

Best Regards,
Oleksandr Shamray


^ permalink raw reply	[flat|nested] 12+ messages in thread

* RE: [patch v21 1/4] drivers: jtag: Add JTAG core driver
  2018-05-15 21:21   ` Andy Shevchenko
@ 2018-05-22 15:00     ` Oleksandr Shamray
  0 siblings, 0 replies; 12+ messages in thread
From: Oleksandr Shamray @ 2018-05-22 15:00 UTC (permalink / raw)
  To: Andy Shevchenko
  Cc: Greg Kroah-Hartman, Arnd Bergmann, Linux Kernel Mailing List,
	linux-arm Mailing List, devicetree, openbmc, Joel Stanley,
	Jiří Pírko, Tobias Klauser,
	open list:SERIAL DRIVERS, Vadim Pasternak, system-sw-low-level,
	Rob Herring, openocd-devel-owner, linux-api, David S. Miller,
	Mauro Carvalho Chehab, Jiri Pirko

Hi Andy. 
Thanks for review.

Please read my answers inline.

> -----Original Message-----
> From: Andy Shevchenko [mailto:andy.shevchenko@gmail.com]
> Sent: 16 мая 2018 г. 0:22
> To: Oleksandr Shamray <oleksandrs@mellanox.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Arnd Bergmann 
> <arnd@arndb.de>; Linux Kernel Mailing List 
> <linux-kernel@vger.kernel.org>; linux-arm Mailing List 
> <linux-arm-kernel@lists.infradead.org>; devicetree 
> <devicetree@vger.kernel.org>; openbmc@lists.ozlabs.org; Joel Stanley 
> <joel@jms.id.au>; Jiří Pírko <jiri@resnulli.us>; Tobias Klauser 
> <tklauser@distanz.ch>; open list:SERIAL DRIVERS <linux- 
> serial@vger.kernel.org>; Vadim Pasternak <vadimp@mellanox.com>; 
> system-sw-low-level <system-sw-low-level@mellanox.com>; Rob Herring 
> <robh+dt@kernel.org>; openocd-devel-owner@lists.sourceforge.net; 
> linux- api@vger.kernel.org; David S. Miller <davem@davemloft.net>; 
> Mauro Carvalho Chehab <mchehab@kernel.org>; Jiri Pirko 
> <jiri@mellanox.com>
> Subject: Re: [patch v21 1/4] drivers: jtag: Add JTAG core driver
> 
> On Tue, May 15, 2018 at 5:21 PM, Oleksandr Shamray 
> <oleksandrs@mellanox.com> wrote:
> > Initial patch for JTAG driver
> > JTAG class driver provide infrastructure to support 
> > hardware/software JTAG platform drivers. It provide user layer API 
> > interface for flashing and debugging external devices which equipped 
> > with JTAG interface using standard transactions.
> >
> > Driver exposes set of IOCTL to user space for:
> > - XFER:
> > - SIR (Scan Instruction Register, IEEE 1149.1 Data Register scan);
> > - SDR (Scan Data Register, IEEE 1149.1 Instruction Register scan);
> > - RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
> >   number of clocks).
> > - SIOCFREQ/GIOCFREQ for setting and reading JTAG frequency.
> >
> > Driver core provides set of internal APIs for allocation and
> > registration:
> > - jtag_register;
> > - jtag_unregister;
> > - jtag_alloc;
> > - jtag_free;
> >
> > Platform driver on registration with jtag-core creates the next 
> > entry in dev folder:
> > /dev/jtagX
> 
> >  0xB0   all     RATIO devices           in development:
> >                                         <mailto:vgo@ratio.de>
> >  0xB1   00-1F   PPPoX                   <mailto:mostrows@styx.uwaterloo.ca>
> > +0xB2   00-0f   linux/jtag.h            JTAG driver
> > +
> > +<mailto:oleksandrs@mellanox.com>
> 
> Consider to preserve style (upper vs. lower).

JTAG in code is lower (jtag) cane but in descriptions and notes it  is upper (JTAG).
In all places which do not correspond to this I will fix. 

> 
> > +         This provides basic core functionality support for JTAG class devices.
> > +         Hardware that is equipped with a JTAG microcontroller can be
> > +         supported by using this driver's interfaces.
> > +         This driver exposes a set of IOCTLs to the user space for
> > +         the following commands:
> > +         SDR: (Scan Data Register) Performs an IEEE 1149.1 Data Register scan
> > +         SIR: (Scan Instruction Register) Performs an IEEE 1149.1 Instruction
> > +         Register scan.
> > +         RUNTEST: Forces the IEEE 1149.1 bus to a run state for a specified
> > +         number of clocks or a specified time period.
> 
> Something feels wrong with formatting here.
> 

Will fix

> > +#define MAX_JTAG_NAME_LEN (sizeof("jtag") + 5)
> 
> Interesting definition. Why not to set to 10 explicitly? And why 10?
> (16 sounds better)
> 
5 - is a max len of JTAG device id in device name. I will add define to it.

In general I don't see the case for the system with hundreds JTAG interfaces.
I will limit maximum jtag master to 255 devices and change  id len to 3

#define MAX_JTAG_ID_STR_LEN 5
#define MAX_JTAG_NAME_LEN (sizeof("jtag") + MAX_JTAG_ID_STR_LEN)

> > +struct jtag {
> > +       struct miscdevice miscdev;
> 
> > +       struct device *dev;
> 
> Doesn't miscdev parent contain exactly this one?

Yes. 
Will fix.

> 
> > +       const struct jtag_ops *ops;
> > +       int id;
> > +       bool opened;
> > +       struct mutex open_lock;
> > +       unsigned long priv[0];
> > +};
> 
> > +               err = copy_to_user(u64_to_user_ptr(xfer.tdio),
> > +                                  (void *)(xfer_data), data_size);
> 
> Redundant parens in one case. Check the rest similar places.
> 

Yes.

> > +static int jtag_open(struct inode *inode, struct file *file) {
> 
> > +       struct jtag *jtag = container_of(file->private_data, struct jtag,
> > +                                        miscdev);
> 
> I would don't care about length and put it on one line.
> 

But following to LINUX kernel style, it should be no longer than 80 symbols. 
It will not pass by  ./scripts/checkpatch.pl

Will it be OK to send a patch which failed 80 symbols limitation check?

> > +       if (jtag->opened) {
> > +       jtag->opened = true;
> > +       jtag->opened = false;
> 
> Can it be opened non exclusively several times? If so, this needs to 
> be a ref counter instead.

It can be opened only once.

> 
> > +       if (!ops->idle || !ops->mode_set || !ops->status_get || !ops->xfer)
> > +               return NULL;
> 
> Are all of them mandatory?
> 

Yes, except "mode_set"
Will remove mode_set from check

> > +int jtag_register(struct jtag *jtag)
> 
> Perhaps devm_ variant.

Jtag driver uses miscdevice and related  misc_register and misc_deregister 
calls for creation and destruction. There is no device object prior to 
call to  misc_register, which could be used in devm_jtag_register.

> 
> > +#define jtag_u64_to_ptr(arg) ((void *)(uintptr_t)arg)
> 

Redundant. Removed.

> Where is this used or supposed to be used?
> 
> > +#define JTAG_MAX_XFER_DATA_LEN 65535
> 
> Is this limitation from some spec?
> Otherwise why not to allow 64K?
> 

It not limited by specification.  
But we enforce an upper bound for the length here, to prevent users from draining 
kernel memory with giant buffers.
So it was limited by  size of unsigned short int (65535)

> > +/**
> > + * struct jtag_ops - callbacks for jtag control functions:
> > + *
> > + * @freq_get: get frequency function. Filled by device driver
> > + * @freq_set: set frequency function. Filled by device driver
> > + * @status_get: set status function. Filled by device driver
> > + * @idle: set JTAG to idle state function. Filled by device driver
> > + * @xfer: send JTAG xfer function. Filled by device driver  */
> 
> Perhaps you need to describe which of them are _really_ mandatory and 
> which are optional.
> 

Ok

> --
> With Best Regards,
> Andy Shevchenko

Best Regards,
Oleksandr Shamray


^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [patch v21 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver
  2018-05-22 15:00     ` Oleksandr Shamray
@ 2018-05-22 20:21       ` Andy Shevchenko
  0 siblings, 0 replies; 12+ messages in thread
From: Andy Shevchenko @ 2018-05-22 20:21 UTC (permalink / raw)
  To: Oleksandr Shamray
  Cc: Greg Kroah-Hartman, Arnd Bergmann, Linux Kernel Mailing List,
	linux-arm Mailing List, devicetree, openbmc, Joel Stanley,
	Jiří Pírko, Tobias Klauser,
	open list:SERIAL DRIVERS, Vadim Pasternak, system-sw-low-level,
	Rob Herring, openocd-devel-owner, linux-api, David S. Miller,
	Mauro Carvalho Chehab, Jiri Pirko

On Tue, May 22, 2018 at 6:00 PM, Oleksandr Shamray
<oleksandrs@mellanox.com> wrote:


> Ok. Changed to:
> #define ASPEED_JTAG_IOUT_LEN(len) \
>                                (ASPEED_JTAG_CTL_ENG_EN | \
>                                ASPEED_JTAG_CTL_ENG_OUT_EN | \
>                                ASPEED_JTAG_CTL_INST_LEN(len))
>
> #define ASPEED_JTAG_DOUT_LEN(len) \
>                                (ASPEED_JTAG_CTL_ENG_EN | \
>                                ASPEED_JTAG_CTL_ENG_OUT_EN | \
>                                ASPEED_JTAG_CTL_DATA_LEN(len))

What about

#define _JTAG_OUT_ENABLE \
( _ENG_EN | _ENG_OUT_EN)

#define _IOUT_LEN(len) \
 (_ENABLE | _INST_LEN(len))

#define _DOUT_LEN(len) \
...

?

>> > +       apb_frq = clk_get_rate(aspeed_jtag->pclk);
>>
>> > +       div = (apb_frq % freq == 0) ? (apb_frq / freq) - 1 :
>> > + (apb_frq / freq);
>>
>> Isn't it the same as
>>
>> div = (apb_frq - 1) / freq;
>>
>> ?

> Seems it is same. Thanks.

Though be careful if apb_frq == 0.
In either case the hw will be screwed, but differently.

>> > +       if (xfer->direction == JTAG_READ_XFER)
>> > +               tdi = UINT_MAX;
>> > +       else
>> > +               tdi = data[index];
>>
>> > +                       if (xfer->direction == JTAG_READ_XFER)
>> > +                               tdi = UINT_MAX;
>> > +                       else
>> > +                               tdi = data[index];
>>
>> Take your time to think how the above duplication can be avoided.
>>
>
> In both cases data[] is different, so I should check it twice, but I will
> change it to, macro like:
>
> #define ASPEED_JTAG_GET_TDI(direction, data) \
>                               (direction == JTAG_READ_XFER) ? UNIT_MAX : data

Perhaps choose better name for data, b/c in the above you are using data[index].

>> > +               dev_err(aspeed_jtag->dev, "irq status:%x\n",
>> > +                       status);

>> Huh, really?! SPAM.

> I will review and delete redundant debug messages.

Just to be sure you got a point. This is interrupt context. Imagine
what might go wrong.


>> > +       err = jtag_register(jtag);
>>
>> Perhaps we might have devm_ variant of this. Check how SPI framework
>> deal with a such.
>>
>
> Jtag driver uses miscdevice and related  misc_register and misc_deregister
> calls for creation and destruction. There is no device object prior
> to call to misc_register, which could be used in devm_jtag_register.

Same question as per previous patch.

-- 
With Best Regards,
Andy Shevchenko

^ permalink raw reply	[flat|nested] 12+ messages in thread

* RE: [patch v21 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver
@ 2018-05-22 13:08 Oleksandr Shamray
  0 siblings, 0 replies; 12+ messages in thread
From: Oleksandr Shamray @ 2018-05-22 13:08 UTC (permalink / raw)
  To: Andy Shevchenko
  Cc: Greg Kroah-Hartman, Arnd Bergmann, Linux Kernel Mailing List,
	linux-arm Mailing List, devicetree, openbmc, Joel Stanley,
	Jiří Pírko, Tobias Klauser,
	open list:SERIAL DRIVERS, Vadim Pasternak, system-sw-low-level,
	Rob Herring, openocd-devel-owner, linux-api, David S. Miller,
	Mauro Carvalho Chehab, Jiri Pirko

[-- Attachment #1: Type: text/plain, Size: 12382 bytes --]

Hi Vadim.

Please check my answer to Andy.





Hi Andy.

Thanks for review.



Please read my answers inline.



> -----Original Message-----

> From: Andy Shevchenko [mailto:andy.shevchenko@gmail.com]

> Sent: 16 мая 2018 г. 0:00

> To: Oleksandr Shamray <oleksandrs@mellanox.com<mailto:oleksandrs@mellanox.com>>

> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org<mailto:gregkh@linuxfoundation.org>>; Arnd Bergmann

> <arnd@arndb.de<mailto:arnd@arndb.de>>; Linux Kernel Mailing List

> <linux-kernel@vger.kernel.org<mailto:linux-kernel@vger.kernel.org>>; linux-arm Mailing List

> <linux-arm-kernel@lists.infradead.org<mailto:linux-arm-kernel@lists.infradead.org>>; devicetree

> <devicetree@vger.kernel.org<mailto:devicetree@vger.kernel.org>>; openbmc@lists.ozlabs.org<mailto:openbmc@lists.ozlabs.org>; Joel Stanley

> <joel@jms.id.au<mailto:joel@jms.id.au>>; Jiří Pírko <jiri@resnulli.us<mailto:jiri@resnulli.us>>; Tobias Klauser

> <tklauser@distanz.ch<mailto:tklauser@distanz.ch>>; open list:SERIAL DRIVERS <linux-

> serial@vger.kernel.org<mailto:serial@vger.kernel.org>>; Vadim Pasternak <vadimp@mellanox.com<mailto:vadimp@mellanox.com>>;

> system-sw-low-level <system-sw-low-level@mellanox.com<mailto:system-sw-low-level@mellanox.com>>; Rob Herring

> <robh+dt@kernel.org<mailto:robh+dt@kernel.org>>; openocd-devel-owner@lists.sourceforge.net<mailto:openocd-devel-owner@lists.sourceforge.net>;

> linux- api@vger.kernel.org<mailto:api@vger.kernel.org>; David S. Miller <davem@davemloft.net<mailto:davem@davemloft.net>>;

> Mauro Carvalho Chehab <mchehab@kernel.org<mailto:mchehab@kernel.org>>; Jiri Pirko

> <jiri@mellanox.com<mailto:jiri@mellanox.com>>

> Subject: Re: [patch v21 2/4] drivers: jtag: Add Aspeed SoC 24xx and

> 25xx families JTAG master driver

>

> On Tue, May 15, 2018 at 5:21 PM, Oleksandr Shamray

> <oleksandrs@mellanox.com<mailto:oleksandrs@mellanox.com>> wrote:

> > Driver adds support of Aspeed 2500/2400 series SOC JTAG master

> controller.

> >

> > Driver implements the following jtag ops:

> > - freq_get;

> > - freq_set;

> > - status_get;

> > - idle;

> > - xfer;

> >

> > It has been tested on Mellanox system with BMC equipped with Aspeed

> > 2520 SoC for programming CPLD devices.

>

> > +#define ASPEED_JTAG_DATA               0x00

> > +#define ASPEED_JTAG_INST               0x04

> > +#define ASPEED_JTAG_CTRL               0x08

> > +#define ASPEED_JTAG_ISR                        0x0C

> > +#define ASPEED_JTAG_SW                 0x10

> > +#define ASPEED_JTAG_TCK                        0x14

> > +#define ASPEED_JTAG_EC                 0x18

> > +

> > +#define ASPEED_JTAG_DATA_MSB           0x01

> > +#define ASPEED_JTAG_DATA_CHUNK_SIZE    0x20

>

>

> > +#define ASPEED_JTAG_IOUT_LEN(len)      (ASPEED_JTAG_CTL_ENG_EN |\

> > +                                        ASPEED_JTAG_CTL_ENG_OUT_EN

> > +|\

> > +

> > +ASPEED_JTAG_CTL_INST_LEN(len))

>

> Better to read

>

> #define MY_COOL_CONST_OR_MACRO(xxx) \

>  ...

>

> > +#define ASPEED_JTAG_DOUT_LEN(len)      (ASPEED_JTAG_CTL_ENG_EN

> |\

> > +                                        ASPEED_JTAG_CTL_ENG_OUT_EN

> > + |\

> > +

> > +ASPEED_JTAG_CTL_DATA_LEN(len))

>

> Ditto.



Ok. Changed to:

#define ASPEED_JTAG_IOUT_LEN(len) \

                               (ASPEED_JTAG_CTL_ENG_EN | \

                               ASPEED_JTAG_CTL_ENG_OUT_EN | \

                               ASPEED_JTAG_CTL_INST_LEN(len))



#define ASPEED_JTAG_DOUT_LEN(len) \

                               (ASPEED_JTAG_CTL_ENG_EN | \

                               ASPEED_JTAG_CTL_ENG_OUT_EN | \

                               ASPEED_JTAG_CTL_DATA_LEN(len))





>

> > +static char *end_status_str[] = {"idle", "ir pause", "drpause"};

>

> > +static int aspeed_jtag_freq_set(struct jtag *jtag, u32 freq) {

> > +       struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);

> > +       unsigned long apb_frq;

> > +       u32 tck_val;

> > +       u16 div;

> > +

> > +       apb_frq = clk_get_rate(aspeed_jtag->pclk);

>

> > +       div = (apb_frq % freq == 0) ? (apb_frq / freq) - 1 :

> > + (apb_frq / freq);

>

> Isn't it the same as

>

> div = (apb_frq - 1) / freq;

>

> ?

>



Seems it is same. Thanks.



> > +       tck_val = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_TCK);

> > +       aspeed_jtag_write(aspeed_jtag,

> > +                         (tck_val & ASPEED_JTAG_TCK_DIVISOR_MASK) | div,

> > +                         ASPEED_JTAG_TCK);

> > +       return 0;

> > +}

>

> > +static void aspeed_jtag_sw_delay(struct aspeed_jtag *aspeed_jtag,

> > +int

> > +cnt) {

> > +       int i;

> > +

> > +       for (i = 0; i < cnt; i++)

> > +               aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_SW);

>

> Isn't it readsl() (or how it's called, I don't remember).

>



No, readsl reads data into buffer. But in this place read used for make software delay.

Aspeed jtag driver supports 2 modes:

1 - hw mode with the hardware controlled JTAG states

and pins

2 - with software controlled pins.

This part of code used in sw-mode and generates delay for JTAG bit-bang .

I will change it to ndelay().



> > +}

>

> > +static void aspeed_jtag_wait_instruction_pause(struct aspeed_jtag

> > +*aspeed_jtag) {

> > +       wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag &

> > +                                ASPEED_JTAG_ISR_INST_PAUSE);

>

> In such cases I prefer to see a new line with a parameter in full.

> Check all places.



Full parameter doesn't fit into max 80 symbols per line limitation.



But following to LINUX kernel style, it should be no longer than 80 symbols.

It will not pass by  ./scripts/checkpatch.pl



What do you think about this?



>

> > +       aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_INST_PAUSE; }

>

> > +static void aspeed_jtag_sm_cycle(struct aspeed_jtag *aspeed_jtag,

> > +const

> u8 *tms,

> > +                                int len) {

> > +       int i;

> > +

> > +       for (i = 0; i < len; i++)

> > +               aspeed_jtag_tck_cycle(aspeed_jtag, tms[i], 0); }

> > +

> > +static void aspeed_jtag_run_test_idle_sw(struct aspeed_jtag

> *aspeed_jtag,

> > +                                        struct jtag_run_test_idle

> > +*runtest) {

> > +       static const u8 sm_pause_irpause[] = {1, 1, 1, 1, 0, 1, 0};

> > +       static const u8 sm_pause_drpause[] = {1, 1, 1, 0, 1, 0};

> > +       static const u8 sm_idle_irpause[] = {1, 1, 0, 1, 0};

> > +       static const u8 sm_idle_drpause[] = {1, 0, 1, 0};

> > +       static const u8 sm_pause_idle[] = {1, 1, 0};

> > +       int i;

> > +

> > +       /* SW mode from idle/pause-> to pause/idle */

> > +       if (runtest->reset) {

> > +               for (i = 0; i < ASPEED_JTAG_RESET_CNTR; i++)

> > +                       aspeed_jtag_tck_cycle(aspeed_jtag, 1, 0);

> > +       }

>

> I would rather split this big switch to a few helper functions per

> each status of surrounding switch.

>



Ok.

Will do it.





> > +

> > +       /* Stay on IDLE for at least  TCK cycle */

> > +       for (i = 0; i < runtest->tck; i++)

> > +               aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0); }

>

>

> > +/**

> > + * aspeed_jtag_run_test_idle:

> > + * JTAG reset: generates at least 9 TMS high and 1 TMS low to force

> > + * devices into Run-Test/Idle State.

> > + */

>

> It's rather broken kernel doc.



Deleted.



>

> > +               aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_CTL_ENG_EN |

> > +                                 ASPEED_JTAG_CTL_ENG_OUT_EN |

> > +                                 ASPEED_JTAG_CTL_FORCE_TMS,

> > + ASPEED_JTAG_CTRL);

>

> > +               aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_EC_GO_IDLE,

> > +                                 ASPEED_JTAG_EC);

>

> > +       aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |

> > +                         ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);

>

> Here you have permutations of flag some of which are repeatetive in

> the code. Perhaps make additional definitions instead.

> Check other similar places.

>



Ok. Will add defined for repeated flags



>

> > +       char          tdo;

>

> Indentation.



Ok.



>

> > +       if (xfer->direction == JTAG_READ_XFER)

> > +               tdi = UINT_MAX;

> > +       else

> > +               tdi = data[index];

>

> > +                       if (xfer->direction == JTAG_READ_XFER)

> > +                               tdi = UINT_MAX;

> > +                       else

> > +                               tdi = data[index];

>

> Take your time to think how the above duplication can be avoided.

>



I can't avoid this but it can changed to define:



#define ASPEED_JTAG_GET_TDI(direction, data) \

                              (direction == JTAG_READ_XFER) ? UNIT_MAX : data; And use as tdi = ASPEED_JTAG_GET_TDI(xfer->direction, data[index]);



> > +               }

> > +       }

> > +

> > +       tdo = aspeed_jtag_tck_cycle(aspeed_jtag, 1, tdi &

> ASPEED_JTAG_DATA_MSB);

> > +       data[index] |= tdo << (shift_bits %

> > +ASPEED_JTAG_DATA_CHUNK_SIZE); }

>

>

> > +       if (endstate != JTAG_STATE_IDLE) {

>

> Why not to use positive check?

>



Will restructure to have positive check

if (endstate == JTAG_STATE_IDLE) {

...

} else {

...

}



> > +       int i;

> > +

> > +       for (i = 0; i <= xfer->length / BITS_PER_BYTE; i++) {

> > +               pos += snprintf(&dbg_str[pos], sizeof(dbg_str) - pos,

> > +                               "0x%02x ", xfer_data[i]);

> > +       }

>

> Oh, NO! Consider reading printk-formats (for %*ph) and other

> documentation about available APIs.



Ok.



>

> > +       if (!(aspeed_jtag->mode & JTAG_XFER_HW_MODE)) {

> > +               /* SW mode */

>

> This is rather too complex to be in one function.

>



Will split to separate functions.



> > +       } else {

>

> > +               /* hw mode */

> > +               aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_SW);

> > +               aspeed_jtag_xfer_hw(aspeed_jtag, xfer, data);

>

> For symmetry it might be another function.

>

> > +       }

>

> > +       dev_dbg(aspeed_jtag->dev, "status %x\n", status);

>

> Perhaps someone should become familiar with tracepoints?

>

> > +               dev_err(aspeed_jtag->dev, "irq status:%x\n",

> > +                       status);

>

>

> Huh, really?! SPAM.





I will review and delete redundant debug messages.



>

> (I would drop it completely, though you may use ratelimited variant)

>

> > +               ret = IRQ_NONE;

> > +       }

> > +       return ret;

> > +}

>

> > +       clk_prepare_enable(aspeed_jtag->pclk);

>

> This might fail.



Will add error check



>

> > +       dev_dbg(&pdev->dev, "IRQ %d.\n", aspeed_jtag->irq);

>

> Noise even for debug.



Agree.



>

> > +       err = jtag_register(jtag);

>

> Perhaps we might have devm_ variant of this. Check how SPI framework

> deal with a such.

>



Jtag driver uses miscdevice and related  misc_register and misc_deregister calls for creation and destruction. There is no device object prior to call to  misc_register, which could be used in devm_jtag_register.



> > +static int aspeed_jtag_remove(struct platform_device *pdev) {

>

> > +       struct jtag *jtag;

> > +

> > +       jtag = platform_get_drvdata(pdev);

>

> Usually we put this on one line



+



>

> > +       aspeed_jtag_deinit(pdev, jtag_priv(jtag));

> > +       jtag_unregister(jtag);

> > +       jtag_free(jtag);

> > +       return 0;

> > +}

>

>

> --

> With Best Regards,

> Andy Shevchenko


Best Regards,

Oleksandr Shamray


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end of thread, other threads:[~2018-05-22 20:21 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-05-15 14:21 [patch v21 0/4] JTAG driver introduction Oleksandr Shamray
2018-05-15 14:21 ` [patch v21 1/4] drivers: jtag: Add JTAG core driver Oleksandr Shamray
2018-05-15 21:21   ` Andy Shevchenko
2018-05-22 15:00     ` Oleksandr Shamray
2018-05-15 14:21 ` [patch v21 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver Oleksandr Shamray
2018-05-15 21:00   ` Andy Shevchenko
2018-05-22 15:00     ` Oleksandr Shamray
2018-05-22 20:21       ` Andy Shevchenko
2018-05-15 14:21 ` [patch v21 3/4] Documentation: jtag: Add bindings for " Oleksandr Shamray
2018-05-15 14:21 ` [patch v21 4/4] Documentation: jtag: Add ABI documentation Oleksandr Shamray
2018-05-16 18:16   ` Randy Dunlap
2018-05-22 13:08 [patch v21 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver Oleksandr Shamray

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