drivers/acpi/glue.c

   1 /*
   2  * Link physical devices with ACPI devices support
   3  *
   4  * Copyright (c) 2005 David Shaohua Li <shaohua.li@intel.com>
   5  * Copyright (c) 2005 Intel Corp.
   6  *
   7  * This file is released under the GPLv2.
   8  */
   9 #include <linux/init.h>
  10 #include <linux/list.h>
  11 #include <linux/device.h>
  12 #include <linux/rwsem.h>
  13 #include <linux/acpi.h>
  14
  15 #define ACPI_GLUE_DEBUG 0
  16 #if ACPI_GLUE_DEBUG
  17 #define DBG(x...) printk(PREFIX x)
  18 #else
  19 #define DBG(x...)
  20 #endif
  21 static LIST_HEAD(bus_type_list);
  22 static DECLARE_RWSEM(bus_type_sem);
  23
  24 int register_acpi_bus_type(struct acpi_bus_type *type)
  25 {
  26         if (acpi_disabled)
  27                 return -ENODEV;
  28         if (type && type->bus && type->find_device) {
  29                 down_write(&bus_type_sem);
  30                 list_add_tail(&type->list, &bus_type_list);
  31                 up_write(&bus_type_sem);
  32                 printk(KERN_INFO PREFIX "bus type %s registered\n",
  33                        type->bus->name);
  34                 return 0;
  35         }
  36         return -ENODEV;
  37 }
  38
  39 EXPORT_SYMBOL(register_acpi_bus_type);
  40
  41 int unregister_acpi_bus_type(struct acpi_bus_type *type)
  42 {
  43         if (acpi_disabled)
  44                 return 0;
  45         if (type) {
  46                 down_write(&bus_type_sem);
  47                 list_del_init(&type->list);
  48                 up_write(&bus_type_sem);
  49                 printk(KERN_INFO PREFIX "ACPI bus type %s unregistered\n",
  50                        type->bus->name);
  51                 return 0;
  52         }
  53         return -ENODEV;
  54 }
  55
  56 EXPORT_SYMBOL(unregister_acpi_bus_type);
  57
  58 static struct acpi_bus_type *acpi_get_bus_type(struct bus_type *type)
  59 {
  60         struct acpi_bus_type *tmp, *ret = NULL;
  61
  62         down_read(&bus_type_sem);
  63         list_for_each_entry(tmp, &bus_type_list, list) {
  64                 if (tmp->bus == type) {
  65                         ret = tmp;
  66                         break;
  67                 }
  68         }
  69         up_read(&bus_type_sem);
  70         return ret;
  71 }
  72
  73 static int acpi_find_bridge_device(struct device *dev, acpi_handle * handle)
  74 {
  75         struct acpi_bus_type *tmp;
  76         int ret = -ENODEV;
  77
  78         down_read(&bus_type_sem);
  79         list_for_each_entry(tmp, &bus_type_list, list) {
  80                 if (tmp->find_bridge && !tmp->find_bridge(dev, handle)) {
  81                         ret = 0;
  82                         break;
  83                 }
  84         }
  85         up_read(&bus_type_sem);
  86         return ret;
  87 }
  88
  89 /* Get device's handler per its address under its parent */
  90 struct acpi_find_child {
  91         acpi_handle handle;
  92         acpi_integer address;
  93 };
  94
  95 static acpi_status
  96 do_acpi_find_child(acpi_handle handle, u32 lvl, void *context, void **rv)
  97 {
  98         acpi_status status;
  99         struct acpi_device_info *info;
 100         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 101         struct acpi_find_child *find = context;
 102
 103         status = acpi_get_object_info(handle, &buffer);
 104         if (ACPI_SUCCESS(status)) {
 105                 info = buffer.pointer;
 106                 if (info->address == find->address)
 107                         find->handle = handle;
 108                 kfree(buffer.pointer);
 109         }
 110         return AE_OK;
 111 }
 112
 113 acpi_handle acpi_get_child(acpi_handle parent, acpi_integer address)
 114 {
 115         struct acpi_find_child find = { NULL, address };
 116
 117         if (!parent)
 118                 return NULL;
 119         acpi_walk_namespace(ACPI_TYPE_DEVICE, parent,
 120                             1, do_acpi_find_child, &find, NULL);
 121         return find.handle;
 122 }
 123
 124 EXPORT_SYMBOL(acpi_get_child);
 125
 126 /* Link ACPI devices with physical devices */
 127 static void acpi_glue_data_handler(acpi_handle handle,
 128                                    u32 function, void *context)
 129 {
 130         /* we provide an empty handler */
 131 }
 132
 133 /* Note: a success call will increase reference count by one */
 134 struct device *acpi_get_physical_device(acpi_handle handle)
 135 {
 136         acpi_status status;
 137         struct device *dev;
 138
 139         status = acpi_get_data(handle, acpi_glue_data_handler, (void **)&dev);
 140         if (ACPI_SUCCESS(status))
 141                 return get_device(dev);
 142         return NULL;
 143 }
 144
 145 EXPORT_SYMBOL(acpi_get_physical_device);
 146
 147 static int acpi_bind_one(struct device *dev, acpi_handle handle)
 148 {
 149         acpi_status status;
 150
 151         if (dev->archdata.acpi_handle) {
 152                 printk(KERN_WARNING PREFIX
 153                        "Drivers changed 'acpi_handle' for %s\n", dev->bus_id);
 154                 return -EINVAL;
 155         }
 156         get_device(dev);
 157         status = acpi_attach_data(handle, acpi_glue_data_handler, dev);
 158         if (ACPI_FAILURE(status)) {
 159                 put_device(dev);
 160                 return -EINVAL;
 161         }
 162         dev->archdata.acpi_handle = handle;
 163
 164         return 0;
 165 }
 166
 167 static int acpi_unbind_one(struct device *dev)
 168 {
 169         if (!dev->archdata.acpi_handle)
 170                 return 0;
 171         if (dev == acpi_get_physical_device(dev->archdata.acpi_handle)) {
 172                 /* acpi_get_physical_device increase refcnt by one */
 173                 put_device(dev);
 174                 acpi_detach_data(dev->archdata.acpi_handle,
 175                                  acpi_glue_data_handler);
 176                 dev->archdata.acpi_handle = NULL;
 177                 /* acpi_bind_one increase refcnt by one */
 178                 put_device(dev);
 179         } else {
 180                 printk(KERN_ERR PREFIX
 181                        "Oops, 'acpi_handle' corrupt for %s\n", dev->bus_id);
 182         }
 183         return 0;
 184 }
 185
 186 static int acpi_platform_notify(struct device *dev)
 187 {
 188         struct acpi_bus_type *type;
 189         acpi_handle handle;
 190         int ret = -EINVAL;
 191
 192         if (!dev->bus || !dev->parent) {
 193                 /* bridge devices genernally haven't bus or parent */
 194                 ret = acpi_find_bridge_device(dev, &handle);
 195                 goto end;
 196         }
 197         type = acpi_get_bus_type(dev->bus);
 198         if (!type) {
 199                 DBG("No ACPI bus support for %s\n", dev->bus_id);
 200                 ret = -EINVAL;
 201                 goto end;
 202         }
 203         if ((ret = type->find_device(dev, &handle)) != 0)
 204                 DBG("Can't get handler for %s\n", dev->bus_id);
 205       end:
 206         if (!ret)
 207                 acpi_bind_one(dev, handle);
 208
 209 #if ACPI_GLUE_DEBUG
 210         if (!ret) {
 211                 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 212
 213                 acpi_get_name(dev->archdata.acpi_handle,
 214                               ACPI_FULL_PATHNAME, &buffer);
 215                 DBG("Device %s -> %s\n", dev->bus_id, (char *)buffer.pointer);
 216                 kfree(buffer.pointer);
 217         } else
 218                 DBG("Device %s -> No ACPI support\n", dev->bus_id);
 219 #endif
 220
 221         return ret;
 222 }
 223
 224 static int acpi_platform_notify_remove(struct device *dev)
 225 {
 226         acpi_unbind_one(dev);
 227         return 0;
 228 }
 229
 230 static int __init init_acpi_device_notify(void)
 231 {
 232         if (acpi_disabled)
 233                 return 0;
 234         if (platform_notify || platform_notify_remove) {
 235                 printk(KERN_ERR PREFIX "Can't use platform_notify\n");
 236                 return 0;
 237         }
 238         platform_notify = acpi_platform_notify;
 239         platform_notify_remove = acpi_platform_notify_remove;
 240         return 0;
 241 }
 242
 243 arch_initcall(init_acpi_device_notify);