LXR linux/drivers/hwspinlock/hwspinlock

   1/*
   2 * Hardware spinlocks internal header
   3 *
   4 * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com
   5 *
   6 * Contact: Ohad Ben-Cohen <ohad@wizery.com>
   7 *
   8 * This program is free software; you can redistribute it and/or modify it
   9 * under the terms of the GNU General Public License version 2 as published
  10 * by the Free Software Foundation.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 */
  17
  18#ifndef __HWSPINLOCK_HWSPINLOCK_H
  19#define __HWSPINLOCK_HWSPINLOCK_H
  20
  21#include <linux/spinlock.h>
  22#include <linux/device.h>
  23
  24struct hwspinlock_device;
  25
  26/**
  27 * struct hwspinlock_ops - platform-specific hwspinlock handlers
  28 *
  29 * @trylock: make a single attempt to take the lock. returns 0 on
  30 *           failure and true on success. may _not_ sleep.
  31 * @unlock:  release the lock. always succeed. may _not_ sleep.
  32 * @relax:   optional, platform-specific relax handler, called by hwspinlock
  33 *           core while spinning on a lock, between two successive
  34 *           invocations of @trylock. may _not_ sleep.
  35 */
  36struct hwspinlock_ops {
  37        int (*trylock)(struct hwspinlock *lock);
  38        void (*unlock)(struct hwspinlock *lock);
  39        void (*relax)(struct hwspinlock *lock);
  40};
  41
  42/**
  43 * struct hwspinlock - this struct represents a single hwspinlock instance
  44 * @bank: the hwspinlock_device structure which owns this lock
  45 * @lock: initialized and used by hwspinlock core
  46 * @priv: private data, owned by the underlying platform-specific hwspinlock drv
  47 */
  48struct hwspinlock {
  49        struct hwspinlock_device *bank;
  50        spinlock_t lock;
  51        void *priv;
  52};
  53
  54/**
  55 * struct hwspinlock_device - a device which usually spans numerous hwspinlocks
  56 * @dev: underlying device, will be used to invoke runtime PM api
  57 * @ops: platform-specific hwspinlock handlers
  58 * @base_id: id index of the first lock in this device
  59 * @num_locks: number of locks in this device
  60 * @lock: dynamically allocated array of 'struct hwspinlock'
  61 */
  62struct hwspinlock_device {
  63        struct device *dev;
  64        const struct hwspinlock_ops *ops;
  65        int base_id;
  66        int num_locks;
  67        struct hwspinlock lock[0];
  68};
  69
  70static inline int hwlock_to_id(struct hwspinlock *hwlock)
  71{
  72        int local_id = hwlock - &hwlock->bank->lock[0];
  73
  74        return hwlock->bank->base_id + local_id;
  75}
  76
  77#endif /* __HWSPINLOCK_HWSPINLOCK_H */
  78