/*
 * 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 "tpm.h"
#include "tpm_tis_core.h"

struct tpm_info {
	struct resource res;
	/* irq > 0 means: use irq $irq;
	 * irq = 0 means: autoprobe for an irq;
	 * irq = -1 means: no irq support
	 */
	int irq;
};

struct tpm_tis_tcg_phy {
	struct tpm_tis_data priv;
	void __iomem *iobase;
};

static inline struct tpm_tis_tcg_phy *to_tpm_tis_tcg_phy(struct tpm_tis_data *data)
{
	return container_of(data, struct tpm_tis_tcg_phy, priv);
}

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

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

static bool force;
#ifdef CONFIG_X86
module_param(force, bool, 0444);
MODULE_PARM_DESC(force, "Force device probe rather than using ACPI entry");
#endif

#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");
}
#else
static inline int is_itpm(struct acpi_device *dev)
{
	return 0;
}
#endif

static int tpm_tcg_read_bytes(struct tpm_tis_data *data, u32 addr, u16 len,
			      u8 *result)
{
	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);

	while (len--)
		*result++ = ioread8(phy->iobase + addr);
	return 0;
}

static int tpm_tcg_write_bytes(struct tpm_tis_data *data, u32 addr, u16 len,
			       u8 *value)
{
	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);

	while (len--)
		iowrite8(*value++, phy->iobase + addr);
	return 0;
}

static int tpm_tcg_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
{
	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);

	*result = ioread16(phy->iobase + addr);
	return 0;
}

static int tpm_tcg_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
{
	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);

	*result = ioread32(phy->iobase + addr);
	return 0;
}

static int tpm_tcg_write32(struct tpm_tis_data *data, u32 addr, u32 value)
{
	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);

	iowrite32(value, phy->iobase + addr);
	return 0;
}

static const struct tpm_tis_phy_ops tpm_tcg = {
	.read_bytes = tpm_tcg_read_bytes,
	.write_bytes = tpm_tcg_write_bytes,
	.read16 = tpm_tcg_read16,
	.read32 = tpm_tcg_read32,
	.write32 = tpm_tcg_write32,
};

static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info,
			acpi_handle acpi_dev_handle)
{
	struct tpm_tis_tcg_phy *phy;
	int irq = -1;

	phy = devm_kzalloc(dev, sizeof(struct tpm_tis_tcg_phy), GFP_KERNEL);
	if (phy == NULL)
		return -ENOMEM;

	phy->iobase = devm_ioremap_resource(dev, &tpm_info->res);
	if (IS_ERR(phy->iobase))
		return PTR_ERR(phy->iobase);

	if (interrupts)
		irq = tpm_info->irq;

	if (itpm)
		phy->priv.flags |= TPM_TIS_ITPM_POSSIBLE;

	return tpm_tis_core_init(dev, &phy->priv, irq, &tpm_tcg,
				 acpi_dev_handle);
}

static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);

static int tpm_tis_pnp_init(struct pnp_dev *pnp_dev,
			    const struct pnp_device_id *pnp_id)
{
	struct tpm_info tpm_info = {};
	acpi_handle acpi_dev_handle = NULL;
	struct resource *res;

	res = pnp_get_resource(pnp_dev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENODEV;
	tpm_info.res = *res;

	if (pnp_irq_valid(pnp_dev, 0))
		tpm_info.irq = pnp_irq(pnp_dev, 0);
	else
		tpm_info.irq = -1;

	if (pnp_acpi_device(pnp_dev)) {
		if (is_itpm(pnp_acpi_device(pnp_dev)))
			itpm = true;

		acpi_dev_handle = ACPI_HANDLE(&pnp_dev->dev);
	}

	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");

#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->res = res;
		tpm_info->res.name = NULL;
	}

	return 1;
}

static int tpm_tis_acpi_init(struct acpi_device *acpi_dev)
{
	struct acpi_table_tpm2 *tbl;
	acpi_status st;
	struct list_head resources;
	struct tpm_info tpm_info = {};
	int ret;

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

	if (tbl->start_method != ACPI_TPM2_MEMORY_MAPPED)
		return -ENODEV;

	INIT_LIST_HEAD(&resources);
	tpm_info.irq = -1;
	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 (resource_type(&tpm_info.res) != IORESOURCE_MEM) {
		dev_err(&acpi_dev->dev,
			FW_BUG "TPM2 ACPI table does not define a memory resource\n");
		return -EINVAL;
	}

	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_device *force_pdev;

static int tpm_tis_plat_probe(struct platform_device *pdev)
{
	struct tpm_info tpm_info = {};
	struct resource *res;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (res == NULL) {
		dev_err(&pdev->dev, "no memory resource defined\n");
		return -ENODEV;
	}
	tpm_info.res = *res;

	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (res) {
		tpm_info.irq = res->start;
	} else {
		if (pdev == force_pdev)
			tpm_info.irq = -1;
		else
			/* When forcing auto probe the IRQ */
			tpm_info.irq = 0;
	}

	return tpm_tis_init(&pdev->dev, &tpm_info, NULL);
}

static int tpm_tis_plat_remove(struct platform_device *pdev)
{
	struct tpm_chip *chip = dev_get_drvdata(&pdev->dev);

	tpm_chip_unregister(chip);
	tpm_tis_remove(chip);

	return 0;
}

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

static int tpm_tis_force_device(void)
{
	struct platform_device *pdev;
	static const struct resource x86_resources[] = {
		{
			.start = 0xFED40000,
			.end = 0xFED40000 + TIS_MEM_LEN - 1,
			.flags = IORESOURCE_MEM,
		},
	};

	if (!force)
		return 0;

	/* The driver core will match the name tpm_tis of the device to
	 * the tpm_tis platform driver and complete the setup via
	 * tpm_tis_plat_probe
	 */
	pdev = platform_device_register_simple("tpm_tis", -1, x86_resources,
					       ARRAY_SIZE(x86_resources));
	if (IS_ERR(pdev))
		return PTR_ERR(pdev);
	force_pdev = pdev;

	return 0;
}

static int __init init_tis(void)
{
	int rc;

	rc = tpm_tis_force_device();
	if (rc)
		goto err_force;

	rc = platform_driver_register(&tis_drv);
	if (rc)
		goto err_platform;

#ifdef CONFIG_ACPI
	rc = acpi_bus_register_driver(&tis_acpi_driver);
	if (rc)
		goto err_acpi;
#endif

	if (IS_ENABLED(CONFIG_PNP)) {
		rc = pnp_register_driver(&tis_pnp_driver);
		if (rc)
			goto err_pnp;
	}

	return 0;

err_pnp:
#ifdef CONFIG_ACPI
	acpi_bus_unregister_driver(&tis_acpi_driver);
err_acpi:
#endif
	platform_driver_unregister(&tis_drv);
err_platform:
	if (force_pdev)
		platform_device_unregister(force_pdev);
err_force:
	return rc;
}

static void __exit cleanup_tis(void)
{
	pnp_unregister_driver(&tis_pnp_driver);
#ifdef CONFIG_ACPI
	acpi_bus_unregister_driver(&tis_acpi_driver);
#endif
	platform_driver_unregister(&tis_drv);

	if (force_pdev)
		platform_device_unregister(force_pdev);
}

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");