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); 283