1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * PowerNV nvram code.
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright 2011 IBM Corp.
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #define DEBUG
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun #include <linux/delay.h>
11*4882a593Smuzhiyun #include <linux/kernel.h>
12*4882a593Smuzhiyun #include <linux/init.h>
13*4882a593Smuzhiyun #include <linux/of.h>
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun #include <asm/opal.h>
16*4882a593Smuzhiyun #include <asm/nvram.h>
17*4882a593Smuzhiyun #include <asm/machdep.h>
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun static unsigned int nvram_size;
20*4882a593Smuzhiyun
opal_nvram_size(void)21*4882a593Smuzhiyun static ssize_t opal_nvram_size(void)
22*4882a593Smuzhiyun {
23*4882a593Smuzhiyun return nvram_size;
24*4882a593Smuzhiyun }
25*4882a593Smuzhiyun
opal_nvram_read(char * buf,size_t count,loff_t * index)26*4882a593Smuzhiyun static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index)
27*4882a593Smuzhiyun {
28*4882a593Smuzhiyun s64 rc;
29*4882a593Smuzhiyun int off;
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun if (*index >= nvram_size)
32*4882a593Smuzhiyun return 0;
33*4882a593Smuzhiyun off = *index;
34*4882a593Smuzhiyun if ((off + count) > nvram_size)
35*4882a593Smuzhiyun count = nvram_size - off;
36*4882a593Smuzhiyun rc = opal_read_nvram(__pa(buf), count, off);
37*4882a593Smuzhiyun if (rc != OPAL_SUCCESS)
38*4882a593Smuzhiyun return -EIO;
39*4882a593Smuzhiyun *index += count;
40*4882a593Smuzhiyun return count;
41*4882a593Smuzhiyun }
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun /*
44*4882a593Smuzhiyun * This can be called in the panic path with interrupts off, so use
45*4882a593Smuzhiyun * mdelay in that case.
46*4882a593Smuzhiyun */
opal_nvram_write(char * buf,size_t count,loff_t * index)47*4882a593Smuzhiyun static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index)
48*4882a593Smuzhiyun {
49*4882a593Smuzhiyun s64 rc = OPAL_BUSY;
50*4882a593Smuzhiyun int off;
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun if (*index >= nvram_size)
53*4882a593Smuzhiyun return 0;
54*4882a593Smuzhiyun off = *index;
55*4882a593Smuzhiyun if ((off + count) > nvram_size)
56*4882a593Smuzhiyun count = nvram_size - off;
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
59*4882a593Smuzhiyun rc = opal_write_nvram(__pa(buf), count, off);
60*4882a593Smuzhiyun if (rc == OPAL_BUSY_EVENT) {
61*4882a593Smuzhiyun if (in_interrupt() || irqs_disabled())
62*4882a593Smuzhiyun mdelay(OPAL_BUSY_DELAY_MS);
63*4882a593Smuzhiyun else
64*4882a593Smuzhiyun msleep(OPAL_BUSY_DELAY_MS);
65*4882a593Smuzhiyun opal_poll_events(NULL);
66*4882a593Smuzhiyun } else if (rc == OPAL_BUSY) {
67*4882a593Smuzhiyun if (in_interrupt() || irqs_disabled())
68*4882a593Smuzhiyun mdelay(OPAL_BUSY_DELAY_MS);
69*4882a593Smuzhiyun else
70*4882a593Smuzhiyun msleep(OPAL_BUSY_DELAY_MS);
71*4882a593Smuzhiyun }
72*4882a593Smuzhiyun }
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun if (rc)
75*4882a593Smuzhiyun return -EIO;
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun *index += count;
78*4882a593Smuzhiyun return count;
79*4882a593Smuzhiyun }
80*4882a593Smuzhiyun
opal_nvram_init_log_partitions(void)81*4882a593Smuzhiyun static int __init opal_nvram_init_log_partitions(void)
82*4882a593Smuzhiyun {
83*4882a593Smuzhiyun /* Scan nvram for partitions */
84*4882a593Smuzhiyun nvram_scan_partitions();
85*4882a593Smuzhiyun nvram_init_oops_partition(0);
86*4882a593Smuzhiyun return 0;
87*4882a593Smuzhiyun }
88*4882a593Smuzhiyun machine_arch_initcall(powernv, opal_nvram_init_log_partitions);
89*4882a593Smuzhiyun
opal_nvram_init(void)90*4882a593Smuzhiyun void __init opal_nvram_init(void)
91*4882a593Smuzhiyun {
92*4882a593Smuzhiyun struct device_node *np;
93*4882a593Smuzhiyun const __be32 *nbytes_p;
94*4882a593Smuzhiyun
95*4882a593Smuzhiyun np = of_find_compatible_node(NULL, NULL, "ibm,opal-nvram");
96*4882a593Smuzhiyun if (np == NULL)
97*4882a593Smuzhiyun return;
98*4882a593Smuzhiyun
99*4882a593Smuzhiyun nbytes_p = of_get_property(np, "#bytes", NULL);
100*4882a593Smuzhiyun if (!nbytes_p) {
101*4882a593Smuzhiyun of_node_put(np);
102*4882a593Smuzhiyun return;
103*4882a593Smuzhiyun }
104*4882a593Smuzhiyun nvram_size = be32_to_cpup(nbytes_p);
105*4882a593Smuzhiyun
106*4882a593Smuzhiyun pr_info("OPAL nvram setup, %u bytes\n", nvram_size);
107*4882a593Smuzhiyun of_node_put(np);
108*4882a593Smuzhiyun
109*4882a593Smuzhiyun ppc_md.nvram_read = opal_nvram_read;
110*4882a593Smuzhiyun ppc_md.nvram_write = opal_nvram_write;
111*4882a593Smuzhiyun ppc_md.nvram_size = opal_nvram_size;
112*4882a593Smuzhiyun }
113*4882a593Smuzhiyun
114