tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * PowerNV nvram code.
3 *
4 * Copyright 2011 IBM Corp.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#define DEBUG
13
14#include <linux/kernel.h>
15#include <linux/init.h>
16#include <linux/of.h>
17
18#include <asm/opal.h>
19#include <asm/machdep.h>
20
21static unsigned int nvram_size;
22
23static ssize_t opal_nvram_size(void)
24{
25 return nvram_size;
26}
27
28static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index)
29{
30 s64 rc;
31 int off;
32
33 if (*index >= nvram_size)
34 return 0;
35 off = *index;
36 if ((off + count) > nvram_size)
37 count = nvram_size - off;
38 rc = opal_read_nvram(__pa(buf), count, off);
39 if (rc != OPAL_SUCCESS)
40 return -EIO;
41 *index += count;
42 return count;
43}
44
45static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index)
46{
47 s64 rc = OPAL_BUSY;
48 int off;
49
50 if (*index >= nvram_size)
51 return 0;
52 off = *index;
53 if ((off + count) > nvram_size)
54 count = nvram_size - off;
55
56 while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
57 rc = opal_write_nvram(__pa(buf), count, off);
58 if (rc == OPAL_BUSY_EVENT)
59 opal_poll_events(NULL);
60 }
61 *index += count;
62 return count;
63}
64
65void __init opal_nvram_init(void)
66{
67 struct device_node *np;
68 const u32 *nbytes_p;
69
70 np = of_find_compatible_node(NULL, NULL, "ibm,opal-nvram");
71 if (np == NULL)
72 return;
73
74 nbytes_p = of_get_property(np, "#bytes", NULL);
75 if (!nbytes_p) {
76 of_node_put(np);
77 return;
78 }
79 nvram_size = *nbytes_p;
80
81 printk(KERN_INFO "OPAL nvram setup, %u bytes\n", nvram_size);
82 of_node_put(np);
83
84 ppc_md.nvram_read = opal_nvram_read;
85 ppc_md.nvram_write = opal_nvram_write;
86 ppc_md.nvram_size = opal_nvram_size;
87}
88