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 #include <linux/uaccess.h>
  29
  30 const struct scom_controller *scom_controller;
  31 EXPORT_SYMBOL_GPL(scom_controller);
  32
  33 struct device_node *scom_find_parent(struct device_node *node)
  34 {
  35         struct device_node *par, *tmp;
  36         const u32 *p;
  37
  38         for (par = of_node_get(node); par;) {
  39                 if (of_get_property(par, "scom-controller", NULL))
  40                         break;
  41                 p = of_get_property(par, "scom-parent", NULL);
  42                 tmp = par;
  43                 if (p == NULL)
  44                         par = of_get_parent(par);
  45                 else
  46                         par = of_find_node_by_phandle(*p);
  47                 of_node_put(tmp);
  48         }
  49         return par;
  50 }
  51 EXPORT_SYMBOL_GPL(scom_find_parent);
  52
  53 scom_map_t scom_map_device(struct device_node *dev, int index)
  54 {
  55         struct device_node *parent;
  56         unsigned int cells, size;
  57         const __be32 *prop, *sprop;
  58         u64 reg, cnt;
  59         scom_map_t ret;
  60
  61         parent = scom_find_parent(dev);
  62
  63         if (parent == NULL)
  64                 return 0;
  65
  66         /*
  67          * We support "scom-reg" properties for adding scom registers
  68          * to a random device-tree node with an explicit scom-parent
  69          *
  70          * We also support the simple "reg" property if the device is
  71          * a direct child of a scom controller.
  72          *
  73          * In case both exist, "scom-reg" takes precedence.
  74          */
  75         prop = of_get_property(dev, "scom-reg", &size);
  76         sprop = of_get_property(parent, "#scom-cells", NULL);
  77         if (!prop && parent == dev->parent) {
  78                 prop = of_get_property(dev, "reg", &size);
  79                 sprop = of_get_property(parent, "#address-cells", NULL);
  80         }
  81         if (!prop)
  82                 return NULL;
  83         cells = sprop ? be32_to_cpup(sprop) : 1;
  84         size >>= 2;
  85
  86         if (index >= (size / (2*cells)))
  87                 return 0;
  88
  89         reg = of_read_number(&prop[index * cells * 2], cells);
  90         cnt = of_read_number(&prop[index * cells * 2 + cells], cells);
  91
  92         ret = scom_map(parent, reg, cnt);
  93         of_node_put(parent);
  94
  95         return ret;
  96 }
  97 EXPORT_SYMBOL_GPL(scom_map_device);
  98
  99 #ifdef CONFIG_SCOM_DEBUGFS
 100 struct scom_debug_entry {
 101         struct device_node *dn;
 102         struct debugfs_blob_wrapper path;
 103         char name[16];
 104 };
 105
 106 static ssize_t scom_debug_read(struct file *filp, char __user *ubuf,
 107                                size_t count, loff_t *ppos)
 108 {
 109         struct scom_debug_entry *ent = filp->private_data;
 110         u64 __user *ubuf64 = (u64 __user *)ubuf;
 111         loff_t off = *ppos;
 112         ssize_t done = 0;
 113         u64 reg, reg_cnt, val;
 114         scom_map_t map;
 115         int rc;
 116
 117         if (off < 0 || (off & 7) || (count & 7))
 118                 return -EINVAL;
 119         reg = off >> 3;
 120         reg_cnt = count >> 3;
 121
 122         map = scom_map(ent->dn, reg, reg_cnt);
 123         if (!scom_map_ok(map))
 124                 return -ENXIO;
 125
 126         for (reg = 0; reg < reg_cnt; reg++) {
 127                 rc = scom_read(map, reg, &val);
 128                 if (!rc)
 129                         rc = put_user(val, ubuf64);
 130                 if (rc) {
 131                         if (!done)
 132                                 done = rc;
 133                         break;
 134                 }
 135                 ubuf64++;
 136                 *ppos += 8;
 137                 done += 8;
 138         }
 139         scom_unmap(map);
 140         return done;
 141 }
 142
 143 static ssize_t scom_debug_write(struct file* filp, const char __user *ubuf,
 144                                 size_t count, loff_t *ppos)
 145 {
 146         struct scom_debug_entry *ent = filp->private_data;
 147         u64 __user *ubuf64 = (u64 __user *)ubuf;
 148         loff_t off = *ppos;
 149         ssize_t done = 0;
 150         u64 reg, reg_cnt, val;
 151         scom_map_t map;
 152         int rc;
 153
 154         if (off < 0 || (off & 7) || (count & 7))
 155                 return -EINVAL;
 156         reg = off >> 3;
 157         reg_cnt = count >> 3;
 158
 159         map = scom_map(ent->dn, reg, reg_cnt);
 160         if (!scom_map_ok(map))
 161                 return -ENXIO;
 162
 163         for (reg = 0; reg < reg_cnt; reg++) {
 164                 rc = get_user(val, ubuf64);
 165                 if (!rc)
 166                         rc = scom_write(map, reg,  val);
 167                 if (rc) {
 168                         if (!done)
 169                                 done = rc;
 170                         break;
 171                 }
 172                 ubuf64++;
 173                 done += 8;
 174         }
 175         scom_unmap(map);
 176         return done;
 177 }
 178
 179 static const struct file_operations scom_debug_fops = {
 180         .read =         scom_debug_read,
 181         .write =        scom_debug_write,
 182         .open =         simple_open,
 183         .llseek =       default_llseek,
 184 };
 185
 186 static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
 187                                int i)
 188 {
 189         struct scom_debug_entry *ent;
 190         struct dentry *dir;
 191
 192         ent = kzalloc(sizeof(*ent), GFP_KERNEL);
 193         if (!ent)
 194                 return -ENOMEM;
 195
 196         ent->dn = of_node_get(dn);
 197         snprintf(ent->name, 16, "%08x", i);
 198         ent->path.data = (void*) dn->full_name;
 199         ent->path.size = strlen(dn->full_name);
 200
 201         dir = debugfs_create_dir(ent->name, root);
 202         if (!dir) {
 203                 of_node_put(dn);
 204                 kfree(ent);
 205                 return -1;
 206         }
 207
 208         debugfs_create_blob("devspec", 0400, dir, &ent->path);
 209         debugfs_create_file("access", 0600, dir, ent, &scom_debug_fops);
 210
 211         return 0;
 212 }
 213
 214 static int scom_debug_init(void)
 215 {
 216         struct device_node *dn;
 217         struct dentry *root;
 218         int i, rc;
 219
 220         root = debugfs_create_dir("scom", powerpc_debugfs_root);
 221         if (!root)
 222                 return -1;
 223
 224         i = rc = 0;
 225         for_each_node_with_property(dn, "scom-controller") {
 226                 int id = of_get_ibm_chip_id(dn);
 227                 if (id == -1)
 228                         id = i;
 229                 rc |= scom_debug_init_one(root, dn, id);
 230                 i++;
 231         }
 232
 233         return rc;
 234 }
 235 device_initcall(scom_debug_init);
 236 #endif /* CONFIG_SCOM_DEBUGFS */