1/*
2 * FRAM driver for MIMC200 board
3 *
4 * Copyright 2008 Mark Jackson <mpfj@mimc.co.uk>
5 *
6 * This module adds *very* simply support for the system's FRAM device.
7 * At the moment, this is hard-coded to the MIMC200 platform, and only
8 * supports mmap().
9 */
10
11#define FRAM_VERSION	"1.0"
12
13#include <linux/miscdevice.h>
14#include <linux/proc_fs.h>
15#include <linux/mm.h>
16#include <linux/io.h>
17
18#define FRAM_BASE	0xac000000
19#define FRAM_SIZE	0x20000
20
21/*
22 * The are the file operation function for user access to /dev/fram
23 */
24
25static int fram_mmap(struct file *filp, struct vm_area_struct *vma)
26{
27	int ret;
28
29	ret = remap_pfn_range(vma,
30		vma->vm_start,
31		virt_to_phys((void *)((unsigned long)FRAM_BASE)) >> PAGE_SHIFT,
32		vma->vm_end-vma->vm_start,
33		PAGE_SHARED);
34
35	if (ret != 0)
36		return -EAGAIN;
37
38	return 0;
39}
40
41static const struct file_operations fram_fops = {
42	.owner			= THIS_MODULE,
43	.mmap			= fram_mmap,
44	.llseek			= noop_llseek,
45};
46
47#define FRAM_MINOR	0
48
49static struct miscdevice fram_dev = {
50	FRAM_MINOR,
51	"fram",
52	&fram_fops
53};
54
55static int __init
56fram_init(void)
57{
58	int ret;
59
60	ret = misc_register(&fram_dev);
61	if (ret) {
62		printk(KERN_ERR "fram: can't misc_register on minor=%d\n",
63		    FRAM_MINOR);
64		return ret;
65	}
66	printk(KERN_INFO "FRAM memory driver v" FRAM_VERSION "\n");
67	return 0;
68}
69
70static void __exit
71fram_cleanup_module(void)
72{
73	misc_deregister(&fram_dev);
74}
75
76module_init(fram_init);
77module_exit(fram_cleanup_module);
78
79MODULE_LICENSE("GPL");
80
81MODULE_ALIAS_MISCDEV(FRAM_MINOR);
82