[PATCH v7 4/6] fpga: m10bmc-sec: expose max10 canceled keys in sysfs

[Russ Weight]

Extend the MAX10 BMC Secure Update driver to provide sysfs
files to expose the canceled code signing key (CSK) bit
vectors. These use the standard bitmap list format
(e.g. 1,2-6,9).

Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
Reviewed-by: Tom Rix <trix@xxxxxxxxxx>
---
v7:
  - Updated Date and KernelVersion in ABI documentation
v6:
  - Added WARN_ON() call for (size / stride) to ensure
    that the proper count is passed to regmap_bulk_read().
v5:
  - No change
v4:
  - Moved sysfs files for displaying the code-signing-key (CSK)
    cancellation vectors from the FPGA Security Manger class driver
    to here. The m10bmc_csk_vector() and m10bmc_csk_cancel_nbits()
    functions are removed and the functionality from these functions
    is moved into a show_canceled_csk() function for for displaying
    the CSK vectors.
  - Added ABI documentation for new sysfs entries
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.
  - Renamed get_csk_vector() to m10bmc_csk_vector()
v2:
  - Replaced small function-creation macros for explicit function
    declarations.
  - Fixed get_csk_vector() function to properly apply the stride
    variable in calls to m10bmc_raw_bulk_read()
  - Added m10bmc_ prefix to functions in m10bmc_iops structure
---
 .../testing/sysfs-driver-intel-m10-bmc-secure | 24 ++++++++++
 drivers/fpga/intel-m10-bmc-secure.c           | 48 +++++++++++++++++++
 2 files changed, 72 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
index 7300038d07c3..27890a9ba355 100644
--- a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
+++ b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-secure
@@ -28,6 +28,30 @@ Description:	Read only. Returns the root entry hash for the BMC image
 		underlying device supports it.
 		Format: "0x%x".
 
+What:		/sys/bus/platform/devices/n3000bmc-secure.*.auto/security/sr_canceled_csks
+Date:		January 2021
+KernelVersion:  5.12
+Contact:	Russ Weight <russell.h.weight@xxxxxxxxx>
+Description:	Read only. Returns a list of indices for canceled code
+		signing keys for the static region. The standard bitmap
+		list format is used (e.g. "1,2-6,9").
+
+What:		/sys/bus/platform/devices/n3000bmc-secure.*.auto/security/pr_canceled_csks
+Date:		January 2021
+KernelVersion:  5.12
+Contact:	Russ Weight <russell.h.weight@xxxxxxxxx>
+Description:	Read only. Returns a list of indices for canceled code
+		signing keys for the partial reconfiguration region. The
+		standard bitmap list format is used (e.g. "1,2-6,9").
+
+What:		/sys/bus/platform/devices/n3000bmc-secure.*.auto/security/bmc_canceled_csks
+Date:		January 2021
+KernelVersion:  5.12
+Contact:	Russ Weight <russell.h.weight@xxxxxxxxx>
+Description:	Read only. Returns a list of indices for canceled code
+		signing keys for the BMC.  The standard bitmap list format
+		is used (e.g. "1,2-6,9").
+
 What:		/sys/bus/platform/devices/n3000bmc-secure.*.auto/security/flash_count
 Date:		January 2021
 KernelVersion:  5.12
diff --git a/drivers/fpga/intel-m10-bmc-secure.c b/drivers/fpga/intel-m10-bmc-secure.c
index ecd63c13cb2d..87e16c146569 100644
--- a/drivers/fpga/intel-m10-bmc-secure.c
+++ b/drivers/fpga/intel-m10-bmc-secure.c
@@ -79,6 +79,51 @@ 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 CSK_BIT_LEN		128U
+#define CSK_32ARRAY_SIZE	DIV_ROUND_UP(CSK_BIT_LEN, 32)
+
+static ssize_t
+show_canceled_csk(struct device *dev, u32 addr, char *buf)
+{
+	unsigned int i, stride, size = CSK_32ARRAY_SIZE * sizeof(u32);
+	struct m10bmc_sec *sec = dev_get_drvdata(dev);
+	DECLARE_BITMAP(csk_map, CSK_BIT_LEN);
+	__le32 csk_le32[CSK_32ARRAY_SIZE];
+	u32 csk32[CSK_32ARRAY_SIZE];
+	int ret;
+
+	stride = regmap_get_reg_stride(sec->m10bmc->regmap);
+
+	WARN_ON(size % stride);
+	ret = regmap_bulk_read(sec->m10bmc->regmap, addr, csk_le32,
+			       size / stride);
+	if (ret) {
+		dev_err(sec->dev, "failed to read CSK vector: %x cnt %x: %d\n",
+			addr, size / stride, ret);
+		return ret;
+	}
+
+	for (i = 0; i < CSK_32ARRAY_SIZE; i++)
+		csk32[i] = le32_to_cpu(((csk_le32[i])));
+
+	bitmap_from_arr32(csk_map, csk32, CSK_BIT_LEN);
+	bitmap_complement(csk_map, csk_map, CSK_BIT_LEN);
+	return bitmap_print_to_pagebuf(1, buf, csk_map, CSK_BIT_LEN);
+}
+
+#define DEVICE_ATTR_SEC_CSK_RO(_name, _addr) \
+static ssize_t _name##_canceled_csks_show(struct device *dev, \
+					  struct device_attribute *attr, \
+					  char *buf) \
+{ return show_canceled_csk(dev, _addr, buf); } \
+static DEVICE_ATTR_RO(_name##_canceled_csks)
+
+#define CSK_VEC_OFFSET 0x34
+
+DEVICE_ATTR_SEC_CSK_RO(bmc, BMC_PROG_ADDR + CSK_VEC_OFFSET);
+DEVICE_ATTR_SEC_CSK_RO(sr, SR_PROG_ADDR + CSK_VEC_OFFSET);
+DEVICE_ATTR_SEC_CSK_RO(pr, PR_PROG_ADDR + CSK_VEC_OFFSET);
+
 #define FLASH_COUNT_SIZE 4096	/* count stored as inverted bit vector */
 
 static ssize_t flash_count_show(struct device *dev,
@@ -119,6 +164,9 @@ static struct attribute *m10bmc_security_attrs[] = {
 	&dev_attr_bmc_root_entry_hash.attr,
 	&dev_attr_sr_root_entry_hash.attr,
 	&dev_attr_pr_root_entry_hash.attr,
+	&dev_attr_sr_canceled_csks.attr,
+	&dev_attr_pr_canceled_csks.attr,
+	&dev_attr_bmc_canceled_csks.attr,
 	NULL,
 };
 
-- 
2.25.1