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* STMicroelectronics TPM SPI Linux driver for TPM ST33ZP24
* Copyright (C) 2009 - 2015 STMicroelectronics
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <linux/module.h>
#include <linux/spi/spi.h>
#include <linux/gpio.h>
#include <linux/of_irq.h>
#include <linux/of_gpio.h>
#include <linux/tpm.h>
#include <linux/platform_data/st33zp24.h>
#include "st33zp24.h"
#define TPM_DATA_FIFO 0x24
#define TPM_INTF_CAPABILITY 0x14
#define TPM_DUMMY_BYTE 0x00
#define MAX_SPI_LATENCY 15
#define LOCALITY0 0
#define ST33ZP24_OK 0x5A
#define ST33ZP24_UNDEFINED_ERR 0x80
#define ST33ZP24_BADLOCALITY 0x81
#define ST33ZP24_TISREGISTER_UKNOWN 0x82
#define ST33ZP24_LOCALITY_NOT_ACTIVATED 0x83
#define ST33ZP24_HASH_END_BEFORE_HASH_START 0x84
#define ST33ZP24_BAD_COMMAND_ORDER 0x85
#define ST33ZP24_INCORECT_RECEIVED_LENGTH 0x86
#define ST33ZP24_TPM_FIFO_OVERFLOW 0x89
#define ST33ZP24_UNEXPECTED_READ_FIFO 0x8A
#define ST33ZP24_UNEXPECTED_WRITE_FIFO 0x8B
#define ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END 0x90
#define ST33ZP24_DUMMY_BYTES 0x00
/*
* TPM command can be up to 2048 byte, A TPM response can be up to
* 1024 byte.
* Between command and response, there are latency byte (up to 15
* usually on st33zp24 2 are enough).
*
* Overall when sending a command and expecting an answer we need if
* worst case:
* 2048 (for the TPM command) + 1024 (for the TPM answer). We need
* some latency byte before the answer is available (max 15).
* We have 2048 + 1024 + 15.
*/
#define ST33ZP24_SPI_BUFFER_SIZE (TPM_BUFSIZE + (TPM_BUFSIZE / 2) +\
MAX_SPI_LATENCY)
struct st33zp24_spi_phy {
struct spi_device *spi_device;
struct spi_transfer spi_xfer;
u8 tx_buf[ST33ZP24_SPI_BUFFER_SIZE];
u8 rx_buf[ST33ZP24_SPI_BUFFER_SIZE];
int io_lpcpd;
int latency;
};
static int st33zp24_status_to_errno(u8 code)
{
switch (code) {
case ST33ZP24_OK:
return 0;
case ST33ZP24_UNDEFINED_ERR:
case ST33ZP24_BADLOCALITY:
case ST33ZP24_TISREGISTER_UKNOWN:
case ST33ZP24_LOCALITY_NOT_ACTIVATED:
case ST33ZP24_HASH_END_BEFORE_HASH_START:
case ST33ZP24_BAD_COMMAND_ORDER:
case ST33ZP24_UNEXPECTED_READ_FIFO:
case ST33ZP24_UNEXPECTED_WRITE_FIFO:
case ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END:
return -EPROTO;
case ST33ZP24_INCORECT_RECEIVED_LENGTH:
case ST33ZP24_TPM_FIFO_OVERFLOW:
return -EMSGSIZE;
case ST33ZP24_DUMMY_BYTES:
return -ENOSYS;
}
return code;
}
/*
* st33zp24_spi_send
* Send byte to the TIS register according to the ST33ZP24 SPI 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: should be zero if success else a negative error code.
*/
static int st33zp24_spi_send(void *phy_id, u8 tpm_register, u8 *tpm_data,
int tpm_size)
{
u8 data = 0;
int total_length = 0, nbr_dummy_bytes = 0, ret = 0;
struct st33zp24_spi_phy *phy = phy_id;
struct spi_device *dev = phy->spi_device;
u8 *tx_buf = (u8 *)phy->spi_xfer.tx_buf;
u8 *rx_buf = phy->spi_xfer.rx_buf;
/* Pre-Header */
data = TPM_WRITE_DIRECTION | LOCALITY0;
memcpy(tx_buf + total_length, &data, sizeof(data));
total_length++;
data = tpm_register;
memcpy(tx_buf + total_length, &data, sizeof(data));
total_length++;
if (tpm_size > 0 && tpm_register == TPM_DATA_FIFO) {
tx_buf[total_length++] = tpm_size >> 8;
tx_buf[total_length++] = tpm_size;
}
memcpy(&tx_buf[total_length], tpm_data, tpm_size);
total_length += tpm_size;
nbr_dummy_bytes = phy->latency;
memset(&tx_buf[total_length], TPM_DUMMY_BYTE, nbr_dummy_bytes);
phy->spi_xfer.len = total_length + nbr_dummy_bytes;
ret = spi_sync_transfer(dev, &phy->spi_xfer, 1);
if (ret == 0)
ret = rx_buf[total_length + nbr_dummy_bytes - 1];
return st33zp24_status_to_errno(ret);
} /* st33zp24_spi_send() */
/*
* read8_recv
* Recv byte from the TIS register according to the ST33ZP24 SPI 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: should be zero if success else a negative error code.
*/
static int read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size)
{
u8 data = 0;
int total_length = 0, nbr_dummy_bytes, ret;
struct st33zp24_spi_phy *phy = phy_id;
struct spi_device *dev = phy->spi_device;
u8 *tx_buf = (u8 *)phy->spi_xfer.tx_buf;
u8 *rx_buf = phy->spi_xfer.rx_buf;
/* Pre-Header */
data = LOCALITY0;
memcpy(tx_buf + total_length, &data, sizeof(data));
total_length++;
data = tpm_register;
memcpy(tx_buf + total_length, &data, sizeof(data));
total_length++;
nbr_dummy_bytes = phy->latency;
memset(&tx_buf[total_length], TPM_DUMMY_BYTE,
nbr_dummy_bytes + tpm_size);
phy->spi_xfer.len = total_length + nbr_dummy_bytes + tpm_size;
/* header + status byte + size of the data + status byte */
ret = spi_sync_transfer(dev, &phy->spi_xfer, 1);
if (tpm_size > 0 && ret == 0) {
ret = rx_buf[total_length + nbr_dummy_bytes - 1];
memcpy(tpm_data, rx_buf + total_length + nbr_dummy_bytes,
tpm_size);
}
return ret;
} /* read8_reg() */
/*
* st33zp24_spi_recv
* Recv byte from the TIS register according to the ST33ZP24 SPI 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_spi_recv(void *phy_id, u8 tpm_register, u8 *tpm_data,
int tpm_size)
{
int ret;
ret = read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
if (!st33zp24_status_to_errno(ret))
return tpm_size;
return ret;
} /* st33zp24_spi_recv() */
static int evaluate_latency(void *phy_id)
{
struct st33zp24_spi_phy *phy = phy_id;
int latency = 1, status = 0;
u8 data = 0;
while (!status && latency < MAX_SPI_LATENCY) {
phy->latency = latency;
status = read8_reg(phy_id, TPM_INTF_CAPABILITY, &data, 1);
latency++;
}
return latency - 1;
} /* evaluate_latency() */
static const struct st33zp24_phy_ops spi_phy_ops = {
.send = st33zp24_spi_send,
.recv = st33zp24_spi_recv,
};
#ifdef CONFIG_OF
static int tpm_stm_spi_of_request_resources(struct st33zp24_spi_phy *phy)
{
struct device_node *pp;
struct spi_device *dev = phy->spi_device;
int gpio;
int ret;
pp = dev->dev.of_node;
if (!pp) {
dev_err(&dev->dev, "No platform data\n");
return -ENODEV;
}
/* Get GPIO from device tree */
gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0);
if (gpio < 0) {
dev_err(&dev->dev,
"Failed to retrieve lpcpd-gpios from dts.\n");
phy->io_lpcpd = -1;
/*
* lpcpd pin is not specified. This is not an issue as
* power management can be also managed by TPM specific
* commands. So leave with a success status code.
*/
return 0;
}
/* GPIO request and configuration */
ret = devm_gpio_request_one(&dev->dev, gpio,
GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD");
if (ret) {
dev_err(&dev->dev, "Failed to request lpcpd pin\n");
return -ENODEV;
}
phy->io_lpcpd = gpio;
return 0;
}
#else
static int tpm_stm_spi_of_request_resources(struct st33zp24_spi_phy *phy)
{
return -ENODEV;
}
#endif
static int tpm_stm_spi_request_resources(struct spi_device *dev,
struct st33zp24_spi_phy *phy)
{
struct st33zp24_platform_data *pdata;
int ret;
pdata = dev->dev.platform_data;
if (!pdata) {
dev_err(&dev->dev, "No platform data\n");
return -ENODEV;
}
/* store for late use */
phy->io_lpcpd = pdata->io_lpcpd;
if (gpio_is_valid(pdata->io_lpcpd)) {
ret = devm_gpio_request_one(&dev->dev,
pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH,
"TPM IO_LPCPD");
if (ret) {
dev_err(&dev->dev, "%s : reset gpio_request failed\n",
__FILE__);
return ret;
}
}
return 0;
}
/*
* tpm_st33_spi_probe initialize the TPM device
* @param: dev, the spi_device drescription (TPM SPI description).
* @return: 0 in case of success.
* or a negative value describing the error.
*/
static int
tpm_st33_spi_probe(struct spi_device *dev)
{
int ret;
struct st33zp24_platform_data *pdata;
struct st33zp24_spi_phy *phy;
/* Check SPI platform functionnalities */
if (!dev) {
pr_info("%s: dev is NULL. Device is not accessible.\n",
__func__);
return -ENODEV;
}
phy = devm_kzalloc(&dev->dev, sizeof(struct st33zp24_spi_phy),
GFP_KERNEL);
if (!phy)
return -ENOMEM;
phy->spi_device = dev;
pdata = dev->dev.platform_data;
if (!pdata && dev->dev.of_node) {
ret = tpm_stm_spi_of_request_resources(phy);
if (ret)
return ret;
} else if (pdata) {
ret = tpm_stm_spi_request_resources(dev, phy);
if (ret)
return ret;
}
phy->spi_xfer.tx_buf = phy->tx_buf;
phy->spi_xfer.rx_buf = phy->rx_buf;
phy->latency = evaluate_latency(phy);
if (phy->latency <= 0)
return -ENODEV;
return st33zp24_probe(phy, &spi_phy_ops, &dev->dev, dev->irq,
phy->io_lpcpd);
}
/*
* tpm_st33_spi_remove remove the TPM device
* @param: client, the spi_device drescription (TPM SPI description).
* @return: 0 in case of success.
*/
static int tpm_st33_spi_remove(struct spi_device *dev)
{
struct tpm_chip *chip = spi_get_drvdata(dev);
return st33zp24_remove(chip);
}
static const struct spi_device_id st33zp24_spi_id[] = {
{TPM_ST33_SPI, 0},
{}
};
MODULE_DEVICE_TABLE(spi, st33zp24_spi_id);
#ifdef CONFIG_OF
static const struct of_device_id of_st33zp24_spi_match[] = {
{ .compatible = "st,st33zp24-spi", },
{}
};
MODULE_DEVICE_TABLE(of, of_st33zp24_spi_match);
#endif
static SIMPLE_DEV_PM_OPS(st33zp24_spi_ops, st33zp24_pm_suspend,
st33zp24_pm_resume);
static struct spi_driver tpm_st33_spi_driver = {
.driver = {
.name = TPM_ST33_SPI,
.pm = &st33zp24_spi_ops,
.of_match_table = of_match_ptr(of_st33zp24_spi_match),
},
.probe = tpm_st33_spi_probe,
.remove = tpm_st33_spi_remove,
.id_table = st33zp24_spi_id,
};
module_spi_driver(tpm_st33_spi_driver);
MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
MODULE_DESCRIPTION("STM TPM 1.2 SPI ST33 Driver");
MODULE_VERSION("1.3.0");
MODULE_LICENSE("GPL");
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