drivers/crypto/nx/nx-842-platform.c

   1
   2 #include "nx-842.h"
   3
   4 /* this is needed, separate from the main nx-842.c driver, because that main
   5  * driver loads the platform drivers during its init(), and it expects one
   6  * (or none) of the platform drivers to set this pointer to its driver.
   7  * That means this pointer can't be in the main nx-842 driver, because it
   8  * wouldn't be accessible until after the main driver loaded, which wouldn't
   9  * be possible as it's waiting for the platform driver to load.  So place it
  10  * here.
  11  */
  12 static struct nx842_driver *driver;
  13 static DEFINE_SPINLOCK(driver_lock);
  14
  15 struct nx842_driver *nx842_platform_driver(void)
  16 {
  17         return driver;
  18 }
  19 EXPORT_SYMBOL_GPL(nx842_platform_driver);
  20
  21 bool nx842_platform_driver_set(struct nx842_driver *_driver)
  22 {
  23         bool ret = false;
  24
  25         spin_lock(&driver_lock);
  26
  27         if (!driver) {
  28                 driver = _driver;
  29                 ret = true;
  30         } else
  31                 WARN(1, "can't set platform driver, already set to %s\n",
  32                      driver->name);
  33
  34         spin_unlock(&driver_lock);
  35         return ret;
  36 }
  37 EXPORT_SYMBOL_GPL(nx842_platform_driver_set);
  38
  39 /* only call this from the platform driver exit function */
  40 void nx842_platform_driver_unset(struct nx842_driver *_driver)
  41 {
  42         spin_lock(&driver_lock);
  43
  44         if (driver == _driver)
  45                 driver = NULL;
  46         else if (driver)
  47                 WARN(1, "can't unset platform driver %s, currently set to %s\n",
  48                      _driver->name, driver->name);
  49         else
  50                 WARN(1, "can't unset platform driver, already unset\n");
  51
  52         spin_unlock(&driver_lock);
  53 }
  54 EXPORT_SYMBOL_GPL(nx842_platform_driver_unset);
  55
  56 bool nx842_platform_driver_get(void)
  57 {
  58         bool ret = false;
  59
  60         spin_lock(&driver_lock);
  61
  62         if (driver)
  63                 ret = try_module_get(driver->owner);
  64
  65         spin_unlock(&driver_lock);
  66
  67         return ret;
  68 }
  69 EXPORT_SYMBOL_GPL(nx842_platform_driver_get);
  70
  71 void nx842_platform_driver_put(void)
  72 {
  73         spin_lock(&driver_lock);
  74
  75         if (driver)
  76                 module_put(driver->owner);
  77
  78         spin_unlock(&driver_lock);
  79 }
  80 EXPORT_SYMBOL_GPL(nx842_platform_driver_put);
  81
  82 MODULE_LICENSE("GPL");
  83 MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");
  84 MODULE_DESCRIPTION("842 H/W Compression platform driver");