summaryrefslogtreecommitdiff
path: root/arch/powerpc/platforms/powernv/opal-nvram.c
blob: 380bc2d7ebbf883c5d84351c5814a3e93148ecae (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * PowerNV nvram code.
 *
 * Copyright 2011 IBM Corp.
 */

#define DEBUG

#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/of.h>

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

static unsigned int nvram_size;

static ssize_t opal_nvram_size(void)
{
	return nvram_size;
}

static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index)
{
	s64 rc;
	int off;

	if (*index >= nvram_size)
		return 0;
	off = *index;
	if ((off + count) > nvram_size)
		count = nvram_size - off;
	rc = opal_read_nvram(__pa(buf), count, off);
	if (rc != OPAL_SUCCESS)
		return -EIO;
	*index += count;
	return count;
}

/*
 * This can be called in the panic path with interrupts off, so use
 * mdelay in that case.
 */
static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index)
{
	s64 rc = OPAL_BUSY;
	int off;

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

	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
		rc = opal_write_nvram(__pa(buf), count, off);
		if (rc == OPAL_BUSY_EVENT) {
			if (in_interrupt() || irqs_disabled())
				mdelay(OPAL_BUSY_DELAY_MS);
			else
				msleep(OPAL_BUSY_DELAY_MS);
			opal_poll_events(NULL);
		} else if (rc == OPAL_BUSY) {
			if (in_interrupt() || irqs_disabled())
				mdelay(OPAL_BUSY_DELAY_MS);
			else
				msleep(OPAL_BUSY_DELAY_MS);
		}
	}

	if (rc)
		return -EIO;

	*index += count;
	return count;
}

static int __init opal_nvram_init_log_partitions(void)
{
	/* Scan nvram for partitions */
	nvram_scan_partitions();
	nvram_init_oops_partition(0);
	return 0;
}
machine_arch_initcall(powernv, opal_nvram_init_log_partitions);

void __init opal_nvram_init(void)
{
	struct device_node *np;
	const __be32 *nbytes_p;

	np = of_find_compatible_node(NULL, NULL, "ibm,opal-nvram");
	if (np == NULL)
		return;

	nbytes_p = of_get_property(np, "#bytes", NULL);
	if (!nbytes_p) {
		of_node_put(np);
		return;
	}
	nvram_size = be32_to_cpup(nbytes_p);

	pr_info("OPAL nvram setup, %u bytes\n", nvram_size);
	of_node_put(np);

	ppc_md.nvram_read = opal_nvram_read;
	ppc_md.nvram_write = opal_nvram_write;
	ppc_md.nvram_size = opal_nvram_size;
}