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 /* Prototype to allow declarations of DEVICE_ATTR(<foo>) before soc_info_show */
  21 static ssize_t soc_info_show(struct device *dev, 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,             0444, soc_info_show,  NULL);
  35 static DEVICE_ATTR(family,              0444, soc_info_show,  NULL);
  36 static DEVICE_ATTR(serial_number,       0444, soc_info_show,  NULL);
  37 static DEVICE_ATTR(soc_id,              0444, soc_info_show,  NULL);
  38 static DEVICE_ATTR(revision,            0444, soc_info_show,  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) && soc_dev->attr->machine)
  53                 return attr->mode;
  54         if ((attr == &dev_attr_family.attr) && soc_dev->attr->family)
  55                 return attr->mode;
  56         if ((attr == &dev_attr_revision.attr) && soc_dev->attr->revision)
  57                 return attr->mode;
  58         if ((attr == &dev_attr_serial_number.attr) && soc_dev->attr->serial_number)
  59                 return attr->mode;
  60         if ((attr == &dev_attr_soc_id.attr) && soc_dev->attr->soc_id)
  61                 return attr->mode;
  62
  63         /* Unknown or unfilled attribute */
  64         return 0;
  65 }
  66
  67 static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr,
  68                              char *buf)
  69 {
  70         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
  71         const char *output;
  72
  73         if (attr == &dev_attr_machine)
  74                 output = soc_dev->attr->machine;
  75         else if (attr == &dev_attr_family)
  76                 output = soc_dev->attr->family;
  77         else if (attr == &dev_attr_revision)
  78                 output = soc_dev->attr->revision;
  79         else if (attr == &dev_attr_serial_number)
  80                 output = soc_dev->attr->serial_number;
  81         else if (attr == &dev_attr_soc_id)
  82                 output = soc_dev->attr->soc_id;
  83         else
  84                 return -EINVAL;
  85
  86         return sysfs_emit(buf, "%s\n", output);
  87 }
  88
  89 static struct attribute *soc_attr[] = {
  90         &dev_attr_machine.attr,
  91         &dev_attr_family.attr,
  92         &dev_attr_serial_number.attr,
  93         &dev_attr_soc_id.attr,
  94         &dev_attr_revision.attr,
  95         NULL,
  96 };
  97
  98 static const struct attribute_group soc_attr_group = {
  99         .attrs = soc_attr,
 100         .is_visible = soc_attribute_mode,
 101 };
 102
 103 static void soc_release(struct device *dev)
 104 {
 105         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
 106
 107         ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
 108         kfree(soc_dev->dev.groups);
 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         const struct attribute_group **soc_attr_groups;
 118         int ret;
 119
 120         if (!soc_bus_type.p) {
 121                 if (early_soc_dev_attr)
 122                         return ERR_PTR(-EBUSY);
 123                 early_soc_dev_attr = soc_dev_attr;
 124                 return NULL;
 125         }
 126
 127         soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL);
 128         if (!soc_dev) {
 129                 ret = -ENOMEM;
 130                 goto out1;
 131         }
 132
 133         soc_attr_groups = kcalloc(3, sizeof(*soc_attr_groups), GFP_KERNEL);
 134         if (!soc_attr_groups) {
 135                 ret = -ENOMEM;
 136                 goto out2;
 137         }
 138         soc_attr_groups[0] = &soc_attr_group;
 139         soc_attr_groups[1] = soc_dev_attr->custom_attr_group;
 140
 141         /* Fetch a unique (reclaimable) SOC ID. */
 142         ret = ida_simple_get(&soc_ida, 0, 0, GFP_KERNEL);
 143         if (ret < 0)
 144                 goto out3;
 145         soc_dev->soc_dev_num = ret;
 146
 147         soc_dev->attr = soc_dev_attr;
 148         soc_dev->dev.bus = &soc_bus_type;
 149         soc_dev->dev.groups = soc_attr_groups;
 150         soc_dev->dev.release = soc_release;
 151
 152         dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num);
 153
 154         ret = device_register(&soc_dev->dev);
 155         if (ret) {
 156                 put_device(&soc_dev->dev);
 157                 return ERR_PTR(ret);
 158         }
 159
 160         return soc_dev;
 161
 162 out3:
 163         kfree(soc_attr_groups);
 164 out2:
 165         kfree(soc_dev);
 166 out1:
 167         return ERR_PTR(ret);
 168 }
 169 EXPORT_SYMBOL_GPL(soc_device_register);
 170
 171 /* Ensure soc_dev->attr is freed after calling soc_device_unregister. */
 172 void soc_device_unregister(struct soc_device *soc_dev)
 173 {
 174         device_unregister(&soc_dev->dev);
 175         early_soc_dev_attr = NULL;
 176 }
 177 EXPORT_SYMBOL_GPL(soc_device_unregister);
 178
 179 static int __init soc_bus_register(void)
 180 {
 181         int ret;
 182
 183         ret = bus_register(&soc_bus_type);
 184         if (ret)
 185                 return ret;
 186
 187         if (early_soc_dev_attr)
 188                 return PTR_ERR(soc_device_register(early_soc_dev_attr));
 189
 190         return 0;
 191 }
 192 core_initcall(soc_bus_register);
 193
 194 static int soc_device_match_attr(const struct soc_device_attribute *attr,
 195                                  const struct soc_device_attribute *match)
 196 {
 197         if (match->machine &&
 198             (!attr->machine || !glob_match(match->machine, attr->machine)))
 199                 return 0;
 200
 201         if (match->family &&
 202             (!attr->family || !glob_match(match->family, attr->family)))
 203                 return 0;
 204
 205         if (match->revision &&
 206             (!attr->revision || !glob_match(match->revision, attr->revision)))
 207                 return 0;
 208
 209         if (match->soc_id &&
 210             (!attr->soc_id || !glob_match(match->soc_id, attr->soc_id)))
 211                 return 0;
 212
 213         return 1;
 214 }
 215
 216 static int soc_device_match_one(struct device *dev, void *arg)
 217 {
 218         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
 219
 220         return soc_device_match_attr(soc_dev->attr, arg);
 221 }
 222
 223 /*
 224  * soc_device_match - identify the SoC in the machine
 225  * @matches: zero-terminated array of possible matches
 226  *
 227  * returns the first matching entry of the argument array, or NULL
 228  * if none of them match.
 229  *
 230  * This function is meant as a helper in place of of_match_node()
 231  * in cases where either no device tree is available or the information
 232  * in a device node is insufficient to identify a particular variant
 233  * by its compatible strings or other properties. For new devices,
 234  * the DT binding should always provide unique compatible strings
 235  * that allow the use of of_match_node() instead.
 236  *
 237  * The calling function can use the .data entry of the
 238  * soc_device_attribute to pass a structure or function pointer for
 239  * each entry.
 240  */
 241 const struct soc_device_attribute *soc_device_match(
 242         const struct soc_device_attribute *matches)
 243 {
 244         int ret = 0;
 245
 246         if (!matches)
 247                 return NULL;
 248
 249         while (!ret) {
 250                 if (!(matches->machine || matches->family ||
 251                       matches->revision || matches->soc_id))
 252                         break;
 253                 ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches,
 254                                        soc_device_match_one);
 255                 if (ret < 0 && early_soc_dev_attr)
 256                         ret = soc_device_match_attr(early_soc_dev_attr,
 257                                                     matches);
 258                 if (ret < 0)
 259                         return NULL;
 260                 if (!ret)
 261                         matches++;
 262                 else
 263                         return matches;
 264         }
 265         return NULL;
 266 }
 267 EXPORT_SYMBOL_GPL(soc_device_match);