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