u-boot/drivers/tpm/tis_i2c.c

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/*
* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include <config.h>
#include <common.h>
#include <fdtdec.h>
#include <i2c.h>
#include "slb9635_i2c/tpm.h"
DECLARE_GLOBAL_DATA_PTR;
/* TPM configuration */
struct tpm {
int i2c_bus;
int slave_addr;
char inited;
int old_bus;
} tpm;
static int tpm_select(void)
{
int ret;
tpm.old_bus = i2c_get_bus_num();
if (tpm.old_bus != tpm.i2c_bus) {
ret = i2c_set_bus_num(tpm.i2c_bus);
if (ret) {
debug("%s: Fail to set i2c bus %d\n", __func__,
tpm.i2c_bus);
return -1;
}
}
return 0;
}
static int tpm_deselect(void)
{
int ret;
if (tpm.old_bus != i2c_get_bus_num()) {
ret = i2c_set_bus_num(tpm.old_bus);
if (ret) {
debug("%s: Fail to restore i2c bus %d\n",
__func__, tpm.old_bus);
return -1;
}
}
tpm.old_bus = -1;
return 0;
}
/**
* Decode TPM configuration.
*
* @param dev Returns a configuration of TPM device
* @return 0 if ok, -1 on error
*/
static int tpm_decode_config(struct tpm *dev)
{
#ifdef CONFIG_OF_CONTROL
const void *blob = gd->fdt_blob;
int node, parent;
int i2c_bus;
node = fdtdec_next_compatible(blob, 0, COMPAT_INFINEON_SLB9635_TPM);
if (node < 0) {
node = fdtdec_next_compatible(blob, 0,
COMPAT_INFINEON_SLB9645_TPM);
}
if (node < 0) {
debug("%s: Node not found\n", __func__);
return -1;
}
parent = fdt_parent_offset(blob, node);
if (parent < 0) {
debug("%s: Cannot find node parent\n", __func__);
return -1;
}
i2c_bus = i2c_get_bus_num_fdt(parent);
if (i2c_bus < 0)
return -1;
dev->i2c_bus = i2c_bus;
dev->slave_addr = fdtdec_get_addr(blob, node, "reg");
#else
dev->i2c_bus = CONFIG_INFINEON_TPM_I2C_BUS;
dev->slave_addr = CONFIG_INFINEON_TPM_I2C_ADDR;
#endif
return 0;
}
int tis_init(void)
{
if (tpm.inited)
return 0;
if (tpm_decode_config(&tpm))
return -1;
if (tpm_select())
return -1;
/*
* Probe TPM twice; the first probing might fail because TPM is asleep,
* and the probing can wake up TPM.
*/
if (i2c_probe(tpm.slave_addr) && i2c_probe(tpm.slave_addr)) {
debug("%s: fail to probe i2c addr 0x%x\n", __func__,
tpm.slave_addr);
return -1;
}
tpm_deselect();
tpm.inited = 1;
return 0;
}
int tis_open(void)
{
int rc;
if (!tpm.inited)
return -1;
if (tpm_select())
return -1;
rc = tpm_open(tpm.slave_addr);
tpm_deselect();
return rc;
}
int tis_close(void)
{
if (!tpm.inited)
return -1;
if (tpm_select())
return -1;
tpm_close();
tpm_deselect();
return 0;
}
int tis_sendrecv(const uint8_t *sendbuf, size_t sbuf_size,
uint8_t *recvbuf, size_t *rbuf_len)
{
int len;
uint8_t buf[4096];
if (!tpm.inited)
return -1;
if (sizeof(buf) < sbuf_size)
return -1;
memcpy(buf, sendbuf, sbuf_size);
if (tpm_select())
return -1;
len = tpm_transmit(buf, sbuf_size);
tpm_deselect();
if (len < 10) {
*rbuf_len = 0;
return -1;
}
memcpy(recvbuf, buf, len);
*rbuf_len = len;
return 0;
}