drivers/i2c/tpm: Split cr50 driver from main driver

Originally I thought it would be cleaner to keep this code in one
place, but as things continue to diverge it ends up being easier
to split this into its own driver.  This way the different drivers
in coreboot, depthcharge, and the kernel, can all be standalone
and if one is changed it is easier to modify the others.

This change splits out the cr50 driver and brings along the basic
elements from the existing driver with no real change in
functionality.  The following commits will modify the code to make
it consistent so it can all be shared with depthcharge and the
linux kernel drivers.

BUG=chrome-os-partner:53336

Change-Id: I3b62b680773d23cc5a7d2217b9754c6c28bccfa7
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://review.coreboot.org/16663
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

1 files changed, 9 insertions, 233 deletions

diff --git a/src/drivers/i2c/tpm/tpm.c b/src/drivers/i2c/tpm/tpm.c
index 6b96774f60..55c25fefa4 100644
--- a/src/drivers/i2c/tpm/tpm.c
+++ b/src/drivers/i2c/tpm/tpm.c
@@ -45,7 +45,6 @@
 
 #define SLEEP_DURATION 60 /* in usec */
 #define SLEEP_DURATION_LONG 210 /* in usec */
-#define SLEEP_DURATION_SAFE 750 /* in usec */
 #define SLEEP_DURATION_PROBE_MS 1000 /* in msec */
 
 /* max. number of iterations after I2C NAK for 'long' commands
@@ -58,19 +57,16 @@
 /* expected value for DIDVID register */
 #define TPM_TIS_I2C_DID_VID_9635 0x000b15d1L
 #define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L
-#define TPM_TIS_I2C_DID_VID_CR50 0x00281ae0L
 
 enum i2c_chip_type {
 	SLB9635,
 	SLB9645,
-	CR50,
 	UNKNOWN,
 };
 
 static const char * const chip_name[] = {
 	[SLB9635] = "slb9635tt",
 	[SLB9645] = "slb9645tt",
-	[CR50] = "cr50",
 	[UNKNOWN] = "unknown/fallback to slb9635",
 };
 
@@ -111,7 +107,6 @@ static int iic_tpm_read(uint8_t addr, uint8_t *buffer, size_t len)
 
 	switch (tpm_dev->chip_type) {
 	case SLB9635:
-	case CR50:
 	case UNKNOWN:
 		/* slb9635 protocol should work in both cases */
 		for (count = 0; count < MAX_COUNT; count++) {
@@ -474,211 +469,6 @@ out_err:
 	return -1;
 }
 
-/*
- * cr50 is a TPM 2.0 capable device that requries special
- * handling for the I2C interface.
- *
- * - Timeouts need to be longer
- * - Must use the older SLB9635 style write+wait+read read protocol
- * - All 4 bytes of status register must be read at once
- * - Burst count max is 63 bytes, and burst count behaves
- *   slightly differently than other I2C TPMs
- * - When reading from FIFO the full burstcnt must be read
- *   instead of just reading header and determining the remainder
- */
-
-/* cr50 max burst count */
-#define CR50_MAX_BURSTCOUNT 63
-
-/* cr50 requires all 4 bytes of status register to be read */
-static uint8_t cr50_tis_i2c_status(struct tpm_chip *chip)
-{
-	uint8_t buf[4];
-	if (iic_tpm_read(TPM_STS(chip->vendor.locality),
-			 buf, sizeof(buf)) < 0) {
-		printk(BIOS_ERR, "%s: Failed to read status\n", __func__);
-		return 0;
-	}
-	return buf[0];
-}
-
-/* cr50 requires all 4 bytes of status register to be written */
-static void cr50_tis_i2c_ready(struct tpm_chip *chip)
-{
-	uint8_t buf[4] = { TPM_STS_COMMAND_READY };
-	iic_tpm_write_long(TPM_STS(chip->vendor.locality), buf, sizeof(buf));
-}
-
-/* cr50 uses bytes 3:2 of status register for burst count and
- * all 4 bytes must be read */
-static int cr50_wait_burst_status(struct tpm_chip *chip, uint8_t mask,
-				  size_t *burst, int *status)
-{
-	uint8_t buf[4];
-	struct stopwatch sw;
-
-	stopwatch_init_msecs_expire(&sw, 2000);
-
-	while (!stopwatch_expired(&sw)) {
-		if (iic_tpm_read(TPM_STS(chip->vendor.locality),
-				 buf, sizeof(buf)) != 0) {
-			printk(BIOS_WARNING, "%s: Read failed\n", __func__);
-			udelay(SLEEP_DURATION_SAFE);
-			continue;
-		}
-
-		*status = buf[0];
-		*burst = read_le16(&buf[1]);
-
-		/* Check if mask matches and burst is valid */
-		if ((*status & mask) == mask &&
-		    *burst > 0 && *burst <= CR50_MAX_BURSTCOUNT)
-			return 0;
-
-		udelay(SLEEP_DURATION_SAFE);
-	}
-
-	printk(BIOS_ERR, "%s: Timeout reading burst and status\n", __func__);
-	return -1;
-}
-
-static int cr50_tis_i2c_recv(struct tpm_chip *chip, uint8_t *buf,
-			     size_t buf_len)
-{
-	size_t burstcnt, current, len, expected;
-	uint8_t addr = TPM_DATA_FIFO(chip->vendor.locality);
-	int status;
-	int ret = -1;
-
-	if (buf_len < TPM_HEADER_SIZE)
-		goto out;
-
-	if (cr50_wait_burst_status(chip, TPM_STS_VALID, &burstcnt, &status) < 0)
-		goto out;
-	if (!(status & TPM_STS_DATA_AVAIL)) {
-		printk(BIOS_ERR, "%s: First chunk not available\n", __func__);
-		goto out;
-	}
-
-	/* Read first chunk of burstcnt bytes */
-	if (iic_tpm_read(addr, buf, burstcnt) != 0) {
-		printk(BIOS_ERR, "%s: Read failed\n", __func__);
-		goto out;
-	}
-
-	/* Determine expected data in the return buffer */
-	expected = read_be32(buf + TPM_RSP_SIZE_BYTE);
-	if (expected > buf_len) {
-		printk(BIOS_ERR, "%s: Too much data: %zu > %zu\n",
-		       __func__, expected, buf_len);
-		goto out;
-	}
-
-	/* Now read the rest of the data */
-	current = burstcnt;
-	while (current < expected) {
-		/* Read updated burst count and check status */
-		if (cr50_wait_burst_status(chip, TPM_STS_VALID,
-					   &burstcnt, &status) < 0)
-			goto out;
-		if (!(status & TPM_STS_DATA_AVAIL)) {
-			printk(BIOS_ERR, "%s: Data not available\n", __func__);
-			goto out;
-		}
-
-		len = min(burstcnt, expected - current);
-		if (iic_tpm_read(addr, buf + current, len) != 0) {
-			printk(BIOS_ERR, "%s: Read failed\n", __func__);
-			goto out;
-		}
-
-		current += len;
-	}
-
-	/* Ensure TPM is done reading data */
-	if (cr50_wait_burst_status(chip, TPM_STS_VALID, &burstcnt, &status) < 0)
-		goto out;
-	if (status & TPM_STS_DATA_AVAIL) {
-		printk(BIOS_ERR, "%s: Data still available\n", __func__);
-		goto out;
-	}
-
-	ret = current;
-
-out:
-	return ret;
-}
-
-static int cr50_tis_i2c_send(struct tpm_chip *chip, uint8_t *buf, size_t len)
-{
-	int status;
-	size_t burstcnt, limit, sent = 0;
-	uint8_t tpm_go[4] = { TPM_STS_GO };
-	struct stopwatch sw;
-
-	if (len > TPM_BUFSIZE)
-		return -1;
-
-	stopwatch_init_msecs_expire(&sw, 2000);
-
-	/* Wait until TPM is ready for a command */
-	while (!(cr50_tis_i2c_status(chip) & TPM_STS_COMMAND_READY)) {
-		if (stopwatch_expired(&sw)) {
-			printk(BIOS_ERR, "%s: Command ready timeout\n",
-			       __func__);
-			return -1;
-		}
-
-		cr50_tis_i2c_ready(chip);
-		udelay(SLEEP_DURATION_SAFE);
-	}
-
-	while (len > 0) {
-		/* Read burst count and check status */
-		if (cr50_wait_burst_status(chip, TPM_STS_VALID,
-					   &burstcnt, &status) < 0)
-			goto out;
-		if (sent > 0 && !(status & TPM_STS_DATA_EXPECT)) {
-			printk(BIOS_ERR, "%s: Data not expected\n", __func__);
-			goto out;
-		}
-
-		/* Use burstcnt - 1 to account for the address byte
-		 * that is inserted by iic_tpm_write() */
-		limit = min(burstcnt - 1, len);
-		if (iic_tpm_write(TPM_DATA_FIFO(chip->vendor.locality),
-				  &buf[sent], limit) != 0) {
-			printk(BIOS_ERR, "%s: Write failed\n", __func__);
-			goto out;
-		}
-
-		sent += limit;
-		len -= limit;
-	}
-
-	/* Ensure TPM is not expecting more data */
-	if (cr50_wait_burst_status(chip, TPM_STS_VALID, &burstcnt, &status) < 0)
-		goto out;
-	if (status & TPM_STS_DATA_EXPECT) {
-		printk(BIOS_ERR, "%s: Data still expected\n", __func__);
-		goto out;
-	}
-
-	/* Start the TPM command */
-	if (iic_tpm_write(TPM_STS(chip->vendor.locality), tpm_go,
-			  sizeof(tpm_go)) < 0) {
-		printk(BIOS_ERR, "%s: Start command failed\n", __func__);
-		goto out;
-	}
-	return sent;
-
-out:
-	/* Abort current transaction if still pending */
-	if (cr50_tis_i2c_status(chip) & TPM_STS_COMMAND_READY)
-		cr50_tis_i2c_ready(chip);
-	return -1;
-}
-
 /* Initialization of I2C TPM */
 
 int tpm_vendor_probe(unsigned bus, uint32_t addr)
@@ -692,8 +482,8 @@ int tpm_vendor_probe(unsigned bus, uint32_t addr)
 	tpm_dev->chip_type = UNKNOWN;
 	tpm_dev->bus = bus;
 	tpm_dev->addr = addr;
-	tpm_dev->sleep_short = SLEEP_DURATION_SAFE;
-	tpm_dev->sleep_long = SLEEP_DURATION_SAFE * 2;
+	tpm_dev->sleep_short = SLEEP_DURATION;
+	tpm_dev->sleep_long = SLEEP_DURATION_LONG;
 
 	/*
 	 * Probe TPM. Check if the TPM_ACCESS register's ValidSts bit is set(1)
@@ -706,7 +496,7 @@ int tpm_vendor_probe(unsigned bus, uint32_t addr)
 			sw_run_duration = stopwatch_duration_msecs(&sw);
 			break;
 		}
-		udelay(SLEEP_DURATION_SAFE);
+		udelay(SLEEP_DURATION);
 	} while (!stopwatch_expired(&sw));
 
 	printk(BIOS_INFO,
@@ -736,10 +526,8 @@ int tpm_vendor_init(struct tpm_chip *chip, unsigned bus, uint32_t dev_addr)
 	tpm_dev->chip_type = UNKNOWN;
 	tpm_dev->bus = bus;
 	tpm_dev->addr = dev_addr;
-
-	/* Use conservative values to read chip id */
-	tpm_dev->sleep_short = SLEEP_DURATION_SAFE;
-	tpm_dev->sleep_long = SLEEP_DURATION_SAFE * 2;
+	tpm_dev->sleep_short = SLEEP_DURATION;
+	tpm_dev->sleep_long = SLEEP_DURATION_LONG;
 
 	memset(&chip->vendor, 0, sizeof(struct tpm_vendor_specific));
 	chip->is_open = 1;
@@ -747,6 +535,10 @@ int tpm_vendor_init(struct tpm_chip *chip, unsigned bus, uint32_t dev_addr)
 	chip->vendor.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID;
 	chip->vendor.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID;
 	chip->vendor.req_canceled = TPM_STS_COMMAND_READY;
+	chip->vendor.status = &tpm_tis_i2c_status;
+	chip->vendor.recv = &tpm_tis_i2c_recv;
+	chip->vendor.send = &tpm_tis_i2c_send;
+	chip->vendor.cancel = &tpm_tis_i2c_ready;
 
 	/* Disable interrupts (not supported) */
 	chip->vendor.irq = 0;
@@ -762,27 +554,11 @@ int tpm_vendor_init(struct tpm_chip *chip, unsigned bus, uint32_t dev_addr)
 		tpm_dev->chip_type = SLB9645;
 	} else if (be32_to_cpu(vendor) == TPM_TIS_I2C_DID_VID_9635) {
 		tpm_dev->chip_type = SLB9635;
-	} else if (vendor == TPM_TIS_I2C_DID_VID_CR50) {
-		tpm_dev->chip_type = CR50;
 	} else {
 		printk(BIOS_DEBUG, "Vendor ID 0x%08x not recognized.\n", vendor);
 		goto out_err;
 	}
 
-	if (tpm_dev->chip_type == CR50) {
-		chip->vendor.status = &cr50_tis_i2c_status;
-		chip->vendor.recv = &cr50_tis_i2c_recv;
-		chip->vendor.send = &cr50_tis_i2c_send;
-		chip->vendor.cancel = &cr50_tis_i2c_ready;
-	} else {
-		tpm_dev->sleep_short = SLEEP_DURATION;
-		tpm_dev->sleep_long = SLEEP_DURATION_LONG;
-		chip->vendor.status = &tpm_tis_i2c_status;
-		chip->vendor.recv = &tpm_tis_i2c_recv;
-		chip->vendor.send = &tpm_tis_i2c_send;
-		chip->vendor.cancel = &tpm_tis_i2c_ready;
-	}
-
 	printk(BIOS_DEBUG, "I2C TPM %u:%02x (chip type %s device-id 0x%X)\n",
 	       tpm_dev->bus, tpm_dev->addr,
 	       chip_name[tpm_dev->chip_type], vendor >> 16);