aboutsummaryrefslogtreecommitdiffstats
path: root/arch/powerpc/sysdev/mmio_nvram.c
blob: 207324209065341df70115612c98b3b902bd4c3a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
/*
 * memory mapped NVRAM
 *
 * (C) Copyright IBM Corp. 2005
 *
 * Authors : Utz Bacher <utz.bacher@de.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/types.h>

#include <asm/machdep.h>
#include <asm/nvram.h>
#include <asm/prom.h>

static void __iomem *mmio_nvram_start;
static long mmio_nvram_len;
static DEFINE_SPINLOCK(mmio_nvram_lock);

static ssize_t mmio_nvram_read(char *buf, size_t count, loff_t *index)
{
	unsigned long flags;

	if (*index >= mmio_nvram_len)
		return 0;
	if (*index + count > mmio_nvram_len)
		count = mmio_nvram_len - *index;

	spin_lock_irqsave(&mmio_nvram_lock, flags);

	memcpy_fromio(buf, mmio_nvram_start + *index, count);

	spin_unlock_irqrestore(&mmio_nvram_lock, flags);
	
	*index += count;
	return count;
}

static unsigned char mmio_nvram_read_val(int addr)
{
	unsigned long flags;
	unsigned char val;

	if (addr >= mmio_nvram_len)
		return 0xff;

	spin_lock_irqsave(&mmio_nvram_lock, flags);

	val = ioread8(mmio_nvram_start + addr);

	spin_unlock_irqrestore(&mmio_nvram_lock, flags);

	return val;
}

static ssize_t mmio_nvram_write(char *buf, size_t count, loff_t *index)
{
	unsigned long flags;

	if (*index >= mmio_nvram_len)
		return 0;
	if (*index + count > mmio_nvram_len)
		count = mmio_nvram_len - *index;

	spin_lock_irqsave(&mmio_nvram_lock, flags);

	memcpy_toio(mmio_nvram_start + *index, buf, count);

	spin_unlock_irqrestore(&mmio_nvram_lock, flags);
	
	*index += count;
	return count;
}

void mmio_nvram_write_val(int addr, unsigned char val)
{
	unsigned long flags;

	if (addr < mmio_nvram_len) {
		spin_lock_irqsave(&mmio_nvram_lock, flags);

		iowrite8(val, mmio_nvram_start + addr);

		spin_unlock_irqrestore(&mmio_nvram_lock, flags);
	}
}

static ssize_t mmio_nvram_get_size(void)
{
	return mmio_nvram_len;
}

int __init mmio_nvram_init(void)
{
	struct device_node *nvram_node;
	unsigned long nvram_addr;
	struct resource r;
	int ret;

	nvram_node = of_find_node_by_type(NULL, "nvram");
	if (!nvram_node) {
		printk(KERN_WARNING "nvram: no node found in device-tree\n");
		return -ENODEV;
	}

	ret = of_address_to_resource(nvram_node, 0, &r);
	if (ret) {
		printk(KERN_WARNING "nvram: failed to get address (err %d)\n",
		       ret);
		goto out;
	}
	nvram_addr = r.start;
	mmio_nvram_len = r.end - r.start + 1;
	if ( (!mmio_nvram_len) || (!nvram_addr) ) {
		printk(KERN_WARNING "nvram: address or length is 0\n");
		ret = -EIO;
		goto out;
	}

	mmio_nvram_start = ioremap(nvram_addr, mmio_nvram_len);
	if (!mmio_nvram_start) {
		printk(KERN_WARNING "nvram: failed to ioremap\n");
		ret = -ENOMEM;
		goto out;
	}

	printk(KERN_INFO "mmio NVRAM, %luk at 0x%lx mapped to %p\n",
	       mmio_nvram_len >> 10, nvram_addr, mmio_nvram_start);

	ppc_md.nvram_read_val	= mmio_nvram_read_val;
	ppc_md.nvram_write_val	= mmio_nvram_write_val;
	ppc_md.nvram_read	= mmio_nvram_read;
	ppc_md.nvram_write	= mmio_nvram_write;
	ppc_md.nvram_size	= mmio_nvram_get_size;

out:
	of_node_put(nvram_node);
	return ret;
}