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/nvram.h>
20#include <asm/machdep.h>
21
22static unsigned int nvram_size;
23
24static ssize_t opal_nvram_size(void)
25{
26	return nvram_size;
27}
28
29static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index)
30{
31	s64 rc;
32	int off;
33
34	if (*index >= nvram_size)
35		return 0;
36	off = *index;
37	if ((off + count) > nvram_size)
38		count = nvram_size - off;
39	rc = opal_read_nvram(__pa(buf), count, off);
40	if (rc != OPAL_SUCCESS)
41		return -EIO;
42	*index += count;
43	return count;
44}
45
46static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index)
47{
48	s64 rc = OPAL_BUSY;
49	int off;
50
51	if (*index >= nvram_size)
52		return 0;
53	off = *index;
54	if ((off + count) > nvram_size)
55		count = nvram_size - off;
56
57	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
58		rc = opal_write_nvram(__pa(buf), count, off);
59		if (rc == OPAL_BUSY_EVENT)
60			opal_poll_events(NULL);
61	}
62	*index += count;
63	return count;
64}
65
66static int __init opal_nvram_init_log_partitions(void)
67{
68	/* Scan nvram for partitions */
69	nvram_scan_partitions();
70	nvram_init_oops_partition(0);
71	return 0;
72}
73machine_arch_initcall(powernv, opal_nvram_init_log_partitions);
74
75void __init opal_nvram_init(void)
76{
77	struct device_node *np;
78	const __be32 *nbytes_p;
79
80	np = of_find_compatible_node(NULL, NULL, "ibm,opal-nvram");
81	if (np == NULL)
82		return;
83
84	nbytes_p = of_get_property(np, "#bytes", NULL);
85	if (!nbytes_p) {
86		of_node_put(np);
87		return;
88	}
89	nvram_size = be32_to_cpup(nbytes_p);
90
91	pr_info("OPAL nvram setup, %u bytes\n", nvram_size);
92	of_node_put(np);
93
94	ppc_md.nvram_read = opal_nvram_read;
95	ppc_md.nvram_write = opal_nvram_write;
96	ppc_md.nvram_size = opal_nvram_size;
97}
98
99