2 * c 2001 PPC 64 Team, IBM Corp
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
9 * /dev/nvram driver for PPC64
13 #include <linux/types.h>
14 #include <linux/errno.h>
15 #include <linux/init.h>
16 #include <linux/spinlock.h>
17 #include <linux/slab.h>
18 #include <linux/ctype.h>
19 #include <linux/uaccess.h>
20 #include <asm/nvram.h>
23 #include <asm/machdep.h>
25 /* Max bytes to read/write in one go */
28 static unsigned int nvram_size;
29 static int nvram_fetch, nvram_store;
30 static char nvram_buf[NVRW_CNT]; /* assume this is in the first 4GB */
31 static DEFINE_SPINLOCK(nvram_lock);
33 /* See clobbering_unread_rtas_event() */
34 #define NVRAM_RTAS_READ_TIMEOUT 5 /* seconds */
35 static time64_t last_unread_rtas_event; /* timestamp */
38 time64_t last_rtas_event;
41 static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index)
50 if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE)
53 if (*index >= nvram_size)
57 if (i + count > nvram_size)
58 count = nvram_size - i;
60 spin_lock_irqsave(&nvram_lock, flags);
62 for (; count != 0; count -= len) {
67 if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf),
68 len) != 0) || len != done) {
69 spin_unlock_irqrestore(&nvram_lock, flags);
73 memcpy(p, nvram_buf, len);
79 spin_unlock_irqrestore(&nvram_lock, flags);
85 static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index)
93 if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE)
96 if (*index >= nvram_size)
100 if (i + count > nvram_size)
101 count = nvram_size - i;
103 spin_lock_irqsave(&nvram_lock, flags);
105 for (; count != 0; count -= len) {
110 memcpy(nvram_buf, p, len);
112 if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf),
113 len) != 0) || len != done) {
114 spin_unlock_irqrestore(&nvram_lock, flags);
121 spin_unlock_irqrestore(&nvram_lock, flags);
127 static ssize_t pSeries_nvram_get_size(void)
129 return nvram_size ? nvram_size : -ENODEV;
132 /* nvram_write_error_log
134 * We need to buffer the error logs into nvram to ensure that we have
135 * the failure information to decode.
137 int nvram_write_error_log(char * buff, int length,
138 unsigned int err_type, unsigned int error_log_cnt)
140 int rc = nvram_write_os_partition(&rtas_log_partition, buff, length,
141 err_type, error_log_cnt);
143 last_unread_rtas_event = ktime_get_real_seconds();
145 last_rtas_event = ktime_get_real_seconds();
152 /* nvram_read_error_log
154 * Reads nvram for error log for at most 'length'
156 int nvram_read_error_log(char *buff, int length,
157 unsigned int *err_type, unsigned int *error_log_cnt)
159 return nvram_read_partition(&rtas_log_partition, buff, length,
160 err_type, error_log_cnt);
163 /* This doesn't actually zero anything, but it sets the event_logged
164 * word to tell that this event is safely in syslog.
166 int nvram_clear_error_log(void)
169 int clear_word = ERR_FLAG_ALREADY_LOGGED;
172 if (rtas_log_partition.index == -1)
175 tmp_index = rtas_log_partition.index;
177 rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index);
179 printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc);
182 last_unread_rtas_event = 0;
188 * Are we using the ibm,rtas-log for oops/panic reports? And if so,
189 * would logging this oops/panic overwrite an RTAS event that rtas_errd
190 * hasn't had a chance to read and process? Return 1 if so, else 0.
192 * We assume that if rtas_errd hasn't read the RTAS event in
193 * NVRAM_RTAS_READ_TIMEOUT seconds, it's probably not going to.
195 int clobbering_unread_rtas_event(void)
197 return (oops_log_partition.index == rtas_log_partition.index
198 && last_unread_rtas_event
199 && ktime_get_real_seconds() - last_unread_rtas_event <=
200 NVRAM_RTAS_READ_TIMEOUT);
203 static int __init pseries_nvram_init_log_partitions(void)
207 /* Scan nvram for partitions */
208 nvram_scan_partitions();
210 rc = nvram_init_os_partition(&rtas_log_partition);
211 nvram_init_oops_partition(rc == 0);
214 machine_arch_initcall(pseries, pseries_nvram_init_log_partitions);
216 int __init pSeries_nvram_init(void)
218 struct device_node *nvram;
219 const __be32 *nbytes_p;
220 unsigned int proplen;
222 nvram = of_find_node_by_type(NULL, "nvram");
226 nbytes_p = of_get_property(nvram, "#bytes", &proplen);
227 if (nbytes_p == NULL || proplen != sizeof(unsigned int)) {
232 nvram_size = be32_to_cpup(nbytes_p);
234 nvram_fetch = rtas_token("nvram-fetch");
235 nvram_store = rtas_token("nvram-store");
236 printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size);
239 ppc_md.nvram_read = pSeries_nvram_read;
240 ppc_md.nvram_write = pSeries_nvram_write;
241 ppc_md.nvram_size = pSeries_nvram_get_size;