[coreboot-gerrit] [L] Change in coreboot[main]: drivers/spi: add RPMC support

[Felix Held (Code Review)]

Felix Held has submitted this change. ( https://review.coreboot.org/c/coreboot/+/84837?usp=email )

Change subject: drivers/spi: add RPMC support
......................................................................

drivers/spi: add RPMC support

Add functions to send the RPMC-related commands to a RPMC-capable SPI
flash to provision the root key, update the HMAC key, increment the
monotonic counter, and request the monotonic counter data. To talk to
the flash chip, the command bytes and polling mechanism described in the
SFDP data structure of the flash are used.

The JESD260 specification was used as a reference.

Some of inspiration was taken from
github.com/teslamotors/coreboot/tree/tesla-4.12-amd

TEST=When used with the later patch that calls some of the functions
added in this patch, sending the RPMC increment monotonic counter
command to the RPMC-capable SPI flash, in this case W74M12JW, is
successful.

Change-Id: Ia9bd69d0105c66bf5ecb6c90e8c782a81912bd40
Signed-off-by: Felix Held 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/84837
Reviewed-by: Matt DeVillier 
Reviewed-by: Marshall Dawson 
Tested-by: build bot (Jenkins) 
---
M src/drivers/spi/spi_flash_rpmc.c
M src/include/spi_flash.h
2 files changed, 357 insertions(+), 0 deletions(-)

Approvals:
  Matt DeVillier: Looks good to me, approved
  Marshall Dawson: Looks good to me, approved
  build bot (Jenkins): Verified

diff --git a/src/drivers/spi/spi_flash_rpmc.c b/src/drivers/spi/spi_flash_rpmc.c
index 148e3bb..27342ab 100644
--- a/src/drivers/spi/spi_flash_rpmc.c
+++ b/src/drivers/spi/spi_flash_rpmc.c
@@ -30,3 +30,308 @@
    flash->rpmc_caps.op2_read_cmd = rpmc_info.op2_read_command;
    flash->rpmc_caps.rpmc_available = true;
 }
+
+static bool spi_flash_rpmc_is_available(const struct spi_flash *flash)
+{
+	return flash->rpmc_caps.rpmc_available;
+}
+
+#define RPMC_OP2_READ_BUF_EXT_STATUS_OFFSET	0
+#define RPMC_OP2_READ_BUF_TAG_OFFSET		1
+#define RPMC_OP2_READ_BUF_COUNTER_DATA_OFFSET	(1 + SPI_RPMC_TAG_LEN)
+#define RPMC_OP2_READ_BUF_SIGNATURE_OFFSET	(1 + SPI_RPMC_TAG_LEN + SPI_RPMC_COUNTER_DATA_LEN)
+
+/*
+ * 'extended_status', 'tag', 'counter_data', and 'signature' may be NULL if the caller
+ * doesn't need the value. 'tag' must be a SPI_RPMC_TAG_LEN bytes long buffer, 'signature'
+ * must be a SPI_RPMC_SIG_LEN bytes long buffer. When only 'extended_status' is non-NULL, only
+ * the extended status is read back.
+ */
+static enum cb_err spi_flash_rpmc_op2_read(const struct spi_flash *flash,
+					   uint8_t *extended_status, uint8_t *tag,
+					   uint8_t *counter_data, uint8_t *signature)
+{
+	int cmd_ret;
+	const bool only_check_extended_status = extended_status != NULL && tag == NULL &&
+			counter_data == NULL && signature == NULL;
+
+	/* command and dummy byte */
+	uint8_t write_buf[1 + 1];
+	/* extended status, tag, counter data, signature */
+	uint8_t read_buf[1 + SPI_RPMC_TAG_LEN + SPI_RPMC_COUNTER_DATA_LEN + SPI_RPMC_SIG_LEN];
+
+	write_buf[0] = flash->rpmc_caps.op2_read_cmd;
+	write_buf[1] = 0x00; /* dummy byte */
+
+	cmd_ret = spi_flash_cmd_multi(&flash->spi, write_buf, sizeof(write_buf), read_buf,
+				      only_check_extended_status ? 1 : sizeof(read_buf));
+
+	if (cmd_ret)
+		return CB_ERR;
+
+	if (extended_status != NULL)
+		*extended_status = read_buf[RPMC_OP2_READ_BUF_EXT_STATUS_OFFSET];
+
+	if (tag != NULL)
+		memcpy(tag, &read_buf[RPMC_OP2_READ_BUF_TAG_OFFSET], SPI_RPMC_TAG_LEN);
+
+	if (counter_data != NULL)
+		memcpy(counter_data, &read_buf[RPMC_OP2_READ_BUF_COUNTER_DATA_OFFSET],
+		       SPI_RPMC_COUNTER_DATA_LEN);
+
+	if (signature != NULL)
+		memcpy(signature, &read_buf[RPMC_OP2_READ_BUF_SIGNATURE_OFFSET],
+		       SPI_RPMC_SIG_LEN);
+
+	return CB_SUCCESS;
+}
+
+static enum cb_err spi_flash_rpmc_op2_get_exteded_status(const struct spi_flash *flash,
+							 uint8_t *extended_status)
+{
+	return spi_flash_rpmc_op2_read(flash, extended_status, NULL, NULL, NULL);
+}
+
+#define RPMC_OP2_EXT_STATUS_SUCCESS		BIT(7)
+#define RPMC_OP2_EXT_STATUS_ERR_FATAL		BIT(5)
+#define RPMC_OP2_EXT_STATUS_ERR_BAD_COUNTER	BIT(4)
+#define RPMC_OP2_EXT_STATUS_ERR_UNINITIALIZED	BIT(3)
+#define RPMC_OP2_EXT_STATUS_ERR_INVALID		BIT(2)
+#define RPMC_OP2_EXT_STATUS_ERR_OTHER		BIT(1)
+#define RPMC_OP2_EXT_STATUS_POLL_BUSY		BIT(0)
+
+static bool spi_flash_rpmc_is_extended_status_successful(uint8_t extended_status)
+{
+	return extended_status & RPMC_OP2_EXT_STATUS_SUCCESS;
+}
+
+static void spi_flash_rpmc_print_extended_status_error(uint8_t extended_status)
+{
+	if (extended_status & RPMC_OP2_EXT_STATUS_POLL_BUSY)
+		printk(BIOS_WARNING, "SPI flash RPMC is busy\n");
+
+	if (extended_status & RPMC_OP2_EXT_STATUS_ERR_OTHER)
+		printk(BIOS_ERR, "SPI flash RPMC other error\n");
+
+	if (extended_status & RPMC_OP2_EXT_STATUS_ERR_INVALID)
+		printk(BIOS_ERR, "SPI flash RPMC invalid input\n");
+
+	if (extended_status & RPMC_OP2_EXT_STATUS_ERR_UNINITIALIZED)
+		printk(BIOS_ERR, "SPI flash RPMC uninitialized\n");
+
+	if (extended_status & RPMC_OP2_EXT_STATUS_ERR_BAD_COUNTER)
+		printk(BIOS_ERR, "SPI flash RPMC counter mismatch\n");
+
+	if (extended_status & RPMC_OP2_EXT_STATUS_ERR_FATAL)
+		printk(BIOS_ERR, "SPI flash RPMC fatal error\n");
+}
+
+static enum cb_err spi_flash_rpmc_check_extended_status(const struct spi_flash *flash)
+{
+	uint8_t extended_status;
+
+	if (spi_flash_rpmc_op2_get_exteded_status(flash, &extended_status) != CB_SUCCESS)
+		return CB_ERR;
+
+	if (spi_flash_rpmc_is_extended_status_successful(extended_status))
+		return CB_SUCCESS;
+
+	spi_flash_rpmc_print_extended_status_error(extended_status);
+
+	return CB_ERR;
+}
+
+static enum cb_err spi_flash_rpmc_poll_op2(const struct spi_flash *flash, uint64_t timeout_ms)
+{
+	unsigned int attempt = 0;
+	uint8_t extended_status;
+	struct stopwatch sw;
+
+	stopwatch_init_msecs_expire(&sw, timeout_ms);
+	do {
+		attempt++;
+
+		if (spi_flash_rpmc_op2_get_exteded_status(flash, &extended_status)) {
+			printk(BIOS_WARNING,
+			       "SPI command failed on attempt %d\n", attempt);
+			return CB_ERR;
+		}
+
+		if ((extended_status & RPMC_OP2_EXT_STATUS_POLL_BUSY) == 0)
+			return CB_SUCCESS;
+	} while (!stopwatch_expired(&sw));
+
+	printk(BIOS_WARNING, "SPI RPMC poll timeout at %lld msec after %d attempts\n",
+	       stopwatch_duration_msecs(&sw), attempt);
+
+	return CB_ERR;
+}
+
+static enum cb_err spi_flash_rpmc_wait_ready(const struct spi_flash *flash,
+					     uint64_t timeout_ms)
+{
+	if (!flash->rpmc_caps.poll_op2_ext_stat) {
+		/* poll read status */
+		if (spi_flash_cmd_wait_ready(flash, timeout_ms))
+			return CB_ERR;
+	} else {
+		/* poll RPMC OP2 extended status */
+		if (spi_flash_rpmc_poll_op2(flash, timeout_ms) != CB_SUCCESS)
+			return CB_ERR;
+	}
+
+	return CB_SUCCESS;
+}
+
+static bool spi_flash_rpmc_is_valid_counter_addr(const struct spi_flash *flash,
+						 uint8_t counter_addr)
+{
+	return counter_addr < flash->rpmc_caps.number_of_counters;
+}
+
+/* TODO: replace with proper value read from SFDP?! */
+#define SPI_FLASH_RPMC_TIMEOUT_MS			200
+
+#define RPMC_OP1_CMD_WRITE_ROOT_KEY_REGISTER		0x00
+#define RPMC_OP1_CMD_UPDATE_HMAC_KEY_REGISTER		0x01
+#define RPMC_OP1_CMD_INCREMENT_MONOTONIC_COUNTER	0x02
+#define RPMC_OP1_CMD_REQUEST_MONOTONIC_COUNTER		0x03
+
+enum cb_err spi_flash_rpmc_write_root_key(const struct spi_flash *flash, uint8_t counter_addr,
+					  const uint8_t *root_key,
+					  const uint8_t *truncated_signature)
+{
+	/* command, command type, counter address, reserved, root key, truncated signature */
+	uint8_t buf[1 + 1 + 1 + 1 + SPI_RPMC_ROOT_KEY_LEN + SPI_RPMC_TRUNCTAED_SIG_LEN];
+
+	if (!spi_flash_rpmc_is_available(flash))
+		return CB_ERR;
+
+	if (!spi_flash_rpmc_is_valid_counter_addr(flash, counter_addr))
+		return CB_ERR;
+
+	buf[0] = flash->rpmc_caps.op1_write_cmd;
+	buf[1] = RPMC_OP1_CMD_WRITE_ROOT_KEY_REGISTER;
+	buf[2] = counter_addr;
+	buf[3] = 0x00; /* reserved */
+	memcpy(&buf[4], root_key, SPI_RPMC_ROOT_KEY_LEN);
+	memcpy(&buf[4 + SPI_RPMC_ROOT_KEY_LEN], truncated_signature,
+	       SPI_RPMC_TRUNCTAED_SIG_LEN);
+
+	if (spi_flash_cmd_multi(&flash->spi, buf, sizeof(buf), NULL, 0))
+		return CB_ERR;
+
+	if (spi_flash_rpmc_wait_ready(flash, SPI_FLASH_RPMC_TIMEOUT_MS) != CB_SUCCESS)
+		return CB_ERR;
+
+	if (spi_flash_rpmc_check_extended_status(flash) != CB_SUCCESS)
+		return CB_ERR;
+
+	return CB_SUCCESS;
+}
+
+enum cb_err spi_flash_rpmc_update_hmac_key(const struct spi_flash *flash, uint8_t counter_addr,
+					   uint8_t *key_data, const uint8_t *signature)
+{
+	/* command, command type, counter address, reserved, key data, signature */
+	uint8_t buf[1 + 1 + 1 + 1 + SPI_RPMC_KEY_DATA_LEN + SPI_RPMC_SIG_LEN];
+
+	if (!spi_flash_rpmc_is_available(flash))
+		return CB_ERR;
+
+	if (!spi_flash_rpmc_is_valid_counter_addr(flash, counter_addr))
+		return CB_ERR;
+
+	buf[0] = flash->rpmc_caps.op1_write_cmd;
+	buf[1] = RPMC_OP1_CMD_UPDATE_HMAC_KEY_REGISTER;
+	buf[2] = counter_addr;
+	buf[3] = 0x00; /* reserved */
+	memcpy(&buf[4], key_data, SPI_RPMC_KEY_DATA_LEN);
+	memcpy(&buf[4 + SPI_RPMC_KEY_DATA_LEN], signature, SPI_RPMC_SIG_LEN);
+
+	if (spi_flash_cmd_multi(&flash->spi, buf, sizeof(buf), NULL, 0))
+		return CB_ERR;
+
+	if (spi_flash_rpmc_wait_ready(flash, SPI_FLASH_RPMC_TIMEOUT_MS) != CB_SUCCESS)
+		return CB_ERR;
+
+	if (spi_flash_rpmc_check_extended_status(flash) != CB_SUCCESS)
+		return CB_ERR;
+
+	return CB_SUCCESS;
+}
+
+enum cb_err spi_flash_rpmc_increment(const struct spi_flash *flash, uint8_t counter_addr,
+				     const uint8_t *counter_data, const uint8_t *signature)
+{
+	/* command, command type, counter address, reserved, counter data, signature */
+	uint8_t buf[1 + 1 + 1 + 1 + SPI_RPMC_COUNTER_DATA_LEN + SPI_RPMC_SIG_LEN];
+
+	if (!spi_flash_rpmc_is_available(flash))
+		return CB_ERR;
+
+	if (!spi_flash_rpmc_is_valid_counter_addr(flash, counter_addr))
+		return CB_ERR;
+
+	buf[0] = flash->rpmc_caps.op1_write_cmd;
+	buf[1] = RPMC_OP1_CMD_INCREMENT_MONOTONIC_COUNTER;
+	buf[2] = counter_addr;
+	buf[3] = 0x00; /* reserved */
+	memcpy(&buf[4], counter_data, SPI_RPMC_COUNTER_DATA_LEN);
+	memcpy(&buf[4 + SPI_RPMC_COUNTER_DATA_LEN], signature, SPI_RPMC_SIG_LEN);
+
+	if (spi_flash_cmd_multi(&flash->spi, buf, sizeof(buf), NULL, 0))
+		return CB_ERR;
+
+	if (spi_flash_rpmc_wait_ready(flash, SPI_FLASH_RPMC_TIMEOUT_MS) != CB_SUCCESS)
+		return CB_ERR;
+
+	if (spi_flash_rpmc_check_extended_status(flash) != CB_SUCCESS)
+		return CB_ERR;
+
+	return CB_SUCCESS;
+}
+
+enum cb_err spi_flash_rpmc_request(const struct spi_flash *flash, uint8_t counter_addr,
+				   const uint8_t *tag, const uint8_t *signature,
+				   uint8_t *counter_data, uint8_t *signature_out)
+{
+	/* command, command type, counter address, reserved, tag, signature */
+	uint8_t buf[1 + 1 + 1 + 1 + SPI_RPMC_TAG_LEN + SPI_RPMC_SIG_LEN];
+	uint8_t extended_status;
+
+	if (!spi_flash_rpmc_is_available(flash))
+		return CB_ERR;
+
+	if (!spi_flash_rpmc_is_valid_counter_addr(flash, counter_addr))
+		return CB_ERR;
+
+	buf[0] = flash->rpmc_caps.op1_write_cmd;
+	buf[1] = RPMC_OP1_CMD_REQUEST_MONOTONIC_COUNTER;
+	buf[2] = counter_addr;
+	buf[3] = 0x00; /* reserved */
+	memcpy(&buf[4], tag, SPI_RPMC_TAG_LEN);
+	memcpy(&buf[4 + SPI_RPMC_TAG_LEN], signature, SPI_RPMC_SIG_LEN);
+
+	if (spi_flash_cmd_multi(&flash->spi, buf, sizeof(buf), NULL, 0))
+		return CB_ERR;
+
+	if (spi_flash_rpmc_wait_ready(flash, SPI_FLASH_RPMC_TIMEOUT_MS) != CB_SUCCESS)
+		return CB_ERR;
+
+	/*
+	 * Since we need to read back more than just the extended status for this command and
+	 * want to avoid unnecessary SPI transactions, spi_flash_rpmc_check_extended_status
+	 * isn't used here.
+	 */
+	if (spi_flash_rpmc_op2_read(flash, &extended_status, NULL, counter_data, signature_out)
+			!= CB_SUCCESS)
+		return CB_ERR;
+
+	if (!spi_flash_rpmc_is_extended_status_successful(extended_status)) {
+		spi_flash_rpmc_print_extended_status_error(extended_status);
+		return CB_ERR;
+	}
+
+	return CB_SUCCESS;
+}
diff --git a/src/include/spi_flash.h b/src/include/spi_flash.h
index 76c33be..9ba5d1f 100644
--- a/src/include/spi_flash.h
+++ b/src/include/spi_flash.h
@@ -15,6 +15,10 @@
 /* SPI RPMC field lengths in bytes */
 #define SPI_RPMC_TAG_LEN		12
 #define SPI_RPMC_SIG_LEN		32
+#define SPI_RPMC_ROOT_KEY_LEN		32
+#define SPI_RPMC_TRUNCTAED_SIG_LEN	28 /* only used in write RPMC root key command */
+#define SPI_RPMC_KEY_DATA_LEN		4
+#define SPI_RPMC_COUNTER_DATA_LEN	4

struct spi_flash;

@@ -261,4 +265,52 @@
 /* Print the SFDP headers read from the SPI flash */
 void spi_flash_print_sfdp_headers(const struct spi_flash *flash);

+/*
+ * Write RPMC root key
+ *
+ * root_key: pointer to 32 bytes long buffer with root key
+ * truncated_signature: pointer to 28 bytes long buffer with truncated signature
+ *
+ * The buffers have the bytes in the order in which they will be sent to the SPI flash
+ */
+enum cb_err spi_flash_rpmc_write_root_key(const struct spi_flash *flash, uint8_t counter_addr,
+					  const uint8_t *root_key,
+					  const uint8_t *truncated_signature);
+
+/*
+ * Update HMAC key
+ *
+ * key_data: pointer to 4 bytes long buffer with key data
+ * signature: pointer to 32 bytes long buffer with signature
+ *
+ * The buffers have the bytes in the order in which they will be sent to the SPI flash
+ */
+enum cb_err spi_flash_rpmc_update_hmac_key(const struct spi_flash *flash, uint8_t counter_addr,
+					   uint8_t *key_data, const uint8_t *signature);
+
+/*
+ * Increment monotonic counter
+ *
+ * counter_data: pointer to 4 bytes long buffer with counter data
+ * signature: pointer to 32 bytes long buffer with signature
+ *
+ * The buffers have the bytes in the order in which they will be sent to the SPI flash
+ */
+enum cb_err spi_flash_rpmc_increment(const struct spi_flash *flash, uint8_t counter_addr,
+				     const uint8_t *counter_data, const uint8_t *signature);
+
+/*
+ * Request monotonic counter
+ *
+ * tag: pointer to 12 bytes long buffer with tag
+ * signature: pointer to 32 bytes long buffer with signature
+ * counter_data: pointer to 4 bytes long buffer with counter data
+ * signature_out: pointer to 32 bytes long buffer with signature
+ *
+ * The buffers have the bytes in the order in which they will be sent to the SPI flash
+ */
+enum cb_err spi_flash_rpmc_request(const struct spi_flash *flash, uint8_t counter_addr,
+				   const uint8_t *tag, const uint8_t *signature,
+				   uint8_t *counter_data, uint8_t *signature_out);
+
 #endif /* _SPI_FLASH_H_ */