diff options
Diffstat (limited to 'drivers/tpm')
| -rw-r--r-- | drivers/tpm/Makefile | 43 | ||||
| -rw-r--r-- | drivers/tpm/generic_lpc_tpm.c | 495 |
2 files changed, 538 insertions, 0 deletions
diff --git a/drivers/tpm/Makefile b/drivers/tpm/Makefile new file mode 100644 index 0000000..be11c8b --- /dev/null +++ b/drivers/tpm/Makefile @@ -0,0 +1,43 @@ +# Copyright (c) 2011 The Chromium OS Authors. All rights reserved. +# +# 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 +# + +include $(TOPDIR)/config.mk + +LIB := $(obj)libtpm.o + +COBJS-$(CONFIG_GENERIC_LPC_TPM) = generic_lpc_tpm.o + +COBJS := $(COBJS-y) +SRCS := $(COBJS:.o=.c) +OBJS := $(addprefix $(obj),$(COBJS)) + +all: $(LIB) + +$(LIB): $(obj).depend $(OBJS) + $(call cmd_link_o_target, $(OBJS)) + +######################################################################### + +include $(SRCTREE)/rules.mk + +sinclude $(obj).depend + +######################################################################### diff --git a/drivers/tpm/generic_lpc_tpm.c b/drivers/tpm/generic_lpc_tpm.c new file mode 100644 index 0000000..6c494eb --- /dev/null +++ b/drivers/tpm/generic_lpc_tpm.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)ptr - (u32)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)ptr - (u32)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)ptr - (u32)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)ptr - (u32)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, recv_len); +} |