/*
* Copyright (C) 2015 Infineon Technologies AG
* Copyright (C) 2016 STMicroelectronics SAS
*
* Authors:
* Peter Huewe <peter.huewe@infineon.com>
* Christophe Ricard <christophe-h.ricard@st.com>
*
* Maintained by: <tpmdd-devel@lists.sourceforge.net>
*
* Device driver for TCG/TCPA TPM (trusted platform module).
* Specifications at www.trustedcomputinggroup.org
*
* This device driver implements the TPM interface as defined in
* the TCG TPM Interface Spec version 1.3, revision 27 via _raw/native
* SPI access_.
*
* It is based on the original tpm_tis device driver from Leendert van
* Dorn and Kyleen Hall and Jarko Sakkinnen.
*
* 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, version 2 of the
* License.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/acpi.h>
#include <linux/freezer.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 "tpm.h"
#include "tpm_tis_core.h"
#define MAX_SPI_FRAMESIZE 64
struct tpm_tis_spi_phy {
struct tpm_tis_data priv;
struct spi_device *spi_device;
u8 *iobuf;
};
static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data)
{
return container_of(data, struct tpm_tis_spi_phy, priv);
}
static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
u8 *in, const u8 *out)
{
struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
int ret = 0;
int i;
struct spi_message m;
struct spi_transfer spi_xfer;
u8 transfer_len;
spi_bus_lock(phy->spi_device->master);
while (len) {
transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
phy->iobuf[1] = 0xd4;
phy->iobuf[2] = addr >> 8;
phy->iobuf[3] = addr;
memset(&spi_xfer, 0, sizeof(spi_xfer));
spi_xfer.tx_buf = phy->iobuf;
spi_xfer.rx_buf = phy->iobuf;
spi_xfer.len = 4;
spi_xfer.cs_change = 1;
spi_message_init(&m);
spi_message_add_tail(&spi_xfer, &m);
ret = spi_sync_locked(phy->spi_device, &m);
if (ret < 0)
goto exit;
if ((phy->iobuf[3] & 0x01) == 0) {
// handle SPI wait states
phy->iobuf[0] = 0;
for (i = 0; i < TPM_RETRY; i++) {
spi_xfer.len = 1;
spi_message_init(&m);
spi_message_add_tail(&spi_xfer, &m);
ret = spi_sync_locked(phy->spi_device, &m);
if (ret < 0)
goto exit;
if (phy->iobuf[0] & 0x01)
break;
}
if (i == TPM_RETRY) {
ret = -ETIMEDOUT;
goto exit;
}
}
spi_xfer.cs_change = 0;
spi_xfer.len = transfer_len;
spi_xfer.delay_usecs = 5;
if (in) {
spi_xfer.tx_buf = NULL;
} else if (out) {
spi_xfer.rx_buf = NULL;
memcpy(phy->iobuf, out, transfer_len);
out += transfer_len;
}
spi_message_init(&m);
spi_message_add_tail(&spi_xfer, &m);
ret = spi_sync_locked(phy->spi_device, &m);
if (ret < 0)
goto exit;
if (in) {
memcpy(in, phy->iobuf, transfer_len);
in += transfer_len;
}
len -= transfer_len;
}
exit:
spi_bus_unlock(phy->spi_device->master);
return ret;
}
static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
u16 len, u8 *result)
{
return tpm_tis_spi_transfer(data, addr, len, result, NULL);
}
static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
u16 len, const u8 *value)
{
return tpm_tis_spi_transfer(data, addr, len, NULL, value);
}
static int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
{
__le16 result_le;
int rc;
rc = data->phy_ops->read_bytes(data, addr, sizeof(u16),
(u8 *)&result_le);
if (!rc)
*result = le16_to_cpu(result_le);
return rc;
}
static int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
{
__le32 result_le;
int rc;
rc = data->phy_ops->read_bytes(data, addr, sizeof(u32),
(u8 *)&result_le);
if (!rc)
*result = le32_to_cpu(result_le);
return rc;
}
static int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
{
__le32 value_le;
int rc;
value_le = cpu_to_le32(value);
rc = data->phy_ops->write_bytes(data, addr, sizeof(u32),
(u8 *)&value_le);
return rc;
}
static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
.read_bytes = tpm_tis_spi_read_bytes,
.write_bytes = tpm_tis_spi_write_bytes,
.read16 = tpm_tis_spi_read16,
.read32 = tpm_tis_spi_read32,
.write32 = tpm_tis_spi_write32,
};
static int tpm_tis_spi_probe(struct spi_device *dev)
{
struct tpm_tis_spi_phy *phy;
int irq;
phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
GFP_KERNEL);
if (!phy)
return -ENOMEM;
phy->spi_device = dev;
phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
if (!phy->iobuf)
return -ENOMEM;
/* If the SPI device has an IRQ then use that */
if (dev->irq > 0)
irq = dev->irq;
else
irq = -1;
return tpm_tis_core_init(&dev->dev, &phy->priv, irq, &tpm_spi_phy_ops,
NULL);
}
static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
static int tpm_tis_spi_remove(struct spi_device *dev)
{
struct tpm_chip *chip = spi_get_drvdata(dev);
tpm_chip_unregister(chip);
tpm_tis_remove(chip);
return 0;
}
static const struct spi_device_id tpm_tis_spi_id[] = {
{"tpm_tis_spi", 0},
{}
};
MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
static const struct of_device_id of_tis_spi_match[] = {
{ .compatible = "st,st33htpm-spi", },
{ .compatible = "infineon,slb9670", },
{ .compatible = "tcg,tpm_tis-spi", },
{}
};
MODULE_DEVICE_TABLE(of, of_tis_spi_match);
static const struct acpi_device_id acpi_tis_spi_match[] = {
{"SMO0768", 0},
{}
};
MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
static struct spi_driver tpm_tis_spi_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "tpm_tis_spi",
.pm = &tpm_tis_pm,
.of_match_table = of_match_ptr(of_tis_spi_match),
.acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
},
.probe = tpm_tis_spi_probe,
.remove = tpm_tis_spi_remove,
.id_table = tpm_tis_spi_id,
};
module_spi_driver(tpm_tis_spi_driver);
MODULE_DESCRIPTION("TPM Driver for native SPI access");
MODULE_LICENSE("GPL");
