[PATCH v5 3/7] fpga: sec-mgr: expose sec-mgr update status

[Russ Weight]

Extend the FPGA Security Manager class driver to
include an update/status sysfs node that can be polled
and read to monitor the progress of an ongoing secure
update. Sysfs_notify() is used to signal transitions
between different phases of the update process.

Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
Reviewed-by: Tom Rix <trix@xxxxxxxxxx>
---
v5:
  - Use new function sysfs_emit() in the status_show() function
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:
  - Use a local variable to read progress once in status_show()
  - Use dev_err to report invalid progress status
v2:
  - Bumped documentation date and version
  - Changed progress state "read_file" to "reading"
---
 .../ABI/testing/sysfs-class-fpga-sec-mgr      | 11 +++++
 drivers/fpga/fpga-sec-mgr.c                   | 42 +++++++++++++++++--
 2 files changed, 49 insertions(+), 4 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr b/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr
index 5f10496b2a54..69b4cf7e1cd4 100644
--- a/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr
+++ b/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr
@@ -78,3 +78,14 @@ Description:	Write only. Write the filename of an image
 		BMC images, BMC firmware, Static Region images,
 		and Root Entry Hashes, and to cancel Code Signing
 		Keys (CSK).
+
+What: 		/sys/class/fpga_sec_mgr/fpga_secX/update/status
+Date:		Oct 2020
+KernelVersion:  5.11
+Contact:	Russ Weight <russell.h.weight@xxxxxxxxx>
+Description:	Read-only. Returns a string describing the current
+		status of an update. The string will be one of the
+		following: idle, reading, preparing, writing,
+		programming. Userspace code can poll on this file,
+		as it will be signaled by sysfs_notify() on each
+		state change.
diff --git a/drivers/fpga/fpga-sec-mgr.c b/drivers/fpga/fpga-sec-mgr.c
index 8248b86ad098..65b89248bd85 100644
--- a/drivers/fpga/fpga-sec-mgr.c
+++ b/drivers/fpga/fpga-sec-mgr.c
@@ -143,6 +143,13 @@ static struct attribute *sec_mgr_security_attrs[] = {
 	NULL,
 };
 
+static void update_progress(struct fpga_sec_mgr *smgr,
+			    enum fpga_sec_prog new_progress)
+{
+	smgr->progress = new_progress;
+	sysfs_notify(&smgr->dev.kobj, "update", "status");
+}
+
 static void fpga_sec_dev_error(struct fpga_sec_mgr *smgr,
 			       enum fpga_sec_err err_code)
 {
@@ -153,7 +160,7 @@ static void fpga_sec_dev_error(struct fpga_sec_mgr *smgr,
 static void progress_complete(struct fpga_sec_mgr *smgr)
 {
 	mutex_lock(&smgr->lock);
-	smgr->progress = FPGA_SEC_PROG_IDLE;
+	update_progress(smgr, FPGA_SEC_PROG_IDLE);
 	complete_all(&smgr->update_done);
 	mutex_unlock(&smgr->lock);
 }
@@ -181,14 +188,14 @@ static void fpga_sec_mgr_update(struct work_struct *work)
 		goto release_fw_exit;
 	}
 
-	smgr->progress = FPGA_SEC_PROG_PREPARING;
+	update_progress(smgr, FPGA_SEC_PROG_PREPARING);
 	ret = smgr->sops->prepare(smgr);
 	if (ret != FPGA_SEC_ERR_NONE) {
 		fpga_sec_dev_error(smgr, ret);
 		goto modput_exit;
 	}
 
-	smgr->progress = FPGA_SEC_PROG_WRITING;
+	update_progress(smgr, FPGA_SEC_PROG_WRITING);
 	size = smgr->remaining_size;
 	while (size) {
 		blk_size = min_t(u32, size, WRITE_BLOCK_SIZE);
@@ -203,7 +210,7 @@ static void fpga_sec_mgr_update(struct work_struct *work)
 		offset += blk_size;
 	}
 
-	smgr->progress = FPGA_SEC_PROG_PROGRAMMING;
+	update_progress(smgr, FPGA_SEC_PROG_PROGRAMMING);
 	ret = smgr->sops->poll_complete(smgr);
 	if (ret != FPGA_SEC_ERR_NONE)
 		fpga_sec_dev_error(smgr, ret);
@@ -261,6 +268,32 @@ static struct attribute_group sec_mgr_security_attr_group = {
 	.is_visible = sec_mgr_visible,
 };
 
+static const char * const sec_mgr_prog_str[] = {
+	"idle",			/* FPGA_SEC_PROG_IDLE */
+	"reading",		/* FPGA_SEC_PROG_READING */
+	"preparing",		/* FPGA_SEC_PROG_PREPARING */
+	"writing",		/* FPGA_SEC_PROG_WRITING */
+	"programming"		/* FPGA_SEC_PROG_PROGRAMMING */
+};
+
+static ssize_t
+status_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct fpga_sec_mgr *smgr = to_sec_mgr(dev);
+	const char *status = "unknown-status";
+	enum fpga_sec_prog progress;
+
+	progress = smgr->progress;
+	if (progress < FPGA_SEC_PROG_MAX)
+		status = sec_mgr_prog_str[progress];
+	else
+		dev_err(dev, "Invalid status during secure update: %d\n",
+			progress);
+
+	return sysfs_emit(buf, "%s\n", status);
+}
+static DEVICE_ATTR_RO(status);
+
 static ssize_t filename_store(struct device *dev, struct device_attribute *attr,
 			      const char *buf, size_t count)
 {
@@ -295,6 +328,7 @@ static DEVICE_ATTR_WO(filename);
 
 static struct attribute *sec_mgr_update_attrs[] = {
 	&dev_attr_filename.attr,
+	&dev_attr_status.attr,
 	NULL,
 };
 
-- 
2.25.1