drivers/base/soc.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Copyright (C) ST-Ericsson SA 2011
0004  *
0005  * Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson.
0006  */
0007
0008 #include <linux/sysfs.h>
0009 #include <linux/init.h>
0010 #include <linux/stat.h>
0011 #include <linux/slab.h>
0012 #include <linux/idr.h>
0013 #include <linux/spinlock.h>
0014 #include <linux/sys_soc.h>
0015 #include <linux/err.h>
0016 #include <linux/glob.h>
0017
0018 static DEFINE_IDA(soc_ida);
0019
0020 /* Prototype to allow declarations of DEVICE_ATTR(<foo>) before soc_info_show */
0021 static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr,
0022                  char *buf);
0023
0024 struct soc_device {
0025     struct device dev;
0026     struct soc_device_attribute *attr;
0027     int soc_dev_num;
0028 };
0029
0030 static struct bus_type soc_bus_type = {
0031     .name  = "soc",
0032 };
0033
0034 static DEVICE_ATTR(machine,     0444, soc_info_show,  NULL);
0035 static DEVICE_ATTR(family,      0444, soc_info_show,  NULL);
0036 static DEVICE_ATTR(serial_number,   0444, soc_info_show,  NULL);
0037 static DEVICE_ATTR(soc_id,      0444, soc_info_show,  NULL);
0038 static DEVICE_ATTR(revision,        0444, soc_info_show,  NULL);
0039
0040 struct device *soc_device_to_device(struct soc_device *soc_dev)
0041 {
0042     return &soc_dev->dev;
0043 }
0044
0045 static umode_t soc_attribute_mode(struct kobject *kobj,
0046                 struct attribute *attr,
0047                 int index)
0048 {
0049     struct device *dev = kobj_to_dev(kobj);
0050     struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
0051
0052     if ((attr == &dev_attr_machine.attr) && soc_dev->attr->machine)
0053         return attr->mode;
0054     if ((attr == &dev_attr_family.attr) && soc_dev->attr->family)
0055         return attr->mode;
0056     if ((attr == &dev_attr_revision.attr) && soc_dev->attr->revision)
0057         return attr->mode;
0058     if ((attr == &dev_attr_serial_number.attr) && soc_dev->attr->serial_number)
0059         return attr->mode;
0060     if ((attr == &dev_attr_soc_id.attr) && soc_dev->attr->soc_id)
0061         return attr->mode;
0062
0063     /* Unknown or unfilled attribute */
0064     return 0;
0065 }
0066
0067 static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr,
0068                  char *buf)
0069 {
0070     struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
0071     const char *output;
0072
0073     if (attr == &dev_attr_machine)
0074         output = soc_dev->attr->machine;
0075     else if (attr == &dev_attr_family)
0076         output = soc_dev->attr->family;
0077     else if (attr == &dev_attr_revision)
0078         output = soc_dev->attr->revision;
0079     else if (attr == &dev_attr_serial_number)
0080         output = soc_dev->attr->serial_number;
0081     else if (attr == &dev_attr_soc_id)
0082         output = soc_dev->attr->soc_id;
0083     else
0084         return -EINVAL;
0085
0086     return sysfs_emit(buf, "%s\n", output);
0087 }
0088
0089 static struct attribute *soc_attr[] = {
0090     &dev_attr_machine.attr,
0091     &dev_attr_family.attr,
0092     &dev_attr_serial_number.attr,
0093     &dev_attr_soc_id.attr,
0094     &dev_attr_revision.attr,
0095     NULL,
0096 };
0097
0098 static const struct attribute_group soc_attr_group = {
0099     .attrs = soc_attr,
0100     .is_visible = soc_attribute_mode,
0101 };
0102
0103 static void soc_release(struct device *dev)
0104 {
0105     struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
0106
0107     ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
0108     kfree(soc_dev->dev.groups);
0109     kfree(soc_dev);
0110 }
0111
0112 static struct soc_device_attribute *early_soc_dev_attr;
0113
0114 struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
0115 {
0116     struct soc_device *soc_dev;
0117     const struct attribute_group **soc_attr_groups;
0118     int ret;
0119
0120     if (!soc_bus_type.p) {
0121         if (early_soc_dev_attr)
0122             return ERR_PTR(-EBUSY);
0123         early_soc_dev_attr = soc_dev_attr;
0124         return NULL;
0125     }
0126
0127     soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL);
0128     if (!soc_dev) {
0129         ret = -ENOMEM;
0130         goto out1;
0131     }
0132
0133     soc_attr_groups = kcalloc(3, sizeof(*soc_attr_groups), GFP_KERNEL);
0134     if (!soc_attr_groups) {
0135         ret = -ENOMEM;
0136         goto out2;
0137     }
0138     soc_attr_groups[0] = &soc_attr_group;
0139     soc_attr_groups[1] = soc_dev_attr->custom_attr_group;
0140
0141     /* Fetch a unique (reclaimable) SOC ID. */
0142     ret = ida_simple_get(&soc_ida, 0, 0, GFP_KERNEL);
0143     if (ret < 0)
0144         goto out3;
0145     soc_dev->soc_dev_num = ret;
0146
0147     soc_dev->attr = soc_dev_attr;
0148     soc_dev->dev.bus = &soc_bus_type;
0149     soc_dev->dev.groups = soc_attr_groups;
0150     soc_dev->dev.release = soc_release;
0151
0152     dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num);
0153
0154     ret = device_register(&soc_dev->dev);
0155     if (ret) {
0156         put_device(&soc_dev->dev);
0157         return ERR_PTR(ret);
0158     }
0159
0160     return soc_dev;
0161
0162 out3:
0163     kfree(soc_attr_groups);
0164 out2:
0165     kfree(soc_dev);
0166 out1:
0167     return ERR_PTR(ret);
0168 }
0169 EXPORT_SYMBOL_GPL(soc_device_register);
0170
0171 /* Ensure soc_dev->attr is freed after calling soc_device_unregister. */
0172 void soc_device_unregister(struct soc_device *soc_dev)
0173 {
0174     device_unregister(&soc_dev->dev);
0175     early_soc_dev_attr = NULL;
0176 }
0177 EXPORT_SYMBOL_GPL(soc_device_unregister);
0178
0179 static int __init soc_bus_register(void)
0180 {
0181     int ret;
0182
0183     ret = bus_register(&soc_bus_type);
0184     if (ret)
0185         return ret;
0186
0187     if (early_soc_dev_attr)
0188         return PTR_ERR(soc_device_register(early_soc_dev_attr));
0189
0190     return 0;
0191 }
0192 core_initcall(soc_bus_register);
0193
0194 static int soc_device_match_attr(const struct soc_device_attribute *attr,
0195                  const struct soc_device_attribute *match)
0196 {
0197     if (match->machine &&
0198         (!attr->machine || !glob_match(match->machine, attr->machine)))
0199         return 0;
0200
0201     if (match->family &&
0202         (!attr->family || !glob_match(match->family, attr->family)))
0203         return 0;
0204
0205     if (match->revision &&
0206         (!attr->revision || !glob_match(match->revision, attr->revision)))
0207         return 0;
0208
0209     if (match->soc_id &&
0210         (!attr->soc_id || !glob_match(match->soc_id, attr->soc_id)))
0211         return 0;
0212
0213     return 1;
0214 }
0215
0216 static int soc_device_match_one(struct device *dev, void *arg)
0217 {
0218     struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
0219
0220     return soc_device_match_attr(soc_dev->attr, arg);
0221 }
0222
0223 /*
0224  * soc_device_match - identify the SoC in the machine
0225  * @matches: zero-terminated array of possible matches
0226  *
0227  * returns the first matching entry of the argument array, or NULL
0228  * if none of them match.
0229  *
0230  * This function is meant as a helper in place of of_match_node()
0231  * in cases where either no device tree is available or the information
0232  * in a device node is insufficient to identify a particular variant
0233  * by its compatible strings or other properties. For new devices,
0234  * the DT binding should always provide unique compatible strings
0235  * that allow the use of of_match_node() instead.
0236  *
0237  * The calling function can use the .data entry of the
0238  * soc_device_attribute to pass a structure or function pointer for
0239  * each entry.
0240  */
0241 const struct soc_device_attribute *soc_device_match(
0242     const struct soc_device_attribute *matches)
0243 {
0244     int ret;
0245
0246     if (!matches)
0247         return NULL;
0248
0249     while (matches->machine || matches->family || matches->revision ||
0250            matches->soc_id) {
0251         ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches,
0252                        soc_device_match_one);
0253         if (ret < 0 && early_soc_dev_attr)
0254             ret = soc_device_match_attr(early_soc_dev_attr,
0255                             matches);
0256         if (ret < 0)
0257             return NULL;
0258         if (ret)
0259             return matches;
0260
0261         matches++;
0262     }
0263     return NULL;
0264 }
0265 EXPORT_SYMBOL_GPL(soc_device_match);