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 #include "user_util.h"
  19
  20 /* These are set in mmapper_init, which is called at boot time */
  21 static unsigned long mmapper_size;
  22 static unsigned long p_buf = 0;
  23 static char *v_buf = NULL;
  24
  25 static ssize_t
  26 mmapper_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
  27 {
  28         return simple_read_from_buffer(buf, count, ppos, v_buf, mmapper_size);
  29 }
  30
  31 static ssize_t
  32 mmapper_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
  33 {
  34         if (*ppos > mmapper_size)
  35                 return -EINVAL;
  36
  37         if (count > mmapper_size - *ppos)
  38                 count = mmapper_size - *ppos;
  39
  40         if (copy_from_user(&v_buf[*ppos], buf, count))
  41                 return -EFAULT;
  42
  43         return count;
  44 }
  45
  46 static int
  47 mmapper_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
  48          unsigned long arg)
  49 {
  50         return(-ENOIOCTLCMD);
  51 }
  52
  53 static int
  54 mmapper_mmap(struct file *file, struct vm_area_struct * vma)
  55 {
  56         int ret = -EINVAL;
  57         int size;
  58
  59         if (vma->vm_pgoff != 0)
  60                 goto out;
  61
  62         size = vma->vm_end - vma->vm_start;
  63         if(size > mmapper_size) return(-EFAULT);
  64
  65         /* XXX A comment above remap_pfn_range says it should only be
  66          * called when the mm semaphore is held
  67          */
  68         if (remap_pfn_range(vma, vma->vm_start, p_buf >> PAGE_SHIFT, size,
  69                              vma->vm_page_prot))
  70                 goto out;
  71         ret = 0;
  72 out:
  73         return ret;
  74 }
  75
  76 static int
  77 mmapper_open(struct inode *inode, struct file *file)
  78 {
  79         return 0;
  80 }
  81
  82 static int
  83 mmapper_release(struct inode *inode, struct file *file)
  84 {
  85         return 0;
  86 }
  87
  88 static const struct file_operations mmapper_fops = {
  89         .owner          = THIS_MODULE,
  90         .read           = mmapper_read,
  91         .write          = mmapper_write,
  92         .ioctl          = mmapper_ioctl,
  93         .mmap           = mmapper_mmap,
  94         .open           = mmapper_open,
  95         .release        = mmapper_release,
  96 };
  97
  98 /* No locking needed - only used (and modified) by below initcall and exitcall. */
  99 static struct miscdevice mmapper_dev = {
 100         .minor          = MISC_DYNAMIC_MINOR,
 101         .name           = "mmapper",
 102         .fops           = &mmapper_fops
 103 };
 104
 105 static int __init mmapper_init(void)
 106 {
 107         int err;
 108
 109         printk(KERN_INFO "Mapper v0.1\n");
 110
 111         v_buf = (char *) find_iomem("mmapper", &mmapper_size);
 112         if(mmapper_size == 0){
 113                 printk(KERN_ERR "mmapper_init - find_iomem failed\n");
 114                 goto out;
 115         }
 116
 117         err = misc_register(&mmapper_dev);
 118         if(err){
 119                 printk(KERN_ERR "mmapper - misc_register failed, err = %d\n",
 120                        err);
 121                 goto out;
 122         }
 123
 124         p_buf = __pa(v_buf);
 125 out:
 126         return 0;
 127 }
 128
 129 static void mmapper_exit(void)
 130 {
 131         misc_deregister(&mmapper_dev);
 132 }
 133
 134 module_init(mmapper_init);
 135 module_exit(mmapper_exit);
 136
 137 MODULE_AUTHOR("Greg Lonnon <glonnon@ridgerun.com>");
 138 MODULE_DESCRIPTION("DSPLinux simulator mmapper driver");
 139 /*
 140  * ---------------------------------------------------------------------------
 141  * Local variables:
 142  * c-file-style: "linux"
 143  * End:
 144  */