tpm_ibmvtpm.c

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/*
 * Copyright (C) 2012 IBM Corporation
 *
 * Author: Ashley Lai <[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 <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/slab.h>
#include <asm/vio.h>
#include <asm/irq.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <asm/prom.h>

#include "tpm.h"
#include "tpm_ibmvtpm.h"

static const char tpm_ibmvtpm_driver_name[] = "tpm_ibmvtpm";

static struct vio_device_id tpm_ibmvtpm_device_table[] __devinitdata = {
    { "IBM,vtpm", "IBM,vtpm"},
    { "", "" }
};
MODULE_DEVICE_TABLE(vio, tpm_ibmvtpm_device_table);

DECLARE_WAIT_QUEUE_HEAD(wq);

static int ibmvtpm_send_crq(struct vio_dev *vdev, u64 w1, u64 w2)
{
    return plpar_hcall_norets(H_SEND_CRQ, vdev->unit_address, w1, w2);
}

static struct ibmvtpm_dev *ibmvtpm_get_data(const struct device *dev)
{
    struct tpm_chip *chip = dev_get_drvdata(dev);
    if (chip)
        return (struct ibmvtpm_dev *)chip->vendor.data;
    return NULL;
}

static int tpm_ibmvtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count)
{
    struct ibmvtpm_dev *ibmvtpm;
    u16 len;

    ibmvtpm = (struct ibmvtpm_dev *)chip->vendor.data;

    if (!ibmvtpm->rtce_buf) {
        dev_err(ibmvtpm->dev, "ibmvtpm device is not ready\n");
        return 0;
    }

    wait_event_interruptible(wq, ibmvtpm->crq_res.len != 0);

    if (count < ibmvtpm->crq_res.len) {
        dev_err(ibmvtpm->dev,
            "Invalid size in recv: count=%ld, crq_size=%d\n",
            count, ibmvtpm->crq_res.len);
        return -EIO;
    }

    spin_lock(&ibmvtpm->rtce_lock);
    memcpy((void *)buf, (void *)ibmvtpm->rtce_buf, ibmvtpm->crq_res.len);
    memset(ibmvtpm->rtce_buf, 0, ibmvtpm->crq_res.len);
    ibmvtpm->crq_res.valid = 0;
    ibmvtpm->crq_res.msg = 0;
    len = ibmvtpm->crq_res.len;
    ibmvtpm->crq_res.len = 0;
    spin_unlock(&ibmvtpm->rtce_lock);
    return len;
}

static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
{
    struct ibmvtpm_dev *ibmvtpm;
    struct ibmvtpm_crq crq;
    u64 *word = (u64 *) &crq;
    int rc;

    ibmvtpm = (struct ibmvtpm_dev *)chip->vendor.data;

    if (!ibmvtpm->rtce_buf) {
        dev_err(ibmvtpm->dev, "ibmvtpm device is not ready\n");
        return 0;
    }

    if (count > ibmvtpm->rtce_size) {
        dev_err(ibmvtpm->dev,
            "Invalid size in send: count=%ld, rtce_size=%d\n",
            count, ibmvtpm->rtce_size);
        return -EIO;
    }

    spin_lock(&ibmvtpm->rtce_lock);
    memcpy((void *)ibmvtpm->rtce_buf, (void *)buf, count);
    crq.valid = (u8)IBMVTPM_VALID_CMD;
    crq.msg = (u8)VTPM_TPM_COMMAND;
    crq.len = (u16)count;
    crq.data = ibmvtpm->rtce_dma_handle;

    rc = ibmvtpm_send_crq(ibmvtpm->vdev, word[0], word[1]);
    if (rc != H_SUCCESS) {
        dev_err(ibmvtpm->dev, "tpm_ibmvtpm_send failed rc=%d\n", rc);
        rc = 0;
    } else
        rc = count;

    spin_unlock(&ibmvtpm->rtce_lock);
    return rc;
}

static void tpm_ibmvtpm_cancel(struct tpm_chip *chip)
{
    return;
}

static u8 tpm_ibmvtpm_status(struct tpm_chip *chip)
{
    return 0;
}

static int ibmvtpm_crq_get_rtce_size(struct ibmvtpm_dev *ibmvtpm)
{
    struct ibmvtpm_crq crq;
    u64 *buf = (u64 *) &crq;
    int rc;

    crq.valid = (u8)IBMVTPM_VALID_CMD;
    crq.msg = (u8)VTPM_GET_RTCE_BUFFER_SIZE;

    rc = ibmvtpm_send_crq(ibmvtpm->vdev, buf[0], buf[1]);
    if (rc != H_SUCCESS)
        dev_err(ibmvtpm->dev,
            "ibmvtpm_crq_get_rtce_size failed rc=%d\n", rc);

    return rc;
}

static int ibmvtpm_crq_get_version(struct ibmvtpm_dev *ibmvtpm)
{
    struct ibmvtpm_crq crq;
    u64 *buf = (u64 *) &crq;
    int rc;

    crq.valid = (u8)IBMVTPM_VALID_CMD;
    crq.msg = (u8)VTPM_GET_VERSION;

    rc = ibmvtpm_send_crq(ibmvtpm->vdev, buf[0], buf[1]);
    if (rc != H_SUCCESS)
        dev_err(ibmvtpm->dev,
            "ibmvtpm_crq_get_version failed rc=%d\n", rc);

    return rc;
}

static int ibmvtpm_crq_send_init_complete(struct ibmvtpm_dev *ibmvtpm)
{
    int rc;

    rc = ibmvtpm_send_crq(ibmvtpm->vdev, INIT_CRQ_COMP_CMD, 0);
    if (rc != H_SUCCESS)
        dev_err(ibmvtpm->dev,
            "ibmvtpm_crq_send_init_complete failed rc=%d\n", rc);

    return rc;
}

static int ibmvtpm_crq_send_init(struct ibmvtpm_dev *ibmvtpm)
{
    int rc;

    rc = ibmvtpm_send_crq(ibmvtpm->vdev, INIT_CRQ_CMD, 0);
    if (rc != H_SUCCESS)
        dev_err(ibmvtpm->dev,
            "ibmvtpm_crq_send_init failed rc=%d\n", rc);

    return rc;
}

static int __devexit tpm_ibmvtpm_remove(struct vio_dev *vdev)
{
    struct ibmvtpm_dev *ibmvtpm = ibmvtpm_get_data(&vdev->dev);
    int rc = 0;

    free_irq(vdev->irq, ibmvtpm);
    tasklet_kill(&ibmvtpm->tasklet);

    do {
        if (rc)
            msleep(100);
        rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
    } while (rc == H_BUSY || H_IS_LONG_BUSY(rc));

    dma_unmap_single(ibmvtpm->dev, ibmvtpm->crq_dma_handle,
             CRQ_RES_BUF_SIZE, DMA_BIDIRECTIONAL);
    free_page((unsigned long)ibmvtpm->crq_queue.crq_addr);

    if (ibmvtpm->rtce_buf) {
        dma_unmap_single(ibmvtpm->dev, ibmvtpm->rtce_dma_handle,
                 ibmvtpm->rtce_size, DMA_BIDIRECTIONAL);
        kfree(ibmvtpm->rtce_buf);
    }

    tpm_remove_hardware(ibmvtpm->dev);

    kfree(ibmvtpm);

    return 0;
}

static unsigned long tpm_ibmvtpm_get_desired_dma(struct vio_dev *vdev)
{
    struct ibmvtpm_dev *ibmvtpm = ibmvtpm_get_data(&vdev->dev);
    return CRQ_RES_BUF_SIZE + ibmvtpm->rtce_size;
}

static int tpm_ibmvtpm_suspend(struct device *dev)
{
    struct ibmvtpm_dev *ibmvtpm = ibmvtpm_get_data(dev);
    struct ibmvtpm_crq crq;
    u64 *buf = (u64 *) &crq;
    int rc = 0;

    crq.valid = (u8)IBMVTPM_VALID_CMD;
    crq.msg = (u8)VTPM_PREPARE_TO_SUSPEND;

    rc = ibmvtpm_send_crq(ibmvtpm->vdev, buf[0], buf[1]);
    if (rc != H_SUCCESS)
        dev_err(ibmvtpm->dev,
            "tpm_ibmvtpm_suspend failed rc=%d\n", rc);

    return rc;
}

static int ibmvtpm_reset_crq(struct ibmvtpm_dev *ibmvtpm)
{
    int rc = 0;

    do {
        if (rc)
            msleep(100);
        rc = plpar_hcall_norets(H_FREE_CRQ,
                    ibmvtpm->vdev->unit_address);
    } while (rc == H_BUSY || H_IS_LONG_BUSY(rc));

    memset(ibmvtpm->crq_queue.crq_addr, 0, CRQ_RES_BUF_SIZE);
    ibmvtpm->crq_queue.index = 0;

    return plpar_hcall_norets(H_REG_CRQ, ibmvtpm->vdev->unit_address,
                  ibmvtpm->crq_dma_handle, CRQ_RES_BUF_SIZE);
}

static int tpm_ibmvtpm_resume(struct device *dev)
{
    struct ibmvtpm_dev *ibmvtpm = ibmvtpm_get_data(dev);
    unsigned long flags;
    int rc = 0;

    do {
        if (rc)
            msleep(100);
        rc = plpar_hcall_norets(H_ENABLE_CRQ,
                    ibmvtpm->vdev->unit_address);
    } while (rc == H_IN_PROGRESS || rc == H_BUSY || H_IS_LONG_BUSY(rc));

    if (rc) {
        dev_err(dev, "Error enabling ibmvtpm rc=%d\n", rc);
        return rc;
    }

    spin_lock_irqsave(&ibmvtpm->lock, flags);
    vio_disable_interrupts(ibmvtpm->vdev);
    tasklet_schedule(&ibmvtpm->tasklet);
    spin_unlock_irqrestore(&ibmvtpm->lock, flags);

    rc = ibmvtpm_crq_send_init(ibmvtpm);
    if (rc)
        dev_err(dev, "Error send_init rc=%d\n", rc);

    return rc;
}

static const struct file_operations ibmvtpm_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(enabled, S_IRUGO, tpm_show_enabled, NULL);
static DEVICE_ATTR(active, S_IRUGO, tpm_show_active, NULL);
static DEVICE_ATTR(owned, S_IRUGO, tpm_show_owned, NULL);
static DEVICE_ATTR(temp_deactivated, S_IRUGO, tpm_show_temp_deactivated,
           NULL);
static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps_1_2, NULL);
static DEVICE_ATTR(cancel, S_IWUSR | S_IWGRP, NULL, tpm_store_cancel);
static DEVICE_ATTR(durations, S_IRUGO, tpm_show_durations, NULL);
static DEVICE_ATTR(timeouts, S_IRUGO, tpm_show_timeouts, NULL);

static struct attribute *ibmvtpm_attrs[] = {
    &dev_attr_pubek.attr,
    &dev_attr_pcrs.attr,
    &dev_attr_enabled.attr,
    &dev_attr_active.attr,
    &dev_attr_owned.attr,
    &dev_attr_temp_deactivated.attr,
    &dev_attr_caps.attr,
    &dev_attr_cancel.attr,
    &dev_attr_durations.attr,
    &dev_attr_timeouts.attr, NULL,
};

static struct attribute_group ibmvtpm_attr_grp = { .attrs = ibmvtpm_attrs };

static const struct tpm_vendor_specific tpm_ibmvtpm = {
    .recv = tpm_ibmvtpm_recv,
    .send = tpm_ibmvtpm_send,
    .cancel = tpm_ibmvtpm_cancel,
    .status = tpm_ibmvtpm_status,
    .req_complete_mask = 0,
    .req_complete_val = 0,
    .req_canceled = 0,
    .attr_group = &ibmvtpm_attr_grp,
    .miscdev = { .fops = &ibmvtpm_ops, },
};

static const struct dev_pm_ops tpm_ibmvtpm_pm_ops = {
    .suspend = tpm_ibmvtpm_suspend,
    .resume = tpm_ibmvtpm_resume,
};

static struct ibmvtpm_crq *ibmvtpm_crq_get_next(struct ibmvtpm_dev *ibmvtpm)
{
    struct ibmvtpm_crq_queue *crq_q = &ibmvtpm->crq_queue;
    struct ibmvtpm_crq *crq = &crq_q->crq_addr[crq_q->index];

    if (crq->valid & VTPM_MSG_RES) {
        if (++crq_q->index == crq_q->num_entry)
            crq_q->index = 0;
        rmb();
    } else
        crq = NULL;
    return crq;
}

static void ibmvtpm_crq_process(struct ibmvtpm_crq *crq,
                struct ibmvtpm_dev *ibmvtpm)
{
    int rc = 0;

    switch (crq->valid) {
    case VALID_INIT_CRQ:
        switch (crq->msg) {
        case INIT_CRQ_RES:
            dev_info(ibmvtpm->dev, "CRQ initialized\n");
            rc = ibmvtpm_crq_send_init_complete(ibmvtpm);
            if (rc)
                dev_err(ibmvtpm->dev, "Unable to send CRQ init complete rc=%d\n", rc);
            return;
        case INIT_CRQ_COMP_RES:
            dev_info(ibmvtpm->dev,
                 "CRQ initialization completed\n");
            return;
        default:
            dev_err(ibmvtpm->dev, "Unknown crq message type: %d\n", crq->msg);
            return;
        }
        return;
    case IBMVTPM_VALID_CMD:
        switch (crq->msg) {
        case VTPM_GET_RTCE_BUFFER_SIZE_RES:
            if (crq->len <= 0) {
                dev_err(ibmvtpm->dev, "Invalid rtce size\n");
                return;
            }
            ibmvtpm->rtce_size = crq->len;
            ibmvtpm->rtce_buf = kmalloc(ibmvtpm->rtce_size,
                            GFP_KERNEL);
            if (!ibmvtpm->rtce_buf) {
                dev_err(ibmvtpm->dev, "Failed to allocate memory for rtce buffer\n");
                return;
            }

            ibmvtpm->rtce_dma_handle = dma_map_single(ibmvtpm->dev,
                ibmvtpm->rtce_buf, ibmvtpm->rtce_size,
                DMA_BIDIRECTIONAL);

            if (dma_mapping_error(ibmvtpm->dev,
                          ibmvtpm->rtce_dma_handle)) {
                kfree(ibmvtpm->rtce_buf);
                ibmvtpm->rtce_buf = NULL;
                dev_err(ibmvtpm->dev, "Failed to dma map rtce buffer\n");
            }

            return;
        case VTPM_GET_VERSION_RES:
            ibmvtpm->vtpm_version = crq->data;
            return;
        case VTPM_TPM_COMMAND_RES:
            ibmvtpm->crq_res.valid = crq->valid;
            ibmvtpm->crq_res.msg = crq->msg;
            ibmvtpm->crq_res.len = crq->len;
            ibmvtpm->crq_res.data = crq->data;
            wake_up_interruptible(&wq);
            return;
        default:
            return;
        }
    }
    return;
}

static irqreturn_t ibmvtpm_interrupt(int irq, void *vtpm_instance)
{
    struct ibmvtpm_dev *ibmvtpm = (struct ibmvtpm_dev *) vtpm_instance;
    unsigned long flags;

    spin_lock_irqsave(&ibmvtpm->lock, flags);
    vio_disable_interrupts(ibmvtpm->vdev);
    tasklet_schedule(&ibmvtpm->tasklet);
    spin_unlock_irqrestore(&ibmvtpm->lock, flags);

    return IRQ_HANDLED;
}

static void ibmvtpm_tasklet(void *data)
{
    struct ibmvtpm_dev *ibmvtpm = data;
    struct ibmvtpm_crq *crq;
    unsigned long flags;

    spin_lock_irqsave(&ibmvtpm->lock, flags);
    while ((crq = ibmvtpm_crq_get_next(ibmvtpm)) != NULL) {
        ibmvtpm_crq_process(crq, ibmvtpm);
        crq->valid = 0;
        wmb();
    }

    vio_enable_interrupts(ibmvtpm->vdev);
    spin_unlock_irqrestore(&ibmvtpm->lock, flags);
}

static int __devinit tpm_ibmvtpm_probe(struct vio_dev *vio_dev,
                   const struct vio_device_id *id)
{
    struct ibmvtpm_dev *ibmvtpm;
    struct device *dev = &vio_dev->dev;
    struct ibmvtpm_crq_queue *crq_q;
    struct tpm_chip *chip;
    int rc = -ENOMEM, rc1;

    chip = tpm_register_hardware(dev, &tpm_ibmvtpm);
    if (!chip) {
        dev_err(dev, "tpm_register_hardware failed\n");
        return -ENODEV;
    }

    ibmvtpm = kzalloc(sizeof(struct ibmvtpm_dev), GFP_KERNEL);
    if (!ibmvtpm) {
        dev_err(dev, "kzalloc for ibmvtpm failed\n");
        goto cleanup;
    }

    crq_q = &ibmvtpm->crq_queue;
    crq_q->crq_addr = (struct ibmvtpm_crq *)get_zeroed_page(GFP_KERNEL);
    if (!crq_q->crq_addr) {
        dev_err(dev, "Unable to allocate memory for crq_addr\n");
        goto cleanup;
    }

    crq_q->num_entry = CRQ_RES_BUF_SIZE / sizeof(*crq_q->crq_addr);
    ibmvtpm->crq_dma_handle = dma_map_single(dev, crq_q->crq_addr,
                         CRQ_RES_BUF_SIZE,
                         DMA_BIDIRECTIONAL);

    if (dma_mapping_error(dev, ibmvtpm->crq_dma_handle)) {
        dev_err(dev, "dma mapping failed\n");
        goto cleanup;
    }

    rc = plpar_hcall_norets(H_REG_CRQ, vio_dev->unit_address,
                ibmvtpm->crq_dma_handle, CRQ_RES_BUF_SIZE);
    if (rc == H_RESOURCE)
        rc = ibmvtpm_reset_crq(ibmvtpm);

    if (rc) {
        dev_err(dev, "Unable to register CRQ rc=%d\n", rc);
        goto reg_crq_cleanup;
    }

    tasklet_init(&ibmvtpm->tasklet, (void *)ibmvtpm_tasklet,
             (unsigned long)ibmvtpm);

    rc = request_irq(vio_dev->irq, ibmvtpm_interrupt, 0,
             tpm_ibmvtpm_driver_name, ibmvtpm);
    if (rc) {
        dev_err(dev, "Error %d register irq 0x%x\n", rc, vio_dev->irq);
        goto init_irq_cleanup;
    }

    rc = vio_enable_interrupts(vio_dev);
    if (rc) {
        dev_err(dev, "Error %d enabling interrupts\n", rc);
        goto init_irq_cleanup;
    }

    crq_q->index = 0;

    ibmvtpm->dev = dev;
    ibmvtpm->vdev = vio_dev;
    chip->vendor.data = (void *)ibmvtpm;

    spin_lock_init(&ibmvtpm->lock);
    spin_lock_init(&ibmvtpm->rtce_lock);

    rc = ibmvtpm_crq_send_init(ibmvtpm);
    if (rc)
        goto init_irq_cleanup;

    rc = ibmvtpm_crq_get_version(ibmvtpm);
    if (rc)
        goto init_irq_cleanup;

    rc = ibmvtpm_crq_get_rtce_size(ibmvtpm);
    if (rc)
        goto init_irq_cleanup;

    return rc;
init_irq_cleanup:
    tasklet_kill(&ibmvtpm->tasklet);
    do {
        rc1 = plpar_hcall_norets(H_FREE_CRQ, vio_dev->unit_address);
    } while (rc1 == H_BUSY || H_IS_LONG_BUSY(rc1));
reg_crq_cleanup:
    dma_unmap_single(dev, ibmvtpm->crq_dma_handle, CRQ_RES_BUF_SIZE,
             DMA_BIDIRECTIONAL);
cleanup:
    if (ibmvtpm) {
        if (crq_q->crq_addr)
            free_page((unsigned long)crq_q->crq_addr);
        kfree(ibmvtpm);
    }

    tpm_remove_hardware(dev);

    return rc;
}

static struct vio_driver ibmvtpm_driver = {
    .id_table    = tpm_ibmvtpm_device_table,
    .probe       = tpm_ibmvtpm_probe,
    .remove      = tpm_ibmvtpm_remove,
    .get_desired_dma = tpm_ibmvtpm_get_desired_dma,
    .name        = tpm_ibmvtpm_driver_name,
    .pm      = &tpm_ibmvtpm_pm_ops,
};

static int __init ibmvtpm_module_init(void)
{
    return vio_register_driver(&ibmvtpm_driver);
}

static void __exit ibmvtpm_module_exit(void)
{
    vio_unregister_driver(&ibmvtpm_driver);
}

module_init(ibmvtpm_module_init);
module_exit(ibmvtpm_module_exit);

MODULE_AUTHOR("[email protected]");
MODULE_DESCRIPTION("IBM vTPM Driver");
MODULE_VERSION("1.0");
MODULE_LICENSE("GPL");