drivers/acpi/event.c

   1 /*
   2  * event.c - exporting ACPI events via procfs
   3  *
   4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   6  *
   7  */
   8
   9 #include <linux/spinlock.h>
  10 #include <linux/proc_fs.h>
  11 #include <linux/init.h>
  12 #include <linux/poll.h>
  13 #include <acpi/acpi_drivers.h>
  14 #include <net/netlink.h>
  15 #include <net/genetlink.h>
  16
  17 #define _COMPONENT              ACPI_SYSTEM_COMPONENT
  18 ACPI_MODULE_NAME("event");
  19
  20 #ifdef CONFIG_ACPI_PROC_EVENT
  21 /* Global vars for handling event proc entry */
  22 static DEFINE_SPINLOCK(acpi_system_event_lock);
  23 int event_is_open = 0;
  24 extern struct list_head acpi_bus_event_list;
  25 extern wait_queue_head_t acpi_bus_event_queue;
  26
  27 static int acpi_system_open_event(struct inode *inode, struct file *file)
  28 {
  29         spin_lock_irq(&acpi_system_event_lock);
  30
  31         if (event_is_open)
  32                 goto out_busy;
  33
  34         event_is_open = 1;
  35
  36         spin_unlock_irq(&acpi_system_event_lock);
  37         return 0;
  38
  39       out_busy:
  40         spin_unlock_irq(&acpi_system_event_lock);
  41         return -EBUSY;
  42 }
  43
  44 static ssize_t
  45 acpi_system_read_event(struct file *file, char __user * buffer, size_t count,
  46                        loff_t * ppos)
  47 {
  48         int result = 0;
  49         struct acpi_bus_event event;
  50         static char str[ACPI_MAX_STRING];
  51         static int chars_remaining = 0;
  52         static char *ptr;
  53
  54         if (!chars_remaining) {
  55                 memset(&event, 0, sizeof(struct acpi_bus_event));
  56
  57                 if ((file->f_flags & O_NONBLOCK)
  58                     && (list_empty(&acpi_bus_event_list)))
  59                         return -EAGAIN;
  60
  61                 result = acpi_bus_receive_event(&event);
  62                 if (result)
  63                         return result;
  64
  65                 chars_remaining = sprintf(str, "%s %s %08x %08x\n",
  66                                           event.device_class ? event.
  67                                           device_class : "<unknown>",
  68                                           event.bus_id ? event.
  69                                           bus_id : "<unknown>", event.type,
  70                                           event.data);
  71                 ptr = str;
  72         }
  73
  74         if (chars_remaining < count) {
  75                 count = chars_remaining;
  76         }
  77
  78         if (copy_to_user(buffer, ptr, count))
  79                 return -EFAULT;
  80
  81         *ppos += count;
  82         chars_remaining -= count;
  83         ptr += count;
  84
  85         return count;
  86 }
  87
  88 static int acpi_system_close_event(struct inode *inode, struct file *file)
  89 {
  90         spin_lock_irq(&acpi_system_event_lock);
  91         event_is_open = 0;
  92         spin_unlock_irq(&acpi_system_event_lock);
  93         return 0;
  94 }
  95
  96 static unsigned int acpi_system_poll_event(struct file *file, poll_table * wait)
  97 {
  98         poll_wait(file, &acpi_bus_event_queue, wait);
  99         if (!list_empty(&acpi_bus_event_list))
 100                 return POLLIN | POLLRDNORM;
 101         return 0;
 102 }
 103
 104 static const struct file_operations acpi_system_event_ops = {
 105         .owner = THIS_MODULE,
 106         .open = acpi_system_open_event,
 107         .read = acpi_system_read_event,
 108         .release = acpi_system_close_event,
 109         .poll = acpi_system_poll_event,
 110 };
 111 #endif  /* CONFIG_ACPI_PROC_EVENT */
 112
 113 /* ACPI notifier chain */
 114 static BLOCKING_NOTIFIER_HEAD(acpi_chain_head);
 115
 116 int acpi_notifier_call_chain(struct acpi_device *dev, u32 type, u32 data)
 117 {
 118         struct acpi_bus_event event;
 119
 120         strcpy(event.device_class, dev->pnp.device_class);
 121         strcpy(event.bus_id, dev->pnp.bus_id);
 122         event.type = type;
 123         event.data = data;
 124         return (blocking_notifier_call_chain(&acpi_chain_head, 0, (void *)&event)
 125                         == NOTIFY_BAD) ? -EINVAL : 0;
 126 }
 127 EXPORT_SYMBOL(acpi_notifier_call_chain);
 128
 129 int register_acpi_notifier(struct notifier_block *nb)
 130 {
 131         return blocking_notifier_chain_register(&acpi_chain_head, nb);
 132 }
 133 EXPORT_SYMBOL(register_acpi_notifier);
 134
 135 int unregister_acpi_notifier(struct notifier_block *nb)
 136 {
 137         return blocking_notifier_chain_unregister(&acpi_chain_head, nb);
 138 }
 139 EXPORT_SYMBOL(unregister_acpi_notifier);
 140
 141 #ifdef CONFIG_NET
 142 static unsigned int acpi_event_seqnum;
 143 struct acpi_genl_event {
 144         acpi_device_class device_class;
 145         char bus_id[15];
 146         u32 type;
 147         u32 data;
 148 };
 149
 150 /* attributes of acpi_genl_family */
 151 enum {
 152         ACPI_GENL_ATTR_UNSPEC,
 153         ACPI_GENL_ATTR_EVENT,   /* ACPI event info needed by user space */
 154         __ACPI_GENL_ATTR_MAX,
 155 };
 156 #define ACPI_GENL_ATTR_MAX (__ACPI_GENL_ATTR_MAX - 1)
 157
 158 /* commands supported by the acpi_genl_family */
 159 enum {
 160         ACPI_GENL_CMD_UNSPEC,
 161         ACPI_GENL_CMD_EVENT,    /* kernel->user notifications for ACPI events */
 162         __ACPI_GENL_CMD_MAX,
 163 };
 164 #define ACPI_GENL_CMD_MAX (__ACPI_GENL_CMD_MAX - 1)
 165
 166 #define ACPI_GENL_FAMILY_NAME           "acpi_event"
 167 #define ACPI_GENL_VERSION               0x01
 168 #define ACPI_GENL_MCAST_GROUP_NAME      "acpi_mc_group"
 169
 170 static struct genl_family acpi_event_genl_family = {
 171         .id = GENL_ID_GENERATE,
 172         .name = ACPI_GENL_FAMILY_NAME,
 173         .version = ACPI_GENL_VERSION,
 174         .maxattr = ACPI_GENL_ATTR_MAX,
 175 };
 176
 177 static struct genl_multicast_group acpi_event_mcgrp = {
 178         .name = ACPI_GENL_MCAST_GROUP_NAME,
 179 };
 180
 181 int acpi_bus_generate_netlink_event(const char *device_class,
 182                                       const char *bus_id,
 183                                       u8 type, int data)
 184 {
 185         struct sk_buff *skb;
 186         struct nlattr *attr;
 187         struct acpi_genl_event *event;
 188         void *msg_header;
 189         int size;
 190         int result;
 191
 192         /* allocate memory */
 193         size = nla_total_size(sizeof(struct acpi_genl_event)) +
 194             nla_total_size(0);
 195
 196         skb = genlmsg_new(size, GFP_ATOMIC);
 197         if (!skb)
 198                 return -ENOMEM;
 199
 200         /* add the genetlink message header */
 201         msg_header = genlmsg_put(skb, 0, acpi_event_seqnum++,
 202                                  &acpi_event_genl_family, 0,
 203                                  ACPI_GENL_CMD_EVENT);
 204         if (!msg_header) {
 205                 nlmsg_free(skb);
 206                 return -ENOMEM;
 207         }
 208
 209         /* fill the data */
 210         attr =
 211             nla_reserve(skb, ACPI_GENL_ATTR_EVENT,
 212                         sizeof(struct acpi_genl_event));
 213         if (!attr) {
 214                 nlmsg_free(skb);
 215                 return -EINVAL;
 216         }
 217
 218         event = nla_data(attr);
 219         if (!event) {
 220                 nlmsg_free(skb);
 221                 return -EINVAL;
 222         }
 223
 224         memset(event, 0, sizeof(struct acpi_genl_event));
 225
 226         strcpy(event->device_class, device_class);
 227         strcpy(event->bus_id, bus_id);
 228         event->type = type;
 229         event->data = data;
 230
 231         /* send multicast genetlink message */
 232         result = genlmsg_end(skb, msg_header);
 233         if (result < 0) {
 234                 nlmsg_free(skb);
 235                 return result;
 236         }
 237
 238         genlmsg_multicast(skb, 0, acpi_event_mcgrp.id, GFP_ATOMIC);
 239         return 0;
 240 }
 241
 242 EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
 243
 244 static int acpi_event_genetlink_init(void)
 245 {
 246         int result;
 247
 248         result = genl_register_family(&acpi_event_genl_family);
 249         if (result)
 250                 return result;
 251
 252         result = genl_register_mc_group(&acpi_event_genl_family,
 253                                         &acpi_event_mcgrp);
 254         if (result)
 255                 genl_unregister_family(&acpi_event_genl_family);
 256
 257         return result;
 258 }
 259
 260 #else
 261 int acpi_bus_generate_netlink_event(const char *device_class,
 262                                       const char *bus_id,
 263                                       u8 type, int data)
 264 {
 265         return 0;
 266 }
 267
 268 EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
 269
 270 static int acpi_event_genetlink_init(void)
 271 {
 272         return -ENODEV;
 273 }
 274 #endif
 275
 276 static int __init acpi_event_init(void)
 277 {
 278 #ifdef CONFIG_ACPI_PROC_EVENT
 279         struct proc_dir_entry *entry;
 280 #endif
 281         int error = 0;
 282
 283         if (acpi_disabled)
 284                 return 0;
 285
 286         /* create genetlink for acpi event */
 287         error = acpi_event_genetlink_init();
 288         if (error)
 289                 printk(KERN_WARNING PREFIX
 290                        "Failed to create genetlink family for ACPI event\n");
 291
 292 #ifdef CONFIG_ACPI_PROC_EVENT
 293         /* 'event' [R] */
 294         entry = proc_create("event", S_IRUSR, acpi_root_dir,
 295                             &acpi_system_event_ops);
 296         if (!entry)
 297                 return -ENODEV;
 298 #endif
 299
 300         return 0;
 301 }
 302
 303 fs_initcall(acpi_event_init);