kernel/platform.c

   1 /*
   2  * platform driver support
   3  */
   4
   5 #include <linux/platform.h>
   6 #include <linux/module.h>
   7 #include <linux/errno.h>
   8
   9
  10 void default_reboot(char * cmd)
  11 {
  12         /* nothing */
  13 }
  14
  15 void default_halt(void)
  16 {
  17         /* nothing */
  18 }
  19
  20 int default_suspend(int state, int flags)
  21 {
  22         return -ENOSYS;
  23 }
  24
  25 static struct platform_t default_platform = {
  26         .name           = "Default Platform",
  27         .suspend_states = 0,
  28         .reboot         = default_reboot,
  29         .halt           = default_halt,
  30         .power_off      = default_halt,
  31         .suspend        = default_suspend,
  32         .idle           = default_idle,
  33 };
  34
  35 struct platform_t * platform = &default_platform;
  36 static spinlock_t platform_lock = SPIN_LOCK_UNLOCKED;
  37
  38 /**
  39  * set_platform_driver - set the platform driver.
  40  * @pf: driver to set it to
  41  *
  42  * Return -EEXIST if someone else already owns it.
  43  */
  44 int set_platform_driver(struct platform_t * pf)
  45 {
  46         if (!pf)
  47                 return -EINVAL;
  48         spin_lock(&platform_lock);
  49         if (platform != &default_platform) {
  50                 spin_unlock(&platform_lock);
  51                 return -EEXIST;
  52         }
  53         platform = pf;
  54         spin_unlock(&platform_lock);
  55         return 0;
  56 }
  57
  58 void remove_platform_driver(struct platform_t * pf)
  59 {
  60         spin_lock(&platform_lock);
  61         if (platform == pf)
  62                 platform = &default_platform;
  63         spin_unlock(&platform_lock);
  64 }
  65
  66 EXPORT_SYMBOL(default_reboot);
  67 EXPORT_SYMBOL(default_halt);
  68 EXPORT_SYMBOL(default_suspend);
  69
  70 EXPORT_SYMBOL(platform);
  71 EXPORT_SYMBOL(set_platform_driver);
  72 EXPORT_SYMBOL(remove_platform_driver);