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
  12
  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>
  21 #include <asm/rtas.h>
  22 #include <asm/prom.h>
  23 #include <asm/machdep.h>
  24
  25 /* Max bytes to read/write in one go */
  26 #define NVRW_CNT 0x20
  27
  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);
  32
  33 /* See clobbering_unread_rtas_event() */
  34 #define NVRAM_RTAS_READ_TIMEOUT 5               /* seconds */
  35 static time64_t last_unread_rtas_event;         /* timestamp */
  36
  37 #ifdef CONFIG_PSTORE
  38 time64_t last_rtas_event;
  39 #endif
  40
  41 static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index)
  42 {
  43         unsigned int i;
  44         unsigned long len;
  45         int done;
  46         unsigned long flags;
  47         char *p = buf;
  48
  49
  50         if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE)
  51                 return -ENODEV;
  52
  53         if (*index >= nvram_size)
  54                 return 0;
  55
  56         i = *index;
  57         if (i + count > nvram_size)
  58                 count = nvram_size - i;
  59
  60         spin_lock_irqsave(&nvram_lock, flags);
  61
  62         for (; count != 0; count -= len) {
  63                 len = count;
  64                 if (len > NVRW_CNT)
  65                         len = NVRW_CNT;
  66
  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);
  70                         return -EIO;
  71                 }
  72
  73                 memcpy(p, nvram_buf, len);
  74
  75                 p += len;
  76                 i += len;
  77         }
  78
  79         spin_unlock_irqrestore(&nvram_lock, flags);
  80
  81         *index = i;
  82         return p - buf;
  83 }
  84
  85 static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index)
  86 {
  87         unsigned int i;
  88         unsigned long len;
  89         int done;
  90         unsigned long flags;
  91         const char *p = buf;
  92
  93         if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE)
  94                 return -ENODEV;
  95
  96         if (*index >= nvram_size)
  97                 return 0;
  98
  99         i = *index;
 100         if (i + count > nvram_size)
 101                 count = nvram_size - i;
 102
 103         spin_lock_irqsave(&nvram_lock, flags);
 104
 105         for (; count != 0; count -= len) {
 106                 len = count;
 107                 if (len > NVRW_CNT)
 108                         len = NVRW_CNT;
 109
 110                 memcpy(nvram_buf, p, len);
 111
 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);
 115                         return -EIO;
 116                 }
 117
 118                 p += len;
 119                 i += len;
 120         }
 121         spin_unlock_irqrestore(&nvram_lock, flags);
 122
 123         *index = i;
 124         return p - buf;
 125 }
 126
 127 static ssize_t pSeries_nvram_get_size(void)
 128 {
 129         return nvram_size ? nvram_size : -ENODEV;
 130 }
 131
 132 /* nvram_write_error_log
 133  *
 134  * We need to buffer the error logs into nvram to ensure that we have
 135  * the failure information to decode.
 136  */
 137 int nvram_write_error_log(char * buff, int length,
 138                           unsigned int err_type, unsigned int error_log_cnt)
 139 {
 140         int rc = nvram_write_os_partition(&rtas_log_partition, buff, length,
 141                                                 err_type, error_log_cnt);
 142         if (!rc) {
 143                 last_unread_rtas_event = ktime_get_real_seconds();
 144 #ifdef CONFIG_PSTORE
 145                 last_rtas_event = ktime_get_real_seconds();
 146 #endif
 147         }
 148
 149         return rc;
 150 }
 151
 152 /* nvram_read_error_log
 153  *
 154  * Reads nvram for error log for at most 'length'
 155  */
 156 int nvram_read_error_log(char *buff, int length,
 157                         unsigned int *err_type, unsigned int *error_log_cnt)
 158 {
 159         return nvram_read_partition(&rtas_log_partition, buff, length,
 160                                                 err_type, error_log_cnt);
 161 }
 162
 163 /* This doesn't actually zero anything, but it sets the event_logged
 164  * word to tell that this event is safely in syslog.
 165  */
 166 int nvram_clear_error_log(void)
 167 {
 168         loff_t tmp_index;
 169         int clear_word = ERR_FLAG_ALREADY_LOGGED;
 170         int rc;
 171
 172         if (rtas_log_partition.index == -1)
 173                 return -1;
 174
 175         tmp_index = rtas_log_partition.index;
 176
 177         rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index);
 178         if (rc <= 0) {
 179                 printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc);
 180                 return rc;
 181         }
 182         last_unread_rtas_event = 0;
 183
 184         return 0;
 185 }
 186
 187 /*
 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.
 191  *
 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.
 194  */
 195 int clobbering_unread_rtas_event(void)
 196 {
 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);
 201 }
 202
 203 static int __init pseries_nvram_init_log_partitions(void)
 204 {
 205         int rc;
 206
 207         /* Scan nvram for partitions */
 208         nvram_scan_partitions();
 209
 210         rc = nvram_init_os_partition(&rtas_log_partition);
 211         nvram_init_oops_partition(rc == 0);
 212         return 0;
 213 }
 214 machine_arch_initcall(pseries, pseries_nvram_init_log_partitions);
 215
 216 int __init pSeries_nvram_init(void)
 217 {
 218         struct device_node *nvram;
 219         const __be32 *nbytes_p;
 220         unsigned int proplen;
 221
 222         nvram = of_find_node_by_type(NULL, "nvram");
 223         if (nvram == NULL)
 224                 return -ENODEV;
 225
 226         nbytes_p = of_get_property(nvram, "#bytes", &proplen);
 227         if (nbytes_p == NULL || proplen != sizeof(unsigned int)) {
 228                 of_node_put(nvram);
 229                 return -EIO;
 230         }
 231
 232         nvram_size = be32_to_cpup(nbytes_p);
 233
 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);
 237         of_node_put(nvram);
 238
 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;
 242
 243         return 0;
 244 }
 245