include/hwspinlock.h

   1 /* SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause */
   2 /*
   3  * Copyright (C) 2018, STMicroelectronics - All Rights Reserved
   4  */
   5
   6 #ifndef _HWSPINLOCK_H_
   7 #define _HWSPINLOCK_H_
   8
   9 /**
  10  * Implement a hwspinlock uclass.
  11  * Hardware spinlocks are used to perform hardware protection of
  12  * critical sections and synchronisation between multiprocessors.
  13  */
  14
  15 struct udevice;
  16
  17 /**
  18  * struct hwspinlock - A handle to (allowing control of) a single hardware
  19  * spinlock.
  20  *
  21  * @dev: The device which implements the hardware spinlock.
  22  * @id: The hardware spinlock ID within the provider.
  23  */
  24 struct hwspinlock {
  25         struct udevice *dev;
  26         unsigned long id;
  27 };
  28
  29 #if CONFIG_IS_ENABLED(DM_HWSPINLOCK)
  30
  31 /**
  32  * hwspinlock_get_by_index - Get a hardware spinlock by integer index
  33  *
  34  * This looks up and request a hardware spinlock. The index is relative to the
  35  * client device; each device is assumed to have n hardware spinlock associated
  36  * with it somehow, and this function finds and requests one of them.
  37  *
  38  * @dev:        The client device.
  39  * @index:      The index of the hardware spinlock to request, within the
  40  *              client's list of hardware spinlock.
  41  * @hws:        A pointer to a hardware spinlock struct to initialize.
  42  * @return 0 if OK, or a negative error code.
  43  */
  44 int hwspinlock_get_by_index(struct udevice *dev,
  45                             int index, struct hwspinlock *hws);
  46
  47 /**
  48  * Lock the hardware spinlock
  49  *
  50  * @hws:        A hardware spinlock struct that previously requested by
  51  *              hwspinlock_get_by_index
  52  * @timeout:    Timeout value in msecs
  53  * @return: 0 if OK, -ETIMEDOUT if timeout, -ve on other errors
  54  */
  55 int hwspinlock_lock_timeout(struct hwspinlock *hws, unsigned int timeout);
  56
  57 /**
  58  * Unlock the hardware spinlock
  59  *
  60  * @hws:        A hardware spinlock struct that previously requested by
  61  *              hwspinlock_get_by_index
  62  * @return: 0 if OK, -ve on error
  63  */
  64 int hwspinlock_unlock(struct hwspinlock *hws);
  65
  66 #else
  67
  68 static inline int hwspinlock_get_by_index(struct udevice *dev,
  69                                           int index,
  70                                           struct hwspinlock *hws)
  71 {
  72         return -ENOSYS;
  73 }
  74
  75 static inline int hwspinlock_lock_timeout(struct hwspinlock *hws,
  76                                           int timeout)
  77 {
  78         return -ENOSYS;
  79 }
  80
  81 static inline int hwspinlock_unlock(struct hwspinlock *hws)
  82 {
  83         return -ENOSYS;
  84 }
  85
  86 #endif /* CONFIG_DM_HWSPINLOCK */
  87
  88 struct ofnode_phandle_args;
  89
  90 /**
  91  * struct hwspinlock_ops - Driver model hwspinlock operations
  92  *
  93  * The uclass interface is implemented by all hwspinlock devices which use
  94  * driver model.
  95  */
  96 struct hwspinlock_ops {
  97         /**
  98          * of_xlate - Translate a client's device-tree (OF) hardware specifier.
  99          *
 100          * The hardware core calls this function as the first step in
 101          * implementing a client's hwspinlock_get_by_*() call.
 102          *
 103          * @hws:        The hardware spinlock struct to hold the translation
 104          *                      result.
 105          * @args:       The hardware spinlock specifier values from device tree.
 106          * @return 0 if OK, or a negative error code.
 107          */
 108         int (*of_xlate)(struct hwspinlock *hws,
 109                         struct ofnode_phandle_args *args);
 110
 111         /**
 112          * Lock the hardware spinlock
 113          *
 114          * @dev:        hwspinlock Device
 115          * @index:      index of the lock to be used
 116          * @return 0 if OK, -ve on error
 117          */
 118         int (*lock)(struct udevice *dev, int index);
 119
 120         /**
 121          * Unlock the hardware spinlock
 122          *
 123          * @dev:        hwspinlock Device
 124          * @index:      index of the lock to be unlocked
 125          * @return 0 if OK, -ve on error
 126          */
 127         int (*unlock)(struct udevice *dev, int index);
 128
 129         /**
 130          * Relax - optional
 131          *       Platform-specific relax method, called by hwspinlock core
 132          *       while spinning on a lock, between two successive call to
 133          *       lock
 134          *
 135          * @dev:        hwspinlock Device
 136          */
 137         void (*relax)(struct udevice *dev);
 138 };
 139
 140 #endif /* _HWSPINLOCK_H_ */