// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2015 Infineon Technologies AG
* Copyright (C) 2016 STMicroelectronics SAS
*
* Authors:
* Peter Huewe <[email protected]>
* Christophe Ricard <[email protected]>
*
* Maintained by: <[email protected]>
*
* 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.
*/
#include <linux/acpi.h>
#include <linux/completion.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/spi/spi.h>
#include <linux/tpm.h>
#include "tpm.h"
#include "tpm_tis_core.h"
#include "tpm_tis_spi.h"
#define MAX_SPI_FRAMESIZE 64
#define SPI_HDRSIZE 4
/*
* TCG SPI flow control is documented in section 6.4 of the spec[1]. In short,
* keep trying to read from the device until MISO goes high indicating the
* wait state has ended.
*
* [1] https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
*/
static int tpm_tis_spi_flow_control(struct tpm_tis_spi_phy *phy,
struct spi_transfer *spi_xfer)
{
struct spi_message m;
int ret, i;
if ((phy->iobuf[3] & 0x01) == 0) {
// handle SPI wait states
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)
return ret;
if (phy->iobuf[0] & 0x01)
break;
}
if (i == TPM_RETRY)
return -ETIMEDOUT;
}
return 0;
}
/*
* Half duplex controller with support for TPM wait state detection like
* Tegra QSPI need CMD, ADDR & DATA sent in single message to manage HW flow
* control. Each phase sent in different transfer for controller to idenity
* phase.
*/
static int tpm_tis_spi_transfer_half(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);
struct spi_transfer spi_xfer[3];
struct spi_message m;
u8 transfer_len;
int ret;
while (len) {
transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
spi_message_init(&m);
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[0].tx_buf = phy->iobuf;
spi_xfer[0].len = 1;
spi_message_add_tail(&spi_xfer[0], &m);
spi_xfer[1].tx_buf = phy->iobuf + 1;
spi_xfer[1].len = 3;
spi_message_add_tail(&spi_xfer[1], &m);
if (out) {
spi_xfer[2].tx_buf = &phy->iobuf[4];
spi_xfer[2].rx_buf = NULL;
memcpy(&phy->iobuf[4], out, transfer_len);
out += transfer_len;
}
if (in) {
spi_xfer[2].tx_buf = NULL;
spi_xfer[2].rx_buf = &phy->iobuf[4];
}
spi_xfer[2].len = transfer_len;
spi_message_add_tail(&spi_xfer[2], &m);
reinit_completion(&phy->ready);
ret = spi_sync(phy->spi_device, &m);
if (ret < 0)
return ret;
if (in) {
memcpy(in, &phy->iobuf[4], transfer_len);
in += transfer_len;
}
len -= transfer_len;
}
return ret;
}
static int tpm_tis_spi_transfer_full(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;
struct spi_message m;
struct spi_transfer spi_xfer;
u8 transfer_len;
spi_bus_lock(phy->spi_device->controller);
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;
/* Flow control transfers are receive only */
spi_xfer.tx_buf = NULL;
ret = phy->flow_control(phy, &spi_xfer);
if (ret < 0)
goto exit;
spi_xfer.cs_change = 0;
spi_xfer.len = transfer_len;
spi_xfer.delay.value = 5;
spi_xfer.delay.unit = SPI_DELAY_UNIT_USECS;
if (out) {
spi_xfer.tx_buf = phy->iobuf;
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);
reinit_completion(&phy->ready);
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:
if (ret < 0) {
/* Deactivate chip select */
memset(&spi_xfer, 0, sizeof(spi_xfer));
spi_message_init(&m);
spi_message_add_tail(&spi_xfer, &m);
spi_sync_locked(phy->spi_device, &m);
}
spi_bus_unlock(phy->spi_device->controller);
return ret;
}
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);
struct spi_controller *ctlr = phy->spi_device->controller;
/*
* TPM flow control over SPI requires full duplex support.
* Send entire message to a half duplex controller to handle
* wait polling in controller.
* Set TPM HW flow control flag..
*/
if (ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX)
return tpm_tis_spi_transfer_half(data, addr, len, in, out);
else
return tpm_tis_spi_transfer_full(data, addr, len, in, out);
}
static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
u16 len, u8 *result, enum tpm_tis_io_mode io_mode)
{
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, enum tpm_tis_io_mode io_mode)
{
return tpm_tis_spi_transfer(data, addr, len, NULL, value);
}
int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy,
int irq, const struct tpm_tis_phy_ops *phy_ops)
{
phy->iobuf = devm_kmalloc(&spi->dev, SPI_HDRSIZE + MAX_SPI_FRAMESIZE, GFP_KERNEL);
if (!phy->iobuf)
return -ENOMEM;
phy->spi_device = spi;
return tpm_tis_core_init(&spi->dev, &phy->priv, irq, phy_ops, NULL);
}
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,
};
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->flow_control = tpm_tis_spi_flow_control;
if (dev->controller->flags & SPI_CONTROLLER_HALF_DUPLEX)
dev->mode |= SPI_TPM_HW_FLOW;
/* If the SPI device has an IRQ then use that */
if (dev->irq > 0)
irq = dev->irq;
else
irq = -1;
init_completion(&phy->ready);
return tpm_tis_spi_init(dev, phy, irq, &tpm_spi_phy_ops);
}
typedef int (*tpm_tis_spi_probe_func)(struct spi_device *);
static int tpm_tis_spi_driver_probe(struct spi_device *spi)
{
const struct spi_device_id *spi_dev_id = spi_get_device_id(spi);
tpm_tis_spi_probe_func probe_func;
probe_func = of_device_get_match_data(&spi->dev);
if (!probe_func) {
if (spi_dev_id) {
probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data;
if (!probe_func)
return -ENODEV;
} else
probe_func = tpm_tis_spi_probe;
}
return probe_func(spi);
}
static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_spi_resume);
static void tpm_tis_spi_remove(struct spi_device *dev)
{
struct tpm_chip *chip = spi_get_drvdata(dev);
tpm_chip_unregister(chip);
tpm_tis_remove(chip);
}
static const struct spi_device_id tpm_tis_spi_id[] = {
{ "attpm20p", (unsigned long)tpm_tis_spi_probe },
{ "st33htpm-spi", (unsigned long)tpm_tis_spi_probe },
{ "slb9670", (unsigned long)tpm_tis_spi_probe },
{ "tpm_tis_spi", (unsigned long)tpm_tis_spi_probe },
{ "tpm_tis-spi", (unsigned long)tpm_tis_spi_probe },
{ "cr50", (unsigned long)cr50_spi_probe },
{}
};
MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
static const struct of_device_id of_tis_spi_match[] __maybe_unused = {
{ .compatible = "atmel,attpm20p", .data = tpm_tis_spi_probe },
{ .compatible = "st,st33htpm-spi", .data = tpm_tis_spi_probe },
{ .compatible = "infineon,slb9670", .data = tpm_tis_spi_probe },
{ .compatible = "tcg,tpm_tis-spi", .data = tpm_tis_spi_probe },
{ .compatible = "google,cr50", .data = cr50_spi_probe },
{}
};
MODULE_DEVICE_TABLE(of, of_tis_spi_match);
static const struct acpi_device_id acpi_tis_spi_match[] __maybe_unused = {
{"SMO0768", 0},
{}
};
MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
static struct spi_driver tpm_tis_spi_driver = {
.driver = {
.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_type = PROBE_PREFER_ASYNCHRONOUS,
},
.probe = tpm_tis_spi_driver_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");
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