tpm_atmel.c

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/*
 * Copyright (C) 2004 IBM Corporation
 *
 * Authors:
 * Leendert van Doorn <[email protected]>
 * Dave Safford <[email protected]>
 * Reiner Sailer <[email protected]>
 * Kylene Hall <[email protected]>
 *
 * Maintained by: <[email protected]>
 *
 * Device driver for TCG/TCPA TPM (trusted platform module).
 * Specifications at www.trustedcomputinggroup.org   
 *
 * 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 "tpm.h"
#include "tpm_atmel.h"

/* 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)
{
    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(chip->vendor.iobase + 1);
        if ((status & ATML_STATUS_DATA_AVAIL) == 0) {
            dev_err(chip->dev, "error reading header\n");
            return -EIO;
        }
        *buf++ = ioread8(chip->vendor.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(chip->vendor.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(chip->vendor.iobase + 1);
        if ((status & ATML_STATUS_DATA_AVAIL) == 0) {
            dev_err(chip->dev, "error reading data\n");
            return -EIO;
        }
        *buf++ = ioread8(chip->vendor.iobase);
    }

    /* make sure data available is gone */
    status = ioread8(chip->vendor.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 count)
{
    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], chip->vendor.iobase);
    }

    return count;
}

static void tpm_atml_cancel(struct tpm_chip *chip)
{
    iowrite8(ATML_STATUS_ABORT, chip->vendor.iobase + 1);
}

static u8 tpm_atml_status(struct tpm_chip *chip)
{
    return ioread8(chip->vendor.iobase + 1);
}

static const struct file_operations atmel_ops = {
    .owner = THIS_MODULE,
    .llseek = no_llseek,
    .open = tpm_open,
    .read = tpm_read,
    .write = tpm_write,
    .release = tpm_release,
};

static DEVICE_ATTR(pubek, S_IRUGO, tpm_show_pubek, NULL);
static DEVICE_ATTR(pcrs, S_IRUGO, tpm_show_pcrs, NULL);
static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps, NULL);
static DEVICE_ATTR(cancel, S_IWUSR |S_IWGRP, NULL, tpm_store_cancel);

static struct attribute* atmel_attrs[] = {
    &dev_attr_pubek.attr,
    &dev_attr_pcrs.attr,
    &dev_attr_caps.attr,
    &dev_attr_cancel.attr,
    NULL,
};

static struct attribute_group atmel_attr_grp = { .attrs = atmel_attrs };

static const struct tpm_vendor_specific 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 = ATML_STATUS_READY,
    .attr_group = &atmel_attr_grp,
    .miscdev = { .fops = &atmel_ops, },
};

static struct platform_device *pdev;

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

    if (chip) {
        if (chip->vendor.have_region)
            atmel_release_region(chip->vendor.base,
                         chip->vendor.region_size);
        atmel_put_base_addr(chip->vendor.iobase);
        tpm_remove_hardware(chip->dev);
        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",
        .owner      = THIS_MODULE,
        .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;

    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
         (tpm_atmel.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;
    }

    if (!(chip = tpm_register_hardware(&pdev->dev, &tpm_atmel))) {
        rc = -ENODEV;
        goto err_unreg_dev;
    }

    chip->vendor.iobase = iobase;
    chip->vendor.base = base;
    chip->vendor.have_region = have_region;
    chip->vendor.region_size = region_size;

    return 0;

err_unreg_dev:
    platform_device_unregister(pdev);
err_rel_reg:
    atmel_put_base_addr(iobase);
    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 ([email protected])");
MODULE_DESCRIPTION("TPM Driver");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");