arch/powerpc/sysdev/scom.c

   1 /*
   2  * Copyright 2010 Benjamin Herrenschmidt, IBM Corp
   3  *                <benh@kernel.crashing.org>
   4  *     and        David Gibson, IBM Corporation.
   5  *
   6  *   This program is free software;  you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  14  *   the GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program;  if not, write to the Free Software
  18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/debugfs.h>
  23 #include <linux/slab.h>
  24 #include <linux/export.h>
  25 #include <asm/debug.h>
  26 #include <asm/prom.h>
  27 #include <asm/scom.h>
  28
  29 const struct scom_controller *scom_controller;
  30 EXPORT_SYMBOL_GPL(scom_controller);
  31
  32 struct device_node *scom_find_parent(struct device_node *node)
  33 {
  34         struct device_node *par, *tmp;
  35         const u32 *p;
  36
  37         for (par = of_node_get(node); par;) {
  38                 if (of_get_property(par, "scom-controller", NULL))
  39                         break;
  40                 p = of_get_property(par, "scom-parent", NULL);
  41                 tmp = par;
  42                 if (p == NULL)
  43                         par = of_get_parent(par);
  44                 else
  45                         par = of_find_node_by_phandle(*p);
  46                 of_node_put(tmp);
  47         }
  48         return par;
  49 }
  50 EXPORT_SYMBOL_GPL(scom_find_parent);
  51
  52 scom_map_t scom_map_device(struct device_node *dev, int index)
  53 {
  54         struct device_node *parent;
  55         unsigned int cells, size;
  56         const u32 *prop;
  57         u64 reg, cnt;
  58         scom_map_t ret;
  59
  60         parent = scom_find_parent(dev);
  61
  62         if (parent == NULL)
  63                 return 0;
  64
  65         prop = of_get_property(parent, "#scom-cells", NULL);
  66         cells = prop ? *prop : 1;
  67
  68         prop = of_get_property(dev, "scom-reg", &size);
  69         if (!prop)
  70                 return 0;
  71         size >>= 2;
  72
  73         if (index >= (size / (2*cells)))
  74                 return 0;
  75
  76         reg = of_read_number(&prop[index * cells * 2], cells);
  77         cnt = of_read_number(&prop[index * cells * 2 + cells], cells);
  78
  79         ret = scom_map(parent, reg, cnt);
  80         of_node_put(parent);
  81
  82         return ret;
  83 }
  84 EXPORT_SYMBOL_GPL(scom_map_device);
  85
  86 #ifdef CONFIG_SCOM_DEBUGFS
  87 struct scom_debug_entry {
  88         struct device_node *dn;
  89         unsigned long addr;
  90         scom_map_t map;
  91         spinlock_t lock;
  92         char name[8];
  93         struct debugfs_blob_wrapper blob;
  94 };
  95
  96 static int scom_addr_set(void *data, u64 val)
  97 {
  98         struct scom_debug_entry *ent = data;
  99
 100         ent->addr = 0;
 101         scom_unmap(ent->map);
 102
 103         ent->map = scom_map(ent->dn, val, 1);
 104         if (scom_map_ok(ent->map))
 105                 ent->addr = val;
 106         else
 107                 return -EFAULT;
 108
 109         return 0;
 110 }
 111
 112 static int scom_addr_get(void *data, u64 *val)
 113 {
 114         struct scom_debug_entry *ent = data;
 115         *val = ent->addr;
 116         return 0;
 117 }
 118 DEFINE_SIMPLE_ATTRIBUTE(scom_addr_fops, scom_addr_get, scom_addr_set,
 119                         "0x%llx\n");
 120
 121 static int scom_val_set(void *data, u64 val)
 122 {
 123         struct scom_debug_entry *ent = data;
 124
 125         if (!scom_map_ok(ent->map))
 126                 return -EFAULT;
 127
 128         scom_write(ent->map, 0, val);
 129
 130         return 0;
 131 }
 132
 133 static int scom_val_get(void *data, u64 *val)
 134 {
 135         struct scom_debug_entry *ent = data;
 136
 137         if (!scom_map_ok(ent->map))
 138                 return -EFAULT;
 139
 140         *val = scom_read(ent->map, 0);
 141         return 0;
 142 }
 143 DEFINE_SIMPLE_ATTRIBUTE(scom_val_fops, scom_val_get, scom_val_set,
 144                         "0x%llx\n");
 145
 146 static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
 147                                int i)
 148 {
 149         struct scom_debug_entry *ent;
 150         struct dentry *dir;
 151
 152         ent = kzalloc(sizeof(*ent), GFP_KERNEL);
 153         if (!ent)
 154                 return -ENOMEM;
 155
 156         ent->dn = of_node_get(dn);
 157         ent->map = SCOM_MAP_INVALID;
 158         spin_lock_init(&ent->lock);
 159         snprintf(ent->name, 8, "scom%d", i);
 160         ent->blob.data = (void*) dn->full_name;
 161         ent->blob.size = strlen(dn->full_name);
 162
 163         dir = debugfs_create_dir(ent->name, root);
 164         if (!dir) {
 165                 of_node_put(dn);
 166                 kfree(ent);
 167                 return -1;
 168         }
 169
 170         debugfs_create_file("addr", 0600, dir, ent, &scom_addr_fops);
 171         debugfs_create_file("value", 0600, dir, ent, &scom_val_fops);
 172         debugfs_create_blob("path", 0400, dir, &ent->blob);
 173
 174         return 0;
 175 }
 176
 177 static int scom_debug_init(void)
 178 {
 179         struct device_node *dn;
 180         struct dentry *root;
 181         int i, rc;
 182
 183         root = debugfs_create_dir("scom", powerpc_debugfs_root);
 184         if (!root)
 185                 return -1;
 186
 187         i = rc = 0;
 188         for_each_node_with_property(dn, "scom-controller")
 189                 rc |= scom_debug_init_one(root, dn, i++);
 190
 191         return rc;
 192 }
 193 device_initcall(scom_debug_init);
 194 #endif /* CONFIG_SCOM_DEBUGFS */