arch/powerpc/platforms/pseries/nvram.c

   1 /*
   2  *  c 2001 PPC 64 Team, IBM Corp
   3  *
   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.
   8  *
   9  * /dev/nvram driver for PPC64
  10  *
  11  * This perhaps should live in drivers/char
  12  */
  13
  14
  15 #include <linux/types.h>
  16 #include <linux/errno.h>
  17 #include <linux/init.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/slab.h>
  20 #include <linux/kmsg_dump.h>
  21 #include <linux/pstore.h>
  22 #include <linux/ctype.h>
  23 #include <asm/uaccess.h>
  24 #include <asm/nvram.h>
  25 #include <asm/rtas.h>
  26 #include <asm/prom.h>
  27 #include <asm/machdep.h>
  28
  29 /* Max bytes to read/write in one go */
  30 #define NVRW_CNT 0x20
  31
  32 static unsigned int nvram_size;
  33 static int nvram_fetch, nvram_store;
  34 static char nvram_buf[NVRW_CNT];        /* assume this is in the first 4GB */
  35 static DEFINE_SPINLOCK(nvram_lock);
  36
  37 /* See clobbering_unread_rtas_event() */
  38 #define NVRAM_RTAS_READ_TIMEOUT 5               /* seconds */
  39 static time64_t last_unread_rtas_event;         /* timestamp */
  40
  41 #ifdef CONFIG_PSTORE
  42 time64_t last_rtas_event;
  43 #endif
  44
  45 static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index)
  46 {
  47         unsigned int i;
  48         unsigned long len;
  49         int done;
  50         unsigned long flags;
  51         char *p = buf;
  52
  53
  54         if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE)
  55                 return -ENODEV;
  56
  57         if (*index >= nvram_size)
  58                 return 0;
  59
  60         i = *index;
  61         if (i + count > nvram_size)
  62                 count = nvram_size - i;
  63
  64         spin_lock_irqsave(&nvram_lock, flags);
  65
  66         for (; count != 0; count -= len) {
  67                 len = count;
  68                 if (len > NVRW_CNT)
  69                         len = NVRW_CNT;
  70
  71                 if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf),
  72                                len) != 0) || len != done) {
  73                         spin_unlock_irqrestore(&nvram_lock, flags);
  74                         return -EIO;
  75                 }
  76
  77                 memcpy(p, nvram_buf, len);
  78
  79                 p += len;
  80                 i += len;
  81         }
  82
  83         spin_unlock_irqrestore(&nvram_lock, flags);
  84
  85         *index = i;
  86         return p - buf;
  87 }
  88
  89 static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index)
  90 {
  91         unsigned int i;
  92         unsigned long len;
  93         int done;
  94         unsigned long flags;
  95         const char *p = buf;
  96
  97         if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE)
  98                 return -ENODEV;
  99
 100         if (*index >= nvram_size)
 101                 return 0;
 102
 103         i = *index;
 104         if (i + count > nvram_size)
 105                 count = nvram_size - i;
 106
 107         spin_lock_irqsave(&nvram_lock, flags);
 108
 109         for (; count != 0; count -= len) {
 110                 len = count;
 111                 if (len > NVRW_CNT)
 112                         len = NVRW_CNT;
 113
 114                 memcpy(nvram_buf, p, len);
 115
 116                 if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf),
 117                                len) != 0) || len != done) {
 118                         spin_unlock_irqrestore(&nvram_lock, flags);
 119                         return -EIO;
 120                 }
 121
 122                 p += len;
 123                 i += len;
 124         }
 125         spin_unlock_irqrestore(&nvram_lock, flags);
 126
 127         *index = i;
 128         return p - buf;
 129 }
 130
 131 static ssize_t pSeries_nvram_get_size(void)
 132 {
 133         return nvram_size ? nvram_size : -ENODEV;
 134 }
 135
 136 /* nvram_write_error_log
 137  *
 138  * We need to buffer the error logs into nvram to ensure that we have
 139  * the failure information to decode.
 140  */
 141 int nvram_write_error_log(char * buff, int length,
 142                           unsigned int err_type, unsigned int error_log_cnt)
 143 {
 144         int rc = nvram_write_os_partition(&rtas_log_partition, buff, length,
 145                                                 err_type, error_log_cnt);
 146         if (!rc) {
 147                 last_unread_rtas_event = ktime_get_real_seconds();
 148 #ifdef CONFIG_PSTORE
 149                 last_rtas_event = ktime_get_real_seconds();
 150 #endif
 151         }
 152
 153         return rc;
 154 }
 155
 156 /* nvram_read_error_log
 157  *
 158  * Reads nvram for error log for at most 'length'
 159  */
 160 int nvram_read_error_log(char *buff, int length,
 161                         unsigned int *err_type, unsigned int *error_log_cnt)
 162 {
 163         return nvram_read_partition(&rtas_log_partition, buff, length,
 164                                                 err_type, error_log_cnt);
 165 }
 166
 167 /* This doesn't actually zero anything, but it sets the event_logged
 168  * word to tell that this event is safely in syslog.
 169  */
 170 int nvram_clear_error_log(void)
 171 {
 172         loff_t tmp_index;
 173         int clear_word = ERR_FLAG_ALREADY_LOGGED;
 174         int rc;
 175
 176         if (rtas_log_partition.index == -1)
 177                 return -1;
 178
 179         tmp_index = rtas_log_partition.index;
 180
 181         rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index);
 182         if (rc <= 0) {
 183                 printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc);
 184                 return rc;
 185         }
 186         last_unread_rtas_event = 0;
 187
 188         return 0;
 189 }
 190
 191 /*
 192  * Are we using the ibm,rtas-log for oops/panic reports?  And if so,
 193  * would logging this oops/panic overwrite an RTAS event that rtas_errd
 194  * hasn't had a chance to read and process?  Return 1 if so, else 0.
 195  *
 196  * We assume that if rtas_errd hasn't read the RTAS event in
 197  * NVRAM_RTAS_READ_TIMEOUT seconds, it's probably not going to.
 198  */
 199 int clobbering_unread_rtas_event(void)
 200 {
 201         return (oops_log_partition.index == rtas_log_partition.index
 202                 && last_unread_rtas_event
 203                 && ktime_get_real_seconds() - last_unread_rtas_event <=
 204                                                 NVRAM_RTAS_READ_TIMEOUT);
 205 }
 206
 207 static int __init pseries_nvram_init_log_partitions(void)
 208 {
 209         int rc;
 210
 211         /* Scan nvram for partitions */
 212         nvram_scan_partitions();
 213
 214         rc = nvram_init_os_partition(&rtas_log_partition);
 215         nvram_init_oops_partition(rc == 0);
 216         return 0;
 217 }
 218 machine_arch_initcall(pseries, pseries_nvram_init_log_partitions);
 219
 220 int __init pSeries_nvram_init(void)
 221 {
 222         struct device_node *nvram;
 223         const __be32 *nbytes_p;
 224         unsigned int proplen;
 225
 226         nvram = of_find_node_by_type(NULL, "nvram");
 227         if (nvram == NULL)
 228                 return -ENODEV;
 229
 230         nbytes_p = of_get_property(nvram, "#bytes", &proplen);
 231         if (nbytes_p == NULL || proplen != sizeof(unsigned int)) {
 232                 of_node_put(nvram);
 233                 return -EIO;
 234         }
 235
 236         nvram_size = be32_to_cpup(nbytes_p);
 237
 238         nvram_fetch = rtas_token("nvram-fetch");
 239         nvram_store = rtas_token("nvram-store");
 240         printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size);
 241         of_node_put(nvram);
 242
 243         ppc_md.nvram_read       = pSeries_nvram_read;
 244         ppc_md.nvram_write      = pSeries_nvram_write;
 245         ppc_md.nvram_size       = pSeries_nvram_get_size;
 246
 247         return 0;
 248 }
 249