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 <linux/miscdevice.h>
  22 #include <asm/uaccess.h>
  23 #include <asm/irq.h>
  24 #include <asm/pgtable.h>
  25 #include "mem_user.h"
  26 #include "user_util.h"
  27
  28 /* These are set in mmapper_init, which is called at boot time */
  29 static unsigned long mmapper_size;
  30 static unsigned long p_buf = 0;
  31 static char *v_buf = NULL;
  32
  33 static ssize_t
  34 mmapper_read(struct file *file, char *buf, size_t count, loff_t *ppos)
  35 {
  36         if(*ppos > mmapper_size)
  37                 return -EINVAL;
  38
  39         if(count + *ppos > mmapper_size)
  40                 count = count + *ppos - mmapper_size;
  41
  42         if(count < 0)
  43                 return -EINVAL;
  44
  45         copy_to_user(buf,&v_buf[*ppos],count);
  46
  47         return count;
  48 }
  49
  50 static ssize_t
  51 mmapper_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
  52 {
  53         if(*ppos > mmapper_size)
  54                 return -EINVAL;
  55
  56         if(count + *ppos > mmapper_size)
  57                 count = count + *ppos - mmapper_size;
  58
  59         if(count < 0)
  60                 return -EINVAL;
  61
  62         copy_from_user(&v_buf[*ppos],buf,count);
  63
  64         return count;
  65 }
  66
  67 static int
  68 mmapper_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
  69          unsigned long arg)
  70 {
  71         return(-ENOIOCTLCMD);
  72 }
  73
  74 static int
  75 mmapper_mmap(struct file *file, struct vm_area_struct * vma)
  76 {
  77         int ret = -EINVAL;
  78         int size;
  79
  80         lock_kernel();
  81         if (vma->vm_pgoff != 0)
  82                 goto out;
  83
  84         size = vma->vm_end - vma->vm_start;
  85         if(size > mmapper_size) return(-EFAULT);
  86
  87         /* XXX A comment above remap_pfn_range says it should only be
  88          * called when the mm semaphore is held
  89          */
  90         if (remap_pfn_range(vma, vma->vm_start, p_buf >> PAGE_SHIFT, size,
  91                              vma->vm_page_prot))
  92                 goto out;
  93         ret = 0;
  94 out:
  95         unlock_kernel();
  96         return ret;
  97 }
  98
  99 static int
 100 mmapper_open(struct inode *inode, struct file *file)
 101 {
 102         return 0;
 103 }
 104
 105 static int
 106 mmapper_release(struct inode *inode, struct file *file)
 107 {
 108         return 0;
 109 }
 110
 111 static struct file_operations mmapper_fops = {
 112         .owner          = THIS_MODULE,
 113         .read           = mmapper_read,
 114         .write          = mmapper_write,
 115         .ioctl          = mmapper_ioctl,
 116         .mmap           = mmapper_mmap,
 117         .open           = mmapper_open,
 118         .release        = mmapper_release,
 119 };
 120
 121 static struct miscdevice mmapper_dev = {
 122         .minor          = MISC_DYNAMIC_MINOR,
 123         .name           = "mmapper",
 124         .fops           = &mmapper_fops
 125 };
 126
 127 static int __init mmapper_init(void)
 128 {
 129         int err;
 130
 131         printk(KERN_INFO "Mapper v0.1\n");
 132
 133         v_buf = (char *) find_iomem("mmapper", &mmapper_size);
 134         if(mmapper_size == 0){
 135                 printk(KERN_ERR "mmapper_init - find_iomem failed\n");
 136                 goto out;
 137         }
 138
 139         err = misc_register(&mmapper_dev);
 140         if(err){
 141                 printk(KERN_ERR "mmapper - misc_register failed, err = %d\n",
 142                        err);
 143                 goto out;
 144         }
 145
 146         p_buf = __pa(v_buf);
 147 out:
 148         return 0;
 149 }
 150
 151 static void mmapper_exit(void)
 152 {
 153         misc_deregister(&mmapper_dev);
 154 }
 155
 156 module_init(mmapper_init);
 157 module_exit(mmapper_exit);
 158
 159 MODULE_AUTHOR("Greg Lonnon <glonnon@ridgerun.com>");
 160 MODULE_DESCRIPTION("DSPLinux simulator mmapper driver");
 161 /*
 162  * ---------------------------------------------------------------------------
 163  * Local variables:
 164  * c-file-style: "linux"
 165  * End:
 166  */