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(soc_id, S_IRUGO, soc_info_get, NULL); 37 static DEVICE_ATTR(revision, S_IRUGO, soc_info_get, NULL); 38 39 struct device *soc_device_to_device(struct soc_device *soc_dev) 40 { 41 return &soc_dev->dev; 42 } 43 44 static umode_t soc_attribute_mode(struct kobject *kobj, 45 struct attribute *attr, 46 int index) 47 { 48 struct device *dev = container_of(kobj, struct device, kobj); 49 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); 50 51 if ((attr == &dev_attr_machine.attr) 52 && (soc_dev->attr->machine != NULL)) 53 return attr->mode; 54 if ((attr == &dev_attr_family.attr) 55 && (soc_dev->attr->family != NULL)) 56 return attr->mode; 57 if ((attr == &dev_attr_revision.attr) 58 && (soc_dev->attr->revision != NULL)) 59 return attr->mode; 60 if ((attr == &dev_attr_soc_id.attr) 61 && (soc_dev->attr->soc_id != NULL)) 62 return attr->mode; 63 64 /* Unknown or unfilled attribute. */ 65 return 0; 66 } 67 68 static ssize_t soc_info_get(struct device *dev, 69 struct device_attribute *attr, 70 char *buf) 71 { 72 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); 73 74 if (attr == &dev_attr_machine) 75 return sprintf(buf, "%s\n", soc_dev->attr->machine); 76 if (attr == &dev_attr_family) 77 return sprintf(buf, "%s\n", soc_dev->attr->family); 78 if (attr == &dev_attr_revision) 79 return sprintf(buf, "%s\n", soc_dev->attr->revision); 80 if (attr == &dev_attr_soc_id) 81 return sprintf(buf, "%s\n", soc_dev->attr->soc_id); 82 83 return -EINVAL; 84 85 } 86 87 static struct attribute *soc_attr[] = { 88 &dev_attr_machine.attr, 89 &dev_attr_family.attr, 90 &dev_attr_soc_id.attr, 91 &dev_attr_revision.attr, 92 NULL, 93 }; 94 95 static const struct attribute_group soc_attr_group = { 96 .attrs = soc_attr, 97 .is_visible = soc_attribute_mode, 98 }; 99 100 static const struct attribute_group *soc_attr_groups[] = { 101 &soc_attr_group, 102 NULL, 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 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 int ret; 118 119 if (!soc_bus_type.p) { 120 if (early_soc_dev_attr) 121 return ERR_PTR(-EBUSY); 122 early_soc_dev_attr = soc_dev_attr; 123 return NULL; 124 } 125 126 soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL); 127 if (!soc_dev) { 128 ret = -ENOMEM; 129 goto out1; 130 } 131 132 /* Fetch a unique (reclaimable) SOC ID. */ 133 ret = ida_simple_get(&soc_ida, 0, 0, GFP_KERNEL); 134 if (ret < 0) 135 goto out2; 136 soc_dev->soc_dev_num = ret; 137 138 soc_dev->attr = soc_dev_attr; 139 soc_dev->dev.bus = &soc_bus_type; 140 soc_dev->dev.groups = soc_attr_groups; 141 soc_dev->dev.release = soc_release; 142 143 dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num); 144 145 ret = device_register(&soc_dev->dev); 146 if (ret) 147 goto out3; 148 149 return soc_dev; 150 151 out3: 152 ida_simple_remove(&soc_ida, soc_dev->soc_dev_num); 153 out2: 154 kfree(soc_dev); 155 out1: 156 return ERR_PTR(ret); 157 } 158 159 /* Ensure soc_dev->attr is freed prior to calling soc_device_unregister. */ 160 void soc_device_unregister(struct soc_device *soc_dev) 161 { 162 ida_simple_remove(&soc_ida, soc_dev->soc_dev_num); 163 164 device_unregister(&soc_dev->dev); 165 early_soc_dev_attr = NULL; 166 } 167 168 static int __init soc_bus_register(void) 169 { 170 int ret; 171 172 ret = bus_register(&soc_bus_type); 173 if (ret) 174 return ret; 175 176 if (early_soc_dev_attr) 177 return PTR_ERR(soc_device_register(early_soc_dev_attr)); 178 179 return 0; 180 } 181 core_initcall(soc_bus_register); 182 183 static int soc_device_match_attr(const struct soc_device_attribute *attr, 184 const struct soc_device_attribute *match) 185 { 186 if (match->machine && 187 (!attr->machine || !glob_match(match->machine, attr->machine))) 188 return 0; 189 190 if (match->family && 191 (!attr->family || !glob_match(match->family, attr->family))) 192 return 0; 193 194 if (match->revision && 195 (!attr->revision || !glob_match(match->revision, attr->revision))) 196 return 0; 197 198 if (match->soc_id && 199 (!attr->soc_id || !glob_match(match->soc_id, attr->soc_id))) 200 return 0; 201 202 return 1; 203 } 204 205 static int soc_device_match_one(struct device *dev, void *arg) 206 { 207 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); 208 209 return soc_device_match_attr(soc_dev->attr, arg); 210 } 211 212 /* 213 * soc_device_match - identify the SoC in the machine 214 * @matches: zero-terminated array of possible matches 215 * 216 * returns the first matching entry of the argument array, or NULL 217 * if none of them match. 218 * 219 * This function is meant as a helper in place of of_match_node() 220 * in cases where either no device tree is available or the information 221 * in a device node is insufficient to identify a particular variant 222 * by its compatible strings or other properties. For new devices, 223 * the DT binding should always provide unique compatible strings 224 * that allow the use of of_match_node() instead. 225 * 226 * The calling function can use the .data entry of the 227 * soc_device_attribute to pass a structure or function pointer for 228 * each entry. 229 */ 230 const struct soc_device_attribute *soc_device_match( 231 const struct soc_device_attribute *matches) 232 { 233 int ret = 0; 234 235 if (!matches) 236 return NULL; 237 238 while (!ret) { 239 if (!(matches->machine || matches->family || 240 matches->revision || matches->soc_id)) 241 break; 242 ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches, 243 soc_device_match_one); 244 if (ret < 0 && early_soc_dev_attr) 245 ret = soc_device_match_attr(early_soc_dev_attr, 246 matches); 247 if (ret < 0) 248 return NULL; 249 if (!ret) 250 matches++; 251 else 252 return matches; 253 } 254 return NULL; 255 } 256 EXPORT_SYMBOL_GPL(soc_device_match); 257