]> pilppa.org Git - linux-2.6-omap-h63xx.git/blob - arch/um/drivers/mmapper_kern.c
Merge branch 'linus' into x86/urgent
[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 <linux/smp_lock.h>
20 #include <asm/uaccess.h>
21 #include "mem_user.h"
22
23 /* These are set in mmapper_init, which is called at boot time */
24 static unsigned long mmapper_size;
25 static unsigned long p_buf;
26 static char *v_buf;
27
28 static ssize_t mmapper_read(struct file *file, char __user *buf, size_t count,
29                             loff_t *ppos)
30 {
31         return simple_read_from_buffer(buf, count, ppos, v_buf, mmapper_size);
32 }
33
34 static ssize_t mmapper_write(struct file *file, const char __user *buf,
35                              size_t count, loff_t *ppos)
36 {
37         if (*ppos > mmapper_size)
38                 return -EINVAL;
39
40         if (count > mmapper_size - *ppos)
41                 count = mmapper_size - *ppos;
42
43         if (copy_from_user(&v_buf[*ppos], buf, count))
44                 return -EFAULT;
45
46         return count;
47 }
48
49 static int mmapper_ioctl(struct inode *inode, struct file *file,
50                          unsigned int cmd, unsigned long arg)
51 {
52         return -ENOIOCTLCMD;
53 }
54
55 static int mmapper_mmap(struct file *file, struct vm_area_struct *vma)
56 {
57         int ret = -EINVAL;
58         int size;
59
60         if (vma->vm_pgoff != 0)
61                 goto out;
62
63         size = vma->vm_end - vma->vm_start;
64         if (size > mmapper_size)
65                 return -EFAULT;
66
67         /*
68          * XXX A comment above remap_pfn_range says it should only be
69          * called when the mm semaphore is held
70          */
71         if (remap_pfn_range(vma, vma->vm_start, p_buf >> PAGE_SHIFT, size,
72                             vma->vm_page_prot))
73                 goto out;
74         ret = 0;
75 out:
76         return ret;
77 }
78
79 static int mmapper_open(struct inode *inode, struct file *file)
80 {
81         cycle_kernel_lock();
82         return 0;
83 }
84
85 static int mmapper_release(struct inode *inode, struct file *file)
86 {
87         return 0;
88 }
89
90 static const struct file_operations mmapper_fops = {
91         .owner          = THIS_MODULE,
92         .read           = mmapper_read,
93         .write          = mmapper_write,
94         .ioctl          = mmapper_ioctl,
95         .mmap           = mmapper_mmap,
96         .open           = mmapper_open,
97         .release        = mmapper_release,
98 };
99
100 /*
101  * No locking needed - only used (and modified) by below initcall and exitcall.
102  */
103 static struct miscdevice mmapper_dev = {
104         .minor          = MISC_DYNAMIC_MINOR,
105         .name           = "mmapper",
106         .fops           = &mmapper_fops
107 };
108
109 static int __init mmapper_init(void)
110 {
111         int err;
112
113         printk(KERN_INFO "Mapper v0.1\n");
114
115         v_buf = (char *) find_iomem("mmapper", &mmapper_size);
116         if (mmapper_size == 0) {
117                 printk(KERN_ERR "mmapper_init - find_iomem failed\n");
118                 goto out;
119         }
120
121         err = misc_register(&mmapper_dev);
122         if (err) {
123                 printk(KERN_ERR "mmapper - misc_register failed, err = %d\n",
124                        err);
125                 goto out;
126         }
127
128         p_buf = __pa(v_buf);
129 out:
130         return 0;
131 }
132
133 static void mmapper_exit(void)
134 {
135         misc_deregister(&mmapper_dev);
136 }
137
138 module_init(mmapper_init);
139 module_exit(mmapper_exit);
140
141 MODULE_AUTHOR("Greg Lonnon <glonnon@ridgerun.com>");
142 MODULE_DESCRIPTION("DSPLinux simulator mmapper driver");