tpm: Rename generic_lpc_tpm to tpm_tis_lpc
authorChe-liang Chiou <clchiou@chromium.org>
Fri, 12 Apr 2013 11:04:34 +0000 (11:04 +0000)
committerSimon Glass <sjg@chromium.org>
Mon, 3 Jun 2013 08:26:25 +0000 (01:26 -0700)
The new name is more aligned with Linux kernel's naming of TPM driver.

Signed-off-by: Peter Huewe <peter.huewe@infineon.com>
Signed-off-by: Che-Liang Chiou <clchiou@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Tom Wai-Hong Tam <waihong@chromium.org>
README
drivers/tpm/Makefile
drivers/tpm/generic_lpc_tpm.c [deleted file]
drivers/tpm/tpm_tis_lpc.c [new file with mode: 0644]

diff --git a/README b/README
index b1b3e1788ec92d8ba088dab91175dfb1a44e2e26..b025dfc24aec94f06b9f235bfe582c4e0897c3af 100644 (file)
--- a/README
+++ b/README
@@ -1209,7 +1209,10 @@ The following options need to be configured:
                        If this option is set, the driver enables cache flush.
 
 - TPM Support:
-               CONFIG_GENERIC_LPC_TPM
+               CONFIG_TPM
+               Support TPM devices.
+
+               CONFIG_TPM_TIS_LPC
                Support for generic parallel port TPM devices. Only one device
                per system is supported at this time.
 
index e8c159c0f3fee868c68c42a34e35799e87ce7c25..d1f9bbf24114f67c0755ebe071262e04c520646c 100644 (file)
@@ -25,7 +25,7 @@ LIB := $(obj)libtpm.o
 
 $(shell mkdir -p $(obj)slb9635_i2c)
 
-COBJS-$(CONFIG_GENERIC_LPC_TPM) = generic_lpc_tpm.o
+COBJS-$(CONFIG_TPM_TIS_LPC) = tpm_tis_lpc.o
 COBJS-$(CONFIG_INFINEON_TPM_I2C) += tis_i2c.o slb9635_i2c/tpm.o
 COBJS-$(CONFIG_INFINEON_TPM_I2C) += slb9635_i2c/tpm_tis_i2c.o
 
diff --git a/drivers/tpm/generic_lpc_tpm.c b/drivers/tpm/generic_lpc_tpm.c
deleted file mode 100644 (file)
index 04ad418..0000000
+++ /dev/null
@@ -1,495 +0,0 @@
-/*
- * 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);
-}
diff --git a/drivers/tpm/tpm_tis_lpc.c b/drivers/tpm/tpm_tis_lpc.c
new file mode 100644 (file)
index 0000000..04ad418
--- /dev/null
@@ -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);
+}