Quelle  tpm_ibmvtpm.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012-2020 IBM Corporation
 *
 * Author: Ashley Lai <ashleydlai@gmail.com>
 *
 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
 *
 * Device driver for TCG/TCPA TPM (trusted platform module).
 * Specifications at www.trustedcomputinggroup.org
 */

#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 const struct vio_device_id tpm_ibmvtpm_device_table[] = {
 { "IBM,vtpm", "IBM,vtpm"},
 { "IBM,vtpm", "IBM,vtpm20"},
 { "", "" }
};
MODULE_DEVICE_TABLE(vio, tpm_ibmvtpm_device_table);

/**
 * ibmvtpm_send_crq_word() - Send a CRQ request
 * @vdev: vio device struct
 * @w1: pre-constructed first word of tpm crq (second word is reserved)
 *
 * Return:
 * 0 - Success
 * Non-zero - Failure
 */
static int ibmvtpm_send_crq_word(struct vio_dev *vdev, u64 w1)
{
 return plpar_hcall_norets(H_SEND_CRQ, vdev->unit_address, w1, 0);
}

/**
 * ibmvtpm_send_crq() - Send a CRQ request
 *
 * @vdev: vio device struct
 * @valid: Valid field
 * @msg: Type field
 * @len: Length field
 * @data: Data field
 *
 * The ibmvtpm crq is defined as follows:
 *
 * Byte  |   0   |   1   |   2   |   3   |   4   |   5   |   6   |   7
 * -----------------------------------------------------------------------
 * Word0 | Valid | Type  |     Length    |              Data
 * -----------------------------------------------------------------------
 * Word1 |                Reserved
 * -----------------------------------------------------------------------
 *
 * Which matches the following structure (on bigendian host):
 *
 * struct ibmvtpm_crq {
 *         u8 valid;
 *         u8 msg;
 *         __be16 len;
 *         __be32 data;
 *         __be64 reserved;
 * } __attribute__((packed, aligned(8)));
 *
 * However, the value is passed in a register so just compute the numeric value
 * to load into the register avoiding byteswap altogether. Endian only affects
 * memory loads and stores - registers are internally represented the same.
 *
 * Return:
 * 0 (H_SUCCESS) - Success
 * Non-zero - Failure
 */
static int ibmvtpm_send_crq(struct vio_dev *vdev,
  u8 valid, u8 msg, u16 len, u32 data)
{
 u64 w1 = ((u64)valid << 56) | ((u64)msg << 48) | ((u64)len << 32) |
  (u64)data;
 return ibmvtpm_send_crq_word(vdev, w1);
}

/**
 * tpm_ibmvtpm_recv - Receive data after send
 *
 * @chip: tpm chip struct
 * @buf: buffer to read
 * @count: size of buffer
 *
 * Return:
 * Number of bytes read
 */
static int tpm_ibmvtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count)
{
 struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev);
 u16 len;

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

 len = ibmvtpm->res_len;

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

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

/**
 * ibmvtpm_crq_send_init - Send a CRQ initialize message
 * @ibmvtpm: vtpm device struct
 *
 * Return:
 * 0 on success.
 * Non-zero on failure.
 */
static int ibmvtpm_crq_send_init(struct ibmvtpm_dev *ibmvtpm)
{
 int rc;

 rc = ibmvtpm_send_crq_word(ibmvtpm->vdev, INIT_CRQ_CMD);
 if (rc != H_SUCCESS)
  dev_err(ibmvtpm->dev,
   "%s failed rc=%d\n", __func__, rc);

 return rc;
}

/**
 * tpm_ibmvtpm_resume - Resume from suspend
 *
 * @dev: device struct
 *
 * Return: Always 0.
 */
static int tpm_ibmvtpm_resume(struct device *dev)
{
 struct tpm_chip *chip = dev_get_drvdata(dev);
 struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev);
 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;
 }

 rc = vio_enable_interrupts(ibmvtpm->vdev);
 if (rc) {
  dev_err(dev, "Error vio_enable_interrupts rc=%d\n", rc);
  return rc;
 }

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

 return rc;
}

/**
 * tpm_ibmvtpm_send() - Send a TPM command
 * @chip: tpm chip struct
 * @buf: buffer contains data to send
 * @bufsiz: size of the buffer
 * @count: length of the command
 *
 * Return:
 *   0 on success,
 *   -errno on error
 */
static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
       size_t count)
{
 struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev);
 bool retry = true;
 int rc, sig;

 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=%zd, rtce_size=%d\n",
   count, ibmvtpm->rtce_size);
  return -EIO;
 }

 if (ibmvtpm->tpm_processing_cmd) {
  dev_info(ibmvtpm->dev,
           "Need to wait for TPM to finish\n");
  /* wait for previous command to finish */
  sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd);
  if (sig)
   return -EINTR;
 }

 spin_lock(&ibmvtpm->rtce_lock);
 ibmvtpm->res_len = 0;
 memcpy((void *)ibmvtpm->rtce_buf, (void *)buf, count);

 /*
 * set the processing flag before the Hcall, since we may get the
 * result (interrupt) before even being able to check rc.
 */
 ibmvtpm->tpm_processing_cmd = 1;

again:
 rc = ibmvtpm_send_crq(ibmvtpm->vdev,
   IBMVTPM_VALID_CMD, VTPM_TPM_COMMAND,
   count, ibmvtpm->rtce_dma_handle);
 if (rc != H_SUCCESS) {
  /*
 * H_CLOSED can be returned after LPM resume.  Call
 * tpm_ibmvtpm_resume() to re-enable the CRQ then retry
 * ibmvtpm_send_crq() once before failing.
 */
  if (rc == H_CLOSED && retry) {
   tpm_ibmvtpm_resume(ibmvtpm->dev);
   retry = false;
   goto again;
  }
  dev_err(ibmvtpm->dev, "tpm_ibmvtpm_send failed rc=%d\n", rc);
  ibmvtpm->tpm_processing_cmd = 0;
 }

 spin_unlock(&ibmvtpm->rtce_lock);
 return 0;
}

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

static u8 tpm_ibmvtpm_status(struct tpm_chip *chip)
{
 struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev);

 return ibmvtpm->tpm_processing_cmd;
}

/**
 * ibmvtpm_crq_get_rtce_size - Send a CRQ request to get rtce size
 *
 * @ibmvtpm: vtpm device struct
 *
 * Return:
 * 0 on success.
 * Non-zero on failure.
 */
static int ibmvtpm_crq_get_rtce_size(struct ibmvtpm_dev *ibmvtpm)
{
 int rc;

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

 return rc;
}

/**
 * ibmvtpm_crq_get_version - Send a CRQ request to get vtpm version
 *    - Note that this is vtpm version and not tpm version
 *
 * @ibmvtpm: vtpm device struct
 *
 * Return:
 * 0 on success.
 * Non-zero on failure.
 */
static int ibmvtpm_crq_get_version(struct ibmvtpm_dev *ibmvtpm)
{
 int rc;

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

 return rc;
}

/**
 * ibmvtpm_crq_send_init_complete - Send a CRQ initialize complete message
 * @ibmvtpm: vtpm device struct
 *
 * Return:
 * 0 on success.
 * Non-zero on failure.
 */
static int ibmvtpm_crq_send_init_complete(struct ibmvtpm_dev *ibmvtpm)
{
 int rc;

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

 return rc;
}

/**
 * tpm_ibmvtpm_remove - ibm vtpm remove entry point
 * @vdev: vio device struct
 *
 * Return: Always 0.
 */
static void tpm_ibmvtpm_remove(struct vio_dev *vdev)
{
 struct tpm_chip *chip = dev_get_drvdata(&vdev->dev);
 struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev);
 int rc = 0;

 tpm_chip_unregister(chip);

 free_irq(vdev->irq, ibmvtpm);

 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);
 }

 kfree(ibmvtpm);
 /* For tpm_ibmvtpm_get_desired_dma */
 dev_set_drvdata(&vdev->dev, NULL);
}

/**
 * tpm_ibmvtpm_get_desired_dma - Get DMA size needed by this driver
 * @vdev: vio device struct
 *
 * Return:
 * Number of bytes the driver needs to DMA map.
 */
static unsigned long tpm_ibmvtpm_get_desired_dma(struct vio_dev *vdev)
{
 struct tpm_chip *chip = dev_get_drvdata(&vdev->dev);
 struct ibmvtpm_dev *ibmvtpm;

 /*
 * ibmvtpm initializes at probe time, so the data we are
 * asking for may not be set yet. Estimate that 4K required
 * for TCE-mapped buffer in addition to CRQ.
 */
 if (chip)
  ibmvtpm = dev_get_drvdata(&chip->dev);
 else
  return CRQ_RES_BUF_SIZE + PAGE_SIZE;

 return CRQ_RES_BUF_SIZE + ibmvtpm->rtce_size;
}

/**
 * tpm_ibmvtpm_suspend - Suspend
 * @dev: device struct
 *
 * Return: Always 0.
 */
static int tpm_ibmvtpm_suspend(struct device *dev)
{
 struct tpm_chip *chip = dev_get_drvdata(dev);
 struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev);
 int rc = 0;

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

 return rc;
}

/**
 * ibmvtpm_reset_crq - Reset CRQ
 *
 * @ibmvtpm: ibm vtpm struct
 *
 * Return:
 * 0 on success.
 * Non-zero on failure.
 */
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 bool tpm_ibmvtpm_req_canceled(struct tpm_chip *chip, u8 status)
{
 return (status == 0);
}

static const struct tpm_class_ops tpm_ibmvtpm = {
 .flags = TPM_OPS_AUTO_STARTUP,
 .recv = tpm_ibmvtpm_recv,
 .send = tpm_ibmvtpm_send,
 .cancel = tpm_ibmvtpm_cancel,
 .status = tpm_ibmvtpm_status,
 .req_complete_mask = 1,
 .req_complete_val = 0,
 .req_canceled = tpm_ibmvtpm_req_canceled,
};

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

/**
 * ibmvtpm_crq_get_next - Get next responded crq
 *
 * @ibmvtpm: vtpm device struct
 *
 * Return: vtpm crq pointer or NULL.
 */
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;
  smp_rmb();
 } else
  crq = NULL;
 return crq;
}

/**
 * ibmvtpm_crq_process - Process responded crq
 *
 * @crq: crq to be processed
 * @ibmvtpm: vtpm device struct
 *
 */
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;
  }
 case IBMVTPM_VALID_CMD:
  switch (crq->msg) {
  case VTPM_GET_RTCE_BUFFER_SIZE_RES:
   if (be16_to_cpu(crq->len) <= 0) {
    dev_err(ibmvtpm->dev, "Invalid rtce size\n");
    return;
   }
   ibmvtpm->rtce_size = be16_to_cpu(crq->len);
   ibmvtpm->rtce_buf = kmalloc(ibmvtpm->rtce_size,
          GFP_ATOMIC);
   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 = be32_to_cpu(crq->data);
   return;
  case VTPM_TPM_COMMAND_RES:
   /* len of the data in rtce buffer */
   ibmvtpm->res_len = be16_to_cpu(crq->len);
   ibmvtpm->tpm_processing_cmd = 0;
   wake_up_interruptible(&ibmvtpm->wq);
   return;
  default:
   return;
  }
 }
 return;
}

/**
 * ibmvtpm_interrupt - Interrupt handler
 *
 * @irq: irq number to handle
 * @vtpm_instance: vtpm that received interrupt
 *
 * Returns:
 * IRQ_HANDLED
 **/
static irqreturn_t ibmvtpm_interrupt(int irq, void *vtpm_instance)
{
 struct ibmvtpm_dev *ibmvtpm = (struct ibmvtpm_dev *) vtpm_instance;
 struct ibmvtpm_crq *crq;

 /* while loop is needed for initial setup (get version and
 * get rtce_size). There should be only one tpm request at any
 * given time.
 */
 while ((crq = ibmvtpm_crq_get_next(ibmvtpm)) != NULL) {
  ibmvtpm_crq_process(crq, ibmvtpm);
  wake_up_interruptible(&ibmvtpm->crq_queue.wq);
  crq->valid = 0;
  smp_wmb();
 }

 return IRQ_HANDLED;
}

/**
 * tpm_ibmvtpm_probe - ibm vtpm initialize entry point
 *
 * @vio_dev: vio device struct
 * @id: vio device id struct
 *
 * Return:
 * 0 on success.
 * Non-zero on failure.
 */
static int 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 = tpmm_chip_alloc(dev, &tpm_ibmvtpm);
 if (IS_ERR(chip))
  return PTR_ERR(chip);

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

 ibmvtpm->dev = dev;
 ibmvtpm->vdev = vio_dev;

 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);
 init_waitqueue_head(&crq_q->wq);
 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;
 }

 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;
 }

 init_waitqueue_head(&ibmvtpm->wq);

 crq_q->index = 0;

 dev_set_drvdata(&chip->dev, ibmvtpm);

 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;

 if (!wait_event_timeout(ibmvtpm->crq_queue.wq,
    ibmvtpm->rtce_buf != NULL,
    HZ)) {
  rc = -ENODEV;
  dev_err(dev, "CRQ response timed out\n");
  goto init_irq_cleanup;
 }


 if (!strcmp(id->compat, "IBM,vtpm20"))
  chip->flags |= TPM_CHIP_FLAG_TPM2;

 return tpm_chip_register(chip);
init_irq_cleanup:
 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);
 }

 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,
};

/**
 * ibmvtpm_module_init - Initialize ibm vtpm module.
 *
 *
 * Return:
 * 0 on success.
 * Non-zero on failure.
 */
static int __init ibmvtpm_module_init(void)
{
 return vio_register_driver(&ibmvtpm_driver);
}

/**
 * ibmvtpm_module_exit - Tear down ibm vtpm module.
 */
static void __exit ibmvtpm_module_exit(void)
{
 vio_unregister_driver(&ibmvtpm_driver);
}

module_init(ibmvtpm_module_init);
module_exit(ibmvtpm_module_exit);

MODULE_AUTHOR("adlai@us.ibm.com");
MODULE_DESCRIPTION("IBM vTPM Driver");
MODULE_VERSION("1.0");
MODULE_LICENSE("GPL");