[PATCH v13 4/4] fpga: m10bmc-sec: add max10 secure update functions

[Russ Weight <russell.h.weight@intel.com>]

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@intel.com>
---
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-secure.c | 310 +++++++++++++++++++++++++++-
 1 file changed, 309 insertions(+), 1 deletion(-)

diff --git a/drivers/fpga/intel-m10-bmc-secure.c b/drivers/fpga/intel-m10-bmc-secure.c
index 749d2b4c48a6..9fdfcc0d5d4a 100644
--- a/drivers/fpga/intel-m10-bmc-secure.c
+++ b/drivers/fpga/intel-m10-bmc-secure.c
@@ -181,7 +181,315 @@ static const struct attribute_group *m10bmc_sec_attr_groups[] = {
 	NULL,
 };
 
-static const struct fpga_sec_mgr_ops m10bmc_sops = { };
+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 enum fpga_sec_err rsu_check_idle(struct m10bmc_sec *sec)
+{
+	u32 doorbell;
+	int ret;
+
+	ret = m10bmc_sys_read(sec->m10bmc, M10BMC_DOORBELL, &doorbell);
+	if (ret)
+		return FPGA_SEC_ERR_RW_ERROR;
+
+	if (rsu_prog(doorbell) != RSU_PROG_IDLE &&
+	    rsu_prog(doorbell) != RSU_PROG_RSU_DONE) {
+		log_error_regs(sec, doorbell);
+		return FPGA_SEC_ERR_BUSY;
+	}
+
+	return FPGA_SEC_ERR_NONE;
+}
+
+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 enum fpga_sec_err 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_SEC_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_SEC_ERR_TIMEOUT;
+	} else if (ret) {
+		return FPGA_SEC_ERR_RW_ERROR;
+	}
+
+	status = rsu_stat(doorbell);
+	if (status == RSU_STAT_WEAROUT) {
+		dev_warn(sec->dev, "Excessive flash update count detected\n");
+		return FPGA_SEC_ERR_WEAROUT;
+	} else if (status == RSU_STAT_ERASE_FAIL) {
+		log_error_regs(sec, doorbell);
+		return FPGA_SEC_ERR_HW_ERROR;
+	}
+
+	return FPGA_SEC_ERR_NONE;
+}
+
+static enum fpga_sec_err 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_SEC_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_SEC_ERR_RW_ERROR;
+	}
+
+	progress = rsu_prog(doorbell);
+	if (progress == RSU_PROG_PREPARE) {
+		log_error_regs(sec, doorbell);
+		return FPGA_SEC_ERR_TIMEOUT;
+	} else if (progress != RSU_PROG_READY) {
+		log_error_regs(sec, doorbell);
+		return FPGA_SEC_ERR_HW_ERROR;
+	}
+
+	return FPGA_SEC_ERR_NONE;
+}
+
+static enum fpga_sec_err 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_SEC_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_SEC_ERR_TIMEOUT;
+	} else if (ret) {
+		return FPGA_SEC_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_SEC_ERR_HW_ERROR;
+	}
+
+	return FPGA_SEC_ERR_NONE;
+}
+
+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 enum fpga_sec_err m10bmc_sec_prepare(struct fpga_sec_mgr *smgr)
+{
+	struct m10bmc_sec *sec = smgr->priv;
+	enum fpga_sec_err ret;
+
+	if (smgr->remaining_size > M10BMC_STAGING_SIZE)
+		return FPGA_SEC_ERR_INVALID_SIZE;
+
+	ret = rsu_check_idle(sec);
+	if (ret != FPGA_SEC_ERR_NONE)
+		return ret;
+
+	ret = rsu_update_init(sec);
+	if (ret != FPGA_SEC_ERR_NONE)
+		return ret;
+
+	return rsu_prog_ready(sec);
+}
+
+#define WRITE_BLOCK_SIZE 0x4000 /* Update remaining_size every 0x4000 bytes */
+
+static enum fpga_sec_err
+m10bmc_sec_write_blk(struct fpga_sec_mgr *smgr, u32 offset)
+{
+	struct m10bmc_sec *sec = smgr->priv;
+	unsigned int stride = regmap_get_reg_stride(sec->m10bmc->regmap);
+	u32 doorbell, blk_size;
+	int ret;
+
+	ret = m10bmc_sys_read(sec->m10bmc, M10BMC_DOORBELL, &doorbell);
+	if (ret) {
+		return FPGA_SEC_ERR_RW_ERROR;
+	} else if (rsu_prog(doorbell) != RSU_PROG_READY) {
+		log_error_regs(sec, doorbell);
+		return FPGA_SEC_ERR_HW_ERROR;
+	}
+
+	blk_size = min_t(u32, smgr->remaining_size, WRITE_BLOCK_SIZE);
+	ret = regmap_bulk_write(sec->m10bmc->regmap,
+				M10BMC_STAGING_BASE + offset,
+				(void *)smgr->data + offset,
+				(blk_size + stride - 1) / stride);
+
+	if (ret)
+		return FPGA_SEC_ERR_RW_ERROR;
+
+	smgr->remaining_size -= blk_size;
+	return FPGA_SEC_ERR_NONE;
+}
+
+/*
+ * m10bmc_sec_poll_complete() is called after handing things off to
+ * the BMC firmware. Depending on the type of update, it could be
+ * 30+ minutes before the BMC firmware completes the update. The
+ * smgr->driver_unload check allows the driver to be unloaded,
+ * but the BMC firmware will continue the update and no further
+ * secure updates can be started for this device until the update
+ * is complete.
+ */
+static enum fpga_sec_err m10bmc_sec_poll_complete(struct fpga_sec_mgr *smgr)
+{
+	struct m10bmc_sec *sec = smgr->priv;
+	unsigned long poll_timeout;
+	enum fpga_sec_err result;
+	u32 doorbell;
+	int ret;
+
+	result = rsu_send_data(sec);
+	if (result != FPGA_SEC_ERR_NONE)
+		return result;
+
+	poll_timeout = jiffies + msecs_to_jiffies(RSU_COMPLETE_TIMEOUT_MS);
+	do {
+		msleep(RSU_COMPLETE_INTERVAL_MS);
+		ret = rsu_check_complete(sec, &doorbell);
+		if (smgr->driver_unload)
+			return FPGA_SEC_ERR_CANCELED;
+	} while (ret == -EAGAIN && !time_after(jiffies, poll_timeout));
+
+	if (ret == -EAGAIN) {
+		log_error_regs(sec, doorbell);
+		return FPGA_SEC_ERR_TIMEOUT;
+	} else if (ret == -EIO) {
+		return FPGA_SEC_ERR_RW_ERROR;
+	} else if (ret) {
+		log_error_regs(sec, doorbell);
+		return FPGA_SEC_ERR_HW_ERROR;
+	}
+
+	return FPGA_SEC_ERR_NONE;
+}
+
+static enum fpga_sec_err m10bmc_sec_cancel(struct fpga_sec_mgr *smgr)
+{
+	struct m10bmc_sec *sec = smgr->priv;
+	u32 doorbell;
+	int ret;
+
+	ret = m10bmc_sys_read(sec->m10bmc, M10BMC_DOORBELL, &doorbell);
+	if (ret)
+		return FPGA_SEC_ERR_RW_ERROR;
+
+	if (rsu_prog(doorbell) != RSU_PROG_READY)
+		return FPGA_SEC_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));
+
+	return ret ? FPGA_SEC_ERR_RW_ERROR : FPGA_SEC_ERR_NONE;
+}
+
+static const struct fpga_sec_mgr_ops m10bmc_sops = {
+	.prepare = m10bmc_sec_prepare,
+	.write_blk = m10bmc_sec_write_blk,
+	.poll_complete = m10bmc_sec_poll_complete,
+	.cancel = m10bmc_sec_cancel,
+};
 
 static int m10bmc_secure_probe(struct platform_device *pdev)
 {
-- 
2.25.1