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