[PATCH v15 6/6] fpga: image-load: enable cancel of image upload

[Russ Weight <russell.h.weight@intel.com>]

Extend the FPGA Image Load class driver to include a cancel IOCTL that
can be used to request that an image upload be canceled. The IOCTL may
return EBUSY if it cannot be canceled by software or ENODEV if there
is no update in progress.

Signed-off-by: Russ Weight <russell.h.weight@intel.com>
---
v15:
 - Compare to previous patch:
     [PATCH v14 6/6] fpga: sec-mgr: enable cancel of secure update
 - Changed file, symbol, and config names to reflect the new driver name
 - Cancel is now initiated by IOCT instead of sysfs
 - Removed signed-off/reviewed-by tags
v14:
 - Updated ABI documentation date and kernel version
v13:
  - No change
v12:
  - Updated Date and KernelVersion fields in ABI documentation
v11:
  - No change
v10:
  - Rebased to 5.12-rc2 next
  - Updated Date and KernelVersion in ABI documentation
v9:
  - Updated Date and KernelVersion in ABI documentation
v8:
  - No change
v7:
  - Changed Date in documentation file to December 2020
v6:
  - No change
v5:
  - No change
v4:
  - Changed from "Intel FPGA Security Manager" to FPGA Security Manager"
    and removed unnecessary references to "Intel".
  - Changed: iops -> sops, imgr -> smgr, IFPGA_ -> FPGA_, ifpga_ to fpga_
v3:
  - No change
v2:
  - Bumped documentation date and version
  - Minor code cleanup per review comments
---
---
 Documentation/fpga/fpga-image-load.rst |  6 ++++
 drivers/fpga/fpga-image-load.c         | 45 +++++++++++++++++++++++---
 include/linux/fpga/fpga-image-load.h   |  1 +
 include/uapi/linux/fpga-image-load.h   |  1 +
 4 files changed, 49 insertions(+), 4 deletions(-)

diff --git a/Documentation/fpga/fpga-image-load.rst b/Documentation/fpga/fpga-image-load.rst
index 3d5eb51223e3..763e7833a6ea 100644
--- a/Documentation/fpga/fpga-image-load.rst
+++ b/Documentation/fpga/fpga-image-load.rst
@@ -37,3 +37,9 @@ FPGA_IMAGE_LOAD_STATUS:
 Collect status for an on-going image upload. The status returned includes
 how much data remains to be transferred, the progress of the image load,
 and error information in the case of a failure.
+
+FPGA_IMAGE_LOAD_CANCEL:
+
+Request that a on-going image upload be cancelled. This IOCTL may return
+EBUSY if it cannot be cancelled by software or ENODEV if there is no update
+in progress.
diff --git a/drivers/fpga/fpga-image-load.c b/drivers/fpga/fpga-image-load.c
index 6ec0a39f07b3..c32e4b1ea35a 100644
--- a/drivers/fpga/fpga-image-load.c
+++ b/drivers/fpga/fpga-image-load.c
@@ -46,6 +46,24 @@ static void fpga_image_dev_error(struct fpga_image_load *imgld,
 	imgld->lops->cancel(imgld);
 }
 
+static int fpga_image_prog_transition(struct fpga_image_load *imgld,
+				      enum fpga_image_prog new_progress)
+{
+	int ret = 0;
+
+	mutex_lock(&imgld->lock);
+	if (imgld->request_cancel) {
+		imgld->err_progress = imgld->progress;
+		imgld->err_code = FPGA_IMAGE_ERR_CANCELED;
+		imgld->lops->cancel(imgld);
+		ret = -ECANCELED;
+	} else {
+		imgld->progress = new_progress;
+	}
+	mutex_unlock(&imgld->lock);
+	return ret;
+}
+
 static void fpga_image_prog_complete(struct fpga_image_load *imgld)
 {
 	mutex_lock(&imgld->lock);
@@ -77,8 +95,10 @@ static void fpga_image_do_load(struct work_struct *work)
 		goto modput_exit;
 	}
 
-	fpga_image_update_progress(imgld, FPGA_IMAGE_PROG_WRITING);
-	while (imgld->remaining_size) {
+	if (fpga_image_prog_transition(imgld, FPGA_IMAGE_PROG_WRITING))
+		goto done;
+
+	while (imgld->remaining_size && !imgld->request_cancel) {
 		ret = imgld->lops->write_blk(imgld, offset);
 		if (ret != FPGA_IMAGE_ERR_NONE) {
 			fpga_image_dev_error(imgld, ret);
@@ -88,7 +108,9 @@ static void fpga_image_do_load(struct work_struct *work)
 		offset = size - imgld->remaining_size;
 	}
 
-	fpga_image_update_progress(imgld, FPGA_IMAGE_PROG_PROGRAMMING);
+	if (fpga_image_prog_transition(imgld, FPGA_IMAGE_PROG_PROGRAMMING))
+		goto done;
+
 	ret = imgld->lops->poll_complete(imgld);
 	if (ret != FPGA_IMAGE_ERR_NONE)
 		fpga_image_dev_error(imgld, ret);
@@ -159,6 +181,7 @@ static int fpga_image_load_ioctl_write(struct fpga_image_load *imgld,
 	imgld->remaining_size = wb.size;
 	imgld->err_code = FPGA_IMAGE_ERR_NONE;
 	imgld->progress = FPGA_IMAGE_PROG_STARTING;
+	imgld->request_cancel = false;
 	reinit_completion(&imgld->update_done);
 	schedule_work(&imgld->work);
 	return 0;
@@ -189,7 +212,7 @@ static long fpga_image_load_ioctl(struct file *filp, unsigned int cmd,
 				  unsigned long arg)
 {
 	struct fpga_image_load *imgld = filp->private_data;
-	int ret = -ENOTTY;
+	int ret = 0;
 
 	mutex_lock(&imgld->lock);
 
@@ -200,6 +223,17 @@ static long fpga_image_load_ioctl(struct file *filp, unsigned int cmd,
 	case FPGA_IMAGE_LOAD_STATUS:
 		ret = fpga_image_load_ioctl_status(imgld, arg);
 		break;
+	case FPGA_IMAGE_LOAD_CANCEL:
+		if (imgld->progress == FPGA_IMAGE_PROG_PROGRAMMING)
+			ret = -EBUSY;
+		else if (imgld->progress == FPGA_IMAGE_PROG_IDLE)
+			ret = -ENODEV;
+		else
+			imgld->request_cancel = true;
+		break;
+	default:
+		ret = -ENOTTY;
+		break;
 	}
 
 	mutex_unlock(&imgld->lock);
@@ -374,6 +408,9 @@ void fpga_image_load_unregister(struct fpga_image_load *imgld)
 		goto unregister;
 	}
 
+	if (imgld->progress != FPGA_IMAGE_PROG_PROGRAMMING)
+		imgld->request_cancel = true;
+
 	mutex_unlock(&imgld->lock);
 	wait_for_completion(&imgld->update_done);
 
diff --git a/include/linux/fpga/fpga-image-load.h b/include/linux/fpga/fpga-image-load.h
index 68f3105b51d2..4e51b9fd1724 100644
--- a/include/linux/fpga/fpga-image-load.h
+++ b/include/linux/fpga/fpga-image-load.h
@@ -52,6 +52,7 @@ struct fpga_image_load {
 	enum fpga_image_prog progress;
 	enum fpga_image_prog err_progress;	/* progress at time of failure */
 	enum fpga_image_err err_code;		/* image load error code */
+	bool request_cancel;
 	bool driver_unload;
 	struct eventfd_ctx *finished;
 	void *priv;
diff --git a/include/uapi/linux/fpga-image-load.h b/include/uapi/linux/fpga-image-load.h
index 6a995bcc0fb7..8d0dfa1f9b77 100644
--- a/include/uapi/linux/fpga-image-load.h
+++ b/include/uapi/linux/fpga-image-load.h
@@ -39,6 +39,7 @@ enum fpga_image_err {
 
 #define FPGA_IMAGE_LOAD_WRITE	_IOW(FPGA_IMAGE_LOAD_MAGIC, 0, struct fpga_image_write)
 #define FPGA_IMAGE_LOAD_STATUS	_IOR(FPGA_IMAGE_LOAD_MAGIC, 1, struct fpga_image_status)
+#define FPGA_IMAGE_LOAD_CANCEL	_IO(FPGA_IMAGE_LOAD_MAGIC, 2)
 
 /**
  * FPGA_IMAGE_LOAD_WRITE - _IOW(FPGA_IMAGE_LOAD_MAGIC, 0,
-- 
2.25.1