[coreboot-gerrit] Change in coreboot[master]: drivers/i2c/tpm/cr50: Add support to get cr50 firmware version

[Tim Wawrzynczak (Code Review)]

Attention is currently required from: Christian Walter.
Tim Wawrzynczak has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/61720 )

Change subject: drivers/i2c/tpm/cr50: Add support to get cr50 firmware version
......................................................................

drivers/i2c/tpm/cr50: Add support to get cr50 firmware version

cr50-based devices that use the I2C protocol may still need to know
the firmware version of the cr50, therefore port this functionality
from the SPI driver to I2C.

Signed-off-by: Tim Wawrzynczak 
Change-Id: I9dbdbc6ec717f1aa89111ae09249cbe2312054d9
---
M src/drivers/i2c/tpm/cr50.c
M src/drivers/i2c/tpm/tpm.h
2 files changed, 79 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/20/61720/1

diff --git a/src/drivers/i2c/tpm/cr50.c b/src/drivers/i2c/tpm/cr50.c
index 6c12ee4..ac07f4d 100644
--- a/src/drivers/i2c/tpm/cr50.c
+++ b/src/drivers/i2c/tpm/cr50.c
@@ -43,6 +43,7 @@
 };

static struct tpm_inf_dev tpm_dev;
+static struct cr50_firmware_version cr50_firmware_version;

__weak int tis_plat_irq_status(void)
 {
@@ -470,6 +471,64 @@
    return -1;
 }

+static int cr50_parse_fw_version(const char *version_str, struct cr50_firmware_version *ver)
+{
+	int epoch, major, minor;
+
+	char *number = strstr(version_str, " RW_A:");
+	if (!number)
+		number = strstr(version_str, " RW_B:");
+	if (!number)
+		return -1;
+	number += 6; /* Skip past the colon. */
+
+	epoch = skip_atoi(&number);
+	if (*number++ != '.')
+		return -2;
+	major = skip_atoi(&number);
+	if (*number++ != '.')
+		return -2;
+	minor = skip_atoi(&number);
+
+	ver->epoch = epoch;
+	ver->major = major;
+	ver->minor = minor;
+	return 0;
+}
+
+static int get_fw_version(void)
+{
+	int chunk_count = 0;
+	size_t chunk_size = 50;
+	char version_str[301];
+
+	/* Read FW version if available */
+	if (cr50_i2c_write(TPM_FW_VER(0), (void *)&chunk_size, 1) == 0) {
+		do {
+			if (cr50_i2c_read(TPM_FW_VER(0),
+					  (uint8_t *)(version_str + chunk_count * chunk_size),
+					  chunk_size))
+				break;
+
+			/* Zero-padding detected, break early */
+			if (!version_str[++chunk_count * chunk_size - 1])
+				break;
+		} while (chunk_count * chunk_size < sizeof(version_str) - chunk_size);
+
+		if (cr50_parse_fw_version(version_str, &cr50_firmware_version)) {
+			printk(BIOS_ERR, "Unrecognized cr50 firmware version string\n");
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+static int first_access_this_boot(void)
+{
+	return ENV_SEPARATE_VERSTAGE || ENV_BOOTBLOCK || !CONFIG(VBOOT);
+}
+
 int tpm_vendor_init(struct tpm_chip *chip, unsigned int bus, uint32_t dev_addr)
 {
    uint32_t did_vid = 0;
@@ -497,6 +556,11 @@
    printk(BIOS_DEBUG, "cr50 TPM 2.0 (i2c %u:0x%02x id 0x%x)\n",
           bus, dev_addr, did_vid >> 16);

+	get_fw_version();
+	printk(BIOS_INFO, "cr50 TPM FW version %d.%d.%d\n",
+	       cr50_firmware_version.epoch, cr50_firmware_version.major,
+	       cr50_firmware_version.minor);
+
    chip->is_open = 1;
    return 0;
 }
@@ -504,3 +568,7 @@
 void tpm_vendor_cleanup(struct tpm_chip *chip)
 {
 }
+void cr50_get_firmware_version(struct cr50_firmware_version *version)
+{
+	*version = cr50_firmware_version;
+}
diff --git a/src/drivers/i2c/tpm/tpm.h b/src/drivers/i2c/tpm/tpm.h
index eb4fef1..b5b084a 100644
--- a/src/drivers/i2c/tpm/tpm.h
+++ b/src/drivers/i2c/tpm/tpm.h
@@ -36,6 +36,7 @@
 #define	TPM_STS(l)			(0x0001 | ((l) << 4))
 #define	TPM_DATA_FIFO(l)		(0x0005 | ((l) << 4))
 #define	TPM_DID_VID(l)			(0x0006 | ((l) << 4))
+#define TPM_FW_VER(l)			(0x000f | ((l) << 4))

struct tpm_chip;

@@ -55,6 +56,16 @@
    struct tpm_vendor_specific vendor;
 };

+/* Structure describing the elements of Cr50 firmware version. */
+struct cr50_firmware_version {
+	int epoch;
+	int major;
+	int minor;
+};
+
+/* Get the cr50 firmware version information. */
+void cr50_get_firmware_version(struct cr50_firmware_version *version);
+
 /* ---------- Interface for TPM vendor ------------ */

int tpm_vendor_probe(unsigned int bus, uint32_t addr);