LXR linux/drivers/platform/x86/intel_scu

   1/*
   2 * intel_scu_ipc.c: Driver for the Intel SCU IPC mechanism
   3 *
   4 * (C) Copyright 2008-2010 Intel Corporation
   5 * Author: Sreedhara DS (sreedhara.ds@intel.com)
   6 *
   7 * This program is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public License
   9 * as published by the Free Software Foundation; version 2
  10 * of the License.
  11 *
  12 * This driver provides ioctl interfaces to call intel scu ipc driver api
  13 */
  14
  15#include <linux/module.h>
  16#include <linux/kernel.h>
  17#include <linux/errno.h>
  18#include <linux/types.h>
  19#include <linux/fs.h>
  20#include <linux/fcntl.h>
  21#include <linux/sched.h>
  22#include <linux/uaccess.h>
  23#include <linux/slab.h>
  24#include <linux/init.h>
  25#include <asm/intel_scu_ipc.h>
  26
  27static u32 major;
  28
  29#define MAX_FW_SIZE 264192
  30
  31/* ioctl commnds */
  32#define INTE_SCU_IPC_REGISTER_READ      0
  33#define INTE_SCU_IPC_REGISTER_WRITE     1
  34#define INTE_SCU_IPC_REGISTER_UPDATE    2
  35#define INTE_SCU_IPC_FW_UPDATE          0xA2
  36
  37struct scu_ipc_data {
  38        u32     count;  /* No. of registers */
  39        u16     addr[5]; /* Register addresses */
  40        u8      data[5]; /* Register data */
  41        u8      mask; /* Valid for read-modify-write */
  42};
  43
  44/**
  45 *      scu_reg_access          -       implement register access ioctls
  46 *      @cmd: command we are doing (read/write/update)
  47 *      @data: kernel copy of ioctl data
  48 *
  49 *      Allow the user to perform register accesses on the SCU via the
  50 *      kernel interface
  51 */
  52
  53static int scu_reg_access(u32 cmd, struct scu_ipc_data  *data)
  54{
  55        int count = data->count;
  56
  57        if (count == 0 || count == 3 || count > 4)
  58                return -EINVAL;
  59
  60        switch (cmd) {
  61        case INTE_SCU_IPC_REGISTER_READ:
  62                return intel_scu_ipc_readv(data->addr, data->data, count);
  63        case INTE_SCU_IPC_REGISTER_WRITE:
  64                return intel_scu_ipc_writev(data->addr, data->data, count);
  65        case INTE_SCU_IPC_REGISTER_UPDATE:
  66                return intel_scu_ipc_update_register(data->addr[0],
  67                                                    data->data[0], data->mask);
  68        default:
  69                return -ENOTTY;
  70        }
  71}
  72
  73/**
  74 *      scu_ipc_ioctl           -       control ioctls for the SCU
  75 *      @fp: file handle of the SCU device
  76 *      @cmd: ioctl coce
  77 *      @arg: pointer to user passed structure
  78 *
  79 *      Support the I/O and firmware flashing interfaces of the SCU
  80 */
  81static long scu_ipc_ioctl(struct file *fp, unsigned int cmd,
  82                                                        unsigned long arg)
  83{
  84        int ret;
  85        struct scu_ipc_data  data;
  86        void __user *argp = (void __user *)arg;
  87
  88        if (!capable(CAP_SYS_RAWIO))
  89                return -EPERM;
  90
  91        if (cmd == INTE_SCU_IPC_FW_UPDATE) {
  92                        u8 *fwbuf = kmalloc(MAX_FW_SIZE, GFP_KERNEL);
  93                        if (fwbuf == NULL)
  94                                return -ENOMEM;
  95                        if (copy_from_user(fwbuf, (u8 *)arg, MAX_FW_SIZE)) {
  96                                kfree(fwbuf);
  97                                return -EFAULT;
  98                        }
  99                        ret = intel_scu_ipc_fw_update(fwbuf, MAX_FW_SIZE);
 100                        kfree(fwbuf);
 101                        return ret;
 102        } else {
 103                if (copy_from_user(&data, argp, sizeof(struct scu_ipc_data)))
 104                        return -EFAULT;
 105                ret = scu_reg_access(cmd, &data);
 106                if (ret < 0)
 107                        return ret;
 108                if (copy_to_user(argp, &data, sizeof(struct scu_ipc_data)))
 109                        return -EFAULT;
 110                return 0;
 111        }
 112}
 113
 114static const struct file_operations scu_ipc_fops = {
 115        .unlocked_ioctl = scu_ipc_ioctl,
 116};
 117
 118static int __init ipc_module_init(void)
 119{
 120        return register_chrdev(0, "intel_mid_scu", &scu_ipc_fops);
 121}
 122
 123static void __exit ipc_module_exit(void)
 124{
 125        unregister_chrdev(major, "intel_mid_scu");
 126}
 127
 128module_init(ipc_module_init);
 129module_exit(ipc_module_exit);
 130
 131MODULE_LICENSE("GPL v2");
 132MODULE_DESCRIPTION("Utility driver for intel scu ipc");
 133MODULE_AUTHOR("Sreedhara <sreedhara.ds@intel.com>");
 134