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authorUtz Bacher <utz.bacher@de.ibm.com>2005-06-22 19:43:31 -0400
committerPaul Mackerras <paulus@samba.org>2005-06-22 19:43:31 -0400
commit5f5b4e669a59be1cf8fc9d6d04ff1ccad8ab6de0 (patch)
treea0737b3295891def01228d11fec8e9cbb7b765b9 /arch/ppc64/kernel
parent6566c6f1f18d42affe73ccdd403e290b64d10473 (diff)
[PATCH] ppc64: add a minimal nvram driver
The firmware provides the location and size of the nvram in the device tree, so it does not really contain any hardware specific bits and could be used on other machines as well. Signed-off-by: Arnd Bergmann <arndb@de.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/ppc64/kernel')
-rw-r--r--arch/ppc64/kernel/bpa_nvram.c118
1 files changed, 118 insertions, 0 deletions
diff --git a/arch/ppc64/kernel/bpa_nvram.c b/arch/ppc64/kernel/bpa_nvram.c
new file mode 100644
index 000000000000..06a119cfceb5
--- /dev/null
+++ b/arch/ppc64/kernel/bpa_nvram.c
@@ -0,0 +1,118 @@
1/*
2 * NVRAM for CPBW
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 *bpa_nvram_start;
34static long bpa_nvram_len;
35static spinlock_t bpa_nvram_lock = SPIN_LOCK_UNLOCKED;
36
37static ssize_t bpa_nvram_read(char *buf, size_t count, loff_t *index)
38{
39 unsigned long flags;
40
41 if (*index >= bpa_nvram_len)
42 return 0;
43 if (*index + count > bpa_nvram_len)
44 count = bpa_nvram_len - *index;
45
46 spin_lock_irqsave(&bpa_nvram_lock, flags);
47
48 memcpy_fromio(buf, bpa_nvram_start + *index, count);
49
50 spin_unlock_irqrestore(&bpa_nvram_lock, flags);
51
52 *index += count;
53 return count;
54}
55
56static ssize_t bpa_nvram_write(char *buf, size_t count, loff_t *index)
57{
58 unsigned long flags;
59
60 if (*index >= bpa_nvram_len)
61 return 0;
62 if (*index + count > bpa_nvram_len)
63 count = bpa_nvram_len - *index;
64
65 spin_lock_irqsave(&bpa_nvram_lock, flags);
66
67 memcpy_toio(bpa_nvram_start + *index, buf, count);
68
69 spin_unlock_irqrestore(&bpa_nvram_lock, flags);
70
71 *index += count;
72 return count;
73}
74
75static ssize_t bpa_nvram_get_size(void)
76{
77 return bpa_nvram_len;
78}
79
80int __init bpa_nvram_init(void)
81{
82 struct device_node *nvram_node;
83 unsigned long *buffer;
84 int proplen;
85 unsigned long nvram_addr;
86 int ret;
87
88 ret = -ENODEV;
89 nvram_node = of_find_node_by_type(NULL, "nvram");
90 if (!nvram_node)
91 goto out;
92
93 ret = -EIO;
94 buffer = (unsigned long *)get_property(nvram_node, "reg", &proplen);
95 if (proplen != 2*sizeof(unsigned long))
96 goto out;
97
98 ret = -ENODEV;
99 nvram_addr = buffer[0];
100 bpa_nvram_len = buffer[1];
101 if ( (!bpa_nvram_len) || (!nvram_addr) )
102 goto out;
103
104 bpa_nvram_start = ioremap(nvram_addr, bpa_nvram_len);
105 if (!bpa_nvram_start)
106 goto out;
107
108 printk(KERN_INFO "BPA NVRAM, %luk mapped to %p\n",
109 bpa_nvram_len >> 10, bpa_nvram_start);
110
111 ppc_md.nvram_read = bpa_nvram_read;
112 ppc_md.nvram_write = bpa_nvram_write;
113 ppc_md.nvram_size = bpa_nvram_get_size;
114
115out:
116 of_node_put(nvram_node);
117 return ret;
118}