u-boot/drivers/tpm/tpm_tis_st33zp24_i2c.c

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/*
* STMicroelectronics TPM ST33ZP24 I2C UBOOT driver
*
* Copyright (C) 2016 STMicroelectronics
*
* Description: Device driver for ST33ZP24 I2C TPM TCG.
*
* This device driver implements the TPM interface as defined in
* the TCG TPM Interface Spec version 1.21, revision 1.0 and the
* STMicroelectronics Protocol Stack Specification version 1.2.0.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <fdtdec.h>
#include <i2c.h>
#include <tpm.h>
#include <errno.h>
#include <linux/types.h>
#include <asm/unaligned.h>
#include "tpm_tis.h"
#include "tpm_internal.h"
#define TPM_ACCESS 0x0
#define TPM_STS 0x18
#define TPM_DATA_FIFO 0x24
#define LOCALITY0 0
#define TPM_DUMMY_BYTE 0xAA
#define TPM_ST33ZP24_I2C_SLAVE_ADDR 0x13
#define TPM_WRITE_DIRECTION 0x80
/*
* st33zp24_i2c_write8_reg
* Send byte to the TIS register according to the ST33ZP24 I2C protocol.
* @param: tpm_register, the tpm tis register where the data should be written
* @param: tpm_data, the tpm_data to write inside the tpm_register
* @param: tpm_size, The length of the data
* @return: Number of byte written successfully else an error code.
*/
static int st33zp24_i2c_write8_reg(struct udevice *dev, u8 tpm_register,
const u8 *tpm_data, size_t tpm_size)
{
struct tpm_chip_priv *chip_priv = dev_get_uclass_priv(dev);
chip_priv->buf[0] = tpm_register;
memcpy(chip_priv->buf + 1, tpm_data, tpm_size);
return dm_i2c_write(dev, 0, chip_priv->buf, tpm_size + 1);
}
/*
* st33zp24_i2c_read8_reg
* Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
* @param: tpm_register, the tpm tis register where the data should be read
* @param: tpm_data, the TPM response
* @param: tpm_size, tpm TPM response size to read.
* @return: Number of byte read successfully else an error code.
*/
static int st33zp24_i2c_read8_reg(struct udevice *dev, u8 tpm_register,
u8 *tpm_data, size_t tpm_size)
{
int status;
u8 data;
data = TPM_DUMMY_BYTE;
status = st33zp24_i2c_write8_reg(dev, tpm_register, &data, 1);
if (status < 0)
return status;
return dm_i2c_read(dev, 0, tpm_data, tpm_size);
}
/*
* st33zp24_i2c_write
* Send byte to the TIS register according to the ST33ZP24 I2C protocol.
* @param: phy_id, the phy description
* @param: tpm_register, the tpm tis register where the data should be written
* @param: tpm_data, the tpm_data to write inside the tpm_register
* @param: tpm_size, the length of the data
* @return: number of byte written successfully: should be one if success.
*/
static int st33zp24_i2c_write(struct udevice *dev, u8 tpm_register,
const u8 *tpm_data, size_t tpm_size)
{
return st33zp24_i2c_write8_reg(dev, tpm_register | TPM_WRITE_DIRECTION,
tpm_data, tpm_size);
}
/*
* st33zp24_i2c_read
* Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
* @param: phy_id, the phy description
* @param: tpm_register, the tpm tis register where the data should be read
* @param: tpm_data, the TPM response
* @param: tpm_size, tpm TPM response size to read.
* @return: number of byte read successfully: should be one if success.
*/
static int st33zp24_i2c_read(struct udevice *dev, u8 tpm_register,
u8 *tpm_data, size_t tpm_size)
{
return st33zp24_i2c_read8_reg(dev, tpm_register, tpm_data, tpm_size);
}
/*
* st33zp24_i2c_release_locality release the active locality
* @param: chip, the tpm chip description.
*/
static void st33zp24_i2c_release_locality(struct udevice *dev)
{
u8 data = TPM_ACCESS_ACTIVE_LOCALITY;
st33zp24_i2c_write(dev, TPM_ACCESS, &data, 1);
}
/*
* st33zp24_i2c_check_locality if the locality is active
* @param: chip, the tpm chip description
* @return: the active locality or -EACCES.
*/
static int st33zp24_i2c_check_locality(struct udevice *dev)
{
struct tpm_chip *chip = dev_get_priv(dev);
u8 data;
u8 status;
status = st33zp24_i2c_read(dev, TPM_ACCESS, &data, 1);
if (!status && (data &
(TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
(TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
return chip->locality;
return -EACCES;
}
/*
* st33zp24_i2c_request_locality request the TPM locality
* @param: chip, the chip description
* @return: the active locality or negative value.
*/
static int st33zp24_i2c_request_locality(struct udevice *dev)
{
struct tpm_chip *chip = dev_get_priv(dev);
unsigned long start, stop;
long ret;
u8 data;
if (st33zp24_i2c_check_locality(dev) == chip->locality)
return chip->locality;
data = TPM_ACCESS_REQUEST_USE;
ret = st33zp24_i2c_write(dev, TPM_ACCESS, &data, 1);
if (ret < 0)
return ret;
/* wait for locality activated */
start = get_timer(0);
stop = chip->timeout_a;
do {
if (st33zp24_i2c_check_locality(dev) >= 0)
return chip->locality;
udelay(TPM_TIMEOUT_MS * 1000);
} while (get_timer(start) < stop);
return -EACCES;
}
/*
* st33zp24_i2c_status return the TPM_STS register
* @param: chip, the tpm chip description
* @return: the TPM_STS register value.
*/
static u8 st33zp24_i2c_status(struct udevice *dev)
{
u8 data;
st33zp24_i2c_read(dev, TPM_STS, &data, 1);
return data;
}
/*
* st33zp24_i2c_get_burstcount return the burstcount address 0x19 0x1A
* @param: chip, the chip description
* return: the burstcount or -TPM_DRIVER_ERR in case of error.
*/
static int st33zp24_i2c_get_burstcount(struct udevice *dev)
{
struct tpm_chip *chip = dev_get_priv(dev);
unsigned long start, stop;
int burstcnt, status;
u8 tpm_reg, temp;
/* wait for burstcount */
start = get_timer(0);
stop = chip->timeout_d;
do {
tpm_reg = TPM_STS + 1;
status = st33zp24_i2c_read(dev, tpm_reg, &temp, 1);
if (status < 0)
return -EBUSY;
tpm_reg = TPM_STS + 2;
burstcnt = temp;
status = st33zp24_i2c_read(dev, tpm_reg, &temp, 1);
if (status < 0)
return -EBUSY;
burstcnt |= temp << 8;
if (burstcnt)
return burstcnt;
udelay(TIS_SHORT_TIMEOUT_MS * 1000);
} while (get_timer(start) < stop);
return -EBUSY;
}
/*
* st33zp24_i2c_cancel, cancel the current command execution or
* set STS to COMMAND READY.
* @param: chip, tpm_chip description.
*/
static void st33zp24_i2c_cancel(struct udevice *dev)
{
u8 data;
data = TPM_STS_COMMAND_READY;
st33zp24_i2c_write(dev, TPM_STS, &data, 1);
}
/*
* st33zp24_i2c_wait_for_stat wait for a TPM_STS value
* @param: chip, the tpm chip description
* @param: mask, the value mask to wait
* @param: timeout, the timeout
* @param: status,
* @return: the tpm status, 0 if success, -ETIME if timeout is reached.
*/
static int st33zp24_i2c_wait_for_stat(struct udevice *dev, u8 mask,
unsigned long timeout, int *status)
{
unsigned long start, stop;
/* Check current status */
*status = st33zp24_i2c_status(dev);
if ((*status & mask) == mask)
return 0;
start = get_timer(0);
stop = timeout;
do {
udelay(TPM_TIMEOUT_MS * 1000);
*status = st33zp24_i2c_status(dev);
if ((*status & mask) == mask)
return 0;
} while (get_timer(start) < stop);
return -ETIME;
}
/*
* st33zp24_i2c_recv_data receive data
* @param: chip, the tpm chip description
* @param: buf, the buffer where the data are received
* @param: count, the number of data to receive
* @return: the number of bytes read from TPM FIFO.
*/
static int st33zp24_i2c_recv_data(struct udevice *dev, u8 *buf, size_t count)
{
struct tpm_chip *chip = dev_get_priv(dev);
int size = 0, burstcnt, len, ret, status;
while (size < count &&
st33zp24_i2c_wait_for_stat(dev, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
chip->timeout_c, &status) == 0) {
burstcnt = st33zp24_i2c_get_burstcount(dev);
if (burstcnt < 0)
return burstcnt;
len = min_t(int, burstcnt, count - size);
ret = st33zp24_i2c_read(dev, TPM_DATA_FIFO, buf + size, len);
if (ret < 0)
return ret;
size += len;
}
return size;
}
/*
* st33zp24_i2c_recv received TPM response through TPM phy.
* @param: chip, tpm_chip description.
* @param: buf, the buffer to store data.
* @param: count, the number of bytes that can received (sizeof buf).
* @return: Returns zero in case of success else -EIO.
*/
static int st33zp24_i2c_recv(struct udevice *dev, u8 *buf, size_t count)
{
struct tpm_chip *chip = dev_get_priv(dev);
int size, expected;
if (!chip)
return -ENODEV;
if (count < TPM_HEADER_SIZE) {
size = -EIO;
goto out;
}
size = st33zp24_i2c_recv_data(dev, buf, TPM_HEADER_SIZE);
if (size < TPM_HEADER_SIZE) {
debug("TPM error, unable to read header\n");
goto out;
}
expected = get_unaligned_be32(buf + 2);
if (expected > count) {
size = -EIO;
goto out;
}
size += st33zp24_i2c_recv_data(dev, &buf[TPM_HEADER_SIZE],
expected - TPM_HEADER_SIZE);
if (size < expected) {
debug("TPM error, unable to read remaining bytes of result\n");
size = -EIO;
goto out;
}
out:
st33zp24_i2c_cancel(dev);
st33zp24_i2c_release_locality(dev);
return size;
}
/*
* st33zp24_i2c_send send TPM commands through TPM phy.
* @param: chip, tpm_chip description.
* @param: buf, the buffer to send.
* @param: len, the number of bytes to send.
* @return: Returns zero in case of success else the negative error code.
*/
static int st33zp24_i2c_send(struct udevice *dev, const u8 *buf, size_t len)
{
struct tpm_chip *chip = dev_get_priv(dev);
u32 i, size;
int burstcnt, ret, status;
u8 data, tpm_stat;
if (!chip)
return -ENODEV;
if (len < TPM_HEADER_SIZE)
return -EIO;
ret = st33zp24_i2c_request_locality(dev);
if (ret < 0)
return ret;
tpm_stat = st33zp24_i2c_status(dev);
if ((tpm_stat & TPM_STS_COMMAND_READY) == 0) {
st33zp24_i2c_cancel(dev);
if (st33zp24_i2c_wait_for_stat(dev, TPM_STS_COMMAND_READY,
chip->timeout_b, &status) < 0) {
ret = -ETIME;
goto out_err;
}
}
for (i = 0; i < len - 1;) {
burstcnt = st33zp24_i2c_get_burstcount(dev);
if (burstcnt < 0)
return burstcnt;
size = min_t(int, len - i - 1, burstcnt);
ret = st33zp24_i2c_write(dev, TPM_DATA_FIFO, buf + i, size);
if (ret < 0)
goto out_err;
i += size;
}
tpm_stat = st33zp24_i2c_status(dev);
if ((tpm_stat & TPM_STS_DATA_EXPECT) == 0) {
ret = -EIO;
goto out_err;
}
ret = st33zp24_i2c_write(dev, TPM_DATA_FIFO, buf + len - 1, 1);
if (ret < 0)
goto out_err;
tpm_stat = st33zp24_i2c_status(dev);
if ((tpm_stat & TPM_STS_DATA_EXPECT) != 0) {
ret = -EIO;
goto out_err;
}
data = TPM_STS_GO;
ret = st33zp24_i2c_write(dev, TPM_STS, &data, 1);
if (ret < 0)
goto out_err;
return len;
out_err:
st33zp24_i2c_cancel(dev);
st33zp24_i2c_release_locality(dev);
return ret;
}
static int st33zp24_i2c_cleanup(struct udevice *dev)
{
st33zp24_i2c_cancel(dev);
/*
* The TPM needs some time to clean up here,
* so we sleep rather than keeping the bus busy
*/
mdelay(2);
st33zp24_i2c_release_locality(dev);
return 0;
}
static int st33zp24_i2c_init(struct udevice *dev)
{
struct tpm_chip *chip = dev_get_priv(dev);
chip->is_open = 1;
/* Default timeouts - these could move to the device tree */
chip->timeout_a = TIS_SHORT_TIMEOUT_MS;
chip->timeout_b = TIS_LONG_TIMEOUT_MS;
chip->timeout_c = TIS_SHORT_TIMEOUT_MS;
chip->timeout_d = TIS_SHORT_TIMEOUT_MS;
chip->locality = LOCALITY0;
/*
* A timeout query to TPM can be placed here.
* Standard timeout values are used so far
*/
return 0;
}
static int st33zp24_i2c_open(struct udevice *dev)
{
struct tpm_chip *chip = dev_get_priv(dev);
int rc;
debug("%s: start\n", __func__);
if (chip->is_open)
return -EBUSY;
rc = st33zp24_i2c_init(dev);
if (rc < 0)
chip->is_open = 0;
return rc;
}
static int st33zp24_i2c_close(struct udevice *dev)
{
struct tpm_chip *chip = dev_get_priv(dev);
if (chip->is_open) {
st33zp24_i2c_release_locality(dev);
chip->is_open = 0;
chip->vend_dev = 0;
}
return 0;
}
static int st33zp24_i2c_get_desc(struct udevice *dev, char *buf, int size)
{
struct tpm_chip *chip = dev_get_priv(dev);
if (size < 50)
return -ENOSPC;
return snprintf(buf, size, "1.2 TPM (%s, chip type %s device-id 0x%x)",
chip->is_open ? "open" : "closed",
dev->name,
chip->vend_dev >> 16);
}
static const struct tpm_ops st33zp24_i2c_tpm_ops = {
.open = st33zp24_i2c_open,
.close = st33zp24_i2c_close,
.recv = st33zp24_i2c_recv,
.send = st33zp24_i2c_send,
.cleanup = st33zp24_i2c_cleanup,
.get_desc = st33zp24_i2c_get_desc,
};
static int st33zp24_i2c_probe(struct udevice *dev)
{
struct tpm_chip *chip = dev_get_priv(dev);
/* Default timeouts */
chip->timeout_a = TIS_SHORT_TIMEOUT_MS;
chip->timeout_b = TIS_LONG_TIMEOUT_MS;
chip->timeout_c = TIS_SHORT_TIMEOUT_MS;
chip->timeout_d = TIS_SHORT_TIMEOUT_MS;
chip->locality = LOCALITY0;
i2c_set_chip_offset_len(dev, 0);
debug("ST33ZP24 I2C TPM from STMicroelectronics found\n");
return 0;
}
static int st33zp24_i2c_remove(struct udevice *dev)
{
st33zp24_i2c_release_locality(dev);
return 0;
}
static const struct udevice_id st33zp24_i2c_ids[] = {
{ .compatible = "st,st33zp24-i2c" },
{ }
};
U_BOOT_DRIVER(st33zp24_i2c) = {
.name = "st33zp24-i2c",
.id = UCLASS_TPM,
.of_match = of_match_ptr(st33zp24_i2c_ids),
.probe = st33zp24_i2c_probe,
.remove = st33zp24_i2c_remove,
.ops = &st33zp24_i2c_tpm_ops,
.priv_auto_alloc_size = sizeof(struct tpm_chip),
};