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(serial_number, S_IRUGO, soc_info_get,  NULL);
  37 static DEVICE_ATTR(soc_id,   S_IRUGO, soc_info_get,  NULL);
  38 static DEVICE_ATTR(revision, S_IRUGO, soc_info_get,  NULL);
  39
  40 struct device *soc_device_to_device(struct soc_device *soc_dev)
  41 {
  42         return &soc_dev->dev;
  43 }
  44
  45 static umode_t soc_attribute_mode(struct kobject *kobj,
  46                                 struct attribute *attr,
  47                                 int index)
  48 {
  49         struct device *dev = kobj_to_dev(kobj);
  50         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
  51
  52         if ((attr == &dev_attr_machine.attr)
  53             && (soc_dev->attr->machine != NULL))
  54                 return attr->mode;
  55         if ((attr == &dev_attr_family.attr)
  56             && (soc_dev->attr->family != NULL))
  57                 return attr->mode;
  58         if ((attr == &dev_attr_revision.attr)
  59             && (soc_dev->attr->revision != NULL))
  60                 return attr->mode;
  61         if ((attr == &dev_attr_serial_number.attr)
  62             && (soc_dev->attr->serial_number != NULL))
  63                 return attr->mode;
  64         if ((attr == &dev_attr_soc_id.attr)
  65             && (soc_dev->attr->soc_id != NULL))
  66                 return attr->mode;
  67
  68         /* Unknown or unfilled attribute. */
  69         return 0;
  70 }
  71
  72 static ssize_t soc_info_get(struct device *dev,
  73                             struct device_attribute *attr,
  74                             char *buf)
  75 {
  76         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
  77
  78         if (attr == &dev_attr_machine)
  79                 return sysfs_emit(buf, "%s\n", soc_dev->attr->machine);
  80         if (attr == &dev_attr_family)
  81                 return sysfs_emit(buf, "%s\n", soc_dev->attr->family);
  82         if (attr == &dev_attr_revision)
  83                 return sysfs_emit(buf, "%s\n", soc_dev->attr->revision);
  84         if (attr == &dev_attr_serial_number)
  85                 return sysfs_emit(buf, "%s\n", soc_dev->attr->serial_number);
  86         if (attr == &dev_attr_soc_id)
  87                 return sysfs_emit(buf, "%s\n", soc_dev->attr->soc_id);
  88
  89         return -EINVAL;
  90
  91 }
  92
  93 static struct attribute *soc_attr[] = {
  94         &dev_attr_machine.attr,
  95         &dev_attr_family.attr,
  96         &dev_attr_serial_number.attr,
  97         &dev_attr_soc_id.attr,
  98         &dev_attr_revision.attr,
  99         NULL,
 100 };
 101
 102 static const struct attribute_group soc_attr_group = {
 103         .attrs = soc_attr,
 104         .is_visible = soc_attribute_mode,
 105 };
 106
 107 static void soc_release(struct device *dev)
 108 {
 109         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
 110
 111         ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
 112         kfree(soc_dev->dev.groups);
 113         kfree(soc_dev);
 114 }
 115
 116 static struct soc_device_attribute *early_soc_dev_attr;
 117
 118 struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
 119 {
 120         struct soc_device *soc_dev;
 121         const struct attribute_group **soc_attr_groups;
 122         int ret;
 123
 124         if (!soc_bus_type.p) {
 125                 if (early_soc_dev_attr)
 126                         return ERR_PTR(-EBUSY);
 127                 early_soc_dev_attr = soc_dev_attr;
 128                 return NULL;
 129         }
 130
 131         soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL);
 132         if (!soc_dev) {
 133                 ret = -ENOMEM;
 134                 goto out1;
 135         }
 136
 137         soc_attr_groups = kcalloc(3, sizeof(*soc_attr_groups), GFP_KERNEL);
 138         if (!soc_attr_groups) {
 139                 ret = -ENOMEM;
 140                 goto out2;
 141         }
 142         soc_attr_groups[0] = &soc_attr_group;
 143         soc_attr_groups[1] = soc_dev_attr->custom_attr_group;
 144
 145         /* Fetch a unique (reclaimable) SOC ID. */
 146         ret = ida_simple_get(&soc_ida, 0, 0, GFP_KERNEL);
 147         if (ret < 0)
 148                 goto out3;
 149         soc_dev->soc_dev_num = ret;
 150
 151         soc_dev->attr = soc_dev_attr;
 152         soc_dev->dev.bus = &soc_bus_type;
 153         soc_dev->dev.groups = soc_attr_groups;
 154         soc_dev->dev.release = soc_release;
 155
 156         dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num);
 157
 158         ret = device_register(&soc_dev->dev);
 159         if (ret) {
 160                 put_device(&soc_dev->dev);
 161                 return ERR_PTR(ret);
 162         }
 163
 164         return soc_dev;
 165
 166 out3:
 167         kfree(soc_attr_groups);
 168 out2:
 169         kfree(soc_dev);
 170 out1:
 171         return ERR_PTR(ret);
 172 }
 173 EXPORT_SYMBOL_GPL(soc_device_register);
 174
 175 /* Ensure soc_dev->attr is freed prior to calling soc_device_unregister. */
 176 void soc_device_unregister(struct soc_device *soc_dev)
 177 {
 178         device_unregister(&soc_dev->dev);
 179         early_soc_dev_attr = NULL;
 180 }
 181 EXPORT_SYMBOL_GPL(soc_device_unregister);
 182
 183 static int __init soc_bus_register(void)
 184 {
 185         int ret;
 186
 187         ret = bus_register(&soc_bus_type);
 188         if (ret)
 189                 return ret;
 190
 191         if (early_soc_dev_attr)
 192                 return PTR_ERR(soc_device_register(early_soc_dev_attr));
 193
 194         return 0;
 195 }
 196 core_initcall(soc_bus_register);
 197
 198 static int soc_device_match_attr(const struct soc_device_attribute *attr,
 199                                  const struct soc_device_attribute *match)
 200 {
 201         if (match->machine &&
 202             (!attr->machine || !glob_match(match->machine, attr->machine)))
 203                 return 0;
 204
 205         if (match->family &&
 206             (!attr->family || !glob_match(match->family, attr->family)))
 207                 return 0;
 208
 209         if (match->revision &&
 210             (!attr->revision || !glob_match(match->revision, attr->revision)))
 211                 return 0;
 212
 213         if (match->soc_id &&
 214             (!attr->soc_id || !glob_match(match->soc_id, attr->soc_id)))
 215                 return 0;
 216
 217         return 1;
 218 }
 219
 220 static int soc_device_match_one(struct device *dev, void *arg)
 221 {
 222         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
 223
 224         return soc_device_match_attr(soc_dev->attr, arg);
 225 }
 226
 227 /*
 228  * soc_device_match - identify the SoC in the machine
 229  * @matches: zero-terminated array of possible matches
 230  *
 231  * returns the first matching entry of the argument array, or NULL
 232  * if none of them match.
 233  *
 234  * This function is meant as a helper in place of of_match_node()
 235  * in cases where either no device tree is available or the information
 236  * in a device node is insufficient to identify a particular variant
 237  * by its compatible strings or other properties. For new devices,
 238  * the DT binding should always provide unique compatible strings
 239  * that allow the use of of_match_node() instead.
 240  *
 241  * The calling function can use the .data entry of the
 242  * soc_device_attribute to pass a structure or function pointer for
 243  * each entry.
 244  */
 245 const struct soc_device_attribute *soc_device_match(
 246         const struct soc_device_attribute *matches)
 247 {
 248         int ret = 0;
 249
 250         if (!matches)
 251                 return NULL;
 252
 253         while (!ret) {
 254                 if (!(matches->machine || matches->family ||
 255                       matches->revision || matches->soc_id))
 256                         break;
 257                 ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches,
 258                                        soc_device_match_one);
 259                 if (ret < 0 && early_soc_dev_attr)
 260                         ret = soc_device_match_attr(early_soc_dev_attr,
 261                                                     matches);
 262                 if (ret < 0)
 263                         return NULL;
 264                 if (!ret)
 265                         matches++;
 266                 else
 267                         return matches;
 268         }
 269         return NULL;
 270 }
 271 EXPORT_SYMBOL_GPL(soc_device_match);