LXR uboot/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
  15struct 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 */
  24struct 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 */
  44int 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 */
  55int 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 */
  64int hwspinlock_unlock(struct hwspinlock *hws);
  65
  66#else
  67
  68static inline int hwspinlock_get_by_index(struct udevice *dev,
  69                                          int index,
  70                                          struct hwspinlock *hws)
  71{
  72        return -ENOSYS;
  73}
  74
  75static inline int hwspinlock_lock_timeout(struct hwspinlock *hws,
  76                                          int timeout)
  77{
  78        return -ENOSYS;
  79}
  80
  81static inline int hwspinlock_unlock(struct hwspinlock *hws)
  82{
  83        return -ENOSYS;
  84}
  85
  86#endif /* CONFIG_DM_HWSPINLOCK */
  87
  88struct 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 */
  96struct 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_ */
 141