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/slab.h>
  23 #include <linux/export.h>
  24 #include <asm/debugfs.h>
  25 #include <asm/prom.h>
  26 #include <asm/scom.h>
  27 #include <linux/uaccess.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 __be32 *prop, *sprop;
  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         /*
  66          * We support "scom-reg" properties for adding scom registers
  67          * to a random device-tree node with an explicit scom-parent
  68          *
  69          * We also support the simple "reg" property if the device is
  70          * a direct child of a scom controller.
  71          *
  72          * In case both exist, "scom-reg" takes precedence.
  73          */
  74         prop = of_get_property(dev, "scom-reg", &size);
  75         sprop = of_get_property(parent, "#scom-cells", NULL);
  76         if (!prop && parent == dev->parent) {
  77                 prop = of_get_property(dev, "reg", &size);
  78                 sprop = of_get_property(parent, "#address-cells", NULL);
  79         }
  80         if (!prop)
  81                 return NULL;
  82         cells = sprop ? be32_to_cpup(sprop) : 1;
  83         size >>= 2;
  84
  85         if (index >= (size / (2*cells)))
  86                 return 0;
  87
  88         reg = of_read_number(&prop[index * cells * 2], cells);
  89         cnt = of_read_number(&prop[index * cells * 2 + cells], cells);
  90
  91         ret = scom_map(parent, reg, cnt);
  92         of_node_put(parent);
  93
  94         return ret;
  95 }
  96 EXPORT_SYMBOL_GPL(scom_map_device);
  97
  98 #ifdef CONFIG_SCOM_DEBUGFS
  99 struct scom_debug_entry {
 100         struct device_node *dn;
 101         struct debugfs_blob_wrapper path;
 102         char name[16];
 103 };
 104
 105 static ssize_t scom_debug_read(struct file *filp, char __user *ubuf,
 106                                size_t count, loff_t *ppos)
 107 {
 108         struct scom_debug_entry *ent = filp->private_data;
 109         u64 __user *ubuf64 = (u64 __user *)ubuf;
 110         loff_t off = *ppos;
 111         ssize_t done = 0;
 112         u64 reg, reg_cnt, val;
 113         scom_map_t map;
 114         int rc;
 115
 116         if (off < 0 || (off & 7) || (count & 7))
 117                 return -EINVAL;
 118         reg = off >> 3;
 119         reg_cnt = count >> 3;
 120
 121         map = scom_map(ent->dn, reg, reg_cnt);
 122         if (!scom_map_ok(map))
 123                 return -ENXIO;
 124
 125         for (reg = 0; reg < reg_cnt; reg++) {
 126                 rc = scom_read(map, reg, &val);
 127                 if (!rc)
 128                         rc = put_user(val, ubuf64);
 129                 if (rc) {
 130                         if (!done)
 131                                 done = rc;
 132                         break;
 133                 }
 134                 ubuf64++;
 135                 *ppos += 8;
 136                 done += 8;
 137         }
 138         scom_unmap(map);
 139         return done;
 140 }
 141
 142 static ssize_t scom_debug_write(struct file* filp, const char __user *ubuf,
 143                                 size_t count, loff_t *ppos)
 144 {
 145         struct scom_debug_entry *ent = filp->private_data;
 146         u64 __user *ubuf64 = (u64 __user *)ubuf;
 147         loff_t off = *ppos;
 148         ssize_t done = 0;
 149         u64 reg, reg_cnt, val;
 150         scom_map_t map;
 151         int rc;
 152
 153         if (off < 0 || (off & 7) || (count & 7))
 154                 return -EINVAL;
 155         reg = off >> 3;
 156         reg_cnt = count >> 3;
 157
 158         map = scom_map(ent->dn, reg, reg_cnt);
 159         if (!scom_map_ok(map))
 160                 return -ENXIO;
 161
 162         for (reg = 0; reg < reg_cnt; reg++) {
 163                 rc = get_user(val, ubuf64);
 164                 if (!rc)
 165                         rc = scom_write(map, reg,  val);
 166                 if (rc) {
 167                         if (!done)
 168                                 done = rc;
 169                         break;
 170                 }
 171                 ubuf64++;
 172                 done += 8;
 173         }
 174         scom_unmap(map);
 175         return done;
 176 }
 177
 178 static const struct file_operations scom_debug_fops = {
 179         .read =         scom_debug_read,
 180         .write =        scom_debug_write,
 181         .open =         simple_open,
 182         .llseek =       default_llseek,
 183 };
 184
 185 static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
 186                                int i)
 187 {
 188         struct scom_debug_entry *ent;
 189         struct dentry *dir;
 190
 191         ent = kzalloc(sizeof(*ent), GFP_KERNEL);
 192         if (!ent)
 193                 return -ENOMEM;
 194
 195         ent->dn = of_node_get(dn);
 196         snprintf(ent->name, 16, "%08x", i);
 197         ent->path.data = (void*) dn->full_name;
 198         ent->path.size = strlen(dn->full_name);
 199
 200         dir = debugfs_create_dir(ent->name, root);
 201         if (!dir) {
 202                 of_node_put(dn);
 203                 kfree(ent);
 204                 return -1;
 205         }
 206
 207         debugfs_create_blob("devspec", 0400, dir, &ent->path);
 208         debugfs_create_file("access", 0600, dir, ent, &scom_debug_fops);
 209
 210         return 0;
 211 }
 212
 213 static int scom_debug_init(void)
 214 {
 215         struct device_node *dn;
 216         struct dentry *root;
 217         int i, rc;
 218
 219         root = debugfs_create_dir("scom", powerpc_debugfs_root);
 220         if (!root)
 221                 return -1;
 222
 223         i = rc = 0;
 224         for_each_node_with_property(dn, "scom-controller") {
 225                 int id = of_get_ibm_chip_id(dn);
 226                 if (id == -1)
 227                         id = i;
 228                 rc |= scom_debug_init_one(root, dn, id);
 229                 i++;
 230         }
 231
 232         return rc;
 233 }
 234 device_initcall(scom_debug_init);
 235 #endif /* CONFIG_SCOM_DEBUGFS */