arch/powerpc/platforms/powernv/opal-nvram.c

   1 /*
   2  * PowerNV nvram code.
   3  *
   4  * Copyright 2011 IBM Corp.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define DEBUG
  13
  14 #include <linux/delay.h>
  15 #include <linux/kernel.h>
  16 #include <linux/init.h>
  17 #include <linux/of.h>
  18
  19 #include <asm/opal.h>
  20 #include <asm/nvram.h>
  21 #include <asm/machdep.h>
  22
  23 static unsigned int nvram_size;
  24
  25 static ssize_t opal_nvram_size(void)
  26 {
  27         return nvram_size;
  28 }
  29
  30 static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index)
  31 {
  32         s64 rc;
  33         int off;
  34
  35         if (*index >= nvram_size)
  36                 return 0;
  37         off = *index;
  38         if ((off + count) > nvram_size)
  39                 count = nvram_size - off;
  40         rc = opal_read_nvram(__pa(buf), count, off);
  41         if (rc != OPAL_SUCCESS)
  42                 return -EIO;
  43         *index += count;
  44         return count;
  45 }
  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                         msleep(OPAL_BUSY_DELAY_MS);
  62                         opal_poll_events(NULL);
  63                 } else if (rc == OPAL_BUSY) {
  64                         msleep(OPAL_BUSY_DELAY_MS);
  65                 }
  66         }
  67
  68         if (rc)
  69                 return -EIO;
  70
  71         *index += count;
  72         return count;
  73 }
  74
  75 static int __init opal_nvram_init_log_partitions(void)
  76 {
  77         /* Scan nvram for partitions */
  78         nvram_scan_partitions();
  79         nvram_init_oops_partition(0);
  80         return 0;
  81 }
  82 machine_arch_initcall(powernv, opal_nvram_init_log_partitions);
  83
  84 void __init opal_nvram_init(void)
  85 {
  86         struct device_node *np;
  87         const __be32 *nbytes_p;
  88
  89         np = of_find_compatible_node(NULL, NULL, "ibm,opal-nvram");
  90         if (np == NULL)
  91                 return;
  92
  93         nbytes_p = of_get_property(np, "#bytes", NULL);
  94         if (!nbytes_p) {
  95                 of_node_put(np);
  96                 return;
  97         }
  98         nvram_size = be32_to_cpup(nbytes_p);
  99
 100         pr_info("OPAL nvram setup, %u bytes\n", nvram_size);
 101         of_node_put(np);
 102
 103         ppc_md.nvram_read = opal_nvram_read;
 104         ppc_md.nvram_write = opal_nvram_write;
 105         ppc_md.nvram_size = opal_nvram_size;
 106 }
 107