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 
22 static unsigned int nvram_size;
23 
24 static ssize_t opal_nvram_size(void)
25 {
26 	return nvram_size;
27 }
28 
29 static 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 
46 static 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 
66 static 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 }
73 machine_arch_initcall(powernv, opal_nvram_init_log_partitions);
74 
75 void __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