1 /* 2 * Copyright (C) ST-Ericsson SA 2011 3 * 4 * Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson. 5 * License terms: GNU General Public License (GPL), version 2 6 */ 7 8 #include <linux/sysfs.h> 9 #include <linux/module.h> 10 #include <linux/init.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 18 static DEFINE_IDA(soc_ida); 19 static DEFINE_SPINLOCK(soc_lock); 20 21 static ssize_t soc_info_get(struct device *dev, 22 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 struct bus_type soc_bus_type = { 32 .name = "soc", 33 }; 34 35 static DEVICE_ATTR(machine, S_IRUGO, soc_info_get, NULL); 36 static DEVICE_ATTR(family, 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_soc_id.attr) 62 && (soc_dev->attr->soc_id != NULL)) 63 return attr->mode; 64 65 /* Unknown or unfilled attribute. */ 66 return 0; 67 } 68 69 static ssize_t soc_info_get(struct device *dev, 70 struct device_attribute *attr, 71 char *buf) 72 { 73 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); 74 75 if (attr == &dev_attr_machine) 76 return sprintf(buf, "%s\n", soc_dev->attr->machine); 77 if (attr == &dev_attr_family) 78 return sprintf(buf, "%s\n", soc_dev->attr->family); 79 if (attr == &dev_attr_revision) 80 return sprintf(buf, "%s\n", soc_dev->attr->revision); 81 if (attr == &dev_attr_soc_id) 82 return sprintf(buf, "%s\n", soc_dev->attr->soc_id); 83 84 return -EINVAL; 85 86 } 87 88 static struct attribute *soc_attr[] = { 89 &dev_attr_machine.attr, 90 &dev_attr_family.attr, 91 &dev_attr_soc_id.attr, 92 &dev_attr_revision.attr, 93 NULL, 94 }; 95 96 static const struct attribute_group soc_attr_group = { 97 .attrs = soc_attr, 98 .is_visible = soc_attribute_mode, 99 }; 100 101 static const struct attribute_group *soc_attr_groups[] = { 102 &soc_attr_group, 103 NULL, 104 }; 105 106 static void soc_release(struct device *dev) 107 { 108 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); 109 110 kfree(soc_dev); 111 } 112 113 struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr) 114 { 115 struct soc_device *soc_dev; 116 int ret; 117 118 soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL); 119 if (!soc_dev) { 120 ret = -ENOMEM; 121 goto out1; 122 } 123 124 /* Fetch a unique (reclaimable) SOC ID. */ 125 do { 126 if (!ida_pre_get(&soc_ida, GFP_KERNEL)) { 127 ret = -ENOMEM; 128 goto out2; 129 } 130 131 spin_lock(&soc_lock); 132 ret = ida_get_new(&soc_ida, &soc_dev->soc_dev_num); 133 spin_unlock(&soc_lock); 134 135 } while (ret == -EAGAIN); 136 137 if (ret) 138 goto out2; 139 140 soc_dev->attr = soc_dev_attr; 141 soc_dev->dev.bus = &soc_bus_type; 142 soc_dev->dev.groups = soc_attr_groups; 143 soc_dev->dev.release = soc_release; 144 145 dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num); 146 147 ret = device_register(&soc_dev->dev); 148 if (ret) 149 goto out3; 150 151 return soc_dev; 152 153 out3: 154 ida_remove(&soc_ida, soc_dev->soc_dev_num); 155 out2: 156 kfree(soc_dev); 157 out1: 158 return ERR_PTR(ret); 159 } 160 161 /* Ensure soc_dev->attr is freed prior to calling soc_device_unregister. */ 162 void soc_device_unregister(struct soc_device *soc_dev) 163 { 164 ida_remove(&soc_ida, soc_dev->soc_dev_num); 165 166 device_unregister(&soc_dev->dev); 167 } 168 169 static int __init soc_bus_register(void) 170 { 171 return bus_register(&soc_bus_type); 172 } 173 core_initcall(soc_bus_register); 174 175 static void __exit soc_bus_unregister(void) 176 { 177 ida_destroy(&soc_ida); 178 179 bus_unregister(&soc_bus_type); 180 } 181 module_exit(soc_bus_unregister); 182