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 <asm/prom.h>
  25 #include <asm/scom.h>
  26
  27 const struct scom_controller *scom_controller;
  28 EXPORT_SYMBOL_GPL(scom_controller);
  29
  30 struct device_node *scom_find_parent(struct device_node *node)
  31 {
  32         struct device_node *par, *tmp;
  33         const u32 *p;
  34
  35         for (par = of_node_get(node); par;) {
  36                 if (of_get_property(par, "scom-controller", NULL))
  37                         break;
  38                 p = of_get_property(par, "scom-parent", NULL);
  39                 tmp = par;
  40                 if (p == NULL)
  41                         par = of_get_parent(par);
  42                 else
  43                         par = of_find_node_by_phandle(*p);
  44                 of_node_put(tmp);
  45         }
  46         return par;
  47 }
  48 EXPORT_SYMBOL_GPL(scom_find_parent);
  49
  50 scom_map_t scom_map_device(struct device_node *dev, int index)
  51 {
  52         struct device_node *parent;
  53         unsigned int cells, size;
  54         const u32 *prop;
  55         u64 reg, cnt;
  56         scom_map_t ret;
  57
  58         parent = scom_find_parent(dev);
  59
  60         if (parent == NULL)
  61                 return 0;
  62
  63         prop = of_get_property(parent, "#scom-cells", NULL);
  64         cells = prop ? *prop : 1;
  65
  66         prop = of_get_property(dev, "scom-reg", &size);
  67         if (!prop)
  68                 return 0;
  69         size >>= 2;
  70
  71         if (index >= (size / (2*cells)))
  72                 return 0;
  73
  74         reg = of_read_number(&prop[index * cells * 2], cells);
  75         cnt = of_read_number(&prop[index * cells * 2 + cells], cells);
  76
  77         ret = scom_map(parent, reg, cnt);
  78         of_node_put(parent);
  79
  80         return ret;
  81 }
  82 EXPORT_SYMBOL_GPL(scom_map_device);
  83
  84 #ifdef CONFIG_SCOM_DEBUGFS
  85 struct scom_debug_entry {
  86         struct device_node *dn;
  87         unsigned long addr;
  88         scom_map_t map;
  89         spinlock_t lock;
  90         char name[8];
  91         struct debugfs_blob_wrapper blob;
  92 };
  93
  94 static int scom_addr_set(void *data, u64 val)
  95 {
  96         struct scom_debug_entry *ent = data;
  97
  98         ent->addr = 0;
  99         scom_unmap(ent->map);
 100
 101         ent->map = scom_map(ent->dn, val, 1);
 102         if (scom_map_ok(ent->map))
 103                 ent->addr = val;
 104         else
 105                 return -EFAULT;
 106
 107         return 0;
 108 }
 109
 110 static int scom_addr_get(void *data, u64 *val)
 111 {
 112         struct scom_debug_entry *ent = data;
 113         *val = ent->addr;
 114         return 0;
 115 }
 116 DEFINE_SIMPLE_ATTRIBUTE(scom_addr_fops, scom_addr_get, scom_addr_set,
 117                         "0x%llx\n");
 118
 119 static int scom_val_set(void *data, u64 val)
 120 {
 121         struct scom_debug_entry *ent = data;
 122
 123         if (!scom_map_ok(ent->map))
 124                 return -EFAULT;
 125
 126         scom_write(ent->map, 0, val);
 127
 128         return 0;
 129 }
 130
 131 static int scom_val_get(void *data, u64 *val)
 132 {
 133         struct scom_debug_entry *ent = data;
 134
 135         if (!scom_map_ok(ent->map))
 136                 return -EFAULT;
 137
 138         *val = scom_read(ent->map, 0);
 139         return 0;
 140 }
 141 DEFINE_SIMPLE_ATTRIBUTE(scom_val_fops, scom_val_get, scom_val_set,
 142                         "0x%llx\n");
 143
 144 static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
 145                                int i)
 146 {
 147         struct scom_debug_entry *ent;
 148         struct dentry *dir;
 149
 150         ent = kzalloc(sizeof(*ent), GFP_KERNEL);
 151         if (!ent)
 152                 return -ENOMEM;
 153
 154         ent->dn = of_node_get(dn);
 155         ent->map = SCOM_MAP_INVALID;
 156         spin_lock_init(&ent->lock);
 157         snprintf(ent->name, 8, "scom%d", i);
 158         ent->blob.data = dn->full_name;
 159         ent->blob.size = strlen(dn->full_name);
 160
 161         dir = debugfs_create_dir(ent->name, root);
 162         if (!dir) {
 163                 of_node_put(dn);
 164                 kfree(ent);
 165                 return -1;
 166         }
 167
 168         debugfs_create_file("addr", 0600, dir, ent, &scom_addr_fops);
 169         debugfs_create_file("value", 0600, dir, ent, &scom_val_fops);
 170         debugfs_create_blob("path", 0400, dir, &ent->blob);
 171
 172         return 0;
 173 }
 174
 175 static int scom_debug_init(void)
 176 {
 177         struct device_node *dn;
 178         struct dentry *root;
 179         int i, rc;
 180
 181         root = debugfs_create_dir("scom", powerpc_debugfs_root);
 182         if (!root)
 183                 return -1;
 184
 185         i = rc = 0;
 186         for_each_node_with_property(dn, "scom-controller")
 187                 rc |= scom_debug_init_one(root, dn, i++);
 188
 189         return rc;
 190 }
 191 device_initcall(scom_debug_init);
 192 #endif /* CONFIG_SCOM_DEBUGFS */