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 #include <linux/kdev_t.h>
  12 #include <linux/time.h>
  13 #include <linux/devfs_fs_kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/mm.h>
  16 #include <linux/slab.h>
  17 #include <linux/init.h>
  18 #include <linux/smp_lock.h>
  19 #include <asm/uaccess.h>
  20 #include <asm/irq.h>
  21 #include <asm/pgtable.h>
  22 #include "mem_user.h"
  23 #include "user_util.h"
  24
  25 /* These are set in mmapper_init, which is called at boot time */
  26 static unsigned long mmapper_size;
  27 static unsigned long p_buf = 0;
  28 static char *v_buf = NULL;
  29
  30 static ssize_t
  31 mmapper_read(struct file *file, char *buf, size_t count, loff_t *ppos)
  32 {
  33         if(*ppos > mmapper_size)
  34                 return -EINVAL;
  35
  36         if(count + *ppos > mmapper_size)
  37                 count = count + *ppos - mmapper_size;
  38
  39         if(count < 0)
  40                 return -EINVAL;
  41
  42         copy_to_user(buf,&v_buf[*ppos],count);
  43
  44         return count;
  45 }
  46
  47 static ssize_t
  48 mmapper_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
  49 {
  50         if(*ppos > mmapper_size)
  51                 return -EINVAL;
  52
  53         if(count + *ppos > mmapper_size)
  54                 count = count + *ppos - mmapper_size;
  55
  56         if(count < 0)
  57                 return -EINVAL;
  58
  59         copy_from_user(&v_buf[*ppos],buf,count);
  60
  61         return count;
  62 }
  63
  64 static int
  65 mmapper_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
  66          unsigned long arg)
  67 {
  68         return(-ENOIOCTLCMD);
  69 }
  70
  71 static int
  72 mmapper_mmap(struct file *file, struct vm_area_struct * vma)
  73 {
  74         int ret = -EINVAL;
  75         int size;
  76
  77         lock_kernel();
  78         if (vma->vm_pgoff != 0)
  79                 goto out;
  80
  81         size = vma->vm_end - vma->vm_start;
  82         if(size > mmapper_size) return(-EFAULT);
  83
  84         /* XXX A comment above remap_page_range says it should only be
  85          * called when the mm semaphore is held
  86          */
  87         if (remap_page_range(vma, vma->vm_start, p_buf, size,
  88                              vma->vm_page_prot))
  89                 goto out;
  90         ret = 0;
  91 out:
  92         unlock_kernel();
  93         return ret;
  94 }
  95
  96 static int
  97 mmapper_open(struct inode *inode, struct file *file)
  98 {
  99         return 0;
 100 }
 101
 102 static int
 103 mmapper_release(struct inode *inode, struct file *file)
 104 {
 105         return 0;
 106 }
 107
 108 static struct file_operations mmapper_fops = {
 109         .owner          = THIS_MODULE,
 110         .read           = mmapper_read,
 111         .write          = mmapper_write,
 112         .ioctl          = mmapper_ioctl,
 113         .mmap           = mmapper_mmap,
 114         .open           = mmapper_open,
 115         .release        = mmapper_release,
 116 };
 117
 118 static int __init mmapper_init(void)
 119 {
 120         printk(KERN_INFO "Mapper v0.1\n");
 121
 122         v_buf = (char *) find_iomem("mmapper", &mmapper_size);
 123         if(mmapper_size == 0) return(0);
 124
 125         p_buf = __pa(v_buf);
 126
 127         devfs_mk_cdev(MKDEV(30, 0), S_IFCHR|S_IRUGO|S_IWUGO, "mmapper");
 128         devfs_mk_symlink("mmapper0", "mmapper");
 129         return(0);
 130 }
 131
 132 static void mmapper_exit(void)
 133 {
 134 }
 135
 136 module_init(mmapper_init);
 137 module_exit(mmapper_exit);
 138
 139 MODULE_AUTHOR("Greg Lonnon <glonnon@ridgerun.com>");
 140 MODULE_DESCRIPTION("DSPLinux simulator mmapper driver");
 141 /*
 142  * ---------------------------------------------------------------------------
 143  * Local variables:
 144  * c-file-style: "linux"
 145  * End:
 146  */