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> --- 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 bd3ee9bc1a92..598db1116d34 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: April 2021 +KernelVersion: 5.13 +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