[PATCH v7 5/7] fpga: sec-mgr: expose sec-mgr update size

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

Extend the FPGA Security Manager class driver to include
an update/remaining_size sysfs node that can be read to
determine how much data remains to be transferred to the
secure update engine. This file can be used to monitor
progress during the "writing" phase of an update.

Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Reviewed-by: Tom Rix <trix@redhat.com>
---
v7:
  - Changed Date in documentation file to December 2020
v6:
  - No change
v5:
  - Use new function sysfs_emit() in the remaining_size_show() function
v4:
  - Changed from "Intel FPGA Security Manager" to FPGA Security Manager"
    and removed unnecessary references to "Intel".
  - Changed: imgr -> smgr, ifpga_ to fpga_
v3:
  - No change
v2:
  - Bumped documentation date and version
---
 Documentation/ABI/testing/sysfs-class-fpga-sec-mgr | 11 +++++++++++
 drivers/fpga/fpga-sec-mgr.c                        | 10 ++++++++++
 2 files changed, 21 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr b/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr
index e6a62054bed8..62dc04e4335d 100644
--- a/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr
+++ b/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr
@@ -28,6 +28,17 @@ Description:	Read-only. Returns a string describing the current
 		as it will be signaled by sysfs_notify() on each
 		state change.
 
+What: 		/sys/class/fpga_sec_mgr/fpga_secX/update/remaining_size
+Date:		December 2020
+KernelVersion:  5.11
+Contact:	Russ Weight <russell.h.weight@intel.com>
+Description:	Read-only. Returns the size of data that remains to
+		be written to the secure update engine. The size
+		value is initialized to the full size of the file
+		image and the value is updated periodically during
+		the "writing" phase of the update.
+		Format: "%u".
+
 What: 		/sys/class/fpga_sec_mgr/fpga_secX/update/error
 Date:		December 2020
 KernelVersion:  5.11
diff --git a/drivers/fpga/fpga-sec-mgr.c b/drivers/fpga/fpga-sec-mgr.c
index 3bd89598cccd..951020942991 100644
--- a/drivers/fpga/fpga-sec-mgr.c
+++ b/drivers/fpga/fpga-sec-mgr.c
@@ -204,6 +204,15 @@ error_show(struct device *dev, struct device_attribute *attr, char *buf)
 }
 static DEVICE_ATTR_RO(error);
 
+static ssize_t remaining_size_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct fpga_sec_mgr *smgr = to_sec_mgr(dev);
+
+	return sysfs_emit(buf, "%u\n", smgr->remaining_size);
+}
+static DEVICE_ATTR_RO(remaining_size);
+
 static ssize_t filename_store(struct device *dev, struct device_attribute *attr,
 			      const char *buf, size_t count)
 {
@@ -240,6 +249,7 @@ static struct attribute *sec_mgr_update_attrs[] = {
 	&dev_attr_filename.attr,
 	&dev_attr_status.attr,
 	&dev_attr_error.attr,
+	&dev_attr_remaining_size.attr,
 	NULL,
 };
 
-- 
2.25.1