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   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
  15 #define _COMPONENT              ACPI_SYSTEM_COMPONENT
  16 ACPI_MODULE_NAME                ("event")
  17
  18 /* Global vars for handling event proc entry */
  19 static DEFINE_SPINLOCK(acpi_system_event_lock);
  20 int                             event_is_open = 0;
  21 extern struct list_head         acpi_bus_event_list;
  22 extern wait_queue_head_t        acpi_bus_event_queue;
  23
  24 static int
  25 acpi_system_open_event(struct inode *inode, struct file *file)
  26 {
  27         spin_lock_irq(&acpi_system_event_lock);
  28
  29         if (event_is_open)
  30                 goto out_busy;
  31
  32         event_is_open = 1;
  33
  34         spin_unlock_irq(&acpi_system_event_lock);
  35         return 0;
  36
  37 out_busy:
  38         spin_unlock_irq(&acpi_system_event_lock);
  39         return -EBUSY;
  40 }
  41
  42 static ssize_t
  43 acpi_system_read_event(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
  44 {
  45         int                     result = 0;
  46         struct acpi_bus_event   event;
  47         static char             str[ACPI_MAX_STRING];
  48         static int              chars_remaining = 0;
  49         static char             *ptr;
  50
  51
  52         ACPI_FUNCTION_TRACE("acpi_system_read_event");
  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_VALUE(-EAGAIN);
  60
  61                 result = acpi_bus_receive_event(&event);
  62                 if (result) {
  63                         return_VALUE(-EIO);
  64                 }
  65
  66                 chars_remaining = sprintf(str, "%s %s %08x %08x\n",
  67                         event.device_class?event.device_class:"<unknown>",
  68                         event.bus_id?event.bus_id:"<unknown>",
  69                         event.type, event.data);
  70                 ptr = str;
  71         }
  72
  73         if (chars_remaining < count) {
  74                 count = chars_remaining;
  75         }
  76
  77         if (copy_to_user(buffer, ptr, count))
  78                 return_VALUE(-EFAULT);
  79
  80         *ppos += count;
  81         chars_remaining -= count;
  82         ptr += count;
  83
  84         return_VALUE(count);
  85 }
  86
  87 static int
  88 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
  97 acpi_system_poll_event(struct file *file, poll_table *wait)
  98 {
  99         poll_wait(file, &acpi_bus_event_queue, wait);
 100         if (!list_empty(&acpi_bus_event_list))
 101                 return POLLIN | POLLRDNORM;
 102         return 0;
 103 }
 104
 105 static struct file_operations acpi_system_event_ops = {
 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
 112 static int __init acpi_event_init(void)
 113 {
 114         struct proc_dir_entry   *entry;
 115         int error = 0;
 116
 117         ACPI_FUNCTION_TRACE("acpi_event_init");
 118
 119         if (acpi_disabled)
 120                 return_VALUE(0);
 121
 122         /* 'event' [R] */
 123         entry = create_proc_entry("event", S_IRUSR, acpi_root_dir);
 124         if (entry)
 125                 entry->proc_fops = &acpi_system_event_ops;
 126         else {
 127                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 128                                   "Unable to create '%s' proc fs entry\n","event" ));
 129                 error = -EFAULT;
 130         }
 131         return_VALUE(error);
 132 }
 133
 134 subsys_initcall(acpi_event_init);