/*
 * Copyright (C) 2005, 2006 IBM Corporation
 * Copyright (C) 2014, 2015 Intel Corporation
 *
 * Authors:
 * Leendert van Doorn <leendert@watson.ibm.com>
 * Kylene Hall <kjhall@us.ibm.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 1.2, revision 1.0.
 *
 * 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/pnp.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/acpi.h>
#include <linux/freezer.h>
#include <acpi/actbl2.h>
#include "tpm.h"

enum tis_access {
	TPM_ACCESS_VALID = 0x80,
	TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
	TPM_ACCESS_REQUEST_PENDING = 0x04,
	TPM_ACCESS_REQUEST_USE = 0x02,
};

enum tis_status {
	TPM_STS_VALID = 0x80,
	TPM_STS_COMMAND_READY = 0x40,
	TPM_STS_GO = 0x20,
	TPM_STS_DATA_AVAIL = 0x10,
	TPM_STS_DATA_EXPECT = 0x08,
};

enum tis_int_flags {
	TPM_GLOBAL_INT_ENABLE = 0x80000000,
	TPM_INTF_BURST_COUNT_STATIC = 0x100,
	TPM_INTF_CMD_READY_INT = 0x080,
	TPM_INTF_INT_EDGE_FALLING = 0x040,
	TPM_INTF_INT_EDGE_RISING = 0x020,
	TPM_INTF_INT_LEVEL_LOW = 0x010,
	TPM_INTF_INT_LEVEL_HIGH = 0x008,
	TPM_INTF_LOCALITY_CHANGE_INT = 0x004,
	TPM_INTF_STS_VALID_INT = 0x002,
	TPM_INTF_DATA_AVAIL_INT = 0x001,
};

enum tis_defaults {
	TIS_MEM_BASE = 0xFED40000,
	TIS_MEM_LEN = 0x5000,
	TIS_SHORT_TIMEOUT = 750,	/* ms */
	TIS_LONG_TIMEOUT = 2000,	/* 2 sec */
};

struct tpm_info {
	unsigned long start;
	unsigned long len;
	unsigned int irq;
};

static struct tpm_info tis_default_info = {
	.start = TIS_MEM_BASE,
	.len = TIS_MEM_LEN,
	.irq = 0,
};

/* Some timeout values are needed before it is known whether the chip is
 * TPM 1.0 or TPM 2.0.
 */
#define TIS_TIMEOUT_A_MAX	max(TIS_SHORT_TIMEOUT, TPM2_TIMEOUT_A)
#define TIS_TIMEOUT_B_MAX	max(TIS_LONG_TIMEOUT, TPM2_TIMEOUT_B)
#define TIS_TIMEOUT_C_MAX	max(TIS_SHORT_TIMEOUT, TPM2_TIMEOUT_C)
#define TIS_TIMEOUT_D_MAX	max(TIS_SHORT_TIMEOUT, TPM2_TIMEOUT_D)

#define	TPM_ACCESS(l)			(0x0000 | ((l) << 12))
#define	TPM_INT_ENABLE(l)		(0x0008 | ((l) << 12))
#define	TPM_INT_VECTOR(l)		(0x000C | ((l) << 12))
#define	TPM_INT_STATUS(l)		(0x0010 | ((l) << 12))
#define	TPM_INTF_CAPS(l)		(0x0014 | ((l) << 12))
#define	TPM_STS(l)			(0x0018 | ((l) << 12))
#define	TPM_STS3(l)			(0x001b | ((l) << 12))
#define	TPM_DATA_FIFO(l)		(0x0024 | ((l) << 12))

#define	TPM_DID_VID(l)			(0x0F00 | ((l) << 12))
#define	TPM_RID(l)			(0x0F04 | ((l) << 12))

struct priv_data {
	bool irq_tested;
};

#if defined(CONFIG_PNP) && defined(CONFIG_ACPI)
static int has_hid(struct acpi_device *dev, const char *hid)
{
	struct acpi_hardware_id *id;

	list_for_each_entry(id, &dev->pnp.ids, list)
		if (!strcmp(hid, id->id))
			return 1;

	return 0;
}

static inline int is_itpm(struct acpi_device *dev)
{
	return has_hid(dev, "INTC0102");
}

static inline int is_fifo(struct acpi_device *dev)
{
	struct acpi_table_tpm2 *tbl;
	acpi_status st;

	/* TPM 1.2 FIFO */
	if (!has_hid(dev, "MSFT0101"))
		return 1;

	st = acpi_get_table(ACPI_SIG_TPM2, 1,
			    (struct acpi_table_header **) &tbl);
	if (ACPI_FAILURE(st)) {
		dev_err(&dev->dev, "failed to get TPM2 ACPI table\n");
		return 0;
	}

	if (le32_to_cpu(tbl->start_method) != TPM2_START_FIFO)
		return 0;

	/* TPM 2.0 FIFO */
	return 1;
}
#else
static inline int is_itpm(struct acpi_device *dev)
{
	return 0;
}

static inline int is_fifo(struct acpi_device *dev)
{
	return 1;
}
#endif

/* Before we attempt to access the TPM we must see that the valid bit is set.
 * The specification says that this bit is 0 at reset and remains 0 until the
 * 'TPM has gone through its self test and initialization and has established
 * correct values in the other bits.' */
static int wait_startup(struct tpm_chip *chip, int l)
{
	unsigned long stop = jiffies + chip->vendor.timeout_a;
	do {
		if (ioread8(chip->vendor.iobase + TPM_ACCESS(l)) &
		    TPM_ACCESS_VALID)
			return 0;
		msleep(TPM_TIMEOUT);
	} while (time_before(jiffies, stop));
	return -1;
}

static int check_locality(struct tpm_chip *chip, int l)
{
	if ((ioread8(chip->vendor.iobase + TPM_ACCESS(l)) &
	     (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
	    (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
		return chip->vendor.locality = l;

	return -1;
}

static void release_locality(struct tpm_chip *chip, int l, int force)
{
	if (force || (ioread8(chip->vendor.iobase + TPM_ACCESS(l)) &
		      (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
	    (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID))
		iowrite8(TPM_ACCESS_ACTIVE_LOCALITY,
			 chip->vendor.iobase + TPM_ACCESS(l));
}

static int request_locality(struct tpm_chip *chip, int l)
{
	unsigned long stop, timeout;
	long rc;

	if (check_locality(chip, l) >= 0)
		return l;

	iowrite8(TPM_ACCESS_REQUEST_USE,
		 chip->vendor.iobase + TPM_ACCESS(l));

	stop = jiffies + chip->vendor.timeout_a;

	if (chip->vendor.irq) {
again:
		timeout = stop - jiffies;
		if ((long)timeout <= 0)
			return -1;
		rc = wait_event_interruptible_timeout(chip->vendor.int_queue,
						      (check_locality
						       (chip, l) >= 0),
						      timeout);
		if (rc > 0)
			return l;
		if (rc == -ERESTARTSYS && freezing(current)) {
			clear_thread_flag(TIF_SIGPENDING);
			goto again;
		}
	} else {
		/* wait for burstcount */
		do {
			if (check_locality(chip, l) >= 0)
				return l;
			msleep(TPM_TIMEOUT);
		}
		while (time_before(jiffies, stop));
	}
	return -1;
}

static u8 tpm_tis_status(struct tpm_chip *chip)
{
	return ioread8(chip->vendor.iobase +
		       TPM_STS(chip->vendor.locality));
}

static void tpm_tis_ready(struct tpm_chip *chip)
{
	/* this causes the current command to be aborted */
	iowrite8(TPM_STS_COMMAND_READY,
		 chip->vendor.iobase + TPM_STS(chip->vendor.locality));
}

static int get_burstcount(struct tpm_chip *chip)
{
	unsigned long stop;
	int burstcnt;

	/* wait for burstcount */
	/* which timeout value, spec has 2 answers (c & d) */
	stop = jiffies + chip->vendor.timeout_d;
	do {
		burstcnt = ioread8(chip->vendor.iobase +
				   TPM_STS(chip->vendor.locality) + 1);
		burstcnt += ioread8(chip->vendor.iobase +
				    TPM_STS(chip->vendor.locality) +
				    2) << 8;
		if (burstcnt)
			return burstcnt;
		msleep(TPM_TIMEOUT);
	} while (time_before(jiffies, stop));
	return -EBUSY;
}

static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
{
	int size = 0, burstcnt;
	while (size < count &&
	       wait_for_tpm_stat(chip,
				 TPM_STS_DATA_AVAIL | TPM_STS_VALID,
				 chip->vendor.timeout_c,
				 &chip->vendor.read_queue, true)
	       == 0) {
		burstcnt = get_burstcount(chip);
		for (; burstcnt > 0 && size < count; burstcnt--)
			buf[size++] = ioread8(chip->vendor.iobase +
					      TPM_DATA_FIFO(chip->vendor.
							    locality));
	}
	return size;
}

static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
{
	int size = 0;
	int status;
	u32 expected;

	if (count < TPM_HEADER_SIZE) {
		size = -EIO;
		goto out;
	}

	/* read first 10 bytes, including tag, paramsize, and result */
	if ((size =
	     recv_data(chip, buf, TPM_HEADER_SIZE)) < TPM_HEADER_SIZE) {
		dev_err(chip->pdev, "Unable to read header\n");
		goto out;
	}

	expected = be32_to_cpu(*(__be32 *) (buf + 2));
	if (expected > count || expected < TPM_HEADER_SIZE) {
		size = -EIO;
		goto out;
	}

	if ((size +=
	     recv_data(chip, &buf[TPM_HEADER_SIZE],
		       expected - TPM_HEADER_SIZE)) < expected) {
		dev_err(chip->pdev, "Unable to read remainder of result\n");
		size = -ETIME;
		goto out;
	}

	wait_for_tpm_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c,
			  &chip->vendor.int_queue, false);
	status = tpm_tis_status(chip);
	if (status & TPM_STS_DATA_AVAIL) {	/* retry? */
		dev_err(chip->pdev, "Error left over data\n");
		size = -EIO;
		goto out;
	}

out:
	tpm_tis_ready(chip);
	release_locality(chip, chip->vendor.locality, 0);
	return size;
}

static bool itpm;
module_param(itpm, bool, 0444);
MODULE_PARM_DESC(itpm, "Force iTPM workarounds (found on some Lenovo laptops)");

/*
 * If interrupts are used (signaled by an irq set in the vendor structure)
 * tpm.c can skip polling for the data to be available as the interrupt is
 * waited for here
 */
static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
{
	int rc, status, burstcnt;
	size_t count = 0;

	if (request_locality(chip, 0) < 0)
		return -EBUSY;

	status = tpm_tis_status(chip);
	if ((status & TPM_STS_COMMAND_READY) == 0) {
		tpm_tis_ready(chip);
		if (wait_for_tpm_stat
		    (chip, TPM_STS_COMMAND_READY, chip->vendor.timeout_b,
		     &chip->vendor.int_queue, false) < 0) {
			rc = -ETIME;
			goto out_err;
		}
	}

	while (count < len - 1) {
		burstcnt = get_burstcount(chip);
		for (; burstcnt > 0 && count < len - 1; burstcnt--) {
			iowrite8(buf[count], chip->vendor.iobase +
				 TPM_DATA_FIFO(chip->vendor.locality));
			count++;
		}

		wait_for_tpm_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c,
				  &chip->vendor.int_queue, false);
		status = tpm_tis_status(chip);
		if (!itpm && (status & TPM_STS_DATA_EXPECT) == 0) {
			rc = -EIO;
			goto out_err;
		}
	}

	/* write last byte */
	iowrite8(buf[count],
		 chip->vendor.iobase + TPM_DATA_FIFO(chip->vendor.locality));
	wait_for_tpm_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c,
			  &chip->vendor.int_queue, false);
	status = tpm_tis_status(chip);
	if ((status & TPM_STS_DATA_EXPECT) != 0) {
		rc = -EIO;
		goto out_err;
	}

	return 0;

out_err:
	tpm_tis_ready(chip);
	release_locality(chip, chip->vendor.locality, 0);
	return rc;
}

static void disable_interrupts(struct tpm_chip *chip)
{
	u32 intmask;

	intmask =
	    ioread32(chip->vendor.iobase +
		     TPM_INT_ENABLE(chip->vendor.locality));
	intmask &= ~TPM_GLOBAL_INT_ENABLE;
	iowrite32(intmask,
		  chip->vendor.iobase +
		  TPM_INT_ENABLE(chip->vendor.locality));
	devm_free_irq(chip->pdev, chip->vendor.irq, chip);
	chip->vendor.irq = 0;
}

/*
 * If interrupts are used (signaled by an irq set in the vendor structure)
 * tpm.c can skip polling for the data to be available as the interrupt is
 * waited for here
 */
static int tpm_tis_send_main(struct tpm_chip *chip, u8 *buf, size_t len)
{
	int rc;
	u32 ordinal;
	unsigned long dur;

	rc = tpm_tis_send_data(chip, buf, len);
	if (rc < 0)
		return rc;

	/* go and do it */
	iowrite8(TPM_STS_GO,
		 chip->vendor.iobase + TPM_STS(chip->vendor.locality));

	if (chip->vendor.irq) {
		ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));

		if (chip->flags & TPM_CHIP_FLAG_TPM2)
			dur = tpm2_calc_ordinal_duration(chip, ordinal);
		else
			dur = tpm_calc_ordinal_duration(chip, ordinal);

		if (wait_for_tpm_stat
		    (chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID, dur,
		     &chip->vendor.read_queue, false) < 0) {
			rc = -ETIME;
			goto out_err;
		}
	}
	return len;
out_err:
	tpm_tis_ready(chip);
	release_locality(chip, chip->vendor.locality, 0);
	return rc;
}

static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
{
	int rc, irq;
	struct priv_data *priv = chip->vendor.priv;

	if (!chip->vendor.irq || priv->irq_tested)
		return tpm_tis_send_main(chip, buf, len);

	/* Verify receipt of the expected IRQ */
	irq = chip->vendor.irq;
	chip->vendor.irq = 0;
	rc = tpm_tis_send_main(chip, buf, len);
	chip->vendor.irq = irq;
	if (!priv->irq_tested)
		msleep(1);
	if (!priv->irq_tested) {
		disable_interrupts(chip);
		dev_err(chip->pdev,
			FW_BUG "TPM interrupt not working, polling instead\n");
	}
	priv->irq_tested = true;
	return rc;
}

struct tis_vendor_timeout_override {
	u32 did_vid;
	unsigned long timeout_us[4];
};

static const struct tis_vendor_timeout_override vendor_timeout_overrides[] = {
	/* Atmel 3204 */
	{ 0x32041114, { (TIS_SHORT_TIMEOUT*1000), (TIS_LONG_TIMEOUT*1000),
			(TIS_SHORT_TIMEOUT*1000), (TIS_SHORT_TIMEOUT*1000) } },
};

static bool tpm_tis_update_timeouts(struct tpm_chip *chip,
				    unsigned long *timeout_cap)
{
	int i;
	u32 did_vid;

	did_vid = ioread32(chip->vendor.iobase + TPM_DID_VID(0));

	for (i = 0; i != ARRAY_SIZE(vendor_timeout_overrides); i++) {
		if (vendor_timeout_overrides[i].did_vid != did_vid)
			continue;
		memcpy(timeout_cap, vendor_timeout_overrides[i].timeout_us,
		       sizeof(vendor_timeout_overrides[i].timeout_us));
		return true;
	}

	return false;
}

/*
 * Early probing for iTPM with STS_DATA_EXPECT flaw.
 * Try sending command without itpm flag set and if that
 * fails, repeat with itpm flag set.
 */
static int probe_itpm(struct tpm_chip *chip)
{
	int rc = 0;
	u8 cmd_getticks[] = {
		0x00, 0xc1, 0x00, 0x00, 0x00, 0x0a,
		0x00, 0x00, 0x00, 0xf1
	};
	size_t len = sizeof(cmd_getticks);
	bool rem_itpm = itpm;
	u16 vendor = ioread16(chip->vendor.iobase + TPM_DID_VID(0));

	/* probe only iTPMS */
	if (vendor != TPM_VID_INTEL)
		return 0;

	itpm = false;

	rc = tpm_tis_send_data(chip, cmd_getticks, len);
	if (rc == 0)
		goto out;

	tpm_tis_ready(chip);
	release_locality(chip, chip->vendor.locality, 0);

	itpm = true;

	rc = tpm_tis_send_data(chip, cmd_getticks, len);
	if (rc == 0) {
		dev_info(chip->pdev, "Detected an iTPM.\n");
		rc = 1;
	} else
		rc = -EFAULT;

out:
	itpm = rem_itpm;
	tpm_tis_ready(chip);
	release_locality(chip, chip->vendor.locality, 0);

	return rc;
}

static bool tpm_tis_req_canceled(struct tpm_chip *chip, u8 status)
{
	switch (chip->vendor.manufacturer_id) {
	case TPM_VID_WINBOND:
		return ((status == TPM_STS_VALID) ||
			(status == (TPM_STS_VALID | TPM_STS_COMMAND_READY)));
	case TPM_VID_STM:
		return (status == (TPM_STS_VALID | TPM_STS_COMMAND_READY));
	default:
		return (status == TPM_STS_COMMAND_READY);
	}
}

static const struct tpm_class_ops tpm_tis = {
	.status = tpm_tis_status,
	.recv = tpm_tis_recv,
	.send = tpm_tis_send,
	.cancel = tpm_tis_ready,
	.update_timeouts = tpm_tis_update_timeouts,
	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
	.req_canceled = tpm_tis_req_canceled,
};

static irqreturn_t tis_int_probe(int irq, void *dev_id)
{
	struct tpm_chip *chip = dev_id;
	u32 interrupt;

	interrupt = ioread32(chip->vendor.iobase +
			     TPM_INT_STATUS(chip->vendor.locality));

	if (interrupt == 0)
		return IRQ_NONE;

	chip->vendor.probed_irq = irq;

	/* Clear interrupts handled with TPM_EOI */
	iowrite32(interrupt,
		  chip->vendor.iobase +
		  TPM_INT_STATUS(chip->vendor.locality));
	return IRQ_HANDLED;
}

static irqreturn_t tis_int_handler(int dummy, void *dev_id)
{
	struct tpm_chip *chip = dev_id;
	u32 interrupt;
	int i;

	interrupt = ioread32(chip->vendor.iobase +
			     TPM_INT_STATUS(chip->vendor.locality));

	if (interrupt == 0)
		return IRQ_NONE;

	((struct priv_data *)chip->vendor.priv)->irq_tested = true;
	if (interrupt & TPM_INTF_DATA_AVAIL_INT)
		wake_up_interruptible(&chip->vendor.read_queue);
	if (interrupt & TPM_INTF_LOCALITY_CHANGE_INT)
		for (i = 0; i < 5; i++)
			if (check_locality(chip, i) >= 0)
				break;
	if (interrupt &
	    (TPM_INTF_LOCALITY_CHANGE_INT | TPM_INTF_STS_VALID_INT |
	     TPM_INTF_CMD_READY_INT))
		wake_up_interruptible(&chip->vendor.int_queue);

	/* Clear interrupts handled with TPM_EOI */
	iowrite32(interrupt,
		  chip->vendor.iobase +
		  TPM_INT_STATUS(chip->vendor.locality));
	ioread32(chip->vendor.iobase + TPM_INT_STATUS(chip->vendor.locality));
	return IRQ_HANDLED;
}

static bool interrupts = true;
module_param(interrupts, bool, 0444);
MODULE_PARM_DESC(interrupts, "Enable interrupts");

static void tpm_tis_remove(struct tpm_chip *chip)
{
	if (chip->flags & TPM_CHIP_FLAG_TPM2)
		tpm2_shutdown(chip, TPM2_SU_CLEAR);

	iowrite32(~TPM_GLOBAL_INT_ENABLE &
		  ioread32(chip->vendor.iobase +
			   TPM_INT_ENABLE(chip->vendor.
					  locality)),
		  chip->vendor.iobase +
		  TPM_INT_ENABLE(chip->vendor.locality));
	release_locality(chip, chip->vendor.locality, 1);
}

static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info,
			acpi_handle acpi_dev_handle)
{
	u32 vendor, intfcaps, intmask;
	int rc, i, irq_s, irq_e, probe;
	struct tpm_chip *chip;
	struct priv_data *priv;

	priv = devm_kzalloc(dev, sizeof(struct priv_data), GFP_KERNEL);
	if (priv == NULL)
		return -ENOMEM;

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

	chip->vendor.priv = priv;
#ifdef CONFIG_ACPI
	chip->acpi_dev_handle = acpi_dev_handle;
#endif

	chip->vendor.iobase = devm_ioremap(dev, tpm_info->start, tpm_info->len);
	if (!chip->vendor.iobase)
		return -EIO;

	/* Maximum timeouts */
	chip->vendor.timeout_a = TIS_TIMEOUT_A_MAX;
	chip->vendor.timeout_b = TIS_TIMEOUT_B_MAX;
	chip->vendor.timeout_c = TIS_TIMEOUT_C_MAX;
	chip->vendor.timeout_d = TIS_TIMEOUT_D_MAX;

	if (wait_startup(chip, 0) != 0) {
		rc = -ENODEV;
		goto out_err;
	}

	if (request_locality(chip, 0) != 0) {
		rc = -ENODEV;
		goto out_err;
	}

	rc = tpm2_probe(chip);
	if (rc)
		goto out_err;

	vendor = ioread32(chip->vendor.iobase + TPM_DID_VID(0));
	chip->vendor.manufacturer_id = vendor;

	dev_info(dev, "%s TPM (device-id 0x%X, rev-id %d)\n",
		 (chip->flags & TPM_CHIP_FLAG_TPM2) ? "2.0" : "1.2",
		 vendor >> 16, ioread8(chip->vendor.iobase + TPM_RID(0)));

	if (!itpm) {
		probe = probe_itpm(chip);
		if (probe < 0) {
			rc = -ENODEV;
			goto out_err;
		}
		itpm = !!probe;
	}

	if (itpm)
		dev_info(dev, "Intel iTPM workaround enabled\n");


	/* Figure out the capabilities */
	intfcaps =
	    ioread32(chip->vendor.iobase +
		     TPM_INTF_CAPS(chip->vendor.locality));
	dev_dbg(dev, "TPM interface capabilities (0x%x):\n",
		intfcaps);
	if (intfcaps & TPM_INTF_BURST_COUNT_STATIC)
		dev_dbg(dev, "\tBurst Count Static\n");
	if (intfcaps & TPM_INTF_CMD_READY_INT)
		dev_dbg(dev, "\tCommand Ready Int Support\n");
	if (intfcaps & TPM_INTF_INT_EDGE_FALLING)
		dev_dbg(dev, "\tInterrupt Edge Falling\n");
	if (intfcaps & TPM_INTF_INT_EDGE_RISING)
		dev_dbg(dev, "\tInterrupt Edge Rising\n");
	if (intfcaps & TPM_INTF_INT_LEVEL_LOW)
		dev_dbg(dev, "\tInterrupt Level Low\n");
	if (intfcaps & TPM_INTF_INT_LEVEL_HIGH)
		dev_dbg(dev, "\tInterrupt Level High\n");
	if (intfcaps & TPM_INTF_LOCALITY_CHANGE_INT)
		dev_dbg(dev, "\tLocality Change Int Support\n");
	if (intfcaps & TPM_INTF_STS_VALID_INT)
		dev_dbg(dev, "\tSts Valid Int Support\n");
	if (intfcaps & TPM_INTF_DATA_AVAIL_INT)
		dev_dbg(dev, "\tData Avail Int Support\n");

	/* INTERRUPT Setup */
	init_waitqueue_head(&chip->vendor.read_queue);
	init_waitqueue_head(&chip->vendor.int_queue);

	intmask =
	    ioread32(chip->vendor.iobase +
		     TPM_INT_ENABLE(chip->vendor.locality));

	intmask |= TPM_INTF_CMD_READY_INT
	    | TPM_INTF_LOCALITY_CHANGE_INT | TPM_INTF_DATA_AVAIL_INT
	    | TPM_INTF_STS_VALID_INT;

	iowrite32(intmask,
		  chip->vendor.iobase +
		  TPM_INT_ENABLE(chip->vendor.locality));
	if (interrupts)
		chip->vendor.irq = tpm_info->irq;
	if (interrupts && !chip->vendor.irq) {
		irq_s =
		    ioread8(chip->vendor.iobase +
			    TPM_INT_VECTOR(chip->vendor.locality));
		if (irq_s) {
			irq_e = irq_s;
		} else {
			irq_s = 3;
			irq_e = 15;
		}

		for (i = irq_s; i <= irq_e && chip->vendor.irq == 0; i++) {
			iowrite8(i, chip->vendor.iobase +
				 TPM_INT_VECTOR(chip->vendor.locality));
			if (devm_request_irq
			    (dev, i, tis_int_probe, IRQF_SHARED,
			     chip->devname, chip) != 0) {
				dev_info(chip->pdev,
					 "Unable to request irq: %d for probe\n",
					 i);
				continue;
			}

			/* Clear all existing */
			iowrite32(ioread32
				  (chip->vendor.iobase +
				   TPM_INT_STATUS(chip->vendor.locality)),
				  chip->vendor.iobase +
				  TPM_INT_STATUS(chip->vendor.locality));

			/* Turn on */
			iowrite32(intmask | TPM_GLOBAL_INT_ENABLE,
				  chip->vendor.iobase +
				  TPM_INT_ENABLE(chip->vendor.locality));

			chip->vendor.probed_irq = 0;

			/* Generate Interrupts */
			if (chip->flags & TPM_CHIP_FLAG_TPM2)
				tpm2_gen_interrupt(chip);
			else
				tpm_gen_interrupt(chip);

			chip->vendor.irq = chip->vendor.probed_irq;

			/* free_irq will call into tis_int_probe;
			   clear all irqs we haven't seen while doing
			   tpm_gen_interrupt */
			iowrite32(ioread32
				  (chip->vendor.iobase +
				   TPM_INT_STATUS(chip->vendor.locality)),
				  chip->vendor.iobase +
				  TPM_INT_STATUS(chip->vendor.locality));

			/* Turn off */
			iowrite32(intmask,
				  chip->vendor.iobase +
				  TPM_INT_ENABLE(chip->vendor.locality));
		}
	}
	if (chip->vendor.irq) {
		iowrite8(chip->vendor.irq,
			 chip->vendor.iobase +
			 TPM_INT_VECTOR(chip->vendor.locality));
		if (devm_request_irq
		    (dev, chip->vendor.irq, tis_int_handler, IRQF_SHARED,
		     chip->devname, chip) != 0) {
			dev_info(chip->pdev,
				 "Unable to request irq: %d for use\n",
				 chip->vendor.irq);
			chip->vendor.irq = 0;
		} else {
			/* Clear all existing */
			iowrite32(ioread32
				  (chip->vendor.iobase +
				   TPM_INT_STATUS(chip->vendor.locality)),
				  chip->vendor.iobase +
				  TPM_INT_STATUS(chip->vendor.locality));

			/* Turn on */
			iowrite32(intmask | TPM_GLOBAL_INT_ENABLE,
				  chip->vendor.iobase +
				  TPM_INT_ENABLE(chip->vendor.locality));
		}
	}

	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
		chip->vendor.timeout_a = msecs_to_jiffies(TPM2_TIMEOUT_A);
		chip->vendor.timeout_b = msecs_to_jiffies(TPM2_TIMEOUT_B);
		chip->vendor.timeout_c = msecs_to_jiffies(TPM2_TIMEOUT_C);
		chip->vendor.timeout_d = msecs_to_jiffies(TPM2_TIMEOUT_D);
		chip->vendor.duration[TPM_SHORT] =
			msecs_to_jiffies(TPM2_DURATION_SHORT);
		chip->vendor.duration[TPM_MEDIUM] =
			msecs_to_jiffies(TPM2_DURATION_MEDIUM);
		chip->vendor.duration[TPM_LONG] =
			msecs_to_jiffies(TPM2_DURATION_LONG);

		rc = tpm2_do_selftest(chip);
		if (rc == TPM2_RC_INITIALIZE) {
			dev_warn(dev, "Firmware has not started TPM\n");
			rc  = tpm2_startup(chip, TPM2_SU_CLEAR);
			if (!rc)
				rc = tpm2_do_selftest(chip);
		}

		if (rc) {
			dev_err(dev, "TPM self test failed\n");
			if (rc > 0)
				rc = -ENODEV;
			goto out_err;
		}
	} else {
		if (tpm_get_timeouts(chip)) {
			dev_err(dev, "Could not get TPM timeouts and durations\n");
			rc = -ENODEV;
			goto out_err;
		}

		if (tpm_do_selftest(chip)) {
			dev_err(dev, "TPM self test failed\n");
			rc = -ENODEV;
			goto out_err;
		}
	}

	return tpm_chip_register(chip);
out_err:
	tpm_tis_remove(chip);
	return rc;
}

#ifdef CONFIG_PM_SLEEP
static void tpm_tis_reenable_interrupts(struct tpm_chip *chip)
{
	u32 intmask;

	/* reenable interrupts that device may have lost or
	   BIOS/firmware may have disabled */
	iowrite8(chip->vendor.irq, chip->vendor.iobase +
		 TPM_INT_VECTOR(chip->vendor.locality));

	intmask =
	    ioread32(chip->vendor.iobase +
		     TPM_INT_ENABLE(chip->vendor.locality));

	intmask |= TPM_INTF_CMD_READY_INT
	    | TPM_INTF_LOCALITY_CHANGE_INT | TPM_INTF_DATA_AVAIL_INT
	    | TPM_INTF_STS_VALID_INT | TPM_GLOBAL_INT_ENABLE;

	iowrite32(intmask,
		  chip->vendor.iobase + TPM_INT_ENABLE(chip->vendor.locality));
}

static int tpm_tis_resume(struct device *dev)
{
	struct tpm_chip *chip = dev_get_drvdata(dev);
	int ret;

	if (chip->vendor.irq)
		tpm_tis_reenable_interrupts(chip);

	ret = tpm_pm_resume(dev);
	if (ret)
		return ret;

	/* TPM 1.2 requires self-test on resume. This function actually returns
	 * an error code but for unknown reason it isn't handled.
	 */
	if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
		tpm_do_selftest(chip);

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);

#ifdef CONFIG_PNP
static int tpm_tis_pnp_init(struct pnp_dev *pnp_dev,
				      const struct pnp_device_id *pnp_id)
{
	struct tpm_info tpm_info = tis_default_info;
	acpi_handle acpi_dev_handle = NULL;

	tpm_info.start = pnp_mem_start(pnp_dev, 0);
	tpm_info.len = pnp_mem_len(pnp_dev, 0);

	if (pnp_irq_valid(pnp_dev, 0))
		tpm_info.irq = pnp_irq(pnp_dev, 0);
	else
		interrupts = false;

#ifdef CONFIG_ACPI
	if (pnp_acpi_device(pnp_dev)) {
		if (is_itpm(pnp_acpi_device(pnp_dev)))
			itpm = true;

		acpi_dev_handle = pnp_acpi_device(pnp_dev)->handle;
	}
#endif

	return tpm_tis_init(&pnp_dev->dev, &tpm_info, acpi_dev_handle);
}

static struct pnp_device_id tpm_pnp_tbl[] = {
	{"PNP0C31", 0},		/* TPM */
	{"ATM1200", 0},		/* Atmel */
	{"IFX0102", 0},		/* Infineon */
	{"BCM0101", 0},		/* Broadcom */
	{"BCM0102", 0},		/* Broadcom */
	{"NSC1200", 0},		/* National */
	{"ICO0102", 0},		/* Intel */
	/* Add new here */
	{"", 0},		/* User Specified */
	{"", 0}			/* Terminator */
};
MODULE_DEVICE_TABLE(pnp, tpm_pnp_tbl);

static void tpm_tis_pnp_remove(struct pnp_dev *dev)
{
	struct tpm_chip *chip = pnp_get_drvdata(dev);

	tpm_chip_unregister(chip);
	tpm_tis_remove(chip);
}

static struct pnp_driver tis_pnp_driver = {
	.name = "tpm_tis",
	.id_table = tpm_pnp_tbl,
	.probe = tpm_tis_pnp_init,
	.remove = tpm_tis_pnp_remove,
	.driver	= {
		.pm = &tpm_tis_pm,
	},
};

#define TIS_HID_USR_IDX sizeof(tpm_pnp_tbl)/sizeof(struct pnp_device_id) -2
module_param_string(hid, tpm_pnp_tbl[TIS_HID_USR_IDX].id,
		    sizeof(tpm_pnp_tbl[TIS_HID_USR_IDX].id), 0444);
MODULE_PARM_DESC(hid, "Set additional specific HID for this driver to probe");
#endif

#ifdef CONFIG_ACPI
static int tpm_check_resource(struct acpi_resource *ares, void *data)
{
	struct tpm_info *tpm_info = (struct tpm_info *) data;
	struct resource res;

	if (acpi_dev_resource_interrupt(ares, 0, &res)) {
		tpm_info->irq = res.start;
	} else if (acpi_dev_resource_memory(ares, &res)) {
		tpm_info->start = res.start;
		tpm_info->len = resource_size(&res);
	}

	return 1;
}

static int tpm_tis_acpi_init(struct acpi_device *acpi_dev)
{
	struct list_head resources;
	struct tpm_info tpm_info = tis_default_info;
	int ret;

	if (!is_fifo(acpi_dev))
		return -ENODEV;

	INIT_LIST_HEAD(&resources);
	ret = acpi_dev_get_resources(acpi_dev, &resources, tpm_check_resource,
				     &tpm_info);
	if (ret < 0)
		return ret;

	acpi_dev_free_resource_list(&resources);

	if (!tpm_info.irq)
		interrupts = false;

	if (is_itpm(acpi_dev))
		itpm = true;

	return tpm_tis_init(&acpi_dev->dev, &tpm_info, acpi_dev->handle);
}

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

	tpm_chip_unregister(chip);
	tpm_tis_remove(chip);

	return 0;
}

static struct acpi_device_id tpm_acpi_tbl[] = {
	{"MSFT0101", 0},	/* TPM 2.0 */
	/* Add new here */
	{"", 0},		/* User Specified */
	{"", 0}			/* Terminator */
};
MODULE_DEVICE_TABLE(acpi, tpm_acpi_tbl);

static struct acpi_driver tis_acpi_driver = {
	.name = "tpm_tis",
	.ids = tpm_acpi_tbl,
	.ops = {
		.add = tpm_tis_acpi_init,
		.remove = tpm_tis_acpi_remove,
	},
	.drv = {
		.pm = &tpm_tis_pm,
	},
};
#endif

static struct platform_driver tis_drv = {
	.driver = {
		.name		= "tpm_tis",
		.pm		= &tpm_tis_pm,
	},
};

static struct platform_device *pdev;

static bool force;
module_param(force, bool, 0444);
MODULE_PARM_DESC(force, "Force device probe rather than using ACPI entry");
static int __init init_tis(void)
{
	int rc;
#ifdef CONFIG_PNP
	if (!force) {
		rc = pnp_register_driver(&tis_pnp_driver);
		if (rc)
			return rc;
	}
#endif
#ifdef CONFIG_ACPI
	if (!force) {
		rc = acpi_bus_register_driver(&tis_acpi_driver);
		if (rc) {
#ifdef CONFIG_PNP
			pnp_unregister_driver(&tis_pnp_driver);
#endif
			return rc;
		}
	}
#endif
	if (!force)
		return 0;

	rc = platform_driver_register(&tis_drv);
	if (rc < 0)
		return rc;
	pdev = platform_device_register_simple("tpm_tis", -1, NULL, 0);
	if (IS_ERR(pdev)) {
		rc = PTR_ERR(pdev);
		goto err_dev;
	}
	rc = tpm_tis_init(&pdev->dev, &tis_default_info, NULL);
	if (rc)
		goto err_init;
	return 0;
err_init:
	platform_device_unregister(pdev);
err_dev:
	platform_driver_unregister(&tis_drv);
	return rc;
}

static void __exit cleanup_tis(void)
{
	struct tpm_chip *chip;
#if defined(CONFIG_PNP) || defined(CONFIG_ACPI)
	if (!force) {
#ifdef CONFIG_ACPI
		acpi_bus_unregister_driver(&tis_acpi_driver);
#endif
#ifdef CONFIG_PNP
		pnp_unregister_driver(&tis_pnp_driver);
#endif
		return;
	}
#endif
	chip = dev_get_drvdata(&pdev->dev);
	tpm_chip_unregister(chip);
	tpm_tis_remove(chip);
	platform_device_unregister(pdev);
	platform_driver_unregister(&tis_drv);
}

module_init(init_tis);
module_exit(cleanup_tis);
MODULE_AUTHOR("Leendert van Doorn (leendert@watson.ibm.com)");
MODULE_DESCRIPTION("TPM Driver");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");