Extend the MAX10 BMC Secure Update driver to provide a
sysfs file to expose the flash update count for the FPGA
user image.
Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
Reviewed-by: Tom Rix <trix@xxxxxxxxxx>
---
v12:
- Updated Date and KernelVersion fields in ABI documentation
v11:
- No change
v10:
- Changed the path expression in the sysfs documentation to
replace the n3000 reference with something more generic to
accomodate other devices that use the same driver.
v9:
- Rebased to 5.12-rc2 next
- Updated Date and KernelVersion in ABI documentation
v8:
- Previously patch 3/6, otherwise no change
v7:
- Updated Date and KernelVersion in ABI documentation
v6:
- Changed flash_count_show() parameter list to achieve
reverse-christmas tree format.
- Added WARN_ON() call for (FLASH_COUNT_SIZE / stride) to ensure
that the proper count is passed to regmap_bulk_read().
v5:
- Renamed sysfs node user_flash_count to flash_count and updated the
sysfs documentation accordingly.
v4:
- Moved the sysfs file for displaying the flash count from the
FPGA Security Manager class driver to here. The
m10bmc_user_flash_count() function is removed and the
functionality is moved into a user_flash_count_show()
function.
- Added ABI documentation for the new sysfs entry
v3:
- Changed: iops -> sops, imgr -> smgr, IFPGA_ -> FPGA_, ifpga_ to fpga_
- Changed "MAX10 BMC Secure Engine driver" to "MAX10 BMC Secure Update
driver"
- Removed wrapper functions (m10bmc_raw_*, m10bmc_sys_*). The
underlying functions are now called directly.
v2:
- Renamed get_qspi_flash_count() to m10bmc_user_flash_count()
- Minor code cleanup per review comments
- Added m10bmc_ prefix to functions in m10bmc_iops structure
---
.../testing/sysfs-driver-intel-m10-bmc-secure | 8 ++++
drivers/fpga/intel-m10-bmc-secure.c | 37 +++++++++++++++++++
2 files changed, 45 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
index 9a0abb147b28..c805c25e776d 100644
--- a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
+++ b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
@@ -27,3 +27,11 @@ Description: Read only. Returns the root entry hash for the BMC image
"hash not programmed". This file is only visible if the
underlying device supports it.
Format: "0x%x".
+
+What: /sys/bus/platform/drivers/intel-m10bmc-secure/.../security/flash_count
+Date: June 2021
+KernelVersion: 5.14
+Contact: Russ Weight <russell.h.weight@xxxxxxxxx>
+Description: Read only. Returns number of times the secure update
+ staging area has been flashed.
+ Format: "%u".
diff --git a/drivers/fpga/intel-m10-bmc-secure.c b/drivers/fpga/intel-m10-bmc-secure.c
index 5ac5f59b5731..ecd63c13cb2d 100644
--- a/drivers/fpga/intel-m10-bmc-secure.c
+++ b/drivers/fpga/intel-m10-bmc-secure.c
@@ -11,6 +11,7 @@
#include <linux/mfd/intel-m10-bmc.h>
#include <linux/module.h>
#include <linux/platform_device.h>
+#include <linux/slab.h>
struct m10bmc_sec {
struct device *dev;
@@ -78,7 +79,43 @@ DEVICE_ATTR_SEC_REH_RO(bmc, BMC_PROG_MAGIC, BMC_PROG_ADDR, BMC_REH_ADDR);
DEVICE_ATTR_SEC_REH_RO(sr, SR_PROG_MAGIC, SR_PROG_ADDR, SR_REH_ADDR);
DEVICE_ATTR_SEC_REH_RO(pr, PR_PROG_MAGIC, PR_PROG_ADDR, PR_REH_ADDR);
+#define FLASH_COUNT_SIZE 4096 /* count stored as inverted bit vector */
+
+static ssize_t flash_count_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct m10bmc_sec *sec = dev_get_drvdata(dev);
+ unsigned int stride, num_bits;
+ u8 *flash_buf;
+ int cnt, ret;
+
+ stride = regmap_get_reg_stride(sec->m10bmc->regmap);
+ num_bits = FLASH_COUNT_SIZE * 8;
+
+ flash_buf = kmalloc(FLASH_COUNT_SIZE, GFP_KERNEL);
+ if (!flash_buf)
+ return -ENOMEM;
+
+ WARN_ON(FLASH_COUNT_SIZE % stride);
+ ret = regmap_bulk_read(sec->m10bmc->regmap, STAGING_FLASH_COUNT,
+ flash_buf, FLASH_COUNT_SIZE / stride);
+ if (ret) {
+ dev_err(sec->dev,
+ "failed to read flash count: %x cnt %x: %d\n",
+ STAGING_FLASH_COUNT, FLASH_COUNT_SIZE / stride, ret);
+ goto exit_free;
+ }
+ cnt = num_bits - bitmap_weight((unsigned long *)flash_buf, num_bits);
+
+exit_free:
+ kfree(flash_buf);
+
+ return ret ? : sysfs_emit(buf, "%u\n", cnt);
+}
+static DEVICE_ATTR_RO(flash_count);
+
static struct attribute *m10bmc_security_attrs[] = {
+ &dev_attr_flash_count.attr,
&dev_attr_bmc_root_entry_hash.attr,
&dev_attr_sr_root_entry_hash.attr,
&dev_attr_pr_root_entry_hash.attr,
--
2.25.1
