1/*
2 * memory mapped NVRAM
3 *
4 * (C) Copyright IBM Corp. 2005
5 *
6 * Authors : Utz Bacher <utz.bacher@de.ibm.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2, or (at your option)
11 * any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23#include <linux/fs.h>
24#include <linux/init.h>
25#include <linux/kernel.h>
26#include <linux/spinlock.h>
27#include <linux/types.h>
28
29#include <asm/machdep.h>
30#include <asm/nvram.h>
31#include <asm/prom.h>
32
33static void __iomem *mmio_nvram_start;
34static long mmio_nvram_len;
35static DEFINE_SPINLOCK(mmio_nvram_lock);
36
37static ssize_t mmio_nvram_read(char *buf, size_t count, loff_t *index)
38{
39	unsigned long flags;
40
41	if (*index >= mmio_nvram_len)
42		return 0;
43	if (*index + count > mmio_nvram_len)
44		count = mmio_nvram_len - *index;
45
46	spin_lock_irqsave(&mmio_nvram_lock, flags);
47
48	memcpy_fromio(buf, mmio_nvram_start + *index, count);
49
50	spin_unlock_irqrestore(&mmio_nvram_lock, flags);
51
52	*index += count;
53	return count;
54}
55
56static ssize_t mmio_nvram_write(char *buf, size_t count, loff_t *index)
57{
58	unsigned long flags;
59
60	if (*index >= mmio_nvram_len)
61		return 0;
62	if (*index + count > mmio_nvram_len)
63		count = mmio_nvram_len - *index;
64
65	spin_lock_irqsave(&mmio_nvram_lock, flags);
66
67	memcpy_toio(mmio_nvram_start + *index, buf, count);
68
69	spin_unlock_irqrestore(&mmio_nvram_lock, flags);
70
71	*index += count;
72	return count;
73}
74
75static ssize_t mmio_nvram_get_size(void)
76{
77	return mmio_nvram_len;
78}
79
80int __init mmio_nvram_init(void)
81{
82	struct device_node *nvram_node;
83	unsigned long nvram_addr;
84	struct resource r;
85	int ret;
86
87	nvram_node = of_find_node_by_type(NULL, "nvram");
88	if (!nvram_node) {
89		printk(KERN_WARNING "nvram: no node found in device-tree\n");
90		return -ENODEV;
91	}
92
93	ret = of_address_to_resource(nvram_node, 0, &r);
94	if (ret) {
95		printk(KERN_WARNING "nvram: failed to get address (err %d)\n",
96		       ret);
97		goto out;
98	}
99	nvram_addr = r.start;
100	mmio_nvram_len = r.end - r.start + 1;
101	if ( (!mmio_nvram_len) || (!nvram_addr) ) {
102		printk(KERN_WARNING "nvram: address or lenght is 0\n");
103		ret = -EIO;
104		goto out;
105	}
106
107	mmio_nvram_start = ioremap(nvram_addr, mmio_nvram_len);
108	if (!mmio_nvram_start) {
109		printk(KERN_WARNING "nvram: failed to ioremap\n");
110		ret = -ENOMEM;
111		goto out;
112	}
113
114	printk(KERN_INFO "mmio NVRAM, %luk at 0x%lx mapped to %p\n",
115	       mmio_nvram_len >> 10, nvram_addr, mmio_nvram_start);
116
117	ppc_md.nvram_read	= mmio_nvram_read;
118	ppc_md.nvram_write	= mmio_nvram_write;
119	ppc_md.nvram_size	= mmio_nvram_get_size;
120
121out:
122	of_node_put(nvram_node);
123	return ret;
124}
125