[PATCH 0/8] Basic ARM device tree support

[PATCH 0/8] Basic ARM device tree support

[Grant Likely]

It's been a while since these patches have been circulated for review.
Much has changed since the last posting and there are no longer any
ugly hacks or workarounds to it working.  From my viewpoint, these
patches are complete and ready to be used.

This patch series allows CONFIG_OF to be enabled on ARM and allows the
kernel to accept a dtb pointer from boot firmware instead of atags.
If a dtb is passed, then the kernel will use the root 'compatible'
property to find a matching machine_desc, and it will use it to obtain
the memory layout, initrd location and kernel parameters string.

Only limited device tree support is enabled here.  It does not perform
any kind of device registration from device tree data.  That support
will be enabled in a later patch set.  Right now those patches depend
on the common struct clk patches that Jeremy is working on, so I'm not
going to post them yet.  Rather, this series is a stable base that
other engineers can use to start working on device tree support for
their platforms.

Tested on Versatile (qemu) and nVidia Tegra Harmony.  Kernel compiles
an boot with CONFIG_OF both on and off, both with and without passing
a device tree blob.

I've published this series to a new branch on my git server:

  git://git.secretlab.ca/git/linux-2.6 devicetree/arm

The way I've managed the devicetree/test branch in the past has made
it hard for other engineers to work with the device tree support, so
I'm changing the way I'm handling it.  I will *not* rebase this new
branch.  My intention is to keep it in essentially 'merge-ready' state
at all times.  ie. I'm only going to put patches into this branch that
I consider complete and are required to enable arm device tree
support.  ie. core dt infrastructure and dt board support.  Device
drivers should be submitted directly to their respective
lists/maintainers.  I'll also be soliciting acks from platform
maintainers before I pick up board support patches into this branch.

Russell:  I'm not expecting you to merge these now, nor am I asking
you to.  I won't do so until I've got a full implementation using the
device tree to register devices on the machine and supporting multiple
machines.  However, would you mind taking a look at these patches and
commenting on the approach?  Particularly the early boot code.
Thanks.

Cheers,
g.


---
The following changes since commit
a25cecce88194b2edf38b8c3b1665e9318eb2d22:

  Merge branch 'next' of git://git.monstr.eu/linux-2.6-microblaze (2011-01-18 08:06:22 -0800)

are available in the git repository at:

  git://git.secretlab.ca/git/linux-2.6 devicetree/arm

Grant Likely (7):
      arm/dt: Make __vet_atags also accept a dtb image
      arm/dt: allow bootmem reservation for device tree blob and initrd
      arm/dt: consolidate atags setup into setup_machine_atags
      arm/dt: probe for platforms via the device tree
      arm/dt: Basic versatile devicetree support
      arm/tegra: Fix tegra irq_data conversion
      arm/dt: Basic tegra devicetree support

Jeremy Kerr (1):
      arm/dt: Allow CONFIG_OF on ARM


 arch/arm/Kconfig                       |    7 ++
 arch/arm/include/asm/mach/arch.h       |    2 +
 arch/arm/include/asm/prom.h            |   34 ++++++++++
 arch/arm/include/asm/setup.h           |    4 +
 arch/arm/kernel/Makefile               |    1 
 arch/arm/kernel/devtree.c              |  107 ++++++++++++++++++++++++++++++++
 arch/arm/kernel/head-common.S          |   19 ++++--
 arch/arm/kernel/head.S                 |    8 +-
 arch/arm/kernel/setup.c                |   78 +++++++++++++----------
 arch/arm/mach-tegra/board-harmony.c    |    6 ++
 arch/arm/mach-tegra/gpio.c             |    4 +
 arch/arm/mach-versatile/versatile_ab.c |    6 ++
 arch/arm/mach-versatile/versatile_pb.c |    6 ++
 arch/arm/mm/init.c                     |   23 +++++++
 14 files changed, 258 insertions(+), 47 deletions(-)
 create mode 100644 arch/arm/include/asm/prom.h
 create mode 100644 arch/arm/kernel/devtree.c

-- 
Signature

[PATCH 1/8] arm/dt: Make __vet_atags also accept a dtb image

[Grant Likely]

The dtb is passed to the kernel via register r2, which is the same
method that is used to pass an atags pointer.  This patch modifies
__vet_atags to not clear r2 when it encounters a dtb image.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
 arch/arm/kernel/head-common.S |   19 +++++++++++++------
 arch/arm/kernel/head.S        |    8 ++++----
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
index 8f57515..d9a9105 100644
--- a/arch/arm/kernel/head-common.S
+++ b/arch/arm/kernel/head-common.S
@@ -14,6 +14,7 @@
 #define ATAG_CORE 0x54410001
 #define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2)
 #define ATAG_CORE_SIZE_EMPTY ((2*4) >> 2)
+#define OF_DT_MAGIC 0xedfe0dd0 /* 0xd00dfeed in big-endian */
 
 /*
  * Exception handling.  Something went wrong and we can't proceed.  We
@@ -105,22 +106,28 @@ __lookup_machine_type_data:
 
 /* Determine validity of the r2 atags pointer.  The heuristic requires
  * that the pointer be aligned, in the first 16k of physical RAM and
- * that the ATAG_CORE marker is first and present.  Future revisions
+ * that the ATAG_CORE marker is first and present.  If CONFIG_OF_FLATTREE
+ * is selected, then it will also accept a dtb pointer.  Future revisions
  * of this function may be more lenient with the physical address and
  * may also be able to move the ATAGS block if necessary.
  *
  * r8  = machinfo
  *
  * Returns:
- *  r2 either valid atags pointer, or zero
+ *  r2 either valid atags pointer, valid dtb pointer, or zero
  *  r5, r6 corrupted
  */
 __vet_atags:
 	tst	r2, #0x3			@ aligned?
 	bne	1f
 
-	ldr	r5, [r2, #0]			@ is first tag ATAG_CORE?
-	cmp	r5, #ATAG_CORE_SIZE
+#ifdef CONFIG_OF_FLATTREE
+	ldr	r5, [r2, #0]			@ is it a DTB?
+	ldr	r6, =OF_DT_MAGIC
+	cmp	r5, r6
+	beq	2f
+#endif
+	cmp	r5, #ATAG_CORE_SIZE		@ is first tag ATAG_CORE?
 	cmpne	r5, #ATAG_CORE_SIZE_EMPTY
 	bne	1f
 	ldr	r5, [r2, #4]
@@ -128,7 +135,7 @@ __vet_atags:
 	cmp	r5, r6
 	bne	1f
 
-	mov	pc, lr				@ atag pointer is ok
+2:	mov	pc, lr				@ atag/dtb pointer is ok
 
 1:	mov	r2, #0
 	mov	pc, lr
@@ -140,7 +147,7 @@ ENDPROC(__vet_atags)
  *
  *  r0  = cp#15 control register
  *  r1  = machine ID
- *  r2  = atags pointer
+ *  r2  = atags/dtb pointer
  *  r9  = processor ID
  */
 	__INIT
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index f17d9a0..65d9489 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -66,7 +66,7 @@
  *
  * This is normally called from the decompressor code.  The requirements
  * are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
- * r1 = machine nr, r2 = atags pointer.
+ * r1 = machine nr, r2 = atags or dtb pointer.
  *
  * This code is mostly position independent, so if you link the kernel at
  * 0xc0008000, you call this at __pa(0xc0008000).
@@ -93,7 +93,7 @@ ENTRY(stext)
 	beq	__error_a			@ yes, error 'a'
 
 	/*
-	 * r1 = machine no, r2 = atags,
+	 * r1 = machine no, r2 = atags or dtb,
 	 * r8 = machinfo, r9 = cpuid, r10 = procinfo
 	 */
 	bl	__vet_atags
@@ -335,7 +335,7 @@ __secondary_data:
  *
  *  r0  = cp#15 control register
  *  r1  = machine ID
- *  r2  = atags pointer
+ *  r2  = atags or dtb pointer
  *  r4  = page table pointer
  *  r9  = processor ID
  *  r13 = *virtual* address to jump to upon completion
@@ -372,7 +372,7 @@ ENDPROC(__enable_mmu)
  *
  *  r0  = cp#15 control register
  *  r1  = machine ID
- *  r2  = atags pointer
+ *  r2  = atags or dtb pointer
  *  r9  = processor ID
  *  r13 = *virtual* address to jump to upon completion
  *

Re: [PATCH 1/8] arm/dt: Make __vet_atags also accept a dtb image

[Nicolas Pitre]

On Tue, 18 Jan 2011, Grant Likely wrote:

> The dtb is passed to the kernel via register r2, which is the same
> method that is used to pass an atags pointer.  This patch modifies
> __vet_atags to not clear r2 when it encounters a dtb image.
> 
> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
> ---
>  arch/arm/kernel/head-common.S |   19 +++++++++++++------
>  arch/arm/kernel/head.S        |    8 ++++----
>  2 files changed, 17 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
> index 8f57515..d9a9105 100644
> --- a/arch/arm/kernel/head-common.S
> +++ b/arch/arm/kernel/head-common.S
> @@ -14,6 +14,7 @@
>  #define ATAG_CORE 0x54410001
>  #define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2)
>  #define ATAG_CORE_SIZE_EMPTY ((2*4) >> 2)
> +#define OF_DT_MAGIC 0xedfe0dd0 /* 0xd00dfeed in big-endian */

ARM can be big endian too.  Would be nice to make this endian 
independent, or at least list this limitation in the commit log.

>  /*
>   * Exception handling.  Something went wrong and we can't proceed.  We
> @@ -105,22 +106,28 @@ __lookup_machine_type_data:
>  
>  /* Determine validity of the r2 atags pointer.  The heuristic requires
>   * that the pointer be aligned, in the first 16k of physical RAM and
> - * that the ATAG_CORE marker is first and present.  Future revisions
> + * that the ATAG_CORE marker is first and present.  If CONFIG_OF_FLATTREE
> + * is selected, then it will also accept a dtb pointer.  Future revisions
>   * of this function may be more lenient with the physical address and
>   * may also be able to move the ATAGS block if necessary.
>   *
>   * r8  = machinfo
>   *
>   * Returns:
> - *  r2 either valid atags pointer, or zero
> + *  r2 either valid atags pointer, valid dtb pointer, or zero
>   *  r5, r6 corrupted
>   */
>  __vet_atags:
>  	tst	r2, #0x3			@ aligned?
>  	bne	1f
>  
> -	ldr	r5, [r2, #0]			@ is first tag ATAG_CORE?
> -	cmp	r5, #ATAG_CORE_SIZE
> +#ifdef CONFIG_OF_FLATTREE
> +	ldr	r5, [r2, #0]			@ is it a DTB?
> +	ldr	r6, =OF_DT_MAGIC
> +	cmp	r5, r6
> +	beq	2f
> +#endif
> +	cmp	r5, #ATAG_CORE_SIZE		@ is first tag ATAG_CORE?

The "ldr r5 ..." is now done only within #ifdef CONFIG_OF_FLATTREE.  So 
if CONFIG_OF_FLATTREE is undefined then r5 will contain garbage.


Nicolas

Re: [PATCH 1/8] arm/dt: Make __vet_atags also accept a dtb image

[Grant Likely]

Hi Nicolas,

On Tue, Jan 18, 2011 at 2:26 PM, Nicolas Pitre <nicolas.pitre@linaro.org> wrote:
> On Tue, 18 Jan 2011, Grant Likely wrote:
>
>> The dtb is passed to the kernel via register r2, which is the same
>> method that is used to pass an atags pointer.  This patch modifies
>> __vet_atags to not clear r2 when it encounters a dtb image.
>>
>> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
>> ---
>>  arch/arm/kernel/head-common.S |   19 +++++++++++++------
>>  arch/arm/kernel/head.S        |    8 ++++----
>>  2 files changed, 17 insertions(+), 10 deletions(-)
>>
>> diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
>> index 8f57515..d9a9105 100644
>> --- a/arch/arm/kernel/head-common.S
>> +++ b/arch/arm/kernel/head-common.S
>> @@ -14,6 +14,7 @@
>>  #define ATAG_CORE 0x54410001
>>  #define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2)
>>  #define ATAG_CORE_SIZE_EMPTY ((2*4) >> 2)
>> +#define OF_DT_MAGIC 0xedfe0dd0 /* 0xd00dfeed in big-endian */
>
> ARM can be big endian too.  Would be nice to make this endian
> independent, or at least list this limitation in the commit log.

How about:
#ifdef CONFIG_CPU_BIG_ENDIAN
#define OF_DT_MAGIC 0xd00dfeed
#else
#define OF_DT_MAGIC 0xedfe0dd0 /* 0xd00dfeed in big-endian */
#endif

Or is there a better way for loading and comparing big endian values in ARM?

>
>>  /*
>>   * Exception handling.  Something went wrong and we can't proceed.  We
>> @@ -105,22 +106,28 @@ __lookup_machine_type_data:
>>
>>  /* Determine validity of the r2 atags pointer.  The heuristic requires
>>   * that the pointer be aligned, in the first 16k of physical RAM and
>> - * that the ATAG_CORE marker is first and present.  Future revisions
>> + * that the ATAG_CORE marker is first and present.  If CONFIG_OF_FLATTREE
>> + * is selected, then it will also accept a dtb pointer.  Future revisions
>>   * of this function may be more lenient with the physical address and
>>   * may also be able to move the ATAGS block if necessary.
>>   *
>>   * r8  = machinfo
>>   *
>>   * Returns:
>> - *  r2 either valid atags pointer, or zero
>> + *  r2 either valid atags pointer, valid dtb pointer, or zero
>>   *  r5, r6 corrupted
>>   */
>>  __vet_atags:
>>       tst     r2, #0x3                        @ aligned?
>>       bne     1f
>>
>> -     ldr     r5, [r2, #0]                    @ is first tag ATAG_CORE?
>> -     cmp     r5, #ATAG_CORE_SIZE
>> +#ifdef CONFIG_OF_FLATTREE
>> +     ldr     r5, [r2, #0]                    @ is it a DTB?
>> +     ldr     r6, =OF_DT_MAGIC
>> +     cmp     r5, r6
>> +     beq     2f
>> +#endif
>> +     cmp     r5, #ATAG_CORE_SIZE             @ is first tag ATAG_CORE?
>
> The "ldr r5 ..." is now done only within #ifdef CONFIG_OF_FLATTREE.  So
> if CONFIG_OF_FLATTREE is undefined then r5 will contain garbage.

Oops, that was a silly oversight.  Fixed now.

g.

>
>
> Nicolas
>



-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.

[PATCH 2/8] arm/dt: allow bootmem reservation for device tree blob and initrd

[Grant Likely]

This patch adds a function, arm_reserve_devtree(), to allow the device
tree code to reserve the memory used by the FDT blob.  It also adds
early_init_dt_setup_initrd() which is the hook used by the flat device
tree code to register the region of memory occupied by an initrd.

[based on original patch written by Jeremy Kerr <jeremy.kerr@canonical.com>]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
 arch/arm/include/asm/setup.h |    2 ++
 arch/arm/mm/init.c           |   23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/arch/arm/include/asm/setup.h b/arch/arm/include/asm/setup.h
index f1e5a9b..0f3e0ac 100644
--- a/arch/arm/include/asm/setup.h
+++ b/arch/arm/include/asm/setup.h
@@ -221,6 +221,8 @@ extern struct meminfo meminfo;
 #define bank_phys_end(bank)	((bank)->start + (bank)->size)
 #define bank_phys_size(bank)	(bank)->size
 
+extern void arm_reserve_devtree(unsigned long start, unsigned long size);
+
 #endif  /*  __KERNEL__  */
 
 #endif
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 5164069..28ccb21 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -71,6 +71,25 @@ static int __init parse_tag_initrd2(const struct tag *tag)
 
 __tagtable(ATAG_INITRD2, parse_tag_initrd2);
 
+#ifdef CONFIG_OF_FLATTREE
+#include <linux/of_fdt.h>
+
+static unsigned long phys_devtree_start __initdata = 0;
+static unsigned long phys_devtree_size __initdata = 0;
+
+void __init early_init_dt_setup_initrd_arch(unsigned long start, unsigned long end)
+{
+	phys_initrd_start = start;
+	phys_initrd_size = end - start + 1;
+}
+
+void __init arm_reserve_devtree(unsigned long start, unsigned long size)
+{
+	phys_devtree_start = start;
+	phys_devtree_size = size;
+}
+#endif /* CONFIG_OF_FLATTREE */
+
 /*
  * This keeps memory configuration data used by a couple memory
  * initialization functions, as well as show_mem() for the skipping
@@ -305,6 +324,10 @@ void __init arm_memblock_init(struct meminfo *mi, struct machine_desc *mdesc)
 		initrd_end = initrd_start + phys_initrd_size;
 	}
 #endif
+#ifdef CONFIG_OF_FLATTREE
+	if (phys_devtree_size)
+		memblock_reserve(phys_devtree_start, phys_devtree_size);
+#endif
 
 	arm_mm_memblock_reserve();
 

[PATCH 3/8] arm/dt: Allow CONFIG_OF on ARM

[Grant Likely]

From: Jeremy Kerr <jeremy.kerr@canonical.com>

Add some basic empty infrastructure for DT support on ARM.

Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
 arch/arm/Kconfig             |    7 ++++++
 arch/arm/include/asm/prom.h  |   25 ++++++++++++++++++++++
 arch/arm/include/asm/setup.h |    1 +
 arch/arm/kernel/Makefile     |    1 +
 arch/arm/kernel/devtree.c    |   47 ++++++++++++++++++++++++++++++++++++++++++
 arch/arm/kernel/setup.c      |    2 +-
 6 files changed, 82 insertions(+), 1 deletions(-)
 create mode 100644 arch/arm/include/asm/prom.h
 create mode 100644 arch/arm/kernel/devtree.c

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 5cff165..d8a330f 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1586,6 +1586,13 @@ endmenu
 
 menu "Boot options"
 
+config USE_OF
+	bool "Flattened Device Tree support"
+	select OF
+	select OF_EARLY_FLATTREE
+	help
+	  Include support for flattened device tree machine descriptions.
+
 # Compressed boot loader in ROM.  Yes, we really want to ask about
 # TEXT and BSS so we preserve their values in the config files.
 config ZBOOT_ROM_TEXT
diff --git a/arch/arm/include/asm/prom.h b/arch/arm/include/asm/prom.h
new file mode 100644
index 0000000..8f1037f
--- /dev/null
+++ b/arch/arm/include/asm/prom.h
@@ -0,0 +1,25 @@
+/*
+ *  arch/arm/include/asm/prom.h
+ *
+ *  Copyright (C) 2009 Canonical Ltd. <jeremy.kerr@canonical.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#ifndef __ASMARM_PROM_H
+#define __ASMARM_PROM_H
+
+#ifdef CONFIG_OF
+
+#include <asm/setup.h>
+#include <asm/irq.h>
+
+static inline void irq_dispose_mapping(unsigned int virq)
+{
+	return;
+}
+
+#endif /* CONFIG_OF */
+#endif /* ASMARM_PROM_H */
diff --git a/arch/arm/include/asm/setup.h b/arch/arm/include/asm/setup.h
index 0f3e0ac..0809235 100644
--- a/arch/arm/include/asm/setup.h
+++ b/arch/arm/include/asm/setup.h
@@ -222,6 +222,7 @@ extern struct meminfo meminfo;
 #define bank_phys_size(bank)	(bank)->size
 
 extern void arm_reserve_devtree(unsigned long start, unsigned long size);
+extern int arm_add_memory(unsigned long start, unsigned long size);
 
 #endif  /*  __KERNEL__  */
 
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 185ee82..8df05fd 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_ARM_THUMBEE)	+= thumbee.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_ARM_UNWIND)	+= unwind.o
 obj-$(CONFIG_HAVE_TCM)		+= tcm.o
+obj-$(CONFIG_OF)		+= devtree.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
 obj-$(CONFIG_SWP_EMULATE)	+= swp_emulate.o
 CFLAGS_swp_emulate.o		:= -Wa,-march=armv7-a
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
new file mode 100644
index 0000000..ac48da2
--- /dev/null
+++ b/arch/arm/kernel/devtree.c
@@ -0,0 +1,47 @@
+/*
+ *  linux/arch/arm/kernel/devtree.c
+ *
+ *  Copyright (C) 2009 Canonical Ltd. <jeremy.kerr@canonical.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/bootmem.h>
+#include <linux/memblock.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+
+#include <asm/setup.h>
+#include <asm/page.h>
+
+void __init early_init_dt_add_memory_arch(u64 base, u64 size)
+{
+	arm_add_memory(base, size);
+}
+
+void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
+{
+	return __va(memblock_alloc(size, align));
+}
+
+/**
+ * irq_create_of_mapping - Hook to resolve OF irq specifier into a Linux irq#
+ *
+ * Currently the mapping mechanism is trivial; simple flat hwirq numbers are
+ * mapped 1:1 onto Linux irq numbers.  Cascaded irq controllers are not
+ * supported.
+ */
+unsigned int irq_create_of_mapping(struct device_node *controller,
+				   const u32 *intspec, unsigned int intsize)
+{
+	return intspec[0];
+}
+EXPORT_SYMBOL_GPL(irq_create_of_mapping);
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 420b8d6..d211609 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -443,7 +443,7 @@ static struct machine_desc * __init setup_machine(unsigned int nr)
 	return list;
 }
 
-static int __init arm_add_memory(unsigned long start, unsigned long size)
+int __init arm_add_memory(unsigned long start, unsigned long size)
 {
 	struct membank *bank = &meminfo.bank[meminfo.nr_banks];
 

[PATCH 4/8] arm/dt: consolidate atags setup into setup_machine_atags

[Grant Likely]

In preparation for adding device tree support, this patch consolidates
all of the atag-specific setup into a single function.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
 arch/arm/kernel/setup.c |   68 ++++++++++++++++++++++++-----------------------
 1 files changed, 35 insertions(+), 33 deletions(-)

diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index d211609..cbc1836 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -424,25 +424,6 @@ void cpu_init(void)
 	    : "r14");
 }
 
-static struct machine_desc * __init setup_machine(unsigned int nr)
-{
-	struct machine_desc *list;
-
-	/*
-	 * locate machine in the list of supported machines.
-	 */
-	list = lookup_machine_type(nr);
-	if (!list) {
-		printk("Machine configuration botched (nr %d), unable "
-		       "to continue.\n", nr);
-		while (1);
-	}
-
-	printk("Machine: %s\n", list->name);
-
-	return list;
-}
-
 int __init arm_add_memory(unsigned long start, unsigned long size)
 {
 	struct membank *bank = &meminfo.bank[meminfo.nr_banks];
@@ -796,21 +777,23 @@ static void __init squash_mem_tags(struct tag *tag)
 			tag->hdr.tag = ATAG_NONE;
 }
 
-void __init setup_arch(char **cmdline_p)
+static struct machine_desc * __init setup_machine_tags(unsigned int nr)
 {
 	struct tag *tags = (struct tag *)&init_tags;
 	struct machine_desc *mdesc;
 	char *from = default_command_line;
 
-	unwind_init();
-
-	setup_processor();
-	mdesc = setup_machine(machine_arch_type);
-	machine_desc = mdesc;
-	machine_name = mdesc->name;
+	/*
+	 * locate machine in the list of supported machines.
+	 */
+	mdesc = lookup_machine_type(nr);
+	if (!mdesc) {
+		printk("Machine configuration botched (nr %d), unable "
+		       "to continue.\n", nr);
+		while (1);
+	}
 
-	if (mdesc->soft_reboot)
-		reboot_setup("s");
+	printk("Machine: %s\n", mdesc->name);
 
 	if (__atags_pointer)
 		tags = phys_to_virt(__atags_pointer);
@@ -838,16 +821,35 @@ void __init setup_arch(char **cmdline_p)
 		parse_tags(tags);
 	}
 
-	init_mm.start_code = (unsigned long) _text;
-	init_mm.end_code   = (unsigned long) _etext;
-	init_mm.end_data   = (unsigned long) _edata;
-	init_mm.brk	   = (unsigned long) _end;
-
 	/* parse_early_param needs a boot_command_line */
 	strlcpy(boot_command_line, from, COMMAND_LINE_SIZE);
 
 	/* populate cmd_line too for later use, preserving boot_command_line */
 	strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);
+
+	return mdesc;
+}
+
+
+void __init setup_arch(char **cmdline_p)
+{
+	struct machine_desc *mdesc;
+
+	unwind_init();
+
+	setup_processor();
+	mdesc = setup_machine_tags(machine_arch_type);
+	machine_desc = mdesc;
+	machine_name = mdesc->name;
+
+	if (mdesc->soft_reboot)
+		reboot_setup("s");
+
+	init_mm.start_code = (unsigned long) _text;
+	init_mm.end_code   = (unsigned long) _etext;
+	init_mm.end_data   = (unsigned long) _edata;
+	init_mm.brk	   = (unsigned long) _end;
+
 	*cmdline_p = cmd_line;
 
 	parse_early_param();

[PATCH 5/8] arm/dt: probe for platforms via the device tree

[Grant Likely]

Add a macro to define a device-tree-probable machine
(DT_MACHINE_START/DT_MACHINE_END), and iterate through compiled-in
mdescs once we have the DT.  This patch creates a new function,
setup_machine_fdt() which is analogous to the setup_machine_atags()
created in the previous patch.  It does all the early setup needed to
use a device tree machine description.

[based on work originally written by Jeremy Kerr <jeremy.kerr@canonical.com>]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
 arch/arm/include/asm/mach/arch.h |    2 +
 arch/arm/include/asm/prom.h      |    9 ++++++
 arch/arm/include/asm/setup.h     |    1 +
 arch/arm/kernel/devtree.c        |   60 ++++++++++++++++++++++++++++++++++++++
 arch/arm/kernel/setup.c          |   10 +++++-
 5 files changed, 80 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/mach/arch.h b/arch/arm/include/asm/mach/arch.h
index 3a0893a..2ed24e7 100644
--- a/arch/arm/include/asm/mach/arch.h
+++ b/arch/arm/include/asm/mach/arch.h
@@ -22,6 +22,8 @@ struct machine_desc {
 	unsigned int		nr;		/* architecture number	*/
 	const char		*name;		/* architecture name	*/
 	unsigned long		boot_params;	/* tagged list		*/
+	const char		**dt_compat;	/* array of device tree
+						 * 'compatible' strings	*/
 
 	unsigned int		nr_irqs;	/* number of IRQs */
 
diff --git a/arch/arm/include/asm/prom.h b/arch/arm/include/asm/prom.h
index 8f1037f..b692f41 100644
--- a/arch/arm/include/asm/prom.h
+++ b/arch/arm/include/asm/prom.h
@@ -21,5 +21,14 @@ static inline void irq_dispose_mapping(unsigned int virq)
 	return;
 }
 
+extern struct machine_desc *setup_machine_fdt(unsigned int dt_phys);
+
+#else /* CONFIG_OF */
+
+static inline struct machine_desc *setup_machine_fdt(unsigned int dt_phys)
+{
+	return NULL;
+}
+
 #endif /* CONFIG_OF */
 #endif /* ASMARM_PROM_H */
diff --git a/arch/arm/include/asm/setup.h b/arch/arm/include/asm/setup.h
index 0809235..b46d320 100644
--- a/arch/arm/include/asm/setup.h
+++ b/arch/arm/include/asm/setup.h
@@ -223,6 +223,7 @@ extern struct meminfo meminfo;
 
 extern void arm_reserve_devtree(unsigned long start, unsigned long size);
 extern int arm_add_memory(unsigned long start, unsigned long size);
+extern char cmd_line[COMMAND_LINE_SIZE];
 
 #endif  /*  __KERNEL__  */
 
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index ac48da2..f7788be 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -21,6 +21,7 @@
 
 #include <asm/setup.h>
 #include <asm/page.h>
+#include <asm/mach/arch.h>
 
 void __init early_init_dt_add_memory_arch(u64 base, u64 size)
 {
@@ -45,3 +46,62 @@ unsigned int irq_create_of_mapping(struct device_node *controller,
 	return intspec[0];
 }
 EXPORT_SYMBOL_GPL(irq_create_of_mapping);
+
+extern struct machine_desc __arch_info_begin, __arch_info_end;
+
+/**
+ * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
+ * @dt_phys: physical address of dt blob
+ *
+ * If a dtb was passed to the kernel in r2, then use it to choose the
+ * correct machine_desc and to setup the system.
+ */
+struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
+{
+	struct boot_param_header *devtree;
+	struct machine_desc *mdesc, *mdesc_best = NULL;
+	unsigned int score, mdesc_score = ~1;
+	unsigned long dt_root;
+	const char *model;
+
+	devtree = phys_to_virt(dt_phys);
+
+	/* check device tree validity */
+	if (be32_to_cpu(devtree->magic) != OF_DT_HEADER)
+		return NULL;
+
+	/* Search the mdescs for the 'best' compatible value match */
+	initial_boot_params = devtree;
+	dt_root = of_get_flat_dt_root();
+	for (mdesc = &__arch_info_begin; mdesc < &__arch_info_end; mdesc++) {
+		score = of_flat_dt_match(dt_root, mdesc->dt_compat);
+		if (score > 0 && score < mdesc_score) {
+			mdesc_best = mdesc;
+			mdesc_score = score;
+		}
+	}
+	if (!mdesc_best) {
+		printk("Machine not supported, unable to continue.\n");
+		while (1);
+	}
+
+	model = of_get_flat_dt_prop(dt_root, "model", NULL);
+	if (!model)
+		model = of_get_flat_dt_prop(dt_root, "compatible", NULL);
+	if (!model)
+		model = "<unknown>";
+	pr_info("Machine: %s, model: %s\n", mdesc_best->name, model);
+
+	arm_reserve_devtree(dt_phys, be32_to_cpu(devtree->totalsize));
+
+	/* Retrieve various information from the /chosen node */
+	of_scan_flat_dt(early_init_dt_scan_chosen, NULL);
+	/* Initialize {size,address}-cells info */
+	of_scan_flat_dt(early_init_dt_scan_root, NULL);
+	/* Setup memory, calling early_init_dt_add_memory_arch */
+	of_scan_flat_dt(early_init_dt_scan_memory, NULL);
+	/* Save command line for /proc/cmdline  */
+	strlcpy(boot_command_line, cmd_line, COMMAND_LINE_SIZE);
+
+	return mdesc_best;
+}
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index cbc1836..3db0cbb 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -20,6 +20,7 @@
 #include <linux/screen_info.h>
 #include <linux/init.h>
 #include <linux/kexec.h>
+#include <linux/of_fdt.h>
 #include <linux/crash_dump.h>
 #include <linux/root_dev.h>
 #include <linux/cpu.h>
@@ -42,6 +43,7 @@
 #include <asm/cachetype.h>
 #include <asm/tlbflush.h>
 
+#include <asm/prom.h>
 #include <asm/mach/arch.h>
 #include <asm/mach/irq.h>
 #include <asm/mach/time.h>
@@ -125,7 +127,7 @@ EXPORT_SYMBOL(elf_platform);
 
 static const char *cpu_name;
 static const char *machine_name;
-static char __initdata cmd_line[COMMAND_LINE_SIZE];
+char cmd_line[COMMAND_LINE_SIZE];
 struct machine_desc *machine_desc __initdata;
 
 static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE;
@@ -838,7 +840,9 @@ void __init setup_arch(char **cmdline_p)
 	unwind_init();
 
 	setup_processor();
-	mdesc = setup_machine_tags(machine_arch_type);
+	mdesc = setup_machine_fdt(__atags_pointer);
+	if (!mdesc)
+		mdesc = setup_machine_tags(machine_arch_type);
 	machine_desc = mdesc;
 	machine_name = mdesc->name;
 
@@ -859,6 +863,8 @@ void __init setup_arch(char **cmdline_p)
 	paging_init(mdesc);
 	request_standard_resources(mdesc);
 
+	unflatten_device_tree();
+
 #ifdef CONFIG_SMP
 	if (is_smp())
 		smp_init_cpus();

[PATCH 6/8] arm/dt: Basic versatile devicetree support

[Grant Likely]

This patch adds adds very basic support for booting versatile with a
device tree.  It simply allows the existing machine_descs to match
against the versatile ab & pb compatible values so that the kernel can
boot.  Kernel parameters and the initrd pointer is read out of the
tree instead of atags.

This is not complete device tree support.  This change will be
reverted when a new machine_desc is added that can populate the
versatile device registrations directly from data in the tree instead
of using hard coded data.  That change will be made in a future patch.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
 arch/arm/mach-versatile/versatile_ab.c |    6 ++++++
 arch/arm/mach-versatile/versatile_pb.c |    6 ++++++
 2 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-versatile/versatile_ab.c b/arch/arm/mach-versatile/versatile_ab.c
index aa9730f..62053df 100644
--- a/arch/arm/mach-versatile/versatile_ab.c
+++ b/arch/arm/mach-versatile/versatile_ab.c
@@ -33,6 +33,11 @@
 
 #include "core.h"
 
+static const char *versatile_ab_match[] __initdata = {
+	"arm,versatile-ab",
+	NULL,
+};
+
 MACHINE_START(VERSATILE_AB, "ARM-Versatile AB")
 	/* Maintainer: ARM Ltd/Deep Blue Solutions Ltd */
 	.boot_params	= 0x00000100,
@@ -40,4 +45,5 @@ MACHINE_START(VERSATILE_AB, "ARM-Versatile AB")
 	.init_irq	= versatile_init_irq,
 	.timer		= &versatile_timer,
 	.init_machine	= versatile_init,
+	.dt_compat	= versatile_ab_match,
 MACHINE_END
diff --git a/arch/arm/mach-versatile/versatile_pb.c b/arch/arm/mach-versatile/versatile_pb.c
index bf46964..eba12fa 100644
--- a/arch/arm/mach-versatile/versatile_pb.c
+++ b/arch/arm/mach-versatile/versatile_pb.c
@@ -106,6 +106,11 @@ static void __init versatile_pb_init(void)
 	}
 }
 
+static const char *versatile_pb_match[] __initdata = {
+	"arm,versatile-pb",
+	NULL,
+};
+
 MACHINE_START(VERSATILE_PB, "ARM-Versatile PB")
 	/* Maintainer: ARM Ltd/Deep Blue Solutions Ltd */
 	.boot_params	= 0x00000100,
@@ -113,4 +118,5 @@ MACHINE_START(VERSATILE_PB, "ARM-Versatile PB")
 	.init_irq	= versatile_init_irq,
 	.timer		= &versatile_timer,
 	.init_machine	= versatile_pb_init,
+	.dt_compat	= versatile_pb_match,
 MACHINE_END

[PATCH 7/8] arm/tegra: Fix tegra irq_data conversion

[Grant Likely]

Commit 37337a8d5e68d6e19075dbdb3acf4f1011dae972, "ARM: tegra: irq_data
conversion." missed changing one reference to 'irq' in the function
tegra_gpio_irq_set_type().  This patch fixes the build error.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
 arch/arm/mach-tegra/gpio.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-tegra/gpio.c b/arch/arm/mach-tegra/gpio.c
index bd06620..ad80488 100644
--- a/arch/arm/mach-tegra/gpio.c
+++ b/arch/arm/mach-tegra/gpio.c
@@ -207,9 +207,9 @@ static int tegra_gpio_irq_set_type(struct irq_data *d, unsigned int type)
 	spin_unlock_irqrestore(&bank->lvl_lock[port], flags);
 
 	if (type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
-		__set_irq_handler_unlocked(irq, handle_level_irq);
+		__set_irq_handler_unlocked(d->irq, handle_level_irq);
 	else if (type & (IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
-		__set_irq_handler_unlocked(irq, handle_edge_irq);
+		__set_irq_handler_unlocked(d->irq, handle_edge_irq);
 
 	return 0;
 }

[PATCH 8/8] arm/dt: Basic tegra devicetree support

[Grant Likely]

This patch adds adds very basic support for booting versatile with a
device tree.  It simply allows the existing machine_descs to match
against the tegra compatible values so that the kernel can boot.
Kernel parameters and the initrd pointer is read out of the tree
instead of atags.

This is not complete device tree support.  This change will be
reverted when a new machine_desc is added that can populate the
versatile device registrations directly from data in the tree instead
of using hard coded data.  That change will be made in a future patch.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
 arch/arm/mach-tegra/board-harmony.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-tegra/board-harmony.c b/arch/arm/mach-tegra/board-harmony.c
index b9dbdb1..99884e9 100644
--- a/arch/arm/mach-tegra/board-harmony.c
+++ b/arch/arm/mach-tegra/board-harmony.c
@@ -113,6 +113,11 @@ static void __init tegra_harmony_init(void)
 	platform_add_devices(harmony_devices, ARRAY_SIZE(harmony_devices));
 }
 
+static const char * tegra_harmony_board_compat[] = {
+	"nvidia,harmony",
+	NULL
+};
+
 MACHINE_START(HARMONY, "harmony")
 	.boot_params  = 0x00000100,
 	.fixup		= tegra_harmony_fixup,
@@ -120,4 +125,5 @@ MACHINE_START(HARMONY, "harmony")
 	.init_machine   = tegra_harmony_init,
 	.map_io         = tegra_map_common_io,
 	.timer          = &tegra_timer,
+	.dt_compat      = tegra_harmony_board_compat,
 MACHINE_END

Re: [PATCH 8/8] arm/dt: Basic tegra devicetree support

[Nicolas Pitre]

On Tue, 18 Jan 2011, Grant Likely wrote:

> This patch adds adds very basic support for booting versatile with a
> device tree.
[...]

Description doesn't match $subject.


Nicolas

Re: [PATCH 8/8] arm/dt: Basic tegra devicetree support

[Grant Likely]

On Tue, Jan 18, 2011 at 2:47 PM, Nicolas Pitre <nico@fluxnic.net> wrote:
> On Tue, 18 Jan 2011, Grant Likely wrote:
>
>> This patch adds adds very basic support for booting versatile with a
>> device tree.
> [...]
>
> Description doesn't match $subject.

Fixed, thanks.

g.

Re: [PATCH 8/8] arm/dt: Basic tegra devicetree support

[Sergei Shtylyov]

Hello.

On 18-01-2011 23:29, Grant Likely wrote:

> This patch adds adds

    One word is enough. :-)

> very basic support for booting versatile with a
> device tree.  It simply allows the existing machine_descs to match
> against the tegra compatible values so that the kernel can boot.
> Kernel parameters and the initrd pointer is read out of the tree
> instead of atags.

> This is not complete device tree support.  This change will be
> reverted when a new machine_desc is added that can populate the
> versatile device registrations directly from data in the tree instead
> of using hard coded data.  That change will be made in a future patch.

> Signed-off-by: Grant Likely<grant.likely@secretlab.ca>

WBR, Sergei

RE: [PATCH 0/8] Basic ARM device tree support

[John Linn]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 5398 bytes --]

> -----Original Message-----
> From: Grant Likely [mailto:glikely@secretlab.ca] On Behalf Of Grant Likely
> Sent: Tuesday, January 18, 2011 1:29 PM
> To: linux-arm-kernel@lists.infradead.org
> Cc: Nicolas Pitre; Russell King; Catalin Marinas; devicetree-discuss@lists.ozlabs.org; linux-
> kernel@vger.kernel.org; Olof Johansson; Jeremy Kerr; John Linn; Lennert Buijtenhek
> Subject: [PATCH 0/8] Basic ARM device tree support
> 
> It's been a while since these patches have been circulated for review.
> Much has changed since the last posting and there are no longer any
> ugly hacks or workarounds to it working.  From my viewpoint, these
> patches are complete and ready to be used.
> 
> This patch series allows CONFIG_OF to be enabled on ARM and allows the
> kernel to accept a dtb pointer from boot firmware instead of atags.
> If a dtb is passed, then the kernel will use the root 'compatible'
> property to find a matching machine_desc, and it will use it to obtain
> the memory layout, initrd location and kernel parameters string.
> 
> Only limited device tree support is enabled here.  It does not perform
> any kind of device registration from device tree data.  That support
> will be enabled in a later patch set.  Right now those patches depend
> on the common struct clk patches that Jeremy is working on, so I'm not
> going to post them yet.  Rather, this series is a stable base that
> other engineers can use to start working on device tree support for
> their platforms.
> 
> Tested on Versatile (qemu) and nVidia Tegra Harmony.  Kernel compiles
> an boot with CONFIG_OF both on and off, both with and without passing
> a device tree blob.

Tested on Xilinx platform.  Did see an issue with loading the device
tree blob into higher memory.  At address 0 there was no issue.  

> 
> I've published this series to a new branch on my git server:
> 
>   git://git.secretlab.ca/git/linux-2.6 devicetree/arm
> 
> The way I've managed the devicetree/test branch in the past has made
> it hard for other engineers to work with the device tree support, so
> I'm changing the way I'm handling it.  I will *not* rebase this new
> branch.  My intention is to keep it in essentially 'merge-ready' state
> at all times.  ie. I'm only going to put patches into this branch that
> I consider complete and are required to enable arm device tree
> support.  ie. core dt infrastructure and dt board support.  Device
> drivers should be submitted directly to their respective
> lists/maintainers.  I'll also be soliciting acks from platform
> maintainers before I pick up board support patches into this branch.
> 
> Russell:  I'm not expecting you to merge these now, nor am I asking
> you to.  I won't do so until I've got a full implementation using the
> device tree to register devices on the machine and supporting multiple
> machines.  However, would you mind taking a look at these patches and
> commenting on the approach?  Particularly the early boot code.
> Thanks.
> 
> Cheers,
> g.
> 

Thanks for this patch set.  Device tree on ARM will be a great help to Xilinx.

Tested-by: John Linn <john.linn@xilinx.com>

> 
> ---
> The following changes since commit
> a25cecce88194b2edf38b8c3b1665e9318eb2d22:
> 
>   Merge branch 'next' of git://git.monstr.eu/linux-2.6-microblaze (2011-01-18 08:06:22 -0800)
> 
> are available in the git repository at:
> 
>   git://git.secretlab.ca/git/linux-2.6 devicetree/arm
> 
> Grant Likely (7):
>       arm/dt: Make __vet_atags also accept a dtb image
>       arm/dt: allow bootmem reservation for device tree blob and initrd
>       arm/dt: consolidate atags setup into setup_machine_atags
>       arm/dt: probe for platforms via the device tree
>       arm/dt: Basic versatile devicetree support
>       arm/tegra: Fix tegra irq_data conversion
>       arm/dt: Basic tegra devicetree support
> 
> Jeremy Kerr (1):
>       arm/dt: Allow CONFIG_OF on ARM
> 
> 
>  arch/arm/Kconfig                       |    7 ++
>  arch/arm/include/asm/mach/arch.h       |    2 +
>  arch/arm/include/asm/prom.h            |   34 ++++++++++
>  arch/arm/include/asm/setup.h           |    4 +
>  arch/arm/kernel/Makefile               |    1
>  arch/arm/kernel/devtree.c              |  107 ++++++++++++++++++++++++++++++++
>  arch/arm/kernel/head-common.S          |   19 ++++--
>  arch/arm/kernel/head.S                 |    8 +-
>  arch/arm/kernel/setup.c                |   78 +++++++++++++----------
>  arch/arm/mach-tegra/board-harmony.c    |    6 ++
>  arch/arm/mach-tegra/gpio.c             |    4 +
>  arch/arm/mach-versatile/versatile_ab.c |    6 ++
>  arch/arm/mach-versatile/versatile_pb.c |    6 ++
>  arch/arm/mm/init.c                     |   23 +++++++
>  14 files changed, 258 insertions(+), 47 deletions(-)
>  create mode 100644 arch/arm/include/asm/prom.h
>  create mode 100644 arch/arm/kernel/devtree.c
> 
> --
> Signature


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Re: [PATCH 0/8] Basic ARM device tree support

[Rob Herring]

On 01/26/2011 02:04 PM, John Linn wrote:
>> -----Original Message-----
>> From: Grant Likely [mailto:glikely@secretlab.ca] On Behalf Of Grant Likely
>> Sent: Tuesday, January 18, 2011 1:29 PM
>> To: linux-arm-kernel@lists.infradead.org
>> Cc: Nicolas Pitre; Russell King; Catalin Marinas; devicetree-discuss@lists.ozlabs.org; linux-
>> kernel@vger.kernel.org; Olof Johansson; Jeremy Kerr; John Linn; Lennert Buijtenhek
>> Subject: [PATCH 0/8] Basic ARM device tree support
>>
>> It's been a while since these patches have been circulated for review.
>> Much has changed since the last posting and there are no longer any
>> ugly hacks or workarounds to it working.  From my viewpoint, these
>> patches are complete and ready to be used.
>>
>> This patch series allows CONFIG_OF to be enabled on ARM and allows the
>> kernel to accept a dtb pointer from boot firmware instead of atags.
>> If a dtb is passed, then the kernel will use the root 'compatible'
>> property to find a matching machine_desc, and it will use it to obtain
>> the memory layout, initrd location and kernel parameters string.
>>
>> Only limited device tree support is enabled here.  It does not perform
>> any kind of device registration from device tree data.  That support
>> will be enabled in a later patch set.  Right now those patches depend
>> on the common struct clk patches that Jeremy is working on, so I'm not
>> going to post them yet.  Rather, this series is a stable base that
>> other engineers can use to start working on device tree support for
>> their platforms.
>>
>> Tested on Versatile (qemu) and nVidia Tegra Harmony.  Kernel compiles
>> an boot with CONFIG_OF both on and off, both with and without passing
>> a device tree blob.
>
> Tested on Xilinx platform.  Did see an issue with loading the device
> tree blob into higher memory.  At address 0 there was no issue.
>

I have a fix for this. The issue is the early mmu page table needs to 
map the dtb. I later realized this is also may be problem for ATAGs as 
well, so I planned to re-work to make it unconditional and work for 
ATAGs. Or perhaps ATAGs only get accessed with the MMU on later than the 
dtb and everything is okay?

This applies to the DT patch set prior to the one Grant sent out
this week, so it may need updates.

From: Rob Herring <rob.herring@calxeda.com>
Date: Tue, 5 Oct 2010 10:32:51 -0500
Subject: [PATCH] arm/dt: map devtree blob in initial page table

If the DTB is not in 1st 1MB of RAM, it will not be mapped before
memblock is setup, so map it early. We assume the dtb is less than
1MB and map 2MB so it can be at any alignment.

Some assembly optimizations from Nicolas Pitre.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
---
  arch/arm/kernel/head.S |   13 +++++++++++++
  1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 0480f25..1fcb962 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -228,6 +228,19 @@ __create_page_tables:
  	.endif
  	str	r6, [r0]

+#ifdef CONFIG_OF_FLATTREE
+	/* Make sure DT blob is mapped */
+	adr	r0, __devtree_pointer
+	ldr	r0, [r0]
+	mov	r0, r0, lsr #20
+	mov	r0, r0, lsl #20
+	add	r3, r0, #PAGE_OFFSET
+	add	r3, r4, r3, lsr #18
+	orr	r6, r7, r0
+	str	r6, [r3]
+	add	r6, r6, #0x100000
+	str	r6, [r3, #4]
+#endif
  #ifdef CONFIG_DEBUG_LL
  #ifndef CONFIG_DEBUG_ICEDCC
  	/*
-- 

Re: [PATCH 0/8] Basic ARM device tree support

[Jason Liu]

Hi, Rob,

2011/1/27 Rob Herring <robherring2@gmail.com>:
> On 01/26/2011 02:04 PM, John Linn wrote:
>>>
>>> -----Original Message-----
>>> From: Grant Likely [mailto:glikely@secretlab.ca] On Behalf Of Grant
>>> Likely
>>> Sent: Tuesday, January 18, 2011 1:29 PM
>>> To: linux-arm-kernel@lists.infradead.org
>>> Cc: Nicolas Pitre; Russell King; Catalin Marinas;
>>> devicetree-discuss@lists.ozlabs.org; linux-
>>> kernel@vger.kernel.org; Olof Johansson; Jeremy Kerr; John Linn; Lennert
>>> Buijtenhek
>>> Subject: [PATCH 0/8] Basic ARM device tree support
>>>
>>> It's been a while since these patches have been circulated for review.
>>> Much has changed since the last posting and there are no longer any
>>> ugly hacks or workarounds to it working.  From my viewpoint, these
>>> patches are complete and ready to be used.
>>>
>>> This patch series allows CONFIG_OF to be enabled on ARM and allows the
>>> kernel to accept a dtb pointer from boot firmware instead of atags.
>>> If a dtb is passed, then the kernel will use the root 'compatible'
>>> property to find a matching machine_desc, and it will use it to obtain
>>> the memory layout, initrd location and kernel parameters string.
>>>
>>> Only limited device tree support is enabled here.  It does not perform
>>> any kind of device registration from device tree data.  That support
>>> will be enabled in a later patch set.  Right now those patches depend
>>> on the common struct clk patches that Jeremy is working on, so I'm not
>>> going to post them yet.  Rather, this series is a stable base that
>>> other engineers can use to start working on device tree support for
>>> their platforms.
>>>
>>> Tested on Versatile (qemu) and nVidia Tegra Harmony.  Kernel compiles
>>> an boot with CONFIG_OF both on and off, both with and without passing
>>> a device tree blob.
>>
>> Tested on Xilinx platform.  Did see an issue with loading the device
>> tree blob into higher memory.  At address 0 there was no issue.
>>
>
> I have a fix for this. The issue is the early mmu page table needs to map
> the dtb. I later realized this is also may be problem for ATAGs as well, so
> I planned to re-work to make it unconditional and work for ATAGs. Or perhaps
> ATAGs only get accessed with the MMU on later than the dtb and everything is
> okay?
>
> This applies to the DT patch set prior to the one Grant sent out
> this week, so it may need updates.
>
> From: Rob Herring <rob.herring@calxeda.com>
> Date: Tue, 5 Oct 2010 10:32:51 -0500
> Subject: [PATCH] arm/dt: map devtree blob in initial page table
>
> If the DTB is not in 1st 1MB of RAM, it will not be mapped before
> memblock is setup, so map it early. We assume the dtb is less than
> 1MB and map 2MB so it can be at any alignment.
>
> Some assembly optimizations from Nicolas Pitre.
>
> Signed-off-by: Rob Herring <rob.herring@calxeda.com>
> ---
>  arch/arm/kernel/head.S |   13 +++++++++++++
>  1 files changed, 13 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
> index 0480f25..1fcb962 100644
> --- a/arch/arm/kernel/head.S
> +++ b/arch/arm/kernel/head.S
> @@ -228,6 +228,19 @@ __create_page_tables:
>        .endif
>        str     r6, [r0]
>
> +#ifdef CONFIG_OF_FLATTREE
> +       /* Make sure DT blob is mapped */
> +       adr     r0, __devtree_pointer
> +       ldr     r0, [r0]
> +       mov     r0, r0, lsr #20
> +       mov     r0, r0, lsl #20
> +       add     r3, r0, #PAGE_OFFSET
> +       add     r3, r4, r3, lsr #18
> +       orr     r6, r7, r0
> +       str     r6, [r3]
> +       add     r6, r6, #0x100000
> +       str     r6, [r3, #4]
> +#endif
>  #ifdef CONFIG_DEBUG_LL
>  #ifndef CONFIG_DEBUG_ICEDCC

Build broken after apply your patch,
arch/arm/kernel/head.S:223: Error: undefined symbol __devtree_pointer
used as an immediate value
make[2]: *** [arch/arm/kernel/head.o] Error 1


BR,
Jason Liu

>        /*
> --
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>

Re: [PATCH 0/8] Basic ARM device tree support

[Grant Likely]

On Wed, Jan 26, 2011 at 01:04:39PM -0700, John Linn wrote:
> > -----Original Message-----
> > From: Grant Likely [mailto:glikely@secretlab.ca] On Behalf Of Grant Likely
> > Sent: Tuesday, January 18, 2011 1:29 PM
> > To: linux-arm-kernel@lists.infradead.org
> > Cc: Nicolas Pitre; Russell King; Catalin Marinas; devicetree-discuss@lists.ozlabs.org; linux-
> > kernel@vger.kernel.org; Olof Johansson; Jeremy Kerr; John Linn; Lennert Buijtenhek
> > Subject: [PATCH 0/8] Basic ARM device tree support
> > 
> 
> Thanks for this patch set.  Device tree on ARM will be a great help to Xilinx.
> 
> Tested-by: John Linn <john.linn@xilinx.com>

Thanks John,

I've had to rework the early init code to be safer, but it turned out
to be a significant change, so I won't add your tested-by line to the
patch yet.  Would you mind retesting when I repost later today?

Thanks,
g.

RE: [PATCH 0/8] Basic ARM device tree support

[John Linn]

> -----Original Message-----
> From: Grant Likely [mailto:glikely@secretlab.ca] On Behalf Of Grant
Likely
> Sent: Monday, January 31, 2011 11:05 AM
> To: John Linn
> Cc: linux-arm-kernel@lists.infradead.org; Nicolas Pitre; Russell King;
Catalin Marinas; devicetree-
> discuss@lists.ozlabs.org; linux-kernel@vger.kernel.org; Olof
Johansson; Jeremy Kerr; Lennert
> Buijtenhek
> Subject: Re: [PATCH 0/8] Basic ARM device tree support
> 
> On Wed, Jan 26, 2011 at 01:04:39PM -0700, John Linn wrote:
> > > -----Original Message-----
> > > From: Grant Likely [mailto:glikely@secretlab.ca] On Behalf Of
Grant Likely
> > > Sent: Tuesday, January 18, 2011 1:29 PM
> > > To: linux-arm-kernel@lists.infradead.org
> > > Cc: Nicolas Pitre; Russell King; Catalin Marinas;
devicetree-discuss@lists.ozlabs.org; linux-
> > > kernel@vger.kernel.org; Olof Johansson; Jeremy Kerr; John Linn;
Lennert Buijtenhek
> > > Subject: [PATCH 0/8] Basic ARM device tree support
> > >
> >
> > Thanks for this patch set.  Device tree on ARM will be a great help
to Xilinx.
> >
> > Tested-by: John Linn <john.linn@xilinx.com>
> 
> Thanks John,
> 
> I've had to rework the early init code to be safer, but it turned out
> to be a significant change, so I won't add your tested-by line to the
> patch yet.  Would you mind retesting when I repost later today?

Sure, will do.

- John

> 
> Thanks,
> g.
> 


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