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 = container_of(kobj, struct device, 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 sprintf(buf, "%s\n", soc_dev->attr->machine); 80 if (attr == &dev_attr_family) 81 return sprintf(buf, "%s\n", soc_dev->attr->family); 82 if (attr == &dev_attr_revision) 83 return sprintf(buf, "%s\n", soc_dev->attr->revision); 84 if (attr == &dev_attr_serial_number) 85 return sprintf(buf, "%s\n", soc_dev->attr->serial_number); 86 if (attr == &dev_attr_soc_id) 87 return sprintf(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); 272