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

This reverts commit c565f9910707b91fcc7a27bab28806e558bb474d.

4 files changed, 237 insertions, 503 deletions

diff --git a/src/drivers/i2c/tpm/Kconfig b/src/drivers/i2c/tpm/Kconfig
index db77b956b9..903fc3bbe5 100644
--- a/src/drivers/i2c/tpm/Kconfig
+++ b/src/drivers/i2c/tpm/Kconfig
@@ -2,19 +2,6 @@ config I2C_TPM
 	bool "I2C TPM"
 	depends on TPM || TPM2
 
-choice
-	prompt "I2C TPM Driver"
-	default I2C_TPM_GENERIC
-	depends on I2C_TPM
-
-config I2C_TPM_GENERIC
-	bool "Generic I2C TPM Driver"
-
-config I2C_TPM_CR50
-	bool "CR50 I2C TPM Driver"
-
-endchoice
-
 config DRIVER_TPM_I2C_BUS
 	hex "I2C TPM chip bus"
 	default 9 # FIXME, workaround for Kconfig BS
diff --git a/src/drivers/i2c/tpm/Makefile.inc b/src/drivers/i2c/tpm/Makefile.inc
index 7fcfc78d56..3eb5de0518 100644
--- a/src/drivers/i2c/tpm/Makefile.inc
+++ b/src/drivers/i2c/tpm/Makefile.inc
@@ -1,17 +1,6 @@
-
-ramstage-$(CONFIG_I2C_TPM) += tis.c
-romstage-$(CONFIG_I2C_TPM) += tis.c
-verstage-$(CONFIG_I2C_TPM) += tis.c
-bootblock-$(CONFIG_I2C_TPM) += tis.c
-
-ramstage-$(CONFIG_I2C_TPM_GENERIC) += tpm.c
-romstage-$(CONFIG_I2C_TPM_GENERIC) += tpm.c
-verstage-$(CONFIG_I2C_TPM_GENERIC) += tpm.c
-bootblock-$(CONFIG_I2C_TPM_GENERIC) += tpm.c
-
-ramstage-$(CONFIG_I2C_TPM_CR50) += cr50.c
-romstage-$(CONFIG_I2C_TPM_CR50) += cr50.c
-verstage-$(CONFIG_I2C_TPM_CR50) += cr50.c
-bootblock-$(CONFIG_I2C_TPM_CR50) += cr50.c
+ramstage-$(CONFIG_I2C_TPM) += tis.c tpm.c
+romstage-$(CONFIG_I2C_TPM) += tis.c tpm.c
+verstage-$(CONFIG_I2C_TPM) += tis.c tpm.c
+bootblock-$(CONFIG_I2C_TPM) += tis.c tpm.c
 
 ramstage-$(CONFIG_DRIVER_I2C_TPM_ACPI) += chip.c
diff --git a/src/drivers/i2c/tpm/cr50.c b/src/drivers/i2c/tpm/cr50.c
deleted file mode 100644
index 419ac1e68f..0000000000
--- a/src/drivers/i2c/tpm/cr50.c
+++ /dev/null
@@ -1,466 +0,0 @@
-/*
- * Copyright 2016 Google Inc.
- *
- * Based on Linux Kernel TPM driver by
- * Peter Huewe <peter.huewe@infineon.com>
- * Copyright (C) 2011 Infineon Technologies
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation, version 2 of the
- * License.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- */
-
-/*
- * cr50 is a TPM 2.0 capable device that requries special
- * handling for the I2C interface.
- *
- * - Use an interrupt for transaction status instead of hardcoded delays
- * - Must use write+wait+read read protocol
- * - All 4 bytes of status register must be read/written 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
- */
-
-#include <arch/early_variables.h>
-#include <commonlib/endian.h>
-#include <stdint.h>
-#include <string.h>
-#include <types.h>
-#include <delay.h>
-#include <console/console.h>
-#include <device/i2c.h>
-#include <endian.h>
-#include <timer.h>
-#include "tpm.h"
-
-#define CR50_MAX_BURSTCOUNT	63
-
-#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 */
-
-#define CR50_DID_VID		0x00281ae0L
-
-struct tpm_inf_dev {
-	int bus;
-	unsigned int addr;
-	uint8_t buf[TPM_BUFSIZE + sizeof(uint8_t)];
-};
-
-static struct tpm_inf_dev g_tpm_dev CAR_GLOBAL;
-
-/*
- * iic_tpm_read() - read from TPM register
- *
- * @addr: register address to read from
- * @buffer: provided by caller
- * @len: number of bytes to read
- *
- * 1) send register address byte 'addr' to the TPM
- * 2) wait for TPM to indicate it is ready
- * 3) read 'len' bytes of TPM response into the provided 'buffer'
- *
- * Return -1 on error, 0 on success.
- */
-static int iic_tpm_read(uint8_t addr, uint8_t *buffer, size_t len)
-{
-	struct tpm_inf_dev *tpm_dev = car_get_var_ptr(&g_tpm_dev);
-
-	if (tpm_dev->addr == 0)
-		return -1;
-
-	/* Send the register address byte to the TPM */
-	if (i2c_write_raw(tpm_dev->bus, tpm_dev->addr, &addr, 1)) {
-		printk(BIOS_ERR, "%s: Address write failed\n", __func__);
-		return -1;
-	}
-
-	/* Wait for TPM to be ready with response data */
-	udelay(SLEEP_DURATION_SAFE);
-
-	/* Read response data from the TPM */
-	if (i2c_read_raw(tpm_dev->bus, tpm_dev->addr, buffer, len)) {
-		printk(BIOS_ERR, "%s: Read response failed\n", __func__);
-		return -1;
-	}
-
-	return 0;
-}
-
-/*
- * iic_tpm_write() - write to TPM register
- *
- * @addr: register address to write to
- * @buffer: data to write
- * @len: number of bytes to write
- *
- * 1) prepend the provided address to the provided data
- * 2) send the address+data to the TPM
- * 3) wait for TPM to indicate it is done writing
- *
- * Returns -1 on error, 0 on success.
- */
-static int iic_tpm_write(uint8_t addr, uint8_t *buffer, size_t len)
-{
-	struct tpm_inf_dev *tpm_dev = car_get_var_ptr(&g_tpm_dev);
-
-	if (tpm_dev->addr == 0)
-		return -1;
-	if (len > TPM_BUFSIZE)
-		return -1;
-
-	/* Prepend the 'register address' to the buffer */
-	tpm_dev->buf[0] = addr;
-	memcpy(tpm_dev->buf + 1, buffer, len);
-
-	/* Send write request buffer with address */
-	if (i2c_write_raw(tpm_dev->bus, tpm_dev->addr, tpm_dev->buf, len + 1)) {
-		printk(BIOS_ERR, "%s: Error writing to TPM\n", __func__);
-		return -1;
-	}
-
-	/* Wait for TPM to be ready */
-	udelay(SLEEP_DURATION_SAFE);
-
-	return 0;
-}
-
-static int check_locality(struct tpm_chip *chip, int loc)
-{
-	uint8_t buf;
-
-	if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
-		return -1;
-
-	if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
-		(TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
-		chip->vendor.locality = loc;
-		return loc;
-	}
-
-	return -1;
-}
-
-static void release_locality(struct tpm_chip *chip, int loc, int force)
-{
-	uint8_t buf;
-	if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
-		return;
-
-	if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
-			(TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
-		buf = TPM_ACCESS_ACTIVE_LOCALITY;
-		iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
-	}
-}
-
-static int request_locality(struct tpm_chip *chip, int loc)
-{
-	uint8_t buf = TPM_ACCESS_REQUEST_USE;
-
-	if (check_locality(chip, loc) >= 0)
-		return loc; /* we already have the locality */
-
-	iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
-
-	/* wait for burstcount */
-	int timeout = 2 * 1000; /* 2s timeout */
-	while (timeout) {
-		if (check_locality(chip, loc) >= 0)
-			return loc;
-		mdelay(TPM_TIMEOUT);
-		timeout--;
-	}
-
-	return -1;
-}
-
-/* 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(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;
-}
-
-static void cr50_vendor_init(struct tpm_chip *chip)
-{
-	memset(&chip->vendor, 0, sizeof(struct tpm_vendor_specific));
-	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 = &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;
-}
-
-int tpm_vendor_probe(unsigned bus, uint32_t addr)
-{
-	struct tpm_inf_dev *tpm_dev = car_get_var_ptr(&g_tpm_dev);
-	struct stopwatch sw;
-	uint8_t buf = 0;
-	int ret;
-	long sw_run_duration = SLEEP_DURATION_PROBE_MS;
-
-	tpm_dev->bus = bus;
-	tpm_dev->addr = addr;
-
-	/* Wait for TPM_ACCESS register ValidSts bit to be set */
-	stopwatch_init_msecs_expire(&sw, sw_run_duration);
-	do {
-		ret = iic_tpm_read(TPM_ACCESS(0), &buf, 1);
-		if (!ret && (buf & TPM_STS_VALID)) {
-			sw_run_duration = stopwatch_duration_msecs(&sw);
-			break;
-		}
-		udelay(SLEEP_DURATION_SAFE);
-	} while (!stopwatch_expired(&sw));
-
-	printk(BIOS_INFO,
-	       "%s: ValidSts bit %s(%d) in TPM_ACCESS register after %ld ms\n",
-	       __func__, (buf & TPM_STS_VALID) ? "set" : "clear",
-	       (buf & TPM_STS_VALID) >> 7, sw_run_duration);
-
-	/* Claim failure if the ValidSts (bit 7) is clear */
-	if (!(buf & TPM_STS_VALID))
-		return -1;
-
-	return 0;
-}
-
-int tpm_vendor_init(struct tpm_chip *chip, unsigned bus, uint32_t dev_addr)
-{
-	struct tpm_inf_dev *tpm_dev = car_get_var_ptr(&g_tpm_dev);
-	uint32_t vendor;
-
-	if (dev_addr == 0) {
-		printk(BIOS_ERR, "%s: missing device address\n", __func__);
-		return -1;
-	}
-
-	tpm_dev->bus = bus;
-	tpm_dev->addr = dev_addr;
-
-	cr50_vendor_init(chip);
-
-	/* Disable interrupts (not supported) */
-	chip->vendor.irq = 0;
-
-	if (request_locality(chip, 0) != 0)
-		return -1;
-
-	/* Read four bytes from DID_VID register */
-	if (iic_tpm_read(TPM_DID_VID(0), (uint8_t *)&vendor, 4) < 0)
-		goto out_err;
-
-	if (vendor != CR50_DID_VID) {
-		printk(BIOS_DEBUG, "Vendor ID 0x%08x not recognized\n", vendor);
-		goto out_err;
-	}
-
-	printk(BIOS_DEBUG, "cr50 TPM %u:%02x (device-id 0x%X)\n",
-	       tpm_dev->bus, tpm_dev->addr, vendor >> 16);
-
-	chip->is_open = 1;
-	return 0;
-
-out_err:
-	release_locality(chip, 0, 1);
-	return -1;
-}
-
-void tpm_vendor_cleanup(struct tpm_chip *chip)
-{
-	release_locality(chip, chip->vendor.locality, 1);
-}
diff --git a/src/drivers/i2c/tpm/tpm.c b/src/drivers/i2c/tpm/tpm.c
index 55c25fefa4..6b96774f60 100644
--- a/src/drivers/i2c/tpm/tpm.c
+++ b/src/drivers/i2c/tpm/tpm.c
@@ -45,6 +45,7 @@
 
 #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
@@ -57,16 +58,19 @@
 /* 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",
 };
 
@@ -107,6 +111,7 @@ 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++) {
@@ -469,6 +474,211 @@ 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)
@@ -482,8 +692,8 @@ 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;
-	tpm_dev->sleep_long = SLEEP_DURATION_LONG;
+	tpm_dev->sleep_short = SLEEP_DURATION_SAFE;
+	tpm_dev->sleep_long = SLEEP_DURATION_SAFE * 2;
 
 	/*
 	 * Probe TPM. Check if the TPM_ACCESS register's ValidSts bit is set(1)
@@ -496,7 +706,7 @@ int tpm_vendor_probe(unsigned bus, uint32_t addr)
 			sw_run_duration = stopwatch_duration_msecs(&sw);
 			break;
 		}
-		udelay(SLEEP_DURATION);
+		udelay(SLEEP_DURATION_SAFE);
 	} while (!stopwatch_expired(&sw));
 
 	printk(BIOS_INFO,
@@ -526,8 +736,10 @@ 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;
-	tpm_dev->sleep_short = SLEEP_DURATION;
-	tpm_dev->sleep_long = SLEEP_DURATION_LONG;
+
+	/* Use conservative values to read chip id */
+	tpm_dev->sleep_short = SLEEP_DURATION_SAFE;
+	tpm_dev->sleep_long = SLEEP_DURATION_SAFE * 2;
 
 	memset(&chip->vendor, 0, sizeof(struct tpm_vendor_specific));
 	chip->is_open = 1;
@@ -535,10 +747,6 @@ 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;
@@ -554,11 +762,27 @@ 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);