[PATCH v15 4/6] fpga: image-load: add status ioctl

[Russ Weight]

Extend the FPGA Image Load class driver to include an
FPGA_IMAGE_LOAD_STATUS IOCTL that can be used to monitor the progress
of an ongoing image load.  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.

Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
---
V15:
 - This patch is new to the patchset and provides an FPGA_IMAGE_LOAD_STATUS
   IOCTL to return the current values for: remaining_size, progress,
   err_progress, and err_code.
 - This patch has elements of the following three patches from the previous
   patch-set:
     [PATCH v14 3/6] fpga: sec-mgr: expose sec-mgr update status
     [PATCH v14 4/6] fpga: sec-mgr: expose sec-mgr update errors
     [PATCH v14 5/6] fpga: sec-mgr: expose sec-mgr update size
 - Changed file, symbol, and config names to reflect the new driver name
 - There are some minor changes to locking to enable this ioctl to return
   coherent data.
---
 Documentation/fpga/fpga-image-load.rst |  6 +++
 drivers/fpga/fpga-image-load.c         | 53 ++++++++++++++++++++++----
 include/uapi/linux/fpga-image-load.h   | 18 +++++++++
 3 files changed, 70 insertions(+), 7 deletions(-)

diff --git a/Documentation/fpga/fpga-image-load.rst b/Documentation/fpga/fpga-image-load.rst
index 739d735592a5..3d5eb51223e3 100644
--- a/Documentation/fpga/fpga-image-load.rst
+++ b/Documentation/fpga/fpga-image-load.rst
@@ -31,3 +31,9 @@ updated. This is an exclusive operation; an attempt to start concurrent image
 load for the same device will fail with EBUSY. An eventfd file descriptor
 parameter is provided to this IOCTL, and it will be signalled at the
 completion of the image load.
+
+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.
diff --git a/drivers/fpga/fpga-image-load.c b/drivers/fpga/fpga-image-load.c
index b784456765b0..99a47b21c995 100644
--- a/drivers/fpga/fpga-image-load.c
+++ b/drivers/fpga/fpga-image-load.c
@@ -22,10 +22,27 @@ static dev_t fpga_image_devt;
 
 #define to_image_load(d) container_of(d, struct fpga_image_load, dev)
 
-static void fpga_image_dev_error(struct fpga_image_load *imgld,
+static void fpga_image_update_progress(struct fpga_image_load *imgld,
+				       enum fpga_image_prog new_progress)
+{
+	mutex_lock(&imgld->lock);
+	imgld->progress = new_progress;
+	mutex_unlock(&imgld->lock);
+}
+
+static void fpga_image_set_error(struct fpga_image_load *imgld,
 				 enum fpga_image_err err_code)
 {
+	mutex_lock(&imgld->lock);
+	imgld->err_progress = imgld->progress;
 	imgld->err_code = err_code;
+	mutex_unlock(&imgld->lock);
+}
+
+static void fpga_image_dev_error(struct fpga_image_load *imgld,
+				 enum fpga_image_err err_code)
+{
+	fpga_image_set_error(imgld, err_code);
 	imgld->lops->cancel(imgld);
 }
 
@@ -49,18 +66,18 @@ static void fpga_image_do_load(struct work_struct *work)
 
 	get_device(&imgld->dev);
 	if (!try_module_get(imgld->dev.parent->driver->owner)) {
-		imgld->err_code = FPGA_IMAGE_ERR_BUSY;
+		fpga_image_set_error(imgld, FPGA_IMAGE_ERR_BUSY);
 		goto idle_exit;
 	}
 
-	imgld->progress = FPGA_IMAGE_PROG_PREPARING;
+	fpga_image_update_progress(imgld, FPGA_IMAGE_PROG_PREPARING);
 	ret = imgld->lops->prepare(imgld);
 	if (ret != FPGA_IMAGE_ERR_NONE) {
 		fpga_image_dev_error(imgld, ret);
 		goto modput_exit;
 	}
 
-	imgld->progress = FPGA_IMAGE_PROG_WRITING;
+	fpga_image_update_progress(imgld, FPGA_IMAGE_PROG_WRITING);
 	while (imgld->remaining_size) {
 		ret = imgld->lops->write_blk(imgld, offset);
 		if (ret != FPGA_IMAGE_ERR_NONE) {
@@ -71,7 +88,7 @@ static void fpga_image_do_load(struct work_struct *work)
 		offset = size - imgld->remaining_size;
 	}
 
-	imgld->progress = FPGA_IMAGE_PROG_PROGRAMMING;
+	fpga_image_update_progress(imgld, FPGA_IMAGE_PROG_PROGRAMMING);
 	ret = imgld->lops->poll_complete(imgld);
 	if (ret != FPGA_IMAGE_ERR_NONE)
 		fpga_image_dev_error(imgld, ret);
@@ -151,20 +168,42 @@ static int fpga_image_load_ioctl_write(struct fpga_image_load *imgld,
 	return ret;
 }
 
+static int fpga_image_load_ioctl_status(struct fpga_image_load *imgld,
+					unsigned long arg)
+{
+	struct fpga_image_status status;
+
+	memset(&status, 0, sizeof(status));
+	status.progress = imgld->progress;
+	status.remaining_size = imgld->remaining_size;
+	status.err_progress = imgld->err_progress;
+	status.err_code = imgld->err_code;
+
+	if (copy_to_user((void __user *)arg, &status, sizeof(status)))
+		return -EFAULT;
+
+	return 0;
+}
+
 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;
 
+	mutex_lock(&imgld->lock);
+
 	switch (cmd) {
 	case FPGA_IMAGE_LOAD_WRITE:
-		mutex_lock(&imgld->lock);
 		ret = fpga_image_load_ioctl_write(imgld, arg);
-		mutex_unlock(&imgld->lock);
+		break;
+	case FPGA_IMAGE_LOAD_STATUS:
+		ret = fpga_image_load_ioctl_status(imgld, arg);
 		break;
 	}
 
+	mutex_unlock(&imgld->lock);
+
 	return ret;
 }
 
diff --git a/include/uapi/linux/fpga-image-load.h b/include/uapi/linux/fpga-image-load.h
index a60da115adf5..6a995bcc0fb7 100644
--- a/include/uapi/linux/fpga-image-load.h
+++ b/include/uapi/linux/fpga-image-load.h
@@ -38,6 +38,7 @@ 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)
 
 /**
  * FPGA_IMAGE_LOAD_WRITE - _IOW(FPGA_IMAGE_LOAD_MAGIC, 0,
@@ -56,4 +57,21 @@ struct fpga_image_write {
 	__u64 buf;		/* User space address of source data */
 };
 
+/**
+ * FPGA_IMAGE_LOAD_STATUS - _IOR(FPGA_IMAGE_LOAD_MAGIC, 1,
+ *				 struct fpga_image_status)
+ *
+ * Request status information for an ongoing update.
+ * data buffer, size, and an eventfd file descriptor.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+struct fpga_image_status {
+	/* Output */
+	__u32 remaining_size;			/* size remaining to transfer */
+	enum fpga_image_prog progress;		/* current progress of image load */
+	enum fpga_image_prog err_progress;	/* progress at time of error */
+	enum fpga_image_err err_code;		/* error code */
+};
+
 #endif /* _UAPI_LINUX_FPGA_IMAGE_LOAD_H */
-- 
2.25.1