// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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.
 */
#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 <linux/of.h>
#include <linux/kernel.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);
}

#ifdef CONFIG_PREEMPT_RT
/*
 * Flush previous write operations with a dummy read operation to the
 * TPM MMIO base address.
 */
static inline void tpm_tis_flush(void __iomem *iobase)
{
        ioread8(iobase + TPM_ACCESS(0));
}
#else
#define tpm_tis_flush(iobase) do { } while (0)
#endif

/*
 * Write a byte word to the TPM MMIO address, and flush the write queue.
 * The flush ensures that the data is sent immediately over the bus and not
 * aggregated with further requests and transferred later in a batch. The large
 * write requests can lead to unwanted latency spikes by blocking the CPU until
 * the complete batch has been transferred.
 */
static inline void tpm_tis_iowrite8(u8 b, void __iomem *iobase, u32 addr)
{
        iowrite8(b, iobase + addr);
        tpm_tis_flush(iobase);
}

/*
 * Write a 32-bit word to the TPM MMIO address, and flush the write queue.
 * The flush ensures that the data is sent immediately over the bus and not
 * aggregated with further requests and transferred later in a batch. The large
 * write requests can lead to unwanted latency spikes by blocking the CPU until
 * the complete batch has been transferred.
 */
static inline void tpm_tis_iowrite32(u32 b, void __iomem *iobase, u32 addr)
{
        iowrite32(b, iobase + addr);
        tpm_tis_flush(iobase);
}

static bool interrupts;
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)
{
        if (!dev)
                return 0;
        return has_hid(dev, "INTC0102");
}
#else
static inline int is_itpm(struct acpi_device *dev)
{
        return 0;
}
#endif

#if defined(CONFIG_ACPI)
#define DEVICE_IS_TPM2 1

static const struct acpi_device_id tpm_acpi_tbl[] = {
        {"MSFT0101", DEVICE_IS_TPM2},
        {},
};
MODULE_DEVICE_TABLE(acpi, tpm_acpi_tbl);

static int check_acpi_tpm2(struct device *dev)
{
        const struct acpi_device_id *aid = acpi_match_device(tpm_acpi_tbl, dev);
        struct acpi_table_tpm2 *tbl;
        acpi_status st;
        int ret = 0;

        if (!aid || aid->driver_data != DEVICE_IS_TPM2)
                return 0;

        /* If the ACPI TPM2 signature is matched then a global ACPI_SIG_TPM2
         * table is mandatory
         */
        st = acpi_get_table(ACPI_SIG_TPM2, 1, (struct acpi_table_header **)&tbl);
        if (ACPI_FAILURE(st) || tbl->header.length < sizeof(*tbl)) {
                dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
                return -EINVAL;
        }

        /* The tpm2_crb driver handles this device */
        if (tbl->start_method != ACPI_TPM2_MEMORY_MAPPED)
                ret = -ENODEV;

        acpi_put_table((struct acpi_table_header *)tbl);
        return ret;
}
#else
static int check_acpi_tpm2(struct device *dev)
{
        return 0;
}
#endif

static int tpm_tcg_read_bytes(struct tpm_tis_data *data, u32 addr, u16 len,
                              u8 *result, enum tpm_tis_io_mode io_mode)
{
        struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
        __le16 result_le16;
        __le32 result_le32;

        switch (io_mode) {
        case TPM_TIS_PHYS_8:
                while (len--)
                        *result++ = ioread8(phy->iobase + addr);
                break;
        case TPM_TIS_PHYS_16:
                result_le16 = cpu_to_le16(ioread16(phy->iobase + addr));
                memcpy(result, &result_le16, sizeof(u16));
                break;
        case TPM_TIS_PHYS_32:
                result_le32 = cpu_to_le32(ioread32(phy->iobase + addr));
                memcpy(result, &result_le32, sizeof(u32));
                break;
        }

        return 0;
}

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

        switch (io_mode) {
        case TPM_TIS_PHYS_8:
                while (len--)
                        tpm_tis_iowrite8(*value++, phy->iobase, addr);
                break;
        case TPM_TIS_PHYS_16:
                return -EINVAL;
        case TPM_TIS_PHYS_32:
                tpm_tis_iowrite32(le32_to_cpu(*((__le32 *)value)), phy->iobase, addr);
                break;
        }

        return 0;
}

static const struct tpm_tis_phy_ops tpm_tcg = {
        .read_bytes = tpm_tcg_read_bytes,
        .write_bytes = tpm_tcg_write_bytes,
};

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

        rc = check_acpi_tpm2(dev);
        if (rc)
                return rc;

        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 || is_itpm(ACPI_COMPANION(dev)))
                set_bit(TPM_TIS_ITPM_WORKAROUND, &phy->priv.flags);

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

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 = {};
        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;

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

/*
 * There is a known bug caused by 93e1b7d42e1e ("[PATCH] tpm: add HID module
 * parameter"). This commit added IFX0102 device ID, which is also used by
 * tpm_infineon but ignored to add quirks to probe which driver ought to be
 * used.
 */

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 (ARRAY_SIZE(tpm_pnp_tbl) - 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");

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;

        tpm_info.irq = platform_get_irq_optional(pdev, 0);
        if (tpm_info.irq <= 0) {
                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);
}

static void 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);
}

#ifdef CONFIG_OF
static const struct of_device_id tis_of_platform_match[] = {
        {.compatible = "atmel,at97sc3204"},
        {.compatible = "tcg,tpm-tis-mmio"},
        {},
};
MODULE_DEVICE_TABLE(of, tis_of_platform_match);
#endif

static struct platform_driver tis_drv = {
        .probe = tpm_tis_plat_probe,
        .remove = tpm_tis_plat_remove,
        .driver = {
                .name           = "tpm_tis",
                .pm             = &tpm_tis_pm,
                .of_match_table = of_match_ptr(tis_of_platform_match),
                .acpi_match_table = ACPI_PTR(tpm_acpi_tbl),
        },
};

static int tpm_tis_force_device(void)
{
        struct platform_device *pdev;
        static const struct resource x86_resources[] = {
                DEFINE_RES_MEM(0xFED40000, TIS_MEM_LEN)
        };

        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;


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

        return 0;

err_pnp:
        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);
        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");