LXR linux/arch/um/drivers/mmapper

   1/*
   2 * arch/um/drivers/mmapper_kern.c
   3 *
   4 * BRIEF MODULE DESCRIPTION
   5 *
   6 * Copyright (C) 2000 RidgeRun, Inc.
   7 * Author: RidgeRun, Inc.
   8 *         Greg Lonnon glonnon@ridgerun.com or info@ridgerun.com
   9 *
  10 */
  11
  12#include <linux/stddef.h>
  13#include <linux/types.h>
  14#include <linux/fs.h>
  15#include <linux/init.h>
  16#include <linux/miscdevice.h>
  17#include <linux/module.h>
  18#include <linux/mm.h>
  19#include <linux/smp_lock.h>
  20#include <asm/uaccess.h>
  21#include "mem_user.h"
  22
  23/* These are set in mmapper_init, which is called at boot time */
  24static unsigned long mmapper_size;
  25static unsigned long p_buf;
  26static char *v_buf;
  27
  28static ssize_t mmapper_read(struct file *file, char __user *buf, size_t count,
  29                            loff_t *ppos)
  30{
  31        return simple_read_from_buffer(buf, count, ppos, v_buf, mmapper_size);
  32}
  33
  34static ssize_t mmapper_write(struct file *file, const char __user *buf,
  35                             size_t count, loff_t *ppos)
  36{
  37        if (*ppos > mmapper_size)
  38                return -EINVAL;
  39
  40        if (count > mmapper_size - *ppos)
  41                count = mmapper_size - *ppos;
  42
  43        if (copy_from_user(&v_buf[*ppos], buf, count))
  44                return -EFAULT;
  45
  46        return count;
  47}
  48
  49static int mmapper_ioctl(struct inode *inode, struct file *file,
  50                         unsigned int cmd, unsigned long arg)
  51{
  52        return -ENOIOCTLCMD;
  53}
  54
  55static int mmapper_mmap(struct file *file, struct vm_area_struct *vma)
  56{
  57        int ret = -EINVAL;
  58        int size;
  59
  60        if (vma->vm_pgoff != 0)
  61                goto out;
  62
  63        size = vma->vm_end - vma->vm_start;
  64        if (size > mmapper_size)
  65                return -EFAULT;
  66
  67        /*
  68         * XXX A comment above remap_pfn_range says it should only be
  69         * called when the mm semaphore is held
  70         */
  71        if (remap_pfn_range(vma, vma->vm_start, p_buf >> PAGE_SHIFT, size,
  72                            vma->vm_page_prot))
  73                goto out;
  74        ret = 0;
  75out:
  76        return ret;
  77}
  78
  79static int mmapper_open(struct inode *inode, struct file *file)
  80{
  81        cycle_kernel_lock();
  82        return 0;
  83}
  84
  85static int mmapper_release(struct inode *inode, struct file *file)
  86{
  87        return 0;
  88}
  89
  90static const struct file_operations mmapper_fops = {
  91        .owner          = THIS_MODULE,
  92        .read           = mmapper_read,
  93        .write          = mmapper_write,
  94        .ioctl          = mmapper_ioctl,
  95        .mmap           = mmapper_mmap,
  96        .open           = mmapper_open,
  97        .release        = mmapper_release,
  98};
  99
 100/*
 101 * No locking needed - only used (and modified) by below initcall and exitcall.
 102 */
 103static struct miscdevice mmapper_dev = {
 104        .minor          = MISC_DYNAMIC_MINOR,
 105        .name           = "mmapper",
 106        .fops           = &mmapper_fops
 107};
 108
 109static int __init mmapper_init(void)
 110{
 111        int err;
 112
 113        printk(KERN_INFO "Mapper v0.1\n");
 114
 115        v_buf = (char *) find_iomem("mmapper", &mmapper_size);
 116        if (mmapper_size == 0) {
 117                printk(KERN_ERR "mmapper_init - find_iomem failed\n");
 118                goto out;
 119        }
 120
 121        err = misc_register(&mmapper_dev);
 122        if (err) {
 123                printk(KERN_ERR "mmapper - misc_register failed, err = %d\n",
 124                       err);
 125                goto out;
 126        }
 127
 128        p_buf = __pa(v_buf);
 129out:
 130        return 0;
 131}
 132
 133static void mmapper_exit(void)
 134{
 135        misc_deregister(&mmapper_dev);
 136}
 137
 138module_init(mmapper_init);
 139module_exit(mmapper_exit);
 140
 141MODULE_AUTHOR("Greg Lonnon <glonnon@ridgerun.com>");
 142MODULE_DESCRIPTION("DSPLinux simulator mmapper driver");
 143