tpm: Clean up I2C TPM driver

Drop a lot of u-boot-isms and share common TIS API
between I2C driver and LPC driver.

Signed-off-by: Stefan Reinauer <reinauer@google.com>

Change-Id: I43be8eea0acbdaef58ef256a2bc5336b83368a0e
Reviewed-on: https://chromium-review.googlesource.com/175670
Commit-Queue: Stefan Reinauer <reinauer@chromium.org>
Tested-by: Stefan Reinauer <reinauer@chromium.org>
Reviewed-by: David Hendricks <dhendrix@chromium.org>
(cherry picked from commit 3fc8515b9dcef66998658e1aa5c020d22509810c)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6855
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

1 files changed, 485 insertions, 70 deletions

diff --git a/src/drivers/i2c/tpm/tpm.c b/src/drivers/i2c/tpm/tpm.c
index d31cc79878..837bd234ac 100644
--- a/src/drivers/i2c/tpm/tpm.c
+++ b/src/drivers/i2c/tpm/tpm.c
@@ -8,6 +8,10 @@
  * Device driver for TCG/TCPA TPM (trusted platform module).
  * Specifications at www.trustedcomputinggroup.org
  *
+ * This device driver implements the TPM interface as defined in
+ * the TCG TPM Interface Spec version 1.2, revision 1.0 and the
+ * Infineon I2C Protocol Stack Specification v0.20.
+ *
  * It is based on the Linux kernel driver tpm.c from Leendert van
  * Dorn, Dave Safford, Reiner Sailer, and Kyleen Hall.
  *
@@ -34,113 +38,524 @@
 
 #include <stdint.h>
 #include <string.h>
-#include <assert.h>
+#include <types.h>
 #include <delay.h>
 #include <console/console.h>
 #include <arch/byteorder.h>
-#include "tis.h"
+#include <device/i2c.h>
 #include "tpm.h"
 
-/* global structure for tpm chip data */
-struct tpm_chip g_chip;
+/* max. buffer size supported by our TPM */
+#ifdef TPM_BUFSIZE
+#undef TPM_BUFSIZE
+#endif
+#define TPM_BUFSIZE 1260
+
+/* Address of the TPM on the I2C bus */
+#define TPM_I2C_ADDR 0x20
+
+/* max. number of iterations after I2C NAK */
+#define MAX_COUNT 3
+
+#define SLEEP_DURATION 60 /* in usec */
+
+/* max. number of iterations after I2C NAK for 'long' commands
+ * we need this especially for sending TPM_READY, since the cleanup after the
+ * transtion to the ready state may take some time, but it is unpredictable
+ * how long it will take.
+ */
+#define MAX_COUNT_LONG 50
+
+#define SLEEP_DURATION_LONG 210 /* in usec */
+
+/* expected value for DIDVID register */
+#define TPM_TIS_I2C_DID_VID_9635 0x000b15d1L
+#define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L
+
+enum i2c_chip_type {
+	SLB9635,
+	SLB9645,
+	UNKNOWN,
+};
+
+static const char * const chip_name[] = {
+	[SLB9635] = "slb9635tt",
+	[SLB9645] = "slb9645tt",
+	[UNKNOWN] = "unknown/fallback to slb9635",
+};
 
-#define TPM_CMD_COUNT_BYTE 2
-#define TPM_CMD_ORDINAL_BYTE 6
+/* Structure to store I2C TPM specific stuff */
+struct tpm_inf_dev {
+	unsigned bus;
+	unsigned int addr;
+	uint8_t buf[TPM_BUFSIZE + sizeof(uint8_t)]; // max. buffer size + addr
+	enum i2c_chip_type chip_type;
+};
 
-ssize_t tpm_transmit(const uint8_t *buf, size_t bufsiz)
+static struct tpm_inf_dev tpm_dev = {
+	.addr = TPM_I2C_ADDR
+};
+
+/*
+ * iic_tpm_read() - read from TPM register
+ * @addr: register address to read from
+ * @buffer: provided by caller
+ * @len: number of bytes to read
+ *
+ * Read len bytes from TPM register and put them into
+ * buffer (little-endian format, i.e. first byte is put into buffer[0]).
+ *
+ * NOTE: TPM is big-endian for multi-byte values. Multi-byte
+ * values have to be swapped.
+ *
+ * Return -1 on error, 0 on success.
+ */
+static int iic_tpm_read(uint8_t addr, uint8_t *buffer, size_t len)
 {
-	ssize_t rc;
-	uint32_t count, ordinal;
+	int rc;
+	int count;
+
+	if (!tpm_dev.bus)
+		return -1;
+	if ((tpm_dev.chip_type == SLB9635) || (tpm_dev.chip_type == UNKNOWN)) {
+		/* slb9635 protocol should work in both cases */
+		for (count = 0; count < MAX_COUNT; count++) {
+			rc = i2c_write(tpm_dev.bus, tpm_dev.addr,
+						0, 0, &addr, 1);
+			if (rc == 0)
+				break;  /* success, break to skip sleep */
+
+			udelay(SLEEP_DURATION);
+		}
 
-	struct tpm_chip *chip = &g_chip;
+		if (rc)
+			return -1;
 
-	memcpy(&count, buf + TPM_CMD_COUNT_BYTE, sizeof(count));
-	count = be32_to_cpu(count);
-	memcpy(&ordinal, buf + TPM_CMD_ORDINAL_BYTE, sizeof(ordinal));
-	ordinal = be32_to_cpu(ordinal);
+		/* After the TPM has successfully received the register address
+		 * it needs some time, thus we're sleeping here again, before
+		 * retrieving the data
+		 */
+		for (count = 0; count < MAX_COUNT; count++) {
+			udelay(SLEEP_DURATION);
+			rc = i2c_read(tpm_dev.bus, tpm_dev.addr,
+					       0, 0, buffer, len);
+			if (rc == 0)
+				break;  /* success, break to skip sleep */
 
-	if (count == 0) {
-		printk(BIOS_DEBUG, "tpm_transmit: no data\n");
-		return -1; //ENODATA;
+		}
+	} else {
+		/* use a combined read for newer chips
+		 * unfortunately the smbus functions are not suitable due to
+		 * the 32 byte limit of the smbus.
+		 * retries should usually not be needed, but are kept just to
+		 * be safe on the safe side.
+		 */
+		for (count = 0; count < MAX_COUNT; count++) {
+			rc = i2c_read(tpm_dev.bus, tpm_dev.addr,
+					       addr, 1, buffer, len);
+			if (rc == 0)
+				break;  /* break here to skip sleep */
+			udelay(SLEEP_DURATION);
+		}
 	}
-	if (count > bufsiz) {
-		printk(BIOS_DEBUG, "tpm_transmit: invalid count value %x %zx\n",
-			count, bufsiz);
-		return -1; //E2BIG;
+
+	/* take care of 'guard time' */
+	udelay(SLEEP_DURATION);
+	if (rc)
+		return -1;
+
+	return 0;
+}
+
+static int iic_tpm_write_generic(uint8_t addr, uint8_t *buffer, size_t len,
+				unsigned int sleep_time,
+				uint8_t max_count)
+{
+	int rc = 0;
+	int count;
+
+	if (len > TPM_BUFSIZE) {
+		printk(BIOS_DEBUG, "%s: Length %d is too large\n", __func__, len);
+		return -1;
 	}
 
-	ASSERT(chip->vendor.send);
-	rc = chip->vendor.send(chip, (uint8_t *) buf, count);
-	if (rc < 0) {
-		printk(BIOS_DEBUG, "tpm_transmit: tpm_send: error %zd\n", rc);
-		goto out;
+	/* prepare send buffer */
+	tpm_dev.buf[0] = addr;
+	memcpy(&(tpm_dev.buf[1]), buffer, len);
+
+	if (!tpm_dev.bus)
+		return -1;
+	for (count = 0; count < max_count; count++) {
+		rc = i2c_write(tpm_dev.bus, tpm_dev.addr, 0, 0,
+					tpm_dev.buf, len + 1);
+		if (rc == 0)
+			break;  /* success, break to skip sleep */
+
+		udelay(sleep_time);
 	}
 
-	if (chip->vendor.irq)
-		goto out_recv;
+	/* take care of 'guard time' */
+	udelay(SLEEP_DURATION);
+	if (rc)
+		return -1;
 
-	int timeout = 2 * 60 * 1000; /* two minutes timeout */
+	return 0;
+}
+
+/*
+ * iic_tpm_write() - write to TPM register
+ * @addr: register address to write to
+ * @buffer: containing data to be written
+ * @len: number of bytes to write
+ *
+ * Write len bytes from provided buffer to TPM register (little
+ * endian format, i.e. buffer[0] is written as first byte).
+ *
+ * NOTE: TPM is big-endian for multi-byte values. Multi-byte
+ * values have to be swapped.
+ *
+ * NOTE: use this function instead of the iic_tpm_write_generic function.
+ *
+ * Return -EIO on error, 0 on success
+ */
+static int iic_tpm_write(uint8_t addr, uint8_t *buffer, size_t len)
+{
+	return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION,
+			MAX_COUNT);
+}
+
+/*
+ * This function is needed especially for the cleanup situation after
+ * sending TPM_READY
+ * */
+static int iic_tpm_write_long(uint8_t addr, uint8_t *buffer, size_t len)
+{
+	return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG,
+			MAX_COUNT_LONG);
+}
+
+#define TPM_HEADER_SIZE 10
+
+enum tis_access {
+	TPM_ACCESS_VALID = 0x80,
+	TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
+	TPM_ACCESS_REQUEST_PENDING = 0x04,
+	TPM_ACCESS_REQUEST_USE = 0x02,
+};
+
+enum tis_status {
+	TPM_STS_VALID = 0x80,
+	TPM_STS_COMMAND_READY = 0x40,
+	TPM_STS_GO = 0x20,
+	TPM_STS_DATA_AVAIL = 0x10,
+	TPM_STS_DATA_EXPECT = 0x08,
+};
+
+#define	TPM_ACCESS(l)			(0x0000 | ((l) << 4))
+#define	TPM_STS(l)			(0x0001 | ((l) << 4))
+#define	TPM_DATA_FIFO(l)		(0x0005 | ((l) << 4))
+#define	TPM_DID_VID(l)			(0x0006 | ((l) << 4))
+
+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) {
-		ASSERT(chip->vendor.status);
-		uint8_t status = chip->vendor.status(chip);
-		if ((status & chip->vendor.req_complete_mask) ==
-		    chip->vendor.req_complete_val) {
-			goto out_recv;
-		}
+		if (check_locality(chip, loc) >= 0)
+			return loc;
+		mdelay(TPM_TIMEOUT);
+		timeout--;
+	}
 
-		if ((status == chip->vendor.req_canceled)) {
-			printk(BIOS_DEBUG, "tpm_transmit: Operation Canceled\n");
-			rc = -1;
-			goto out;
-		}
+	return -1;
+}
+
+static uint8_t tpm_tis_i2c_status(struct tpm_chip *chip)
+{
+	/* NOTE: Since I2C read may fail, return 0 in this case --> time-out */
+	uint8_t buf;
+	if (iic_tpm_read(TPM_STS(chip->vendor.locality), &buf, 1) < 0)
+		return 0;
+	else
+		return buf;
+}
+
+static void tpm_tis_i2c_ready(struct tpm_chip *chip)
+{
+	/* this causes the current command to be aborted */
+	uint8_t buf = TPM_STS_COMMAND_READY;
+	iic_tpm_write_long(TPM_STS(chip->vendor.locality), &buf, 1);
+}
+
+static ssize_t get_burstcount(struct tpm_chip *chip)
+{
+	ssize_t burstcnt;
+	uint8_t buf[3];
+
+	/* wait for burstcount */
+	int timeout = 2 * 1000; /* 2s timeout */
+	while (timeout) {
+		/* Note: STS is little endian */
+		if (iic_tpm_read(TPM_STS(chip->vendor.locality) + 1, buf, 3) < 0)
+			burstcnt = 0;
+		else
+			burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];
+
+		if (burstcnt)
+			return burstcnt;
 		mdelay(TPM_TIMEOUT);
 		timeout--;
 	}
+	return -1;
+}
+
+static int wait_for_stat(struct tpm_chip *chip, uint8_t mask, int *status)
+{
+	unsigned long timeout = 2 * 1024;
+	while (timeout) {
+		*status = tpm_tis_i2c_status(chip);
+		if ((*status & mask) == mask)
+			return 0;
+		mdelay(TPM_TIMEOUT);
+		timeout--;
+	}
+
+	return -1;
+}
+
+static int recv_data(struct tpm_chip *chip, uint8_t *buf, size_t count)
+{
+	size_t size = 0;
+
+	while (size < count) {
+		ssize_t burstcnt = get_burstcount(chip);
+		int rc;
+
+		/* burstcount < 0 = TPM is busy */
+		if (burstcnt < 0)
+			return burstcnt;
+
+		/* limit received data to max. left */
+		if (burstcnt > (count - size))
+			burstcnt = count - size;
+
+		rc = iic_tpm_read(TPM_DATA_FIFO(chip->vendor.locality),
+				  &(buf[size]),
+				  burstcnt);
+		if (rc == 0)
+			size += burstcnt;
+
+	}
+	return size;
+}
 
-	ASSERT(chip->vendor.cancel);
-	chip->vendor.cancel(chip);
-	printk(BIOS_DEBUG, "tpm_transmit: Operation Timed out\n");
-	rc = -1; //ETIME;
-	goto out;
+static int tpm_tis_i2c_recv(struct tpm_chip *chip, uint8_t *buf, size_t count)
+{
+	int size = 0;
+	uint32_t expected;
+	int status;
 
-out_recv:
+	if (count < TPM_HEADER_SIZE) {
+		size = -1;
+		goto out;
+	}
+
+	/* read first 10 bytes, including tag, paramsize, and result */
+	size = recv_data(chip, buf, TPM_HEADER_SIZE);
+	if (size < TPM_HEADER_SIZE) {
+		printk(BIOS_DEBUG, "tpm_tis_i2c_recv: Unable to read header\n");
+		goto out;
+	}
+
+	memcpy(&expected, buf + TPM_RSP_SIZE_BYTE, sizeof(expected));
+	expected = be32_to_cpu(expected);
+	if ((size_t)expected > count) {
+		size = -1;
+		goto out;
+	}
+
+	size += recv_data(chip, &buf[TPM_HEADER_SIZE],
+				expected - TPM_HEADER_SIZE);
+	if (size < expected) {
+		printk(BIOS_DEBUG, "tpm_tis_i2c_recv: Unable to "
+			"read remainder of result\n");
+		size = -1;
+		goto out;
+	}
+
+	wait_for_stat(chip, TPM_STS_VALID, &status);
+	if (status & TPM_STS_DATA_AVAIL) {	/* retry? */
+		printk(BIOS_DEBUG, "tpm_tis_i2c_recv: Error left over data\n");
+		size = -1;
+		goto out;
+	}
 
-	rc = chip->vendor.recv(chip, (uint8_t *) buf, TPM_BUFSIZE);
-	if (rc < 0)
-		printk(BIOS_DEBUG, "tpm_transmit: tpm_recv: error %zd\n", rc);
 out:
-	return rc;
+	tpm_tis_i2c_ready(chip);
+
+	return size;
 }
 
-#define TPM_ERROR_SIZE 10
+static int tpm_tis_i2c_send(struct tpm_chip *chip, uint8_t *buf, size_t len)
+{
+	int status;
+	size_t count = 0;
+	uint8_t sts = TPM_STS_GO;
+
+	if (len > TPM_BUFSIZE)
+		return -1; /* command is too long for our TPM, sorry */
+
+	status = tpm_tis_i2c_status(chip);
+	if ((status & TPM_STS_COMMAND_READY) == 0) {
+		tpm_tis_i2c_ready(chip);
+		if (wait_for_stat(chip, TPM_STS_COMMAND_READY, &status) < 0)
+			goto out_err;
+	}
+
+	while (count < len - 1) {
+		ssize_t burstcnt = get_burstcount(chip);
+
+		/* burstcount < 0 = TPM is busy */
+		if (burstcnt < 0)
+			return burstcnt;
+
+		if (burstcnt > (len-1-count))
+			burstcnt = len-1-count;
+
+#ifdef CONFIG_TPM_I2C_BURST_LIMITATION
+		if (burstcnt > CONFIG_TPM_I2C_BURST_LIMITATION)
+			burstcnt = CONFIG_TPM_I2C_BURST_LIMITATION;
+#endif /* CONFIG_TPM_I2C_BURST_LIMITATION */
+
+		if (iic_tpm_write(TPM_DATA_FIFO(chip->vendor.locality),
+						&(buf[count]), burstcnt) == 0)
+			count += burstcnt;
+
+		wait_for_stat(chip, TPM_STS_VALID, &status);
+		if ((status & TPM_STS_DATA_EXPECT) == 0)
+			goto out_err;
+	}
+
+	/* write last byte */
+	iic_tpm_write(TPM_DATA_FIFO(chip->vendor.locality), &(buf[count]), 1);
+
+	wait_for_stat(chip, TPM_STS_VALID, &status);
+	if ((status & TPM_STS_DATA_EXPECT) != 0)
+		goto out_err;
+
+	/* go and do it */
+	iic_tpm_write(TPM_STS(chip->vendor.locality), &sts, 1);
+
+	return len;
 
-struct tpm_chip *tpm_register_hardware(const struct tpm_vendor_specific *entry)
+out_err:
+	tpm_tis_i2c_ready(chip);
+
+	return -1;
+}
+
+static struct tpm_vendor_specific tpm_tis_i2c = {
+	.status = tpm_tis_i2c_status,
+	.recv = tpm_tis_i2c_recv,
+	.send = tpm_tis_i2c_send,
+	.cancel = tpm_tis_i2c_ready,
+	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+	.req_canceled = TPM_STS_COMMAND_READY,
+};
+
+/* Initialization of I2C TPM */
+
+int tpm_vendor_init(unsigned bus, uint32_t dev_addr)
 {
+	uint32_t vendor;
+	unsigned int old_addr;
 	struct tpm_chip *chip;
+	extern struct tpm_chip g_chip;
+
+	old_addr = tpm_dev.addr;
+	if (dev_addr != 0)
+		tpm_dev.addr = dev_addr;
+	tpm_dev.bus = bus;
 
-	/* Driver specific per-device data */
 	chip = &g_chip;
-	memcpy(&chip->vendor, entry, sizeof(struct tpm_vendor_specific));
+	memcpy(&chip->vendor, &tpm_tis_i2c, sizeof(struct tpm_vendor_specific));
 	chip->is_open = 1;
 
-	return chip;
-}
+	/* Disable interrupts (not supported) */
+	chip->vendor.irq = 0;
 
-int tpm_open(unsigned bus, uint32_t dev_addr)
-{
-	int rc;
-	if (g_chip.is_open)
-		return -1; //EBUSY;
-	rc = tpm_vendor_init(bus, dev_addr);
-	if (rc < 0)
-		g_chip.is_open = 0;
-	return rc;
+	if (request_locality(chip, 0) != 0)
+		goto out_err;
+
+	/* Read four bytes from DID_VID register */
+	if (iic_tpm_read(TPM_DID_VID(0), (uint8_t *)&vendor, 4) < 0)
+		goto out_release;
+
+	if (vendor == TPM_TIS_I2C_DID_VID_9645) {
+		tpm_dev.chip_type = SLB9645;
+	} else if (be32_to_cpu(vendor) == TPM_TIS_I2C_DID_VID_9635) {
+		tpm_dev.chip_type = SLB9635;
+	} else {
+		printk(BIOS_DEBUG, "Vendor ID 0x%08x not recognized.\n", vendor);
+		goto out_release;
+	}
+
+	printk(BIOS_DEBUG, "1.2 TPM (chip type %s device-id 0x%X)\n",
+		 chip_name[tpm_dev.chip_type], vendor >> 16);
+
+	/*
+	 * A timeout query to TPM can be placed here.
+	 * Standard timeout values are used so far
+	 */
+
+	return 0;
+
+out_release:
+	release_locality(chip, 0, 1);
+
+out_err:
+	tpm_dev.addr = old_addr;
+	return -1;
 }
 
-void tpm_close(void)
+void tpm_vendor_cleanup(struct tpm_chip *chip)
 {
-	if (g_chip.is_open) {
-		tpm_vendor_cleanup(&g_chip);
-		g_chip.is_open = 0;
-	}
+	release_locality(chip, chip->vendor.locality, 1);
 }