1 files changed, 466 insertions, 0 deletions
diff --git a/src/drivers/i2c/tpm/cr50.c b/src/drivers/i2c/tpm/cr50.c
new file mode 100644
index 0000000000..419ac1e68f
--- /dev/null
+++ b/src/drivers/i2c/tpm/cr50.c
@@ -0,0 +1,466 @@
+/*
+ * 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);
+}