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