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/types.h>
  13 #include <linux/kdev_t.h>
  14 #include <linux/time.h>
  15 #include <linux/devfs_fs_kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/mm.h>
  18 #include <linux/slab.h>
  19 #include <linux/init.h>
  20 #include <linux/smp_lock.h>
  21 #include <asm/uaccess.h>
  22 #include <asm/irq.h>
  23 #include <asm/pgtable.h>
  24 #include "mem_user.h"
  25 #include "user_util.h"
  26
  27 /* These are set in mmapper_init, which is called at boot time */
  28 static unsigned long mmapper_size;
  29 static unsigned long p_buf = 0;
  30 static char *v_buf = NULL;
  31
  32 static ssize_t
  33 mmapper_read(struct file *file, char *buf, size_t count, loff_t *ppos)
  34 {
  35         if(*ppos > mmapper_size)
  36                 return -EINVAL;
  37
  38         if(count + *ppos > mmapper_size)
  39                 count = count + *ppos - mmapper_size;
  40
  41         if(count < 0)
  42                 return -EINVAL;
  43
  44         copy_to_user(buf,&v_buf[*ppos],count);
  45
  46         return count;
  47 }
  48
  49 static ssize_t
  50 mmapper_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
  51 {
  52         if(*ppos > mmapper_size)
  53                 return -EINVAL;
  54
  55         if(count + *ppos > mmapper_size)
  56                 count = count + *ppos - mmapper_size;
  57
  58         if(count < 0)
  59                 return -EINVAL;
  60
  61         copy_from_user(&v_buf[*ppos],buf,count);
  62
  63         return count;
  64 }
  65
  66 static int
  67 mmapper_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
  68          unsigned long arg)
  69 {
  70         return(-ENOIOCTLCMD);
  71 }
  72
  73 static int
  74 mmapper_mmap(struct file *file, struct vm_area_struct * vma)
  75 {
  76         int ret = -EINVAL;
  77         int size;
  78
  79         lock_kernel();
  80         if (vma->vm_pgoff != 0)
  81                 goto out;
  82
  83         size = vma->vm_end - vma->vm_start;
  84         if(size > mmapper_size) return(-EFAULT);
  85
  86         /* XXX A comment above remap_pfn_range says it should only be
  87          * called when the mm semaphore is held
  88          */
  89         if (remap_pfn_range(vma, vma->vm_start, p_buf >> PAGE_SHIFT, size,
  90                              vma->vm_page_prot))
  91                 goto out;
  92         ret = 0;
  93 out:
  94         unlock_kernel();
  95         return ret;
  96 }
  97
  98 static int
  99 mmapper_open(struct inode *inode, struct file *file)
 100 {
 101         return 0;
 102 }
 103
 104 static int
 105 mmapper_release(struct inode *inode, struct file *file)
 106 {
 107         return 0;
 108 }
 109
 110 static struct file_operations mmapper_fops = {
 111         .owner          = THIS_MODULE,
 112         .read           = mmapper_read,
 113         .write          = mmapper_write,
 114         .ioctl          = mmapper_ioctl,
 115         .mmap           = mmapper_mmap,
 116         .open           = mmapper_open,
 117         .release        = mmapper_release,
 118 };
 119
 120 static int __init mmapper_init(void)
 121 {
 122         printk(KERN_INFO "Mapper v0.1\n");
 123
 124         v_buf = (char *) find_iomem("mmapper", &mmapper_size);
 125         if(mmapper_size == 0){
 126                 printk(KERN_ERR "mmapper_init - find_iomem failed\n");
 127                 return(0);
 128         }
 129
 130         p_buf = __pa(v_buf);
 131
 132         devfs_mk_cdev(MKDEV(30, 0), S_IFCHR|S_IRUGO|S_IWUGO, "mmapper");
 133         return(0);
 134 }
 135
 136 static void mmapper_exit(void)
 137 {
 138 }
 139
 140 module_init(mmapper_init);
 141 module_exit(mmapper_exit);
 142
 143 MODULE_AUTHOR("Greg Lonnon <glonnon@ridgerun.com>");
 144 MODULE_DESCRIPTION("DSPLinux simulator mmapper driver");
 145 /*
 146  * ---------------------------------------------------------------------------
 147  * Local variables:
 148  * c-file-style: "linux"
 149  * End:
 150  */