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 static bool soc_bus_registered; 34 35 static DEVICE_ATTR(machine, 0444, soc_info_show, NULL); 36 static DEVICE_ATTR(family, 0444, soc_info_show, NULL); 37 static DEVICE_ATTR(serial_number, 0444, soc_info_show, NULL); 38 static DEVICE_ATTR(soc_id, 0444, soc_info_show, NULL); 39 static DEVICE_ATTR(revision, 0444, soc_info_show, NULL); 40 41 struct device *soc_device_to_device(struct soc_device *soc_dev) 42 { 43 return &soc_dev->dev; 44 } 45 46 static umode_t soc_attribute_mode(struct kobject *kobj, 47 struct attribute *attr, 48 int index) 49 { 50 struct device *dev = kobj_to_dev(kobj); 51 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); 52 53 if ((attr == &dev_attr_machine.attr) && soc_dev->attr->machine) 54 return attr->mode; 55 if ((attr == &dev_attr_family.attr) && soc_dev->attr->family) 56 return attr->mode; 57 if ((attr == &dev_attr_revision.attr) && soc_dev->attr->revision) 58 return attr->mode; 59 if ((attr == &dev_attr_serial_number.attr) && soc_dev->attr->serial_number) 60 return attr->mode; 61 if ((attr == &dev_attr_soc_id.attr) && soc_dev->attr->soc_id) 62 return attr->mode; 63 64 /* Unknown or unfilled attribute */ 65 return 0; 66 } 67 68 static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr, 69 char *buf) 70 { 71 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); 72 const char *output; 73 74 if (attr == &dev_attr_machine) 75 output = soc_dev->attr->machine; 76 else if (attr == &dev_attr_family) 77 output = soc_dev->attr->family; 78 else if (attr == &dev_attr_revision) 79 output = soc_dev->attr->revision; 80 else if (attr == &dev_attr_serial_number) 81 output = soc_dev->attr->serial_number; 82 else if (attr == &dev_attr_soc_id) 83 output = soc_dev->attr->soc_id; 84 else 85 return -EINVAL; 86 87 return sysfs_emit(buf, "%s\n", output); 88 } 89 90 static struct attribute *soc_attr[] = { 91 &dev_attr_machine.attr, 92 &dev_attr_family.attr, 93 &dev_attr_serial_number.attr, 94 &dev_attr_soc_id.attr, 95 &dev_attr_revision.attr, 96 NULL, 97 }; 98 99 static const struct attribute_group soc_attr_group = { 100 .attrs = soc_attr, 101 .is_visible = soc_attribute_mode, 102 }; 103 104 static void soc_release(struct device *dev) 105 { 106 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); 107 108 ida_simple_remove(&soc_ida, soc_dev->soc_dev_num); 109 kfree(soc_dev->dev.groups); 110 kfree(soc_dev); 111 } 112 113 static struct soc_device_attribute *early_soc_dev_attr; 114 115 struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr) 116 { 117 struct soc_device *soc_dev; 118 const struct attribute_group **soc_attr_groups; 119 int ret; 120 121 if (!soc_bus_registered) { 122 if (early_soc_dev_attr) 123 return ERR_PTR(-EBUSY); 124 early_soc_dev_attr = soc_dev_attr; 125 return NULL; 126 } 127 128 soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL); 129 if (!soc_dev) { 130 ret = -ENOMEM; 131 goto out1; 132 } 133 134 soc_attr_groups = kcalloc(3, sizeof(*soc_attr_groups), GFP_KERNEL); 135 if (!soc_attr_groups) { 136 ret = -ENOMEM; 137 goto out2; 138 } 139 soc_attr_groups[0] = &soc_attr_group; 140 soc_attr_groups[1] = soc_dev_attr->custom_attr_group; 141 142 /* Fetch a unique (reclaimable) SOC ID. */ 143 ret = ida_simple_get(&soc_ida, 0, 0, GFP_KERNEL); 144 if (ret < 0) 145 goto out3; 146 soc_dev->soc_dev_num = ret; 147 148 soc_dev->attr = soc_dev_attr; 149 soc_dev->dev.bus = &soc_bus_type; 150 soc_dev->dev.groups = soc_attr_groups; 151 soc_dev->dev.release = soc_release; 152 153 dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num); 154 155 ret = device_register(&soc_dev->dev); 156 if (ret) { 157 put_device(&soc_dev->dev); 158 return ERR_PTR(ret); 159 } 160 161 return soc_dev; 162 163 out3: 164 kfree(soc_attr_groups); 165 out2: 166 kfree(soc_dev); 167 out1: 168 return ERR_PTR(ret); 169 } 170 EXPORT_SYMBOL_GPL(soc_device_register); 171 172 /* Ensure soc_dev->attr is freed after calling soc_device_unregister. */ 173 void soc_device_unregister(struct soc_device *soc_dev) 174 { 175 device_unregister(&soc_dev->dev); 176 early_soc_dev_attr = NULL; 177 } 178 EXPORT_SYMBOL_GPL(soc_device_unregister); 179 180 static int __init soc_bus_register(void) 181 { 182 int ret; 183 184 ret = bus_register(&soc_bus_type); 185 if (ret) 186 return ret; 187 soc_bus_registered = true; 188 189 if (early_soc_dev_attr) 190 return PTR_ERR(soc_device_register(early_soc_dev_attr)); 191 192 return 0; 193 } 194 core_initcall(soc_bus_register); 195 196 static int soc_device_match_attr(const struct soc_device_attribute *attr, 197 const struct soc_device_attribute *match) 198 { 199 if (match->machine && 200 (!attr->machine || !glob_match(match->machine, attr->machine))) 201 return 0; 202 203 if (match->family && 204 (!attr->family || !glob_match(match->family, attr->family))) 205 return 0; 206 207 if (match->revision && 208 (!attr->revision || !glob_match(match->revision, attr->revision))) 209 return 0; 210 211 if (match->soc_id && 212 (!attr->soc_id || !glob_match(match->soc_id, attr->soc_id))) 213 return 0; 214 215 return 1; 216 } 217 218 static int soc_device_match_one(struct device *dev, void *arg) 219 { 220 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); 221 222 return soc_device_match_attr(soc_dev->attr, arg); 223 } 224 225 /* 226 * soc_device_match - identify the SoC in the machine 227 * @matches: zero-terminated array of possible matches 228 * 229 * returns the first matching entry of the argument array, or NULL 230 * if none of them match. 231 * 232 * This function is meant as a helper in place of of_match_node() 233 * in cases where either no device tree is available or the information 234 * in a device node is insufficient to identify a particular variant 235 * by its compatible strings or other properties. For new devices, 236 * the DT binding should always provide unique compatible strings 237 * that allow the use of of_match_node() instead. 238 * 239 * The calling function can use the .data entry of the 240 * soc_device_attribute to pass a structure or function pointer for 241 * each entry. 242 */ 243 const struct soc_device_attribute *soc_device_match( 244 const struct soc_device_attribute *matches) 245 { 246 int ret; 247 248 if (!matches) 249 return NULL; 250 251 while (matches->machine || matches->family || matches->revision || 252 matches->soc_id) { 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 return matches; 262 263 matches++; 264 } 265 return NULL; 266 } 267 EXPORT_SYMBOL_GPL(soc_device_match); 268