// SPDX-License-Identifier: GPL-2.0-or-later
/*
* STMicroelectronics TPM SPI Linux driver for TPM ST33ZP24
* Copyright (C) 2009 - 2016 STMicroelectronics
*/
#include <linux/module.h>
#include <linux/spi/spi.h>
#include <linux/of.h>
#include <linux/acpi.h>
#include <linux/tpm.h>
#include "../tpm.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_UNKNOWN 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 (ST33ZP24_BUFSIZE + (ST33ZP24_BUFSIZE / 2) +\
MAX_SPI_LATENCY)
struct st33zp24_spi_phy {
struct spi_device *spi_device;
u8 tx_buf[ST33ZP24_SPI_BUFFER_SIZE];
u8 rx_buf[ST33ZP24_SPI_BUFFER_SIZE];
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_UNKNOWN:
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)
{
int total_length = 0, ret = 0;
struct st33zp24_spi_phy *phy = phy_id;
struct spi_device *dev = phy->spi_device;
struct spi_transfer spi_xfer = {
.tx_buf = phy->tx_buf,
.rx_buf = phy->rx_buf,
};
/* Pre-Header */
phy->tx_buf[total_length++] = TPM_WRITE_DIRECTION | LOCALITY0;
phy->tx_buf[total_length++] = tpm_register;
if (tpm_size > 0 && tpm_register == TPM_DATA_FIFO) {
phy->tx_buf[total_length++] = tpm_size >> 8;
phy->tx_buf[total_length++] = tpm_size;
}
memcpy(&phy->tx_buf[total_length], tpm_data, tpm_size);
total_length += tpm_size;
memset(&phy->tx_buf[total_length], TPM_DUMMY_BYTE, phy->latency);
spi_xfer.len = total_length + phy->latency;
ret = spi_sync_transfer(dev, &spi_xfer, 1);
if (ret == 0)
ret = phy->rx_buf[total_length + phy->latency - 1];
return st33zp24_status_to_errno(ret);
} /* st33zp24_spi_send() */
/*
* st33zp24_spi_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 st33zp24_spi_read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data,
int tpm_size)
{
int total_length = 0, ret;
struct st33zp24_spi_phy *phy = phy_id;
struct spi_device *dev = phy->spi_device;
struct spi_transfer spi_xfer = {
.tx_buf = phy->tx_buf,
.rx_buf = phy->rx_buf,
};
/* Pre-Header */
phy->tx_buf[total_length++] = LOCALITY0;
phy->tx_buf[total_length++] = tpm_register;
memset(&phy->tx_buf[total_length], TPM_DUMMY_BYTE,
phy->latency + tpm_size);
spi_xfer.len = total_length + phy->latency + tpm_size;
/* header + status byte + size of the data + status byte */
ret = spi_sync_transfer(dev, &spi_xfer, 1);
if (tpm_size > 0 && ret == 0) {
ret = phy->rx_buf[total_length + phy->latency - 1];
memcpy(tpm_data, phy->rx_buf + total_length + phy->latency,
tpm_size);
}
return ret;
} /* st33zp24_spi_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 = st33zp24_spi_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 st33zp24_spi_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 = st33zp24_spi_read8_reg(phy_id, TPM_INTF_CAPABILITY,
&data, 1);
latency++;
}
if (status < 0)
return status;
if (latency == MAX_SPI_LATENCY)
return -ENODEV;
return latency - 1;
} /* evaluate_latency() */
static const struct st33zp24_phy_ops spi_phy_ops = {
.send = st33zp24_spi_send,
.recv = st33zp24_spi_recv,
};
/*
* st33zp24_spi_probe initialize the TPM device
* @param: dev, the spi_device description (TPM SPI description).
* @return: 0 in case of success.
* or a negative value describing the error.
*/
static int st33zp24_spi_probe(struct spi_device *dev)
{
struct st33zp24_spi_phy *phy;
phy = devm_kzalloc(&dev->dev, sizeof(struct st33zp24_spi_phy),
GFP_KERNEL);
if (!phy)
return -ENOMEM;
phy->spi_device = dev;
phy->latency = st33zp24_spi_evaluate_latency(phy);
if (phy->latency <= 0)
return -ENODEV;
return st33zp24_probe(phy, &spi_phy_ops, &dev->dev, dev->irq);
}
/*
* st33zp24_spi_remove remove the TPM device
* @param: client, the spi_device description (TPM SPI description).
* @return: 0 in case of success.
*/
static void st33zp24_spi_remove(struct spi_device *dev)
{
struct tpm_chip *chip = spi_get_drvdata(dev);
st33zp24_remove(chip);
}
static const struct spi_device_id st33zp24_spi_id[] = {
{TPM_ST33_SPI, 0},
{}
};
MODULE_DEVICE_TABLE(spi, st33zp24_spi_id);
static const struct of_device_id of_st33zp24_spi_match[] __maybe_unused = {
{ .compatible = "st,st33zp24-spi", },
{}
};
MODULE_DEVICE_TABLE(of, of_st33zp24_spi_match);
static const struct acpi_device_id st33zp24_spi_acpi_match[] __maybe_unused = {
{"SMO3324"},
{}
};
MODULE_DEVICE_TABLE(acpi, st33zp24_spi_acpi_match);
static SIMPLE_DEV_PM_OPS(st33zp24_spi_ops, st33zp24_pm_suspend,
st33zp24_pm_resume);
static struct spi_driver st33zp24_spi_driver = {
.driver = {
.name = "st33zp24-spi",
.pm = &st33zp24_spi_ops,
.of_match_table = of_match_ptr(of_st33zp24_spi_match),
.acpi_match_table = ACPI_PTR(st33zp24_spi_acpi_match),
},
.probe = st33zp24_spi_probe,
.remove = st33zp24_spi_remove,
.id_table = st33zp24_spi_id,
};
module_spi_driver(st33zp24_spi_driver);
MODULE_AUTHOR("TPM support <[email protected]>");
MODULE_DESCRIPTION("STM TPM 1.2 SPI ST33 Driver");
MODULE_VERSION("1.3.0");
MODULE_LICENSE("GPL");
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