linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * OMAP hardware spinlock driver

 *

 * Copyright (C) 2010-2015 Texas Instruments Incorporated - http://www.ti.com

 *

 * Contact: Simon Que <sque@ti.com>

 *          Hari Kanigeri <h-kanigeri2@ti.com>

 *          Ohad Ben-Cohen <ohad@wizery.com>

 */

​

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/device.h>

#include <linux/delay.h>

#include <linux/io.h>

#include <linux/bitops.h>

#include <linux/pm_runtime.h>

#include <linux/slab.h>

#include <linux/spinlock.h>

#include <linux/hwspinlock.h>

#include <linux/of.h>

#include <linux/platform_device.h>

​

#include "hwspinlock_internal.h"

​

/* Spinlock register offsets */

#define SYSSTATUS_OFFSET        0x0014

#define LOCK_BASE_OFFSET        0x0800

​

#define SPINLOCK_NUMLOCKS_BIT_OFFSET    (24)

​

/* Possible values of SPINLOCK_LOCK_REG */

#define SPINLOCK_NOTTAKEN       (0) /* free */

#define SPINLOCK_TAKEN          (1) /* locked */

​

static int omap_hwspinlock_trylock(struct hwspinlock *lock)

{

    void __iomem *lock_addr = lock->priv;

​

    /* attempt to acquire the lock by reading its value */

    return (SPINLOCK_NOTTAKEN == readl(lock_addr));

}

​

static void omap_hwspinlock_unlock(struct hwspinlock *lock)

{

    void __iomem *lock_addr = lock->priv;

​

    /* release the lock by writing 0 to it */

    writel(SPINLOCK_NOTTAKEN, lock_addr);

}

​

/*

 * relax the OMAP interconnect while spinning on it.

 *

 * The specs recommended that the retry delay time will be

 * just over half of the time that a requester would be

 * expected to hold the lock.

 *

 * The number below is taken from an hardware specs example,

 * obviously it is somewhat arbitrary.

 */

static void omap_hwspinlock_relax(struct hwspinlock *lock)