4 * Copyright 2011 IBM Corp.
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.
14 #include <linux/kernel.h>
15 #include <linux/init.h>
19 #include <asm/machdep.h>
21 static unsigned int nvram_size;
23 static ssize_t opal_nvram_size(void)
28 static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index)
33 if (*index >= nvram_size)
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)
45 static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index)
50 if (*index >= nvram_size)
53 if ((off + count) > nvram_size)
54 count = nvram_size - off;
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);
65 void __init opal_nvram_init(void)
67 struct device_node *np;
68 const __be32 *nbytes_p;
70 np = of_find_compatible_node(NULL, NULL, "ibm,opal-nvram");
74 nbytes_p = of_get_property(np, "#bytes", NULL);
79 nvram_size = be32_to_cpup(nbytes_p);
81 pr_info("OPAL nvram setup, %u bytes\n", nvram_size);
84 ppc_md.nvram_read = opal_nvram_read;
85 ppc_md.nvram_write = opal_nvram_write;
86 ppc_md.nvram_size = opal_nvram_size;