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path: root/drivers/tpm/tpm_tis_lpc.c
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Diffstat (limited to 'drivers/tpm/tpm_tis_lpc.c')
-rw-r--r--drivers/tpm/tpm_tis_lpc.c495
1 files changed, 495 insertions, 0 deletions
diff --git a/drivers/tpm/tpm_tis_lpc.c b/drivers/tpm/tpm_tis_lpc.c
new file mode 100644
index 0000000000..04ad418973
--- /dev/null
+++ b/drivers/tpm/tpm_tis_lpc.c
@@ -0,0 +1,495 @@
+/*
+ * Copyright (c) 2011 The Chromium OS Authors.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * The code in this file is based on the article "Writing a TPM Device Driver"
+ * published on http://ptgmedia.pearsoncmg.com.
+ *
+ * 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.
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <tpm.h>
+
+#define PREFIX "lpc_tpm: "
+
+struct tpm_locality {
+ u32 access;
+ u8 padding0[4];
+ u32 int_enable;
+ u8 vector;
+ u8 padding1[3];
+ u32 int_status;
+ u32 int_capability;
+ u32 tpm_status;
+ u8 padding2[8];
+ u8 data;
+ u8 padding3[3803];
+ u32 did_vid;
+ u8 rid;
+ u8 padding4[251];
+};
+
+/*
+ * This pointer refers to the TPM chip, 5 of its localities are mapped as an
+ * array.
+ */
+#define TPM_TOTAL_LOCALITIES 5
+static struct tpm_locality *lpc_tpm_dev =
+ (struct tpm_locality *)CONFIG_TPM_TIS_BASE_ADDRESS;
+
+/* 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 -1,
+ * so this value is a safe error indication to be mixed with possible status
+ * register values.
+ */
+#define TPM_TIMEOUT_ERR (-1)
+
+/* Error value returned on various TPM driver errors. */
+#define TPM_DRIVER_ERR (1)
+
+ /* 1 second is plenty for anything TPM does. */
+#define MAX_DELAY_US (1000 * 1000)
+
+/* Retrieve burst count value out of the status register contents. */
+static u16 burst_count(u32 status)
+{
+ return (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;
+ const struct device_name *dev_names;
+};
+
+static const 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;
+
+/* TPM access wrappers to support tracing */
+static u8 tpm_read_byte(const u8 *ptr)
+{
+ u8 ret = readb(ptr);
+ debug(PREFIX "Read reg 0x%4.4x returns 0x%2.2x\n",
+ (u32)(uintptr_t)ptr - (u32)(uintptr_t)lpc_tpm_dev, ret);
+ return ret;
+}
+
+static u32 tpm_read_word(const u32 *ptr)
+{
+ u32 ret = readl(ptr);
+ debug(PREFIX "Read reg 0x%4.4x returns 0x%8.8x\n",
+ (u32)(uintptr_t)ptr - (u32)(uintptr_t)lpc_tpm_dev, ret);
+ return ret;
+}
+
+static void tpm_write_byte(u8 value, u8 *ptr)
+{
+ debug(PREFIX "Write reg 0x%4.4x with 0x%2.2x\n",
+ (u32)(uintptr_t)ptr - (u32)(uintptr_t)lpc_tpm_dev, value);
+ writeb(value, ptr);
+}
+
+static void tpm_write_word(u32 value, u32 *ptr)
+{
+ debug(PREFIX "Write reg 0x%4.4x with 0x%8.8x\n",
+ (u32)(uintptr_t)ptr - (u32)(uintptr_t)lpc_tpm_dev, value);
+ writel(value, ptr);
+}
+
+/*
+ * 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 - pointer to the TPM register
+ * @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(u32 *reg, u8 mask, u8 expected)
+{
+ u32 time_us = MAX_DELAY_US;
+
+ while (time_us > 0) {
+ u32 value = tpm_read_word(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.
+ */
+int tis_init(void)
+{
+ u32 didvid = tpm_read_word(&lpc_tpm_dev[0].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", __func__);
+ 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;
+ }
+
+ printf("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(&lpc_tpm_dev[locality].tpm_status,
+ 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_word(&lpc_tpm_dev
+ [locality].tpm_status));
+ }
+
+ 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_byte(data[offset++],
+ &lpc_tpm_dev[locality].data);
+
+ value = tis_wait_reg(&lpc_tpm_dev[locality].tpm_status,
+ 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_byte(data[offset++], &lpc_tpm_dev[locality].data);
+ /*
+ * Verify that TPM does not expect any more data as part of this
+ * command.
+ */
+ value = tis_wait_reg(&lpc_tpm_dev[locality].tpm_status,
+ 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_word(TIS_STS_TPM_GO, &lpc_tpm_dev[locality].tpm_status);
+ 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, u32 *len)
+{
+ u16 burst;
+ u32 value;
+ 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. */
+ value = tis_wait_reg(&lpc_tpm_dev[locality].tpm_status,
+ has_data, has_data);
+ if (value == TPM_TIMEOUT_ERR) {
+ printf("%s:%d failed processing command\n",
+ __FILE__, __LINE__);
+ return TPM_DRIVER_ERR;
+ }
+
+ do {
+ while ((burst = burst_count(value)) == 0) {
+ if (max_cycles++ == MAX_DELAY_US) {
+ printf("%s:%d TPM stuck on read\n",
+ __FILE__, __LINE__);
+ return TPM_DRIVER_ERR;
+ }
+ udelay(1);
+ value = tpm_read_word(&lpc_tpm_dev
+ [locality].tpm_status);
+ }
+
+ max_cycles = 0;
+
+ while (burst-- && (offset < expected_count)) {
+ buffer[offset++] = tpm_read_byte(&lpc_tpm_dev
+ [locality].data);
+
+ 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. */
+ value = tis_wait_reg(&lpc_tpm_dev[locality].tpm_status,
+ TIS_STS_VALID, TIS_STS_VALID);
+ if (value == 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 needed. */
+
+ } while ((value & has_data) == has_data);
+
+ /*
+ * Make sure we indeed read all there was. The TIS_STS_VALID bit is
+ * known to be set.
+ */
+ if (value & TIS_STS_DATA_AVAILABLE) {
+ printf("%s:%d wrong receive status %x\n",
+ __FILE__, __LINE__, value);
+ return TPM_DRIVER_ERR;
+ }
+
+ /* Tell the TPM that we are done. */
+ tpm_write_word(TIS_STS_COMMAND_READY, &lpc_tpm_dev
+ [locality].tpm_status);
+ *len = offset;
+ return 0;
+}
+
+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_word(TIS_ACCESS_REQUEST_USE, &lpc_tpm_dev[locality].access);
+
+ /* did we get a lock? */
+ if (tis_wait_reg(&lpc_tpm_dev[locality].access,
+ 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_word(TIS_STS_COMMAND_READY,
+ &lpc_tpm_dev[locality].tpm_status);
+ return 0;
+}
+
+int tis_close(void)
+{
+ u8 locality = 0;
+
+ if (tpm_read_word(&lpc_tpm_dev[locality].access) &
+ TIS_ACCESS_ACTIVE_LOCALITY) {
+ tpm_write_word(TIS_ACCESS_ACTIVE_LOCALITY,
+ &lpc_tpm_dev[locality].access);
+
+ if (tis_wait_reg(&lpc_tpm_dev[locality].access,
+ 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;
+}
+
+int tis_sendrecv(const u8 *sendbuf, size_t send_size,
+ u8 *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, (u32 *)recv_len);
+}
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