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Merge branch 'for-linus' of git://oss.sgi.com:8090/xfs/xfs-2.6
[linux-2.6-omap-h63xx.git] / 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/stddef.h>
13 #include <linux/types.h>
14 #include <linux/fs.h>
15 #include <linux/init.h>
16 #include <linux/miscdevice.h>
17 #include <linux/module.h>
18 #include <linux/mm.h>
19 #include <asm/uaccess.h>
20 #include "mem_user.h"
21
22 /* These are set in mmapper_init, which is called at boot time */
23 static unsigned long mmapper_size;
24 static unsigned long p_buf;
25 static char *v_buf;
26
27 static ssize_t mmapper_read(struct file *file, char __user *buf, size_t count,
28                             loff_t *ppos)
29 {
30         return simple_read_from_buffer(buf, count, ppos, v_buf, mmapper_size);
31 }
32
33 static ssize_t mmapper_write(struct file *file, const char __user *buf,
34                              size_t count, loff_t *ppos)
35 {
36         if (*ppos > mmapper_size)
37                 return -EINVAL;
38
39         if (count > mmapper_size - *ppos)
40                 count = mmapper_size - *ppos;
41
42         if (copy_from_user(&v_buf[*ppos], buf, count))
43                 return -EFAULT;
44
45         return count;
46 }
47
48 static int mmapper_ioctl(struct inode *inode, struct file *file,
49                          unsigned int cmd, unsigned long arg)
50 {
51         return -ENOIOCTLCMD;
52 }
53
54 static int 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)
64                 return -EFAULT;
65
66         /*
67          * XXX A comment above remap_pfn_range says it should only be
68          * called when the mm semaphore is held
69          */
70         if (remap_pfn_range(vma, vma->vm_start, p_buf >> PAGE_SHIFT, size,
71                             vma->vm_page_prot))
72                 goto out;
73         ret = 0;
74 out:
75         return ret;
76 }
77
78 static int mmapper_open(struct inode *inode, struct file *file)
79 {
80         return 0;
81 }
82
83 static int 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 /*
99  * No locking needed - only used (and modified) by below initcall and exitcall.
100  */
101 static struct miscdevice mmapper_dev = {
102         .minor          = MISC_DYNAMIC_MINOR,
103         .name           = "mmapper",
104         .fops           = &mmapper_fops
105 };
106
107 static int __init mmapper_init(void)
108 {
109         int err;
110
111         printk(KERN_INFO "Mapper v0.1\n");
112
113         v_buf = (char *) find_iomem("mmapper", &mmapper_size);
114         if (mmapper_size == 0) {
115                 printk(KERN_ERR "mmapper_init - find_iomem failed\n");
116                 goto out;
117         }
118
119         err = misc_register(&mmapper_dev);
120         if (err) {
121                 printk(KERN_ERR "mmapper - misc_register failed, err = %d\n",
122                        err);
123                 goto out;
124         }
125
126         p_buf = __pa(v_buf);
127 out:
128         return 0;
129 }
130
131 static void mmapper_exit(void)
132 {
133         misc_deregister(&mmapper_dev);
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");