Linux 2.6.28-rc5
[cris-mirror.git] / arch / powerpc / sysdev / mmio_nvram.c
blob7b49633a4bd0590960af399f67b70c41c7c5e841
1 /*
2 * memory mapped NVRAM
4 * (C) Copyright IBM Corp. 2005
6 * Authors : Utz Bacher <utz.bacher@de.ibm.com>
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.
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.
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.
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>
29 #include <asm/machdep.h>
30 #include <asm/nvram.h>
31 #include <asm/prom.h>
33 static void __iomem *mmio_nvram_start;
34 static long mmio_nvram_len;
35 static DEFINE_SPINLOCK(mmio_nvram_lock);
37 static ssize_t mmio_nvram_read(char *buf, size_t count, loff_t *index)
39 unsigned long flags;
41 if (*index >= mmio_nvram_len)
42 return 0;
43 if (*index + count > mmio_nvram_len)
44 count = mmio_nvram_len - *index;
46 spin_lock_irqsave(&mmio_nvram_lock, flags);
48 memcpy_fromio(buf, mmio_nvram_start + *index, count);
50 spin_unlock_irqrestore(&mmio_nvram_lock, flags);
52 *index += count;
53 return count;
56 static ssize_t mmio_nvram_write(char *buf, size_t count, loff_t *index)
58 unsigned long flags;
60 if (*index >= mmio_nvram_len)
61 return 0;
62 if (*index + count > mmio_nvram_len)
63 count = mmio_nvram_len - *index;
65 spin_lock_irqsave(&mmio_nvram_lock, flags);
67 memcpy_toio(mmio_nvram_start + *index, buf, count);
69 spin_unlock_irqrestore(&mmio_nvram_lock, flags);
71 *index += count;
72 return count;
75 static ssize_t mmio_nvram_get_size(void)
77 return mmio_nvram_len;
80 int __init mmio_nvram_init(void)
82 struct device_node *nvram_node;
83 unsigned long nvram_addr;
84 struct resource r;
85 int ret;
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;
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;
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 length is 0\n");
103 ret = -EIO;
104 goto out;
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;
114 printk(KERN_INFO "mmio NVRAM, %luk at 0x%lx mapped to %p\n",
115 mmio_nvram_len >> 10, nvram_addr, mmio_nvram_start);
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;
121 out:
122 of_node_put(nvram_node);
123 return ret;