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/*
* Copyright (C) 2017 Intel Corporation
*
* 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.
*/
#include <arch/early_variables.h>
#include <stdint.h>
#include <assert.h>
#include <commonlib/endian.h>
#include <console/console.h>
#include <delay.h>
#include <device/i2c_simple.h>
#include <endian.h>
#include <lib.h>
#include <security/tpm/tis.h>
#include <timer.h>
#define RECV_TIMEOUT (1 * 1000) /* 1 second */
#define XMIT_TIMEOUT (1 * 1000) /* 1 second */
#define SLEEP_DURATION 1000 /* microseconds */
struct tpm_output_header {
uint16_t tag;
uint32_t length;
uint32_t return_code;
} __packed;
int tis_open(void)
{
return 0;
}
int tis_close(void)
{
return 0;
}
int tis_init(void)
{
return 0;
}
int tis_sendrecv(const uint8_t *sendbuf, size_t sbuf_size,
uint8_t *recvbuf, size_t *rbuf_len)
{
size_t hdr_bytes;
struct tpm_output_header *header;
size_t max_recv_bytes;
size_t recv_bytes;
int status;
struct stopwatch sw;
ASSERT(sbuf_size >= 10);
if (CONFIG(DRIVER_TPM_DISPLAY_TIS_BYTES)) {
/* Display the TPM command */
if (sbuf_size >= 10)
printk(BIOS_DEBUG, "TPM Command: 0x%08x\n",
read_at_be32(sendbuf, sizeof(uint16_t)
+ sizeof(uint32_t)));
hexdump(sendbuf, sbuf_size);
}
/* Send the command to the TPM */
stopwatch_init_msecs_expire(&sw, XMIT_TIMEOUT);
while (1) {
status = i2c_write_raw(CONFIG_DRIVER_TPM_I2C_BUS,
CONFIG_DRIVER_TPM_I2C_ADDR, (uint8_t *)sendbuf,
sbuf_size);
if ((status < 0) && (!stopwatch_expired(&sw)))
continue;
if (status < 0)
return status;
break;
}
/* Read the TPM response header */
max_recv_bytes = *rbuf_len;
ASSERT(max_recv_bytes >= sizeof(*header));
hdr_bytes = sizeof(*header);
header = (struct tpm_output_header *)recvbuf;
stopwatch_init_msecs_expire(&sw, RECV_TIMEOUT);
do {
status = i2c_read_raw(CONFIG_DRIVER_TPM_I2C_BUS,
CONFIG_DRIVER_TPM_I2C_ADDR, recvbuf, hdr_bytes);
if (status > 0)
break;
udelay(SLEEP_DURATION);
} while (!stopwatch_expired(&sw));
if (status != sizeof(*header))
return -1;
/* Determine the number of bytes remaining */
recv_bytes = min(be32_to_cpu(*(uint32_t *)&header->length),
max_recv_bytes);
/* Determine if there is additional response data */
if (recv_bytes > hdr_bytes) {
/* Display the TPM response */
if (CONFIG(DRIVER_TPM_DISPLAY_TIS_BYTES))
hexdump(recvbuf, hdr_bytes);
/* Read the full TPM response */
status = i2c_read_raw(CONFIG_DRIVER_TPM_I2C_BUS,
CONFIG_DRIVER_TPM_I2C_ADDR, recvbuf, recv_bytes);
if (status < 0)
return status;
}
/* Return the number of bytes received */
*rbuf_len = status;
/* Display the TPM response */
if (CONFIG(DRIVER_TPM_DISPLAY_TIS_BYTES)) {
printk(BIOS_DEBUG, "TPM Response: 0x%08x\n",
read_at_be32(recvbuf, sizeof(uint16_t)
+ sizeof(uint32_t)));
hexdump(recvbuf, *rbuf_len);
}
/* Successful transfer */
return 0;
}
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