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 prior to 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); 268