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/of.h>
  11 #include <linux/stat.h>
  12 #include <linux/slab.h>
  13 #include <linux/idr.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/sys_soc.h>
  16 #include <linux/err.h>
  17 #include <linux/glob.h>
  18
  19 static DEFINE_IDA(soc_ida);
  20
  21 /* Prototype to allow declarations of DEVICE_ATTR(<foo>) before soc_info_show */
  22 static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr,
  23                              char *buf);
  24
  25 struct soc_device {
  26         struct device dev;
  27         struct soc_device_attribute *attr;
  28         int soc_dev_num;
  29 };
  30
  31 static const struct bus_type soc_bus_type = {
  32         .name  = "soc",
  33 };
  34 static bool soc_bus_registered;
  35
  36 static DEVICE_ATTR(machine,             0444, soc_info_show,  NULL);
  37 static DEVICE_ATTR(family,              0444, soc_info_show,  NULL);
  38 static DEVICE_ATTR(serial_number,       0444, soc_info_show,  NULL);
  39 static DEVICE_ATTR(soc_id,              0444, soc_info_show,  NULL);
  40 static DEVICE_ATTR(revision,            0444, soc_info_show,  NULL);
  41
  42 struct device *soc_device_to_device(struct soc_device *soc_dev)
  43 {
  44         return &soc_dev->dev;
  45 }
  46
  47 static umode_t soc_attribute_mode(struct kobject *kobj,
  48                                 struct attribute *attr,
  49                                 int index)
  50 {
  51         struct device *dev = kobj_to_dev(kobj);
  52         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
  53
  54         if ((attr == &dev_attr_machine.attr) && soc_dev->attr->machine)
  55                 return attr->mode;
  56         if ((attr == &dev_attr_family.attr) && soc_dev->attr->family)
  57                 return attr->mode;
  58         if ((attr == &dev_attr_revision.attr) && soc_dev->attr->revision)
  59                 return attr->mode;
  60         if ((attr == &dev_attr_serial_number.attr) && soc_dev->attr->serial_number)
  61                 return attr->mode;
  62         if ((attr == &dev_attr_soc_id.attr) && soc_dev->attr->soc_id)
  63                 return attr->mode;
  64
  65         /* Unknown or unfilled attribute */
  66         return 0;
  67 }
  68
  69 static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr,
  70                              char *buf)
  71 {
  72         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
  73         const char *output;
  74
  75         if (attr == &dev_attr_machine)
  76                 output = soc_dev->attr->machine;
  77         else if (attr == &dev_attr_family)
  78                 output = soc_dev->attr->family;
  79         else if (attr == &dev_attr_revision)
  80                 output = soc_dev->attr->revision;
  81         else if (attr == &dev_attr_serial_number)
  82                 output = soc_dev->attr->serial_number;
  83         else if (attr == &dev_attr_soc_id)
  84                 output = soc_dev->attr->soc_id;
  85         else
  86                 return -EINVAL;
  87
  88         return sysfs_emit(buf, "%s\n", output);
  89 }
  90
  91 static struct attribute *soc_attr[] = {
  92         &dev_attr_machine.attr,
  93         &dev_attr_family.attr,
  94         &dev_attr_serial_number.attr,
  95         &dev_attr_soc_id.attr,
  96         &dev_attr_revision.attr,
  97         NULL,
  98 };
  99
 100 static const struct attribute_group soc_attr_group = {
 101         .attrs = soc_attr,
 102         .is_visible = soc_attribute_mode,
 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         ida_free(&soc_ida, soc_dev->soc_dev_num);
 110         kfree(soc_dev->dev.groups);
 111         kfree(soc_dev);
 112 }
 113
 114 static void soc_device_get_machine(struct soc_device_attribute *soc_dev_attr)
 115 {
 116         struct device_node *np;
 117
 118         if (soc_dev_attr->machine)
 119                 return;
 120
 121         np = of_find_node_by_path("/");
 122         of_property_read_string(np, "model", &soc_dev_attr->machine);
 123         of_node_put(np);
 124 }
 125
 126 static struct soc_device_attribute *early_soc_dev_attr;
 127
 128 struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
 129 {
 130         struct soc_device *soc_dev;
 131         const struct attribute_group **soc_attr_groups;
 132         int ret;
 133
 134         soc_device_get_machine(soc_dev_attr);
 135
 136         if (!soc_bus_registered) {
 137                 if (early_soc_dev_attr)
 138                         return ERR_PTR(-EBUSY);
 139                 early_soc_dev_attr = soc_dev_attr;
 140                 return NULL;
 141         }
 142
 143         soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL);
 144         if (!soc_dev) {
 145                 ret = -ENOMEM;
 146                 goto out1;
 147         }
 148
 149         soc_attr_groups = kcalloc(3, sizeof(*soc_attr_groups), GFP_KERNEL);
 150         if (!soc_attr_groups) {
 151                 ret = -ENOMEM;
 152                 goto out2;
 153         }
 154         soc_attr_groups[0] = &soc_attr_group;
 155         soc_attr_groups[1] = soc_dev_attr->custom_attr_group;
 156
 157         /* Fetch a unique (reclaimable) SOC ID. */
 158         ret = ida_alloc(&soc_ida, GFP_KERNEL);
 159         if (ret < 0)
 160                 goto out3;
 161         soc_dev->soc_dev_num = ret;
 162
 163         soc_dev->attr = soc_dev_attr;
 164         soc_dev->dev.bus = &soc_bus_type;
 165         soc_dev->dev.groups = soc_attr_groups;
 166         soc_dev->dev.release = soc_release;
 167
 168         dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num);
 169
 170         ret = device_register(&soc_dev->dev);
 171         if (ret) {
 172                 put_device(&soc_dev->dev);
 173                 return ERR_PTR(ret);
 174         }
 175
 176         return soc_dev;
 177
 178 out3:
 179         kfree(soc_attr_groups);
 180 out2:
 181         kfree(soc_dev);
 182 out1:
 183         return ERR_PTR(ret);
 184 }
 185 EXPORT_SYMBOL_GPL(soc_device_register);
 186
 187 /* Ensure soc_dev->attr is freed after calling soc_device_unregister. */
 188 void soc_device_unregister(struct soc_device *soc_dev)
 189 {
 190         device_unregister(&soc_dev->dev);
 191         early_soc_dev_attr = NULL;
 192 }
 193 EXPORT_SYMBOL_GPL(soc_device_unregister);
 194
 195 static int __init soc_bus_register(void)
 196 {
 197         int ret;
 198
 199         ret = bus_register(&soc_bus_type);
 200         if (ret)
 201                 return ret;
 202         soc_bus_registered = true;
 203
 204         if (early_soc_dev_attr)
 205                 return PTR_ERR(soc_device_register(early_soc_dev_attr));
 206
 207         return 0;
 208 }
 209 core_initcall(soc_bus_register);
 210
 211 static int soc_device_match_attr(const struct soc_device_attribute *attr,
 212                                  const struct soc_device_attribute *match)
 213 {
 214         if (match->machine &&
 215             (!attr->machine || !glob_match(match->machine, attr->machine)))
 216                 return 0;
 217
 218         if (match->family &&
 219             (!attr->family || !glob_match(match->family, attr->family)))
 220                 return 0;
 221
 222         if (match->revision &&
 223             (!attr->revision || !glob_match(match->revision, attr->revision)))
 224                 return 0;
 225
 226         if (match->soc_id &&
 227             (!attr->soc_id || !glob_match(match->soc_id, attr->soc_id)))
 228                 return 0;
 229
 230         return 1;
 231 }
 232
 233 static int soc_device_match_one(struct device *dev, void *arg)
 234 {
 235         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
 236
 237         return soc_device_match_attr(soc_dev->attr, arg);
 238 }
 239
 240 /*
 241  * soc_device_match - identify the SoC in the machine
 242  * @matches: zero-terminated array of possible matches
 243  *
 244  * returns the first matching entry of the argument array, or NULL
 245  * if none of them match.
 246  *
 247  * This function is meant as a helper in place of of_match_node()
 248  * in cases where either no device tree is available or the information
 249  * in a device node is insufficient to identify a particular variant
 250  * by its compatible strings or other properties. For new devices,
 251  * the DT binding should always provide unique compatible strings
 252  * that allow the use of of_match_node() instead.
 253  *
 254  * The calling function can use the .data entry of the
 255  * soc_device_attribute to pass a structure or function pointer for
 256  * each entry.
 257  */
 258 const struct soc_device_attribute *soc_device_match(
 259         const struct soc_device_attribute *matches)
 260 {
 261         int ret;
 262
 263         if (!matches)
 264                 return NULL;
 265
 266         while (matches->machine || matches->family || matches->revision ||
 267                matches->soc_id) {
 268                 ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches,
 269                                        soc_device_match_one);
 270                 if (ret < 0 && early_soc_dev_attr)
 271                         ret = soc_device_match_attr(early_soc_dev_attr,
 272                                                     matches);
 273                 if (ret < 0)
 274                         return NULL;
 275                 if (ret)
 276                         return matches;
 277
 278                 matches++;
 279         }
 280         return NULL;
 281 }
 282 EXPORT_SYMBOL_GPL(soc_device_match);