[PATCH v16 4/4] fpga: m10bmc-sec: add max10 secure update functions

[Russ Weight]

Invoke an instance of the FPGA Image Load framework and extend the MAX10
BMC Secure Update driver to include the functions that enable secure
updates of BMC images, FPGA images, etc.

Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
---
v16:
  - Use 0 instead of FPGA_IMAGE_ERR_NONE to indicate success.
  - The size alignment check was moved from the FPGA Image Load framework
    to the prepare() op.
  - Added cancel_request boolean flag to struct m10bmc_sec.
  - Moved the RSU cancellation logic from m10bmc_sec_cancel() to a new
    rsu_cancel() function.
  - The m10bmc_sec_cancel() function ONLY sets the cancel_request flag.
    The cancel_request flag is checked at the beginning of the
    m10bmc_sec_write() and m10bmc_sec_poll_complete() functions.
  - Adapt to changed prototypes for the prepare() and write() ops. The
    m10bmc_sec_write_blk() function has been renamed to
    m10bmc_sec_write().
  - Created a cleanup() op, m10bmc_sec_cleanup(), to attempt to cancel an
    ongoing op during when exiting the update process.
v15:
  - Adapted to changes in the FPGA Image Load framework:
    (1) All enum types (progress and errors) are now type u32
    (2) m10bmc_sec_write_blk() adds *blk_size and max_size parameters
        and uses *blk_size as provided by the caller.
    (3) m10bmc_sec_poll_complete() no long checks the driver_unload
        flag.
v14:
  - Changed symbol names to reflect the renaming of the Security Manager
    Class driver to FPGA Image Load.
v13:
  - No change
v12:
  - Updated Date and KernelVersion fields in ABI documentation
  - Removed size parameter from the write_blk() op. m10bmc_sec_write_blk()
    no longer has a size parameter, and the block size is determined
    in this (the lower-level) driver.
v11:
  - No change
v10:
  - No change
v9:
  - No change
v8:
  - Previously patch 5/6, otherwise no change
v7:
  - No change
v6:
  - Changed (size / stride) calculation to ((size + stride - 1) / stride)
    to ensure that the proper count is passed to regmap_bulk_write().
  - Removed unnecessary call to rsu_check_complete() in
    m10bmc_sec_poll_complete() and changed while loop to
    do/while loop.
v5:
  - No change
v4:
  - No change
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.
  - Changed calling functions of functions that return "enum fpga_sec_err"
    to check for (ret != FPGA_SEC_ERR_NONE) instead of (ret)
v2:
  - Reworked the rsu_start_done() function to make it more readable
  - Reworked while-loop condition/content in rsu_prog_ready()
  - Minor code cleanup per review comments
  - Added a comment to the m10bmc_sec_poll_complete() function to
    explain the context (could take 30+ minutes to complete).
  - Added m10bmc_ prefix to functions in m10bmc_iops structure
  - Moved MAX10 BMC address and function definitions to a separate
    patch.
---
 drivers/fpga/intel-m10-bmc-sec-update.c | 330 +++++++++++++++++++++++-
 1 file changed, 329 insertions(+), 1 deletion(-)

diff --git a/drivers/fpga/intel-m10-bmc-sec-update.c b/drivers/fpga/intel-m10-bmc-sec-update.c
index bccffc62a747..e6eaf1e04b73 100644
--- a/drivers/fpga/intel-m10-bmc-sec-update.c
+++ b/drivers/fpga/intel-m10-bmc-sec-update.c
@@ -17,6 +17,7 @@ struct m10bmc_sec {
 	struct device *dev;
 	struct intel_m10bmc *m10bmc;
 	struct fpga_image_load *imgld;
+	bool cancel_request;
 };
 
 /* Root Entry Hash (REH) support */
@@ -181,7 +182,334 @@ static const struct attribute_group *m10bmc_sec_attr_groups[] = {
 	NULL,
 };
 
-static const struct fpga_image_load_ops m10bmc_ops = { };
+static void log_error_regs(struct m10bmc_sec *sec, u32 doorbell)
+{
+	u32 auth_result;
+
+	dev_err(sec->dev, "RSU error status: 0x%08x\n", doorbell);
+
+	if (!m10bmc_sys_read(sec->m10bmc, M10BMC_AUTH_RESULT, &auth_result))
+		dev_err(sec->dev, "RSU auth result: 0x%08x\n", auth_result);
+}
+
+static u32 rsu_check_idle(struct m10bmc_sec *sec)
+{
+	u32 doorbell;
+	int ret;
+
+	ret = m10bmc_sys_read(sec->m10bmc, M10BMC_DOORBELL, &doorbell);
+	if (ret)
+		return FPGA_IMAGE_ERR_RW_ERROR;
+
+	if (rsu_prog(doorbell) != RSU_PROG_IDLE &&
+	    rsu_prog(doorbell) != RSU_PROG_RSU_DONE) {
+		log_error_regs(sec, doorbell);
+		return FPGA_IMAGE_ERR_BUSY;
+	}
+
+	return 0;
+}
+
+static inline bool rsu_start_done(u32 doorbell)
+{
+	u32 status, progress;
+
+	if (doorbell & DRBL_RSU_REQUEST)
+		return false;
+
+	status = rsu_stat(doorbell);
+	if (status == RSU_STAT_ERASE_FAIL || status == RSU_STAT_WEAROUT)
+		return true;
+
+	progress = rsu_prog(doorbell);
+	if (progress != RSU_PROG_IDLE && progress != RSU_PROG_RSU_DONE)
+		return true;
+
+	return false;
+}
+
+static u32 rsu_update_init(struct m10bmc_sec *sec)
+{
+	u32 doorbell, status;
+	int ret;
+
+	ret = regmap_update_bits(sec->m10bmc->regmap,
+				 M10BMC_SYS_BASE + M10BMC_DOORBELL,
+				 DRBL_RSU_REQUEST | DRBL_HOST_STATUS,
+				 DRBL_RSU_REQUEST |
+				 FIELD_PREP(DRBL_HOST_STATUS,
+					    HOST_STATUS_IDLE));
+	if (ret)
+		return FPGA_IMAGE_ERR_RW_ERROR;
+
+	ret = regmap_read_poll_timeout(sec->m10bmc->regmap,
+				       M10BMC_SYS_BASE + M10BMC_DOORBELL,
+				       doorbell,
+				       rsu_start_done(doorbell),
+				       NIOS_HANDSHAKE_INTERVAL_US,
+				       NIOS_HANDSHAKE_TIMEOUT_US);
+
+	if (ret == -ETIMEDOUT) {
+		log_error_regs(sec, doorbell);
+		return FPGA_IMAGE_ERR_TIMEOUT;
+	} else if (ret) {
+		return FPGA_IMAGE_ERR_RW_ERROR;
+	}
+
+	status = rsu_stat(doorbell);
+	if (status == RSU_STAT_WEAROUT) {
+		dev_warn(sec->dev, "Excessive flash update count detected\n");
+		return FPGA_IMAGE_ERR_WEAROUT;
+	} else if (status == RSU_STAT_ERASE_FAIL) {
+		log_error_regs(sec, doorbell);
+		return FPGA_IMAGE_ERR_HW_ERROR;
+	}
+
+	return 0;
+}
+
+static u32 rsu_prog_ready(struct m10bmc_sec *sec)
+{
+	unsigned long poll_timeout;
+	u32 doorbell, progress;
+	int ret;
+
+	ret = m10bmc_sys_read(sec->m10bmc, M10BMC_DOORBELL, &doorbell);
+	if (ret)
+		return FPGA_IMAGE_ERR_RW_ERROR;
+
+	poll_timeout = jiffies + msecs_to_jiffies(RSU_PREP_TIMEOUT_MS);
+	while (rsu_prog(doorbell) == RSU_PROG_PREPARE) {
+		msleep(RSU_PREP_INTERVAL_MS);
+		if (time_after(jiffies, poll_timeout))
+			break;
+
+		ret = m10bmc_sys_read(sec->m10bmc, M10BMC_DOORBELL, &doorbell);
+		if (ret)
+			return FPGA_IMAGE_ERR_RW_ERROR;
+	}
+
+	progress = rsu_prog(doorbell);
+	if (progress == RSU_PROG_PREPARE) {
+		log_error_regs(sec, doorbell);
+		return FPGA_IMAGE_ERR_TIMEOUT;
+	} else if (progress != RSU_PROG_READY) {
+		log_error_regs(sec, doorbell);
+		return FPGA_IMAGE_ERR_HW_ERROR;
+	}
+
+	return 0;
+}
+
+static u32 rsu_send_data(struct m10bmc_sec *sec)
+{
+	u32 doorbell;
+	int ret;
+
+	ret = regmap_update_bits(sec->m10bmc->regmap,
+				 M10BMC_SYS_BASE + M10BMC_DOORBELL,
+				 DRBL_HOST_STATUS,
+				 FIELD_PREP(DRBL_HOST_STATUS,
+					    HOST_STATUS_WRITE_DONE));
+	if (ret)
+		return FPGA_IMAGE_ERR_RW_ERROR;
+
+	ret = regmap_read_poll_timeout(sec->m10bmc->regmap,
+				       M10BMC_SYS_BASE + M10BMC_DOORBELL,
+				       doorbell,
+				       rsu_prog(doorbell) != RSU_PROG_READY,
+				       NIOS_HANDSHAKE_INTERVAL_US,
+				       NIOS_HANDSHAKE_TIMEOUT_US);
+
+	if (ret == -ETIMEDOUT) {
+		log_error_regs(sec, doorbell);
+		return FPGA_IMAGE_ERR_TIMEOUT;
+	} else if (ret) {
+		return FPGA_IMAGE_ERR_RW_ERROR;
+	}
+
+	switch (rsu_stat(doorbell)) {
+	case RSU_STAT_NORMAL:
+	case RSU_STAT_NIOS_OK:
+	case RSU_STAT_USER_OK:
+	case RSU_STAT_FACTORY_OK:
+		break;
+	default:
+		log_error_regs(sec, doorbell);
+		return FPGA_IMAGE_ERR_HW_ERROR;
+	}
+
+	return 0;
+}
+
+static int rsu_check_complete(struct m10bmc_sec *sec, u32 *doorbell)
+{
+	if (m10bmc_sys_read(sec->m10bmc, M10BMC_DOORBELL, doorbell))
+		return -EIO;
+
+	switch (rsu_stat(*doorbell)) {
+	case RSU_STAT_NORMAL:
+	case RSU_STAT_NIOS_OK:
+	case RSU_STAT_USER_OK:
+	case RSU_STAT_FACTORY_OK:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	switch (rsu_prog(*doorbell)) {
+	case RSU_PROG_IDLE:
+	case RSU_PROG_RSU_DONE:
+		return 0;
+	case RSU_PROG_AUTHENTICATING:
+	case RSU_PROG_COPYING:
+	case RSU_PROG_UPDATE_CANCEL:
+	case RSU_PROG_PROGRAM_KEY_HASH:
+		return -EAGAIN;
+	default:
+		return -EINVAL;
+	}
+}
+
+static u32 rsu_cancel(struct m10bmc_sec *sec)
+{
+	u32 doorbell;
+	int ret;
+
+	ret = m10bmc_sys_read(sec->m10bmc, M10BMC_DOORBELL, &doorbell);
+	if (ret)
+		return FPGA_IMAGE_ERR_RW_ERROR;
+
+	if (rsu_prog(doorbell) != RSU_PROG_READY)
+		return FPGA_IMAGE_ERR_BUSY;
+
+	ret = regmap_update_bits(sec->m10bmc->regmap,
+				 M10BMC_SYS_BASE + M10BMC_DOORBELL,
+				 DRBL_HOST_STATUS,
+				 FIELD_PREP(DRBL_HOST_STATUS,
+					    HOST_STATUS_ABORT_RSU));
+	if (ret)
+		return FPGA_IMAGE_ERR_RW_ERROR;
+
+	return FPGA_IMAGE_ERR_CANCELED;
+}
+
+static u32 m10bmc_sec_prepare(struct fpga_image_load *imgld, const u8 *data,
+			      u32 size)
+{
+	struct m10bmc_sec *sec = imgld->priv;
+	u32 ret;
+
+	sec->cancel_request = false;
+
+	if (size & 0x3 || size > M10BMC_STAGING_SIZE)
+		return FPGA_IMAGE_ERR_INVALID_SIZE;
+
+	ret = rsu_check_idle(sec);
+	if (ret)
+		return ret;
+
+	ret = rsu_update_init(sec);
+	if (ret)
+		return ret;
+
+	return rsu_prog_ready(sec);
+}
+
+#define WRITE_BLOCK_SIZE 0x4000	/* Default write-block size is 0x4000 bytes */
+
+static s32 m10bmc_sec_write(struct fpga_image_load *imgld, const u8 *data,
+			    u32 offset, u32 size)
+{
+	struct m10bmc_sec *sec = imgld->priv;
+	unsigned int stride = regmap_get_reg_stride(sec->m10bmc->regmap);
+	u32 blk_size, doorbell;
+	int ret;
+
+	if (sec->cancel_request)
+		return -rsu_cancel(sec);
+
+	ret = m10bmc_sys_read(sec->m10bmc, M10BMC_DOORBELL, &doorbell);
+	if (ret) {
+		return -FPGA_IMAGE_ERR_RW_ERROR;
+	} else if (rsu_prog(doorbell) != RSU_PROG_READY) {
+		log_error_regs(sec, doorbell);
+		return -FPGA_IMAGE_ERR_HW_ERROR;
+	}
+
+	blk_size = min_t(u32, WRITE_BLOCK_SIZE, size);
+	ret = regmap_bulk_write(sec->m10bmc->regmap,
+				M10BMC_STAGING_BASE + offset,
+				(void *)data + offset,
+				(blk_size + stride - 1) / stride);
+
+	if (ret)
+		return -FPGA_IMAGE_ERR_RW_ERROR;
+
+	return blk_size;
+}
+
+static u32 m10bmc_sec_poll_complete(struct fpga_image_load *imgld)
+{
+	struct m10bmc_sec *sec = imgld->priv;
+	unsigned long poll_timeout;
+	u32 doorbell, result;
+	int ret;
+
+	if (sec->cancel_request)
+		return rsu_cancel(sec);
+
+	result = rsu_send_data(sec);
+	if (result)
+		return result;
+
+	poll_timeout = jiffies + msecs_to_jiffies(RSU_COMPLETE_TIMEOUT_MS);
+	do {
+		msleep(RSU_COMPLETE_INTERVAL_MS);
+		ret = rsu_check_complete(sec, &doorbell);
+	} while (ret == -EAGAIN && !time_after(jiffies, poll_timeout));
+
+	if (ret == -EAGAIN) {
+		log_error_regs(sec, doorbell);
+		return FPGA_IMAGE_ERR_TIMEOUT;
+	} else if (ret == -EIO) {
+		return FPGA_IMAGE_ERR_RW_ERROR;
+	} else if (ret) {
+		log_error_regs(sec, doorbell);
+		return FPGA_IMAGE_ERR_HW_ERROR;
+	}
+
+	return 0;
+}
+
+/*
+ * m10bmc_sec_cancel() may be called asynchronously with an on-going update.
+ * All other functions are called sequentially in a single thread. To avoid
+ * contention on register accesses, m10bmc_sec_cancel() must only update
+ * the cancel_request flag. Other functions will check this flag and handle
+ * the cancel request synchronously.
+ */
+static void m10bmc_sec_cancel(struct fpga_image_load *imgld)
+{
+	struct m10bmc_sec *sec = imgld->priv;
+
+	sec->cancel_request = true;
+}
+
+static void m10bmc_sec_cleanup(struct fpga_image_load *imgld)
+{
+	struct m10bmc_sec *sec = imgld->priv;
+
+	(void)rsu_cancel(sec);
+}
+
+static const struct fpga_image_load_ops m10bmc_ops = {
+	.prepare = m10bmc_sec_prepare,
+	.write = m10bmc_sec_write,
+	.poll_complete = m10bmc_sec_poll_complete,
+	.cancel = m10bmc_sec_cancel,
+	.cleanup = m10bmc_sec_cleanup,
+};
 
 static int m10bmc_sec_probe(struct platform_device *pdev)
 {
-- 
2.25.1