drivers/base/soc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) ST-Ericsson SA 2011
   4  *
   5  * Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson.
   6  */
   7
   8 #include <linux/sysfs.h>
   9 #include <linux/init.h>
  10 #include <linux/stat.h>
  11 #include <linux/slab.h>
  12 #include <linux/idr.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/sys_soc.h>
  15 #include <linux/err.h>
  16 #include <linux/glob.h>
  17
  18 static DEFINE_IDA(soc_ida);
  19
  20 static ssize_t soc_info_get(struct device *dev,
  21                             struct device_attribute *attr,
  22                             char *buf);
  23
  24 struct soc_device {
  25         struct device dev;
  26         struct soc_device_attribute *attr;
  27         int soc_dev_num;
  28 };
  29
  30 static struct bus_type soc_bus_type = {
  31         .name  = "soc",
  32 };
  33
  34 static DEVICE_ATTR(machine,  S_IRUGO, soc_info_get,  NULL);
  35 static DEVICE_ATTR(family,   S_IRUGO, soc_info_get,  NULL);
  36 static DEVICE_ATTR(soc_id,   S_IRUGO, soc_info_get,  NULL);
  37 static DEVICE_ATTR(revision, S_IRUGO, soc_info_get,  NULL);
  38
  39 struct device *soc_device_to_device(struct soc_device *soc_dev)
  40 {
  41         return &soc_dev->dev;
  42 }
  43
  44 static umode_t soc_attribute_mode(struct kobject *kobj,
  45                                 struct attribute *attr,
  46                                 int index)
  47 {
  48         struct device *dev = container_of(kobj, struct device, kobj);
  49         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
  50
  51         if ((attr == &dev_attr_machine.attr)
  52             && (soc_dev->attr->machine != NULL))
  53                 return attr->mode;
  54         if ((attr == &dev_attr_family.attr)
  55             && (soc_dev->attr->family != NULL))
  56                 return attr->mode;
  57         if ((attr == &dev_attr_revision.attr)
  58             && (soc_dev->attr->revision != NULL))
  59                 return attr->mode;
  60         if ((attr == &dev_attr_soc_id.attr)
  61             && (soc_dev->attr->soc_id != NULL))
  62                 return attr->mode;
  63
  64         /* Unknown or unfilled attribute. */
  65         return 0;
  66 }
  67
  68 static ssize_t soc_info_get(struct device *dev,
  69                             struct device_attribute *attr,
  70                             char *buf)
  71 {
  72         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
  73
  74         if (attr == &dev_attr_machine)
  75                 return sprintf(buf, "%s\n", soc_dev->attr->machine);
  76         if (attr == &dev_attr_family)
  77                 return sprintf(buf, "%s\n", soc_dev->attr->family);
  78         if (attr == &dev_attr_revision)
  79                 return sprintf(buf, "%s\n", soc_dev->attr->revision);
  80         if (attr == &dev_attr_soc_id)
  81                 return sprintf(buf, "%s\n", soc_dev->attr->soc_id);
  82
  83         return -EINVAL;
  84
  85 }
  86
  87 static struct attribute *soc_attr[] = {
  88         &dev_attr_machine.attr,
  89         &dev_attr_family.attr,
  90         &dev_attr_soc_id.attr,
  91         &dev_attr_revision.attr,
  92         NULL,
  93 };
  94
  95 static const struct attribute_group soc_attr_group = {
  96         .attrs = soc_attr,
  97         .is_visible = soc_attribute_mode,
  98 };
  99
 100 static const struct attribute_group *soc_attr_groups[] = {
 101         &soc_attr_group,
 102         NULL,
 103 };
 104
 105 static void soc_release(struct device *dev)
 106 {
 107         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
 108
 109         kfree(soc_dev);
 110 }
 111
 112 static struct soc_device_attribute *early_soc_dev_attr;
 113
 114 struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
 115 {
 116         struct soc_device *soc_dev;
 117         int ret;
 118
 119         if (!soc_bus_type.p) {
 120                 if (early_soc_dev_attr)
 121                         return ERR_PTR(-EBUSY);
 122                 early_soc_dev_attr = soc_dev_attr;
 123                 return NULL;
 124         }
 125
 126         soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL);
 127         if (!soc_dev) {
 128                 ret = -ENOMEM;
 129                 goto out1;
 130         }
 131
 132         /* Fetch a unique (reclaimable) SOC ID. */
 133         ret = ida_simple_get(&soc_ida, 0, 0, GFP_KERNEL);
 134         if (ret < 0)
 135                 goto out2;
 136         soc_dev->soc_dev_num = ret;
 137
 138         soc_dev->attr = soc_dev_attr;
 139         soc_dev->dev.bus = &soc_bus_type;
 140         soc_dev->dev.groups = soc_attr_groups;
 141         soc_dev->dev.release = soc_release;
 142
 143         dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num);
 144
 145         ret = device_register(&soc_dev->dev);
 146         if (ret)
 147                 goto out3;
 148
 149         return soc_dev;
 150
 151 out3:
 152         ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
 153         put_device(&soc_dev->dev);
 154         soc_dev = NULL;
 155 out2:
 156         kfree(soc_dev);
 157 out1:
 158         return ERR_PTR(ret);
 159 }
 160
 161 /* Ensure soc_dev->attr is freed prior to calling soc_device_unregister. */
 162 void soc_device_unregister(struct soc_device *soc_dev)
 163 {
 164         ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
 165
 166         device_unregister(&soc_dev->dev);
 167         early_soc_dev_attr = NULL;
 168 }
 169
 170 static int __init soc_bus_register(void)
 171 {
 172         int ret;
 173
 174         ret = bus_register(&soc_bus_type);
 175         if (ret)
 176                 return ret;
 177
 178         if (early_soc_dev_attr)
 179                 return PTR_ERR(soc_device_register(early_soc_dev_attr));
 180
 181         return 0;
 182 }
 183 core_initcall(soc_bus_register);
 184
 185 static int soc_device_match_attr(const struct soc_device_attribute *attr,
 186                                  const struct soc_device_attribute *match)
 187 {
 188         if (match->machine &&
 189             (!attr->machine || !glob_match(match->machine, attr->machine)))
 190                 return 0;
 191
 192         if (match->family &&
 193             (!attr->family || !glob_match(match->family, attr->family)))
 194                 return 0;
 195
 196         if (match->revision &&
 197             (!attr->revision || !glob_match(match->revision, attr->revision)))
 198                 return 0;
 199
 200         if (match->soc_id &&
 201             (!attr->soc_id || !glob_match(match->soc_id, attr->soc_id)))
 202                 return 0;
 203
 204         return 1;
 205 }
 206
 207 static int soc_device_match_one(struct device *dev, void *arg)
 208 {
 209         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
 210
 211         return soc_device_match_attr(soc_dev->attr, arg);
 212 }
 213
 214 /*
 215  * soc_device_match - identify the SoC in the machine
 216  * @matches: zero-terminated array of possible matches
 217  *
 218  * returns the first matching entry of the argument array, or NULL
 219  * if none of them match.
 220  *
 221  * This function is meant as a helper in place of of_match_node()
 222  * in cases where either no device tree is available or the information
 223  * in a device node is insufficient to identify a particular variant
 224  * by its compatible strings or other properties. For new devices,
 225  * the DT binding should always provide unique compatible strings
 226  * that allow the use of of_match_node() instead.
 227  *
 228  * The calling function can use the .data entry of the
 229  * soc_device_attribute to pass a structure or function pointer for
 230  * each entry.
 231  */
 232 const struct soc_device_attribute *soc_device_match(
 233         const struct soc_device_attribute *matches)
 234 {
 235         int ret = 0;
 236
 237         if (!matches)
 238                 return NULL;
 239
 240         while (!ret) {
 241                 if (!(matches->machine || matches->family ||
 242                       matches->revision || matches->soc_id))
 243                         break;
 244                 ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches,
 245                                        soc_device_match_one);
 246                 if (ret < 0 && early_soc_dev_attr)
 247                         ret = soc_device_match_attr(early_soc_dev_attr,
 248                                                     matches);
 249                 if (ret < 0)
 250                         return NULL;
 251                 if (!ret)
 252                         matches++;
 253                 else
 254                         return matches;
 255         }
 256         return NULL;
 257 }
 258 EXPORT_SYMBOL_GPL(soc_device_match);