Add TPM support to coreboot

and initialize the TPM on S3 resume

This patch integrates the TPM driver and runs TPM resume upon an ACPI S3
resume without including any other parts of vboot.

We could link against vboot_fw.a but it is compiled with u-boot's CFLAGS
(that are incompatible with coreboot's) and it does a lot more than we
want it to do.

Change-Id: I000d4322ef313e931e23c56defaa17e3a4d7f8cf
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/731
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

2 files changed, 555 insertions, 0 deletions

diff --git a/src/pc80/Makefile.inc b/src/pc80/Makefile.inc
index 2c8a80ee15..cd6ea33483 100644
--- a/src/pc80/Makefile.inc
+++ b/src/pc80/Makefile.inc
@@ -4,6 +4,7 @@ ramstage-y += i8254.c
 ramstage-y += i8259.c
 ramstage-$(CONFIG_UDELAY_IO) += udelay_io.c
 ramstage-y += keyboard.c
+ramstage-$(CONFIG_TPM) += tpm.c
 
 romstage-$(CONFIG_USE_OPTION_TABLE) += mc146818rtc_early.c
 subdirs-y += vga
diff --git a/src/pc80/tpm.c b/src/pc80/tpm.c
new file mode 100644
index 0000000000..1cbf800571
--- /dev/null
+++ b/src/pc80/tpm.c
@@ -0,0 +1,554 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2011 The Chromium OS Authors. All rights reserved.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/*
+ * The code in this file has been heavily based on the article "Writing a TPM
+ * Device Driver" published on http://ptgmedia.pearsoncmg.com and the
+ * submission by Stefan Berger on Qemu-devel mailing list.
+ *
+ * One principal difference is that in the simplest config the other than 0
+ * TPM localities do not get mapped by some devices (for instance, by
+ * Infineon slb9635), so this driver provides access to locality 0 only.
+ */
+
+/* #define DEBUG */
+#include <stdlib.h>
+#include <string.h>
+#include <delay.h>
+#include <arch/io.h>
+#include <arch/byteorder.h>
+#include <console/console.h>
+#include <pc80/tpm.h>
+
+#ifdef DEBUG
+#define TPM_DEBUG_ON	1
+#else
+#define TPM_DEBUG_ON	0
+#endif
+
+#define PREFIX "lpc_tpm: "
+
+/* coreboot wrapper for TPM driver (start) */
+#define	TPM_DEBUG(fmt, args...)		\
+	if (TPM_DEBUG_ON) {		\
+		printk(BIOS_DEBUG, PREFIX);		\
+		printk(BIOS_DEBUG, fmt , ##args);	\
+	}
+#define printf(x...) printk(BIOS_ERR, x)
+
+#define min(a,b) MIN(a,b)
+#define max(a,b) MAX(a,b)
+#define readb(_a) (*(volatile unsigned char *) (_a))
+#define writeb(_v, _a) (*(volatile unsigned char *) (_a) = (_v))
+#define readl(_a) (*(volatile unsigned long *) (_a))
+#define writel(_v, _a) (*(volatile unsigned long *) (_a) = (_v))
+/* coreboot wrapper for TPM driver (end) */
+
+#ifndef CONFIG_TPM_TIS_BASE_ADDRESS
+/* Base TPM address standard for x86 systems */
+#define CONFIG_TPM_TIS_BASE_ADDRESS        0xfed40000
+#endif
+
+/* the macro accepts the locality value, but only locality 0 is operational */
+#define TIS_REG(LOCALITY, REG) \
+    (void *)(CONFIG_TPM_TIS_BASE_ADDRESS + (LOCALITY << 12) + REG)
+
+/* hardware registers' offsets */
+#define TIS_REG_ACCESS                 0x0
+#define TIS_REG_INT_ENABLE             0x8
+#define TIS_REG_INT_VECTOR             0xc
+#define TIS_REG_INT_STATUS             0x10
+#define TIS_REG_INTF_CAPABILITY        0x14
+#define TIS_REG_STS                    0x18
+#define TIS_REG_DATA_FIFO              0x24
+#define TIS_REG_DID_VID                0xf00
+#define TIS_REG_RID                    0xf04
+
+/* Some registers' bit field definitions */
+#define TIS_STS_VALID                  (1 << 7) /* 0x80 */
+#define TIS_STS_COMMAND_READY          (1 << 6) /* 0x40 */
+#define TIS_STS_TPM_GO                 (1 << 5) /* 0x20 */
+#define TIS_STS_DATA_AVAILABLE         (1 << 4) /* 0x10 */
+#define TIS_STS_EXPECT                 (1 << 3) /* 0x08 */
+#define TIS_STS_RESPONSE_RETRY         (1 << 1) /* 0x02 */
+
+#define TIS_ACCESS_TPM_REG_VALID_STS   (1 << 7) /* 0x80 */
+#define TIS_ACCESS_ACTIVE_LOCALITY     (1 << 5) /* 0x20 */
+#define TIS_ACCESS_BEEN_SEIZED         (1 << 4) /* 0x10 */
+#define TIS_ACCESS_SEIZE               (1 << 3) /* 0x08 */
+#define TIS_ACCESS_PENDING_REQUEST     (1 << 2) /* 0x04 */
+#define TIS_ACCESS_REQUEST_USE         (1 << 1) /* 0x02 */
+#define TIS_ACCESS_TPM_ESTABLISHMENT   (1 << 0) /* 0x01 */
+
+#define TIS_STS_BURST_COUNT_MASK       (0xffff)
+#define TIS_STS_BURST_COUNT_SHIFT      (8)
+
+/*
+ * Error value returned if a tpm register does not enter the expected state
+ * after continuous polling. No actual TPM register reading ever returns ~0,
+ * so this value is a safe error indication to be mixed with possible status
+ * register values.
+ */
+#define TPM_TIMEOUT_ERR			(~0)
+
+/* Error value returned on various TPM driver errors */
+#define TPM_DRIVER_ERR		(~0)
+
+ /* 1 second is plenty for anything TPM does.*/
+#define MAX_DELAY_US	(1000 * 1000)
+
+/* Retrieve burst count value out of the status register contents. */
+#define BURST_COUNT(status) ((u16)(((status) >> TIS_STS_BURST_COUNT_SHIFT) & \
+				   TIS_STS_BURST_COUNT_MASK))
+
+/*
+ * Structures defined below allow creating descriptions of TPM vendor/device
+ * ID information for run time discovery. The only device the system knows
+ * about at this time is Infineon slb9635
+ */
+struct device_name {
+	u16 dev_id;
+	const char * const dev_name;
+};
+
+struct vendor_name {
+	u16 vendor_id;
+	const char * vendor_name;
+	struct device_name* dev_names;
+};
+
+static struct device_name infineon_devices[] = {
+	{0xb, "SLB9635 TT 1.2"},
+	{0}
+};
+
+static const struct vendor_name vendor_names[] = {
+	{0x15d1, "Infineon", infineon_devices},
+};
+
+/*
+ * Cached vendor/device ID pair to indicate that the device has been already
+ * discovered
+ */
+static u32 vendor_dev_id;
+
+static int is_byte_reg(u32 reg)
+{
+	/*
+	 * These TPM registers are 8 bits wide and as such require byte access
+	 * on writes and truncated value on reads.
+	 */
+	return ((reg == TIS_REG_ACCESS)	||
+		(reg == TIS_REG_INT_VECTOR) ||
+		(reg == TIS_REG_DATA_FIFO));
+}
+
+/* TPM access functions are carved out to make tracing easier. */
+static u32 tpm_read(int locality, u32 reg)
+{
+	u32 value;
+	/*
+	 * Data FIFO register must be read and written in byte access mode,
+	 * otherwise the FIFO values are returned 4 bytes at a time.
+	 */
+	if (is_byte_reg(reg))
+		value = readb(TIS_REG(locality, reg));
+	else
+		value = readl(TIS_REG(locality, reg));
+
+	TPM_DEBUG("Read reg 0x%x returns 0x%x\n", reg, value);
+	return value;
+}
+
+static void tpm_write(u32 value, int locality,  u32 reg)
+{
+	TPM_DEBUG("Write reg 0x%x with 0x%x\n", reg, value);
+
+	if (is_byte_reg(reg))
+		writeb(value & 0xff, TIS_REG(locality, reg));
+	else
+		writel(value, TIS_REG(locality, reg));
+}
+
+/*
+ * tis_wait_reg()
+ *
+ * Wait for at least a second for a register to change its state to match the
+ * expected state. Normally the transition happens within microseconds.
+ *
+ * @reg - the TPM register offset
+ * @locality - locality
+ * @mask - bitmask for the bitfield(s) to watch
+ * @expected - value the field(s) are supposed to be set to
+ *
+ * Returns the register contents in case the expected value was found in the
+ * appropriate register bits, or TPM_TIMEOUT_ERR on timeout.
+ */
+static u32 tis_wait_reg(u8 reg, u8 locality, u8 mask, u8 expected)
+{
+	u32 time_us = MAX_DELAY_US;
+	while (time_us > 0) {
+		u32 value = tpm_read(locality, reg);
+		if ((value & mask) == expected)
+			return value;
+		udelay(1); /* 1 us */
+		time_us--;
+	}
+	return TPM_TIMEOUT_ERR;
+}
+
+/*
+ * Probe the TPM device and try determining its manufacturer/device name.
+ *
+ * Returns 0 on success (the device is found or was found during an earlier
+ * invocation) or TPM_DRIVER_ERR if the device is not found.
+ */
+static u32 tis_probe(void)
+{
+	u32 didvid = tpm_read(0, TIS_REG_DID_VID);
+	int i;
+	const char *device_name = "unknown";
+	const char *vendor_name = device_name;
+	u16 vid, did;
+
+	if (vendor_dev_id)
+		return 0;  /* Already probed. */
+
+	if (!didvid || (didvid == 0xffffffff)) {
+		printf("%s: No TPM device found\n", __FUNCTION__);
+		return TPM_DRIVER_ERR;
+	}
+
+	vendor_dev_id = didvid;
+
+	vid = didvid & 0xffff;
+	did = (didvid >> 16) & 0xffff;
+	for (i = 0; i < ARRAY_SIZE(vendor_names); i++) {
+		int j = 0;
+		u16 known_did;
+		if (vid == vendor_names[i].vendor_id) {
+			vendor_name = vendor_names[i].vendor_name;
+		}
+		while ((known_did = vendor_names[i].dev_names[j].dev_id) != 0) {
+			if (known_did == did) {
+				device_name =
+					vendor_names[i].dev_names[j].dev_name;
+				break;
+			}
+			j++;
+		}
+		break;
+	}
+	/* this will have to be converted into debug printout */
+	TPM_DEBUG("Found TPM %s by %s\n", device_name, vendor_name);
+	return 0;
+}
+
+/*
+ * tis_senddata()
+ *
+ * send the passed in data to the TPM device.
+ *
+ * @data - address of the data to send, byte by byte
+ * @len - length of the data to send
+ *
+ * Returns 0 on success, TPM_DRIVER_ERR on error (in case the device does
+ * not accept the entire command).
+ */
+static u32 tis_senddata(const u8 * const data, u32 len)
+{
+	u32 offset = 0;
+	u16 burst = 0;
+	u32 max_cycles = 0;
+	u8 locality = 0;
+	u32 value;
+
+	value = tis_wait_reg(TIS_REG_STS, locality, TIS_STS_COMMAND_READY,
+			     TIS_STS_COMMAND_READY);
+	if (value == TPM_TIMEOUT_ERR) {
+		printf("%s:%d - failed to get 'command_ready' status\n",
+		       __FILE__, __LINE__);
+		return TPM_DRIVER_ERR;
+	}
+	burst = BURST_COUNT(value);
+
+	while (1) {
+		unsigned count;
+
+		/* Wait till the device is ready to accept more data. */
+		while (!burst) {
+			if (max_cycles++ == MAX_DELAY_US) {
+				printf("%s:%d failed to feed %d bytes of %d\n",
+				       __FILE__, __LINE__, len - offset, len);
+				return TPM_DRIVER_ERR;
+			}
+			udelay(1);
+			burst = BURST_COUNT(tpm_read(locality, TIS_REG_STS));
+		}
+
+		max_cycles = 0;
+
+		/*
+		 * Calculate number of bytes the TPM is ready to accept in one
+		 * shot.
+		 *
+		 * We want to send the last byte outside of the loop (hence
+		 * the -1 below) to make sure that the 'expected' status bit
+		 * changes to zero exactly after the last byte is fed into the
+		 * FIFO.
+		 */
+		count = min(burst, len - offset - 1);
+		while (count--)
+			tpm_write(data[offset++], locality, TIS_REG_DATA_FIFO);
+
+		value = tis_wait_reg(TIS_REG_STS, locality,
+				     TIS_STS_VALID, TIS_STS_VALID);
+
+		if ((value == TPM_TIMEOUT_ERR) || !(value & TIS_STS_EXPECT)) {
+			printf("%s:%d TPM command feed overflow\n",
+			       __FILE__, __LINE__);
+			return TPM_DRIVER_ERR;
+		}
+
+		burst = BURST_COUNT(value);
+		if ((offset == (len - 1)) && burst)
+			/*
+			 * We need to be able to send the last byte to the
+			 * device, so burst size must be nonzero before we
+			 * break out.
+			 */
+			break;
+	}
+
+	/* Send the last byte. */
+	tpm_write(data[offset++], locality, TIS_REG_DATA_FIFO);
+
+	/*
+	 * Verify that TPM does not expect any more data as part of this
+	 * command.
+	 */
+	value = tis_wait_reg(TIS_REG_STS, locality,
+			     TIS_STS_VALID, TIS_STS_VALID);
+	if ((value == TPM_TIMEOUT_ERR) || (value & TIS_STS_EXPECT)) {
+		printf("%s:%d unexpected TPM status 0x%x\n",
+		       __FILE__, __LINE__, value);
+		return TPM_DRIVER_ERR;
+	}
+
+	/* OK, sitting pretty, let's start the command execution. */
+	tpm_write(TIS_STS_TPM_GO, locality, TIS_REG_STS);
+
+	return 0;
+}
+
+/*
+ * tis_readresponse()
+ *
+ * read the TPM device response after a command was issued.
+ *
+ * @buffer - address where to read the response, byte by byte.
+ * @len - pointer to the size of buffer
+ *
+ * On success stores the number of received bytes to len and returns 0. On
+ * errors (misformatted TPM data or synchronization problems) returns
+ * TPM_DRIVER_ERR.
+ */
+static u32 tis_readresponse(u8 *buffer, size_t *len)
+{
+	u16 burst_count;
+	u32 status;
+	u32 offset = 0;
+	u8 locality = 0;
+	const u32 has_data = TIS_STS_DATA_AVAILABLE | TIS_STS_VALID;
+	u32 expected_count = *len;
+	int max_cycles = 0;
+
+	/* Wait for the TPM to process the command */
+	status = tis_wait_reg(TIS_REG_STS, locality, has_data, has_data);
+	if (status == TPM_TIMEOUT_ERR) {
+		printf("%s:%d failed processing command\n",
+		       __FILE__, __LINE__);
+		return TPM_DRIVER_ERR;
+	}
+
+	do {
+		while ((burst_count = BURST_COUNT(status)) == 0) {
+			if (max_cycles++ == MAX_DELAY_US) {
+				printf("%s:%d TPM stuck on read\n",
+				       __FILE__, __LINE__);
+				return TPM_DRIVER_ERR;
+			}
+			udelay(1);
+			status = tpm_read(locality, TIS_REG_STS);
+		}
+
+		max_cycles = 0;
+
+		while (burst_count-- && (offset < expected_count)) {
+			buffer[offset++] = (u8) tpm_read(locality,
+							 TIS_REG_DATA_FIFO);
+			if (offset == 6) {
+				/*
+				 * We got the first six bytes of the reply,
+				 * let's figure out how many bytes to expect
+				 * total - it is stored as a 4 byte number in
+				 * network order, starting with offset 2 into
+				 * the body of the reply.
+				 */
+				u32 real_length;
+				memcpy(&real_length,
+				       buffer + 2,
+				       sizeof(real_length));
+				expected_count = be32_to_cpu(real_length);
+
+				if ((expected_count < offset) ||
+				    (expected_count > *len)) {
+					printf("%s:%d bad response size %d\n",
+					       __FILE__, __LINE__,
+					       expected_count);
+					return TPM_DRIVER_ERR;
+				}
+			}
+		}
+
+		/* Wait for the next portion */
+		status = tis_wait_reg(TIS_REG_STS, locality,
+				      TIS_STS_VALID, TIS_STS_VALID);
+		if (status == TPM_TIMEOUT_ERR) {
+			printf("%s:%d failed to read response\n",
+			       __FILE__, __LINE__);
+			return TPM_DRIVER_ERR;
+		}
+
+		if (offset == expected_count)
+			break;	/* We got all we need */
+
+	} while ((status & has_data) == has_data);
+
+	/*
+	 * Make sure we indeed read all there was. The TIS_STS_VALID bit is
+	 * known to be set.
+	 */
+	if (status & TIS_STS_DATA_AVAILABLE) {
+		printf("%s:%d wrong receive status %x\n",
+		       __FILE__, __LINE__, status);
+		return TPM_DRIVER_ERR;
+	}
+
+	/* Tell the TPM that we are done. */
+	tpm_write(TIS_STS_COMMAND_READY, locality, TIS_REG_STS);
+
+	*len = offset;
+	return 0;
+}
+
+/*
+ * tis_init()
+ *
+ * Initialize the TPM device. Returns 0 on success or TPM_DRIVER_ERR on
+ * failure (in case device probing did not succeed).
+ */
+int tis_init(void)
+{
+	if (tis_probe())
+		return TPM_DRIVER_ERR;
+	return 0;
+}
+
+/*
+ * tis_open()
+ *
+ * Requests access to locality 0 for the caller. After all commands have been
+ * completed the caller is supposed to call tis_close().
+ *
+ * Returns 0 on success, TPM_DRIVER_ERR on failure.
+ */
+int tis_open(void)
+{
+	u8 locality = 0; /* we use locality zero for everything */
+
+	if (tis_close())
+		return TPM_DRIVER_ERR;
+
+	/* now request access to locality */
+	tpm_write(TIS_ACCESS_REQUEST_USE, locality, TIS_REG_ACCESS);
+
+	/* did we get a lock? */
+	if (tis_wait_reg(TIS_REG_ACCESS, locality,
+			 TIS_ACCESS_ACTIVE_LOCALITY,
+			 TIS_ACCESS_ACTIVE_LOCALITY) == TPM_TIMEOUT_ERR) {
+		printf("%s:%d - failed to lock locality %d\n",
+		       __FILE__, __LINE__, locality);
+		return TPM_DRIVER_ERR;
+	}
+
+	tpm_write(TIS_STS_COMMAND_READY, locality, TIS_REG_STS);
+
+	return 0;
+}
+
+/*
+ * tis_close()
+ *
+ * terminate the currect session with the TPM by releasing the locked
+ * locality. Returns 0 on success of TPM_DRIVER_ERR on failure (in case lock
+ * removal did not succeed).
+ */
+int tis_close(void)
+{
+	u8 locality = 0;
+	if (tpm_read(locality, TIS_REG_ACCESS) &
+	    TIS_ACCESS_ACTIVE_LOCALITY) {
+		tpm_write(TIS_ACCESS_ACTIVE_LOCALITY, locality, TIS_REG_ACCESS);
+
+		if (tis_wait_reg(TIS_REG_ACCESS, locality,
+				 TIS_ACCESS_ACTIVE_LOCALITY, 0) ==
+		    TPM_TIMEOUT_ERR) {
+			printf("%s:%d - failed to release locality %d\n",
+			       __FILE__, __LINE__, locality);
+			return TPM_DRIVER_ERR;
+		}
+	}
+	return 0;
+}
+
+/*
+ * tis_sendrecv()
+ *
+ * Send the requested data to the TPM and then try to get its response
+ *
+ * @sendbuf - buffer of the data to send
+ * @send_size size of the data to send
+ * @recvbuf - memory to save the response to
+ * @recv_len - pointer to the size of the response buffer
+ *
+ * Returns 0 on success (and places the number of response bytes at recv_len)
+ * or TPM_DRIVER_ERR on failure.
+ */
+int tis_sendrecv(const uint8_t *sendbuf, size_t send_size,
+		 uint8_t *recvbuf, size_t *recv_len)
+{
+	if (tis_senddata(sendbuf, send_size)) {
+		printf("%s:%d failed sending data to TPM\n",
+		       __FILE__, __LINE__);
+		return TPM_DRIVER_ERR;
+	}
+
+	return tis_readresponse(recvbuf, recv_len);
+}