// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2004 IBM Corporation
 *
 * Authors:
 * Leendert van Doorn <leendert@watson.ibm.com>
 * Dave Safford <safford@watson.ibm.com>
 * Reiner Sailer <sailer@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       
 */

#include "tpm.h"

struct tpm_atmel_priv {
        int region_size;
        int have_region;
        unsigned long base;
        void __iomem *iobase;
};

#define atmel_getb(chip, offset) inb(atmel_get_priv(chip)->base + (offset))
#define atmel_putb(val, chip, offset) \
        outb(val, atmel_get_priv(chip)->base + (offset))
#define atmel_request_region request_region
#define atmel_release_region release_region
/* Atmel definitions */
enum tpm_atmel_addr {
        TPM_ATMEL_BASE_ADDR_LO = 0x08,
        TPM_ATMEL_BASE_ADDR_HI = 0x09
};

static inline int tpm_read_index(int base, int index)
{
        outb(index, base);
        return inb(base + 1) & 0xFF;
}

/* Verify this is a 1.1 Atmel TPM */
static int atmel_verify_tpm11(void)
{
        /* verify that it is an Atmel part */
        if (tpm_read_index(TPM_ADDR, 4) != 'A' ||
            tpm_read_index(TPM_ADDR, 5) != 'T' ||
            tpm_read_index(TPM_ADDR, 6) != 'M' ||
            tpm_read_index(TPM_ADDR, 7) != 'L')
                return 1;

        /* query chip for its version number */
        if (tpm_read_index(TPM_ADDR, 0x00) != 1 ||
            tpm_read_index(TPM_ADDR, 0x01) != 1)
                return 1;

        /* This is an atmel supported part */
        return 0;
}

/* Determine where to talk to device */
static void __iomem *atmel_get_base_addr(unsigned long *base, int *region_size)
{
        int lo, hi;

        if (atmel_verify_tpm11() != 0)
                return NULL;

        lo = tpm_read_index(TPM_ADDR, TPM_ATMEL_BASE_ADDR_LO);
        hi = tpm_read_index(TPM_ADDR, TPM_ATMEL_BASE_ADDR_HI);

        *base = (hi << 8) | lo;
        *region_size = 2;

        return ioport_map(*base, *region_size);
}

/* write status bits */
enum tpm_atmel_write_status {
        ATML_STATUS_ABORT = 0x01,
        ATML_STATUS_LASTBYTE = 0x04
};
/* read status bits */
enum tpm_atmel_read_status {
        ATML_STATUS_BUSY = 0x01,
        ATML_STATUS_DATA_AVAIL = 0x02,
        ATML_STATUS_REWRITE = 0x04,
        ATML_STATUS_READY = 0x08
};

static int tpm_atml_recv(struct tpm_chip *chip, u8 *buf, size_t count)
{
        struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);
        u8 status, *hdr = buf;
        u32 size;
        int i;
        __be32 *native_size;

        /* start reading header */
        if (count < 6)
                return -EIO;

        for (i = 0; i < 6; i++) {
                status = ioread8(priv->iobase + 1);
                if ((status & ATML_STATUS_DATA_AVAIL) == 0) {
                        dev_err(&chip->dev, "error reading header\n");
                        return -EIO;
                }
                *buf++ = ioread8(priv->iobase);
        }

        /* size of the data received */
        native_size = (__force __be32 *) (hdr + 2);
        size = be32_to_cpu(*native_size);

        if (count < size) {
                dev_err(&chip->dev,
                        "Recv size(%d) less than available space\n", size);
                for (; i < size; i++) { /* clear the waiting data anyway */
                        status = ioread8(priv->iobase + 1);
                        if ((status & ATML_STATUS_DATA_AVAIL) == 0) {
                                dev_err(&chip->dev, "error reading data\n");
                                return -EIO;
                        }
                }
                return -EIO;
        }

        /* read all the data available */
        for (; i < size; i++) {
                status = ioread8(priv->iobase + 1);
                if ((status & ATML_STATUS_DATA_AVAIL) == 0) {
                        dev_err(&chip->dev, "error reading data\n");
                        return -EIO;
                }
                *buf++ = ioread8(priv->iobase);
        }

        /* make sure data available is gone */
        status = ioread8(priv->iobase + 1);

        if (status & ATML_STATUS_DATA_AVAIL) {
                dev_err(&chip->dev, "data available is stuck\n");
                return -EIO;
        }

        return size;
}

static int tpm_atml_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
                         size_t count)
{
        struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);
        int i;

        dev_dbg(&chip->dev, "tpm_atml_send:\n");
        for (i = 0; i < count; i++) {
                dev_dbg(&chip->dev, "%d 0x%x(%d)\n",  i, buf[i], buf[i]);
                iowrite8(buf[i], priv->iobase);
        }

        return 0;
}

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

        iowrite8(ATML_STATUS_ABORT, priv->iobase + 1);
}

static u8 tpm_atml_status(struct tpm_chip *chip)
{
        struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);

        return ioread8(priv->iobase + 1);
}

static bool tpm_atml_req_canceled(struct tpm_chip *chip, u8 status)
{
        return (status == ATML_STATUS_READY);
}

static const struct tpm_class_ops tpm_atmel = {
        .recv = tpm_atml_recv,
        .send = tpm_atml_send,
        .cancel = tpm_atml_cancel,
        .status = tpm_atml_status,
        .req_complete_mask = ATML_STATUS_BUSY | ATML_STATUS_DATA_AVAIL,
        .req_complete_val = ATML_STATUS_DATA_AVAIL,
        .req_canceled = tpm_atml_req_canceled,
};

static struct platform_device *pdev;

static void atml_plat_remove(void)
{
        struct tpm_chip *chip = dev_get_drvdata(&pdev->dev);
        struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);

        tpm_chip_unregister(chip);
        if (priv->have_region)
                atmel_release_region(priv->base, priv->region_size);
        platform_device_unregister(pdev);
}

static SIMPLE_DEV_PM_OPS(tpm_atml_pm, tpm_pm_suspend, tpm_pm_resume);

static struct platform_driver atml_drv = {
        .driver = {
                .name = "tpm_atmel",
                .pm             = &tpm_atml_pm,
        },
};

static int __init init_atmel(void)
{
        int rc = 0;
        void __iomem *iobase = NULL;
        int have_region, region_size;
        unsigned long base;
        struct  tpm_chip *chip;
        struct tpm_atmel_priv *priv;

        rc = platform_driver_register(&atml_drv);
        if (rc)
                return rc;

        if ((iobase = atmel_get_base_addr(&base, &region_size)) == NULL) {
                rc = -ENODEV;
                goto err_unreg_drv;
        }

        have_region =
            (atmel_request_region
             (base, region_size, "tpm_atmel0") == NULL) ? 0 : 1;

        pdev = platform_device_register_simple("tpm_atmel", -1, NULL, 0);
        if (IS_ERR(pdev)) {
                rc = PTR_ERR(pdev);
                goto err_rel_reg;
        }

        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv) {
                rc = -ENOMEM;
                goto err_unreg_dev;
        }

        priv->iobase = iobase;
        priv->base = base;
        priv->have_region = have_region;
        priv->region_size = region_size;

        chip = tpmm_chip_alloc(&pdev->dev, &tpm_atmel);
        if (IS_ERR(chip)) {
                rc = PTR_ERR(chip);
                goto err_unreg_dev;
        }

        dev_set_drvdata(&chip->dev, priv);

        rc = tpm_chip_register(chip);
        if (rc)
                goto err_unreg_dev;

        return 0;

err_unreg_dev:
        platform_device_unregister(pdev);
err_rel_reg:
        if (have_region)
                atmel_release_region(base,
                                     region_size);
err_unreg_drv:
        platform_driver_unregister(&atml_drv);
        return rc;
}

static void __exit cleanup_atmel(void)
{
        platform_driver_unregister(&atml_drv);
        atml_plat_remove();
}

module_init(init_atmel);
module_exit(cleanup_atmel);

MODULE_AUTHOR("Leendert van Doorn <leendert@watson.ibm.com>");
MODULE_DESCRIPTION("TPM Driver");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");