arch/um/drivers/mmapper_kern.c

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