drivers/char/tpm/tpm_crb.c - kernel/msm-5.4 - Gitiles

 /*
  * Copyright (C) 2014 Intel Corporation
  *
  * Authors:
  * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
  *
  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
  *
  * This device driver implements the TPM interface as defined in
  * the TCG CRB 2.0 TPM specification.
  *
  * 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/acpi.h>
 #include <linux/highmem.h>
 #include <linux/rculist.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
 #include "tpm.h"

 #define ACPI_SIG_TPM2 "TPM2"

 static const u8 CRB_ACPI_START_UUID[] = {
 	/* 0000 */ 0xAB, 0x6C, 0xBF, 0x6B, 0x63, 0x54, 0x14, 0x47,
 	/* 0008 */ 0xB7, 0xCD, 0xF0, 0x20, 0x3C, 0x03, 0x68, 0xD4
 };

 enum crb_defaults {
 	CRB_ACPI_START_REVISION_ID = 1,
 	CRB_ACPI_START_INDEX = 1,
 };

 enum crb_ctrl_req {
 	CRB_CTRL_REQ_CMD_READY	= BIT(0),
 	CRB_CTRL_REQ_GO_IDLE	= BIT(1),
 };

 enum crb_ctrl_sts {
 	CRB_CTRL_STS_ERROR	= BIT(0),
 	CRB_CTRL_STS_TPM_IDLE	= BIT(1),
 };

 enum crb_start {
 	CRB_START_INVOKE	= BIT(0),
 };

 enum crb_cancel {
 	CRB_CANCEL_INVOKE	= BIT(0),
 };

 struct crb_control_area {
 	u32 req;
 	u32 sts;
 	u32 cancel;
 	u32 start;
 	u32 int_enable;
 	u32 int_sts;
 	u32 cmd_size;
 	u32 cmd_pa_low;
 	u32 cmd_pa_high;
 	u32 rsp_size;
 	u64 rsp_pa;
 } __packed;

 enum crb_status {
 	CRB_DRV_STS_COMPLETE	= BIT(0),
 };

 enum crb_flags {
 	CRB_FL_ACPI_START	= BIT(0),
 	CRB_FL_CRB_START	= BIT(1),
 };

 struct crb_priv {
 	unsigned int flags;
 	void __iomem *iobase;
 	struct crb_control_area __iomem *cca;
 	u8 __iomem *cmd;
 	u8 __iomem *rsp;
 	u32 cmd_size;
 };

 /**
  * crb_go_idle - request tpm crb device to go the idle state
  *
  * @dev:  crb device
  * @priv: crb private data
  *
  * Write CRB_CTRL_REQ_GO_IDLE to TPM_CRB_CTRL_REQ
  * The device should respond within TIMEOUT_C by clearing the bit.
  * Anyhow, we do not wait here as a consequent CMD_READY request
  * will be handled correctly even if idle was not completed.
  *
  * The function does nothing for devices with ACPI-start method.
  *
  * Return: 0 always
  */
 static int __maybe_unused crb_go_idle(struct device *dev, struct crb_priv *priv)
 {
 	if (priv->flags & CRB_FL_ACPI_START)
 		return 0;

 	iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->cca->req);
 	/* we don't really care when this settles */

 	return 0;
 }

 /**
  * crb_cmd_ready - request tpm crb device to enter ready state
  *
  * @dev:  crb device
  * @priv: crb private data
  *
  * Write CRB_CTRL_REQ_CMD_READY to TPM_CRB_CTRL_REQ
  * and poll till the device acknowledge it by clearing the bit.
  * The device should respond within TIMEOUT_C.
  *
  * The function does nothing for devices with ACPI-start method
  *
  * Return: 0 on success -ETIME on timeout;
  */
 static int __maybe_unused crb_cmd_ready(struct device *dev,
 					struct crb_priv *priv)
 {
 	ktime_t stop, start;

 	if (priv->flags & CRB_FL_ACPI_START)
 		return 0;

 	iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->cca->req);

 	start = ktime_get();
 	stop = ktime_add(start, ms_to_ktime(TPM2_TIMEOUT_C));
 	do {
 		if (!(ioread32(&priv->cca->req) & CRB_CTRL_REQ_CMD_READY))
 			return 0;
 		usleep_range(50, 100);
 	} while (ktime_before(ktime_get(), stop));

 	if (ioread32(&priv->cca->req) & CRB_CTRL_REQ_CMD_READY) {
 		dev_warn(dev, "cmdReady timed out\n");
 		return -ETIME;
 	}

 	return 0;
 }

 static u8 crb_status(struct tpm_chip *chip)
 {
 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 	u8 sts = 0;

 	if ((ioread32(&priv->cca->start) & CRB_START_INVOKE) !=
 	    CRB_START_INVOKE)
 		sts |= CRB_DRV_STS_COMPLETE;

 	return sts;
 }

 static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 {
 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 	unsigned int expected;

 	/* sanity check */
 	if (count < 6)
 		return -EIO;

 	if (ioread32(&priv->cca->sts) & CRB_CTRL_STS_ERROR)
 		return -EIO;

 	memcpy_fromio(buf, priv->rsp, 6);
 	expected = be32_to_cpup((__be32 *) &buf[2]);

 	if (expected > count)
 		return -EIO;

 	memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6);

 	return expected;
 }

 static int crb_do_acpi_start(struct tpm_chip *chip)
 {
 	union acpi_object *obj;
 	int rc;

 	obj = acpi_evaluate_dsm(chip->acpi_dev_handle,
 				CRB_ACPI_START_UUID,
 				CRB_ACPI_START_REVISION_ID,
 				CRB_ACPI_START_INDEX,
 				NULL);
 	if (!obj)
 		return -ENXIO;
 	rc = obj->integer.value == 0 ? 0 : -ENXIO;
 	ACPI_FREE(obj);
 	return rc;
 }

 static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
 {
 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 	int rc = 0;

 	/* Zero the cancel register so that the next command will not get
 	 * canceled.
 	 */
 	iowrite32(0, &priv->cca->cancel);

 	if (len > priv->cmd_size) {
 		dev_err(&chip->dev, "invalid command count value %zd %d\n",
 			len, priv->cmd_size);
 		return -E2BIG;
 	}

 	memcpy_toio(priv->cmd, buf, len);

 	/* Make sure that cmd is populated before issuing start. */
 	wmb();

 	if (priv->flags & CRB_FL_CRB_START)
 		iowrite32(CRB_START_INVOKE, &priv->cca->start);

 	if (priv->flags & CRB_FL_ACPI_START)
 		rc = crb_do_acpi_start(chip);

 	return rc;
 }

 static void crb_cancel(struct tpm_chip *chip)
 {
 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);

 	iowrite32(CRB_CANCEL_INVOKE, &priv->cca->cancel);

 	if ((priv->flags & CRB_FL_ACPI_START) && crb_do_acpi_start(chip))
 		dev_err(&chip->dev, "ACPI Start failed\n");
 }

 static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
 {
 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 	u32 cancel = ioread32(&priv->cca->cancel);

 	return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
 }

 static const struct tpm_class_ops tpm_crb = {
 	.flags = TPM_OPS_AUTO_STARTUP,
 	.status = crb_status,
 	.recv = crb_recv,
 	.send = crb_send,
 	.cancel = crb_cancel,
 	.req_canceled = crb_req_canceled,
 	.req_complete_mask = CRB_DRV_STS_COMPLETE,
 	.req_complete_val = CRB_DRV_STS_COMPLETE,
 };

 static int crb_check_resource(struct acpi_resource *ares, void *data)
 {
 	struct resource *io_res = data;
 	struct resource_win win;
 	struct resource *res = &(win.res);

 	if (acpi_dev_resource_memory(ares, res) ||
 	    acpi_dev_resource_address_space(ares, &win)) {
 		*io_res = *res;
 		io_res->name = NULL;
 	}

 	return 1;
 }

 static void __iomem *crb_map_res(struct device *dev, struct crb_priv *priv,
 				 struct resource *io_res, u64 start, u32 size)
 {
 	struct resource new_res = {
 		.start	= start,
 		.end	= start + size - 1,
 		.flags	= IORESOURCE_MEM,
 	};

 	/* Detect a 64 bit address on a 32 bit system */
 	if (start != new_res.start)
 		return (void __iomem *) ERR_PTR(-EINVAL);

 	if (!resource_contains(io_res, &new_res))
 		return devm_ioremap_resource(dev, &new_res);

 	return priv->iobase + (new_res.start - io_res->start);
 }

 static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
 		      struct acpi_table_tpm2 *buf)
 {
 	struct list_head resources;
 	struct resource io_res;
 	struct device *dev = &device->dev;
 	u32 pa_high, pa_low;
 	u64 cmd_pa;
 	u32 cmd_size;
 	u64 rsp_pa;
 	u32 rsp_size;
 	int ret;

 	INIT_LIST_HEAD(&resources);
 	ret = acpi_dev_get_resources(device, &resources, crb_check_resource,
 				     &io_res);
 	if (ret < 0)
 		return ret;
 	acpi_dev_free_resource_list(&resources);

 	if (resource_type(&io_res) != IORESOURCE_MEM) {
 		dev_err(dev, FW_BUG "TPM2 ACPI table does not define a memory resource\n");
 		return -EINVAL;
 	}

 	priv->iobase = devm_ioremap_resource(dev, &io_res);
 	if (IS_ERR(priv->iobase))
 		return PTR_ERR(priv->iobase);

 	priv->cca = crb_map_res(dev, priv, &io_res, buf->control_address,
 				sizeof(struct crb_control_area));
 	if (IS_ERR(priv->cca))
 		return PTR_ERR(priv->cca);

 	/*
 	 * PTT HW bug w/a: wake up the device to access
 	 * possibly not retained registers.
 	 */
 	ret = crb_cmd_ready(dev, priv);
 	if (ret)
 		return ret;

 	pa_high = ioread32(&priv->cca->cmd_pa_high);
 	pa_low  = ioread32(&priv->cca->cmd_pa_low);
 	cmd_pa = ((u64)pa_high << 32) | pa_low;
 	cmd_size = ioread32(&priv->cca->cmd_size);

 	dev_dbg(dev, "cmd_hi = %X cmd_low = %X cmd_size %X\n",
 		pa_high, pa_low, cmd_size);

 	priv->cmd = crb_map_res(dev, priv, &io_res, cmd_pa, cmd_size);
 	if (IS_ERR(priv->cmd)) {
 		ret = PTR_ERR(priv->cmd);
 		goto out;
 	}

 	memcpy_fromio(&rsp_pa, &priv->cca->rsp_pa, 8);
 	rsp_pa = le64_to_cpu(rsp_pa);
 	rsp_size = ioread32(&priv->cca->rsp_size);

 	if (cmd_pa != rsp_pa) {
 		priv->rsp = crb_map_res(dev, priv, &io_res, rsp_pa, rsp_size);
 		ret = PTR_ERR_OR_ZERO(priv->rsp);
 		goto out;
 	}

 	/* According to the PTP specification, overlapping command and response
 	 * buffer sizes must be identical.
 	 */
 	if (cmd_size != rsp_size) {
 		dev_err(dev, FW_BUG "overlapping command and response buffer sizes are not identical");
 		ret = -EINVAL;
 		goto out;
 	}

 	priv->cmd_size = cmd_size;

 	priv->rsp = priv->cmd;

 out:
 	crb_go_idle(dev, priv);

 	return ret;
 }

 static int crb_acpi_add(struct acpi_device *device)
 {
 	struct acpi_table_tpm2 *buf;
 	struct crb_priv *priv;
 	struct tpm_chip *chip;
 	struct device *dev = &device->dev;
 	acpi_status status;
 	u32 sm;
 	int rc;

 	status = acpi_get_table(ACPI_SIG_TPM2, 1,
 				(struct acpi_table_header **) &buf);
 	if (ACPI_FAILURE(status) || buf->header.length < sizeof(*buf)) {
 		dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
 		return -EINVAL;
 	}

 	/* Should the FIFO driver handle this? */
 	sm = buf->start_method;
 	if (sm == ACPI_TPM2_MEMORY_MAPPED)
 		return -ENODEV;

 	priv = devm_kzalloc(dev, sizeof(struct crb_priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	/* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
 	 * report only ACPI start but in practice seems to require both
 	 * ACPI start and CRB start.
 	 */
 	if (sm == ACPI_TPM2_COMMAND_BUFFER || sm == ACPI_TPM2_MEMORY_MAPPED ||
 	    !strcmp(acpi_device_hid(device), "MSFT0101"))
 		priv->flags |= CRB_FL_CRB_START;

 	if (sm == ACPI_TPM2_START_METHOD ||
 	    sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
 		priv->flags |= CRB_FL_ACPI_START;

 	rc = crb_map_io(device, priv, buf);
 	if (rc)
 		return rc;

 	chip = tpmm_chip_alloc(dev, &tpm_crb);
 	if (IS_ERR(chip))
 		return PTR_ERR(chip);

 	dev_set_drvdata(&chip->dev, priv);
 	chip->acpi_dev_handle = device->handle;
 	chip->flags = TPM_CHIP_FLAG_TPM2;

 	rc  = crb_cmd_ready(dev, priv);
 	if (rc)
 		return rc;

 	pm_runtime_get_noresume(dev);
 	pm_runtime_set_active(dev);
 	pm_runtime_enable(dev);

 	rc = tpm_chip_register(chip);
 	if (rc) {
 		crb_go_idle(dev, priv);
 		pm_runtime_put_noidle(dev);
 		pm_runtime_disable(dev);
 		return rc;
 	}

 	pm_runtime_put(dev);

 	return 0;
 }

 static int crb_acpi_remove(struct acpi_device *device)
 {
 	struct device *dev = &device->dev;
 	struct tpm_chip *chip = dev_get_drvdata(dev);

 	tpm_chip_unregister(chip);

 	pm_runtime_disable(dev);

 	return 0;
 }

 #ifdef CONFIG_PM
 static int crb_pm_runtime_suspend(struct device *dev)
 {
 	struct tpm_chip *chip = dev_get_drvdata(dev);
 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);

 	return crb_go_idle(dev, priv);
 }

 static int crb_pm_runtime_resume(struct device *dev)
 {
 	struct tpm_chip *chip = dev_get_drvdata(dev);
 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);

 	return crb_cmd_ready(dev, priv);
 }
 #endif /* CONFIG_PM */

 static const struct dev_pm_ops crb_pm = {
 	SET_SYSTEM_SLEEP_PM_OPS(tpm_pm_suspend, tpm_pm_resume)
 	SET_RUNTIME_PM_OPS(crb_pm_runtime_suspend, crb_pm_runtime_resume, NULL)
 };

 static struct acpi_device_id crb_device_ids[] = {
 	{"MSFT0101", 0},
 	{"", 0},
 };
 MODULE_DEVICE_TABLE(acpi, crb_device_ids);

 static struct acpi_driver crb_acpi_driver = {
 	.name = "tpm_crb",
 	.ids = crb_device_ids,
 	.ops = {
 		.add = crb_acpi_add,
 		.remove = crb_acpi_remove,
 	},
 	.drv = {
 		.pm = &crb_pm,
 	},
 };

 module_acpi_driver(crb_acpi_driver);
 MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
 MODULE_DESCRIPTION("TPM2 Driver");
 MODULE_VERSION("0.1");
 MODULE_LICENSE("GPL");
	/*
	* Copyright (C) 2014 Intel Corporation
	*
	* Authors:
	* Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
	*
	* Maintained by: <tpmdd-devel@lists.sourceforge.net>
	*
	* This device driver implements the TPM interface as defined in
	* the TCG CRB 2.0 TPM specification.
	*
	* 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/acpi.h>
	#include <linux/highmem.h>
	#include <linux/rculist.h>
	#include <linux/module.h>
	#include <linux/pm_runtime.h>
	#include "tpm.h"

	#define ACPI_SIG_TPM2 "TPM2"

	static const u8 CRB_ACPI_START_UUID[] = {
	/* 0000 */ 0xAB, 0x6C, 0xBF, 0x6B, 0x63, 0x54, 0x14, 0x47,
	/* 0008 */ 0xB7, 0xCD, 0xF0, 0x20, 0x3C, 0x03, 0x68, 0xD4
	};

	enum crb_defaults {
	CRB_ACPI_START_REVISION_ID = 1,
	CRB_ACPI_START_INDEX = 1,
	};

	enum crb_ctrl_req {
	CRB_CTRL_REQ_CMD_READY = BIT(0),
	CRB_CTRL_REQ_GO_IDLE = BIT(1),
	};

	enum crb_ctrl_sts {
	CRB_CTRL_STS_ERROR = BIT(0),
	CRB_CTRL_STS_TPM_IDLE = BIT(1),
	};

	enum crb_start {
	CRB_START_INVOKE = BIT(0),
	};

	enum crb_cancel {
	CRB_CANCEL_INVOKE = BIT(0),
	};

	struct crb_control_area {
	u32 req;
	u32 sts;
	u32 cancel;
	u32 start;
	u32 int_enable;
	u32 int_sts;
	u32 cmd_size;
	u32 cmd_pa_low;
	u32 cmd_pa_high;
	u32 rsp_size;
	u64 rsp_pa;
	} __packed;

	enum crb_status {
	CRB_DRV_STS_COMPLETE = BIT(0),
	};

	enum crb_flags {
	CRB_FL_ACPI_START = BIT(0),
	CRB_FL_CRB_START = BIT(1),
	};

	struct crb_priv {
	unsigned int flags;
	void __iomem *iobase;
	struct crb_control_area __iomem *cca;
	u8 __iomem *cmd;
	u8 __iomem *rsp;
	u32 cmd_size;
	};

	/**
	* crb_go_idle - request tpm crb device to go the idle state
	*
	* @dev: crb device
	* @priv: crb private data
	*
	* Write CRB_CTRL_REQ_GO_IDLE to TPM_CRB_CTRL_REQ
	* The device should respond within TIMEOUT_C by clearing the bit.
	* Anyhow, we do not wait here as a consequent CMD_READY request
	* will be handled correctly even if idle was not completed.
	*
	* The function does nothing for devices with ACPI-start method.
	*
	* Return: 0 always
	*/
	static int __maybe_unused crb_go_idle(struct device dev, struct crb_priv priv)
	{
	if (priv->flags & CRB_FL_ACPI_START)
	return 0;

	iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->cca->req);
	/* we don't really care when this settles */

	return 0;
	}

	/**
	* crb_cmd_ready - request tpm crb device to enter ready state
	*
	* @dev: crb device
	* @priv: crb private data
	*
	* Write CRB_CTRL_REQ_CMD_READY to TPM_CRB_CTRL_REQ
	* and poll till the device acknowledge it by clearing the bit.
	* The device should respond within TIMEOUT_C.
	*
	* The function does nothing for devices with ACPI-start method
	*
	* Return: 0 on success -ETIME on timeout;
	*/
	static int __maybe_unused crb_cmd_ready(struct device *dev,
	struct crb_priv *priv)
	{
	ktime_t stop, start;

	if (priv->flags & CRB_FL_ACPI_START)
	return 0;

	iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->cca->req);

	start = ktime_get();
	stop = ktime_add(start, ms_to_ktime(TPM2_TIMEOUT_C));
	do {
	if (!(ioread32(&priv->cca->req) & CRB_CTRL_REQ_CMD_READY))
	return 0;
	usleep_range(50, 100);
	} while (ktime_before(ktime_get(), stop));

	if (ioread32(&priv->cca->req) & CRB_CTRL_REQ_CMD_READY) {
	dev_warn(dev, "cmdReady timed out\n");
	return -ETIME;
	}

	return 0;
	}

	static u8 crb_status(struct tpm_chip *chip)
	{
	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
	u8 sts = 0;

	if ((ioread32(&priv->cca->start) & CRB_START_INVOKE) !=
	CRB_START_INVOKE)
	sts \|= CRB_DRV_STS_COMPLETE;

	return sts;
	}

	static int crb_recv(struct tpm_chip chip, u8 buf, size_t count)
	{
	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
	unsigned int expected;

	/* sanity check */
	if (count < 6)
	return -EIO;

	if (ioread32(&priv->cca->sts) & CRB_CTRL_STS_ERROR)
	return -EIO;

	memcpy_fromio(buf, priv->rsp, 6);
	expected = be32_to_cpup((__be32 *) &buf[2]);

	if (expected > count)
	return -EIO;

	memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6);

	return expected;
	}

	static int crb_do_acpi_start(struct tpm_chip *chip)
	{
	union acpi_object *obj;
	int rc;

	obj = acpi_evaluate_dsm(chip->acpi_dev_handle,
	CRB_ACPI_START_UUID,
	CRB_ACPI_START_REVISION_ID,
	CRB_ACPI_START_INDEX,
	NULL);
	if (!obj)
	return -ENXIO;
	rc = obj->integer.value == 0 ? 0 : -ENXIO;
	ACPI_FREE(obj);
	return rc;
	}

	static int crb_send(struct tpm_chip chip, u8 buf, size_t len)
	{
	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
	int rc = 0;

	/* Zero the cancel register so that the next command will not get
	* canceled.
	*/
	iowrite32(0, &priv->cca->cancel);

	if (len > priv->cmd_size) {
	dev_err(&chip->dev, "invalid command count value %zd %d\n",
	len, priv->cmd_size);
	return -E2BIG;
	}

	memcpy_toio(priv->cmd, buf, len);

	/* Make sure that cmd is populated before issuing start. */
	wmb();

	if (priv->flags & CRB_FL_CRB_START)
	iowrite32(CRB_START_INVOKE, &priv->cca->start);

	if (priv->flags & CRB_FL_ACPI_START)
	rc = crb_do_acpi_start(chip);

	return rc;
	}

	static void crb_cancel(struct tpm_chip *chip)
	{
	struct crb_priv *priv = dev_get_drvdata(&chip->dev);

	iowrite32(CRB_CANCEL_INVOKE, &priv->cca->cancel);

	if ((priv->flags & CRB_FL_ACPI_START) && crb_do_acpi_start(chip))
	dev_err(&chip->dev, "ACPI Start failed\n");
	}

	static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
	{
	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
	u32 cancel = ioread32(&priv->cca->cancel);

	return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
	}

	static const struct tpm_class_ops tpm_crb = {
	.flags = TPM_OPS_AUTO_STARTUP,
	.status = crb_status,
	.recv = crb_recv,
	.send = crb_send,
	.cancel = crb_cancel,
	.req_canceled = crb_req_canceled,
	.req_complete_mask = CRB_DRV_STS_COMPLETE,
	.req_complete_val = CRB_DRV_STS_COMPLETE,
	};

	static int crb_check_resource(struct acpi_resource ares, void data)
	{
	struct resource *io_res = data;
	struct resource_win win;
	struct resource *res = &(win.res);

	if (acpi_dev_resource_memory(ares, res) \|\|
	acpi_dev_resource_address_space(ares, &win)) {
	io_res = res;
	io_res->name = NULL;
	}

	return 1;
	}

	static void __iomem crb_map_res(struct device dev, struct crb_priv *priv,
	struct resource *io_res, u64 start, u32 size)
	{
	struct resource new_res = {
	.start = start,
	.end = start + size - 1,
	.flags = IORESOURCE_MEM,
	};

	/* Detect a 64 bit address on a 32 bit system */
	if (start != new_res.start)
	return (void __iomem *) ERR_PTR(-EINVAL);

	if (!resource_contains(io_res, &new_res))
	return devm_ioremap_resource(dev, &new_res);

	return priv->iobase + (new_res.start - io_res->start);
	}

	static int crb_map_io(struct acpi_device device, struct crb_priv priv,
	struct acpi_table_tpm2 *buf)
	{
	struct list_head resources;
	struct resource io_res;
	struct device *dev = &device->dev;
	u32 pa_high, pa_low;
	u64 cmd_pa;
	u32 cmd_size;
	u64 rsp_pa;
	u32 rsp_size;
	int ret;

	INIT_LIST_HEAD(&resources);
	ret = acpi_dev_get_resources(device, &resources, crb_check_resource,
	&io_res);
	if (ret < 0)
	return ret;
	acpi_dev_free_resource_list(&resources);

	if (resource_type(&io_res) != IORESOURCE_MEM) {
	dev_err(dev, FW_BUG "TPM2 ACPI table does not define a memory resource\n");
	return -EINVAL;
	}

	priv->iobase = devm_ioremap_resource(dev, &io_res);
	if (IS_ERR(priv->iobase))
	return PTR_ERR(priv->iobase);

	priv->cca = crb_map_res(dev, priv, &io_res, buf->control_address,
	sizeof(struct crb_control_area));
	if (IS_ERR(priv->cca))
	return PTR_ERR(priv->cca);

	/*
	* PTT HW bug w/a: wake up the device to access
	* possibly not retained registers.
	*/
	ret = crb_cmd_ready(dev, priv);
	if (ret)
	return ret;

	pa_high = ioread32(&priv->cca->cmd_pa_high);
	pa_low = ioread32(&priv->cca->cmd_pa_low);
	cmd_pa = ((u64)pa_high << 32) \| pa_low;
	cmd_size = ioread32(&priv->cca->cmd_size);

	dev_dbg(dev, "cmd_hi = %X cmd_low = %X cmd_size %X\n",
	pa_high, pa_low, cmd_size);

	priv->cmd = crb_map_res(dev, priv, &io_res, cmd_pa, cmd_size);
	if (IS_ERR(priv->cmd)) {
	ret = PTR_ERR(priv->cmd);
	goto out;
	}

	memcpy_fromio(&rsp_pa, &priv->cca->rsp_pa, 8);
	rsp_pa = le64_to_cpu(rsp_pa);
	rsp_size = ioread32(&priv->cca->rsp_size);

	if (cmd_pa != rsp_pa) {
	priv->rsp = crb_map_res(dev, priv, &io_res, rsp_pa, rsp_size);
	ret = PTR_ERR_OR_ZERO(priv->rsp);
	goto out;
	}

	/* According to the PTP specification, overlapping command and response
	* buffer sizes must be identical.
	*/
	if (cmd_size != rsp_size) {
	dev_err(dev, FW_BUG "overlapping command and response buffer sizes are not identical");
	ret = -EINVAL;
	goto out;
	}

	priv->cmd_size = cmd_size;

	priv->rsp = priv->cmd;

	out:
	crb_go_idle(dev, priv);

	return ret;
	}

	static int crb_acpi_add(struct acpi_device *device)
	{
	struct acpi_table_tpm2 *buf;
	struct crb_priv *priv;
	struct tpm_chip *chip;
	struct device *dev = &device->dev;
	acpi_status status;
	u32 sm;
	int rc;

	status = acpi_get_table(ACPI_SIG_TPM2, 1,
	(struct acpi_table_header **) &buf);
	if (ACPI_FAILURE(status) \|\| buf->header.length < sizeof(*buf)) {
	dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
	return -EINVAL;
	}

	/* Should the FIFO driver handle this? */
	sm = buf->start_method;
	if (sm == ACPI_TPM2_MEMORY_MAPPED)
	return -ENODEV;

	priv = devm_kzalloc(dev, sizeof(struct crb_priv), GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	/* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
	* report only ACPI start but in practice seems to require both
	* ACPI start and CRB start.
	*/
	if (sm == ACPI_TPM2_COMMAND_BUFFER \|\| sm == ACPI_TPM2_MEMORY_MAPPED \|\|
	!strcmp(acpi_device_hid(device), "MSFT0101"))
	priv->flags \|= CRB_FL_CRB_START;

	if (sm == ACPI_TPM2_START_METHOD \|\|
	sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
	priv->flags \|= CRB_FL_ACPI_START;

	rc = crb_map_io(device, priv, buf);
	if (rc)
	return rc;

	chip = tpmm_chip_alloc(dev, &tpm_crb);
	if (IS_ERR(chip))
	return PTR_ERR(chip);

	dev_set_drvdata(&chip->dev, priv);
	chip->acpi_dev_handle = device->handle;
	chip->flags = TPM_CHIP_FLAG_TPM2;

	rc = crb_cmd_ready(dev, priv);
	if (rc)
	return rc;

	pm_runtime_get_noresume(dev);
	pm_runtime_set_active(dev);
	pm_runtime_enable(dev);

	rc = tpm_chip_register(chip);
	if (rc) {
	crb_go_idle(dev, priv);
	pm_runtime_put_noidle(dev);
	pm_runtime_disable(dev);
	return rc;
	}

	pm_runtime_put(dev);

	return 0;
	}

	static int crb_acpi_remove(struct acpi_device *device)
	{
	struct device *dev = &device->dev;
	struct tpm_chip *chip = dev_get_drvdata(dev);

	tpm_chip_unregister(chip);

	pm_runtime_disable(dev);

	return 0;
	}

	#ifdef CONFIG_PM
	static int crb_pm_runtime_suspend(struct device *dev)
	{
	struct tpm_chip *chip = dev_get_drvdata(dev);
	struct crb_priv *priv = dev_get_drvdata(&chip->dev);

	return crb_go_idle(dev, priv);
	}

	static int crb_pm_runtime_resume(struct device *dev)
	{
	struct tpm_chip *chip = dev_get_drvdata(dev);
	struct crb_priv *priv = dev_get_drvdata(&chip->dev);

	return crb_cmd_ready(dev, priv);
	}
	#endif /* CONFIG_PM */

	static const struct dev_pm_ops crb_pm = {
	SET_SYSTEM_SLEEP_PM_OPS(tpm_pm_suspend, tpm_pm_resume)
	SET_RUNTIME_PM_OPS(crb_pm_runtime_suspend, crb_pm_runtime_resume, NULL)
	};

	static struct acpi_device_id crb_device_ids[] = {
	{"MSFT0101", 0},
	{"", 0},
	};
	MODULE_DEVICE_TABLE(acpi, crb_device_ids);

	static struct acpi_driver crb_acpi_driver = {
	.name = "tpm_crb",
	.ids = crb_device_ids,
	.ops = {
	.add = crb_acpi_add,
	.remove = crb_acpi_remove,
	},
	.drv = {
	.pm = &crb_pm,
	},
	};

	module_acpi_driver(crb_acpi_driver);
	MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
	MODULE_DESCRIPTION("TPM2 Driver");
	MODULE_VERSION("0.1");
	MODULE_LICENSE("GPL");