drivers/char/tpm/tpm_tis_spi_main.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * 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.
  */

 #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_device.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

 /*
  * 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;
 }

 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;
 	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;

 		/* 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:
 	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);
 }

 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;
 }

 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;
 }

 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;
 }

 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, 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,
 	.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->flow_control = tpm_tis_spi_flow_control;

 	/* 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 && spi_dev_id)
 		probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data;
 	if (!probe_func)
 		return -ENODEV;

 	return probe_func(spi);
 }

 static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_spi_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", (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[] = {
 	{ .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[] = {
 	{"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");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* 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.
	*/

	#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_device.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

	/*
	* 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;
	}

	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;
	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;

	/* 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:
	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);
	}

	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;
	}

	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;
	}

	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;
	}

	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, 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,
	.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->flow_control = tpm_tis_spi_flow_control;

	/* 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 && spi_dev_id)
	probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data;
	if (!probe_func)
	return -ENODEV;

	return probe_func(spi);
	}

	static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_spi_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", (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[] = {
	{ .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[] = {
	{"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");