314 lines
11 KiB
C
314 lines
11 KiB
C
/*
|
|
* Hardware spinlock public header
|
|
*
|
|
* Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com
|
|
*
|
|
* Contact: Ohad Ben-Cohen <ohad@wizery.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 as published
|
|
* by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*/
|
|
|
|
#ifndef __LINUX_HWSPINLOCK_H
|
|
#define __LINUX_HWSPINLOCK_H
|
|
|
|
#include <linux/err.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/device.h>
|
|
|
|
/* hwspinlock mode argument */
|
|
#define HWLOCK_IRQSTATE 0x01 /* Disable interrupts, save state */
|
|
#define HWLOCK_IRQ 0x02 /* Disable interrupts, don't save state */
|
|
|
|
struct hwspinlock;
|
|
struct hwspinlock_device;
|
|
struct hwspinlock_ops;
|
|
|
|
/**
|
|
* struct hwspinlock_pdata - platform data for hwspinlock drivers
|
|
* @base_id: base id for this hwspinlock device
|
|
*
|
|
* hwspinlock devices provide system-wide hardware locks that are used
|
|
* by remote processors that have no other way to achieve synchronization.
|
|
*
|
|
* To achieve that, each physical lock must have a system-wide id number
|
|
* that is agreed upon, otherwise remote processors can't possibly assume
|
|
* they're using the same hardware lock.
|
|
*
|
|
* Usually boards have a single hwspinlock device, which provides several
|
|
* hwspinlocks, and in this case, they can be trivially numbered 0 to
|
|
* (num-of-locks - 1).
|
|
*
|
|
* In case boards have several hwspinlocks devices, a different base id
|
|
* should be used for each hwspinlock device (they can't all use 0 as
|
|
* a starting id!).
|
|
*
|
|
* This platform data structure should be used to provide the base id
|
|
* for each device (which is trivially 0 when only a single hwspinlock
|
|
* device exists). It can be shared between different platforms, hence
|
|
* its location.
|
|
*/
|
|
struct hwspinlock_pdata {
|
|
int base_id;
|
|
};
|
|
|
|
#if defined(CONFIG_HWSPINLOCK) || defined(CONFIG_HWSPINLOCK_MODULE)
|
|
|
|
int hwspin_lock_register(struct hwspinlock_device *bank, struct device *dev,
|
|
const struct hwspinlock_ops *ops, int base_id, int num_locks);
|
|
int hwspin_lock_unregister(struct hwspinlock_device *bank);
|
|
struct hwspinlock *hwspin_lock_request(void);
|
|
struct hwspinlock *hwspin_lock_request_specific(unsigned int id);
|
|
int hwspin_lock_free(struct hwspinlock *hwlock);
|
|
int hwspin_lock_get_id(struct hwspinlock *hwlock);
|
|
int __hwspin_lock_timeout(struct hwspinlock *, unsigned int, int,
|
|
unsigned long *);
|
|
int __hwspin_trylock(struct hwspinlock *, int, unsigned long *);
|
|
void __hwspin_unlock(struct hwspinlock *, int, unsigned long *);
|
|
|
|
#else /* !CONFIG_HWSPINLOCK */
|
|
|
|
/*
|
|
* We don't want these functions to fail if CONFIG_HWSPINLOCK is not
|
|
* enabled. We prefer to silently succeed in this case, and let the
|
|
* code path get compiled away. This way, if CONFIG_HWSPINLOCK is not
|
|
* required on a given setup, users will still work.
|
|
*
|
|
* The only exception is hwspin_lock_register/hwspin_lock_unregister, with which
|
|
* we _do_ want users to fail (no point in registering hwspinlock instances if
|
|
* the framework is not available).
|
|
*
|
|
* Note: ERR_PTR(-ENODEV) will still be considered a success for NULL-checking
|
|
* users. Others, which care, can still check this with IS_ERR.
|
|
*/
|
|
static inline struct hwspinlock *hwspin_lock_request(void)
|
|
{
|
|
return ERR_PTR(-ENODEV);
|
|
}
|
|
|
|
static inline struct hwspinlock *hwspin_lock_request_specific(unsigned int id)
|
|
{
|
|
return ERR_PTR(-ENODEV);
|
|
}
|
|
|
|
static inline int hwspin_lock_free(struct hwspinlock *hwlock)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline
|
|
int __hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int to,
|
|
int mode, unsigned long *flags)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline
|
|
int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline
|
|
void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
|
|
{
|
|
}
|
|
|
|
static inline int hwspin_lock_get_id(struct hwspinlock *hwlock)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
#endif /* !CONFIG_HWSPINLOCK */
|
|
|
|
/**
|
|
* hwspin_trylock_irqsave() - try to lock an hwspinlock, disable interrupts
|
|
* @hwlock: an hwspinlock which we want to trylock
|
|
* @flags: a pointer to where the caller's interrupt state will be saved at
|
|
*
|
|
* This function attempts to lock the underlying hwspinlock, and will
|
|
* immediately fail if the hwspinlock is already locked.
|
|
*
|
|
* Upon a successful return from this function, preemption and local
|
|
* interrupts are disabled (previous interrupts state is saved at @flags),
|
|
* so the caller must not sleep, and is advised to release the hwspinlock
|
|
* as soon as possible.
|
|
*
|
|
* Returns 0 if we successfully locked the hwspinlock, -EBUSY if
|
|
* the hwspinlock was already taken, and -EINVAL if @hwlock is invalid.
|
|
*/
|
|
static inline
|
|
int hwspin_trylock_irqsave(struct hwspinlock *hwlock, unsigned long *flags)
|
|
{
|
|
return __hwspin_trylock(hwlock, HWLOCK_IRQSTATE, flags);
|
|
}
|
|
|
|
/**
|
|
* hwspin_trylock_irq() - try to lock an hwspinlock, disable interrupts
|
|
* @hwlock: an hwspinlock which we want to trylock
|
|
*
|
|
* This function attempts to lock the underlying hwspinlock, and will
|
|
* immediately fail if the hwspinlock is already locked.
|
|
*
|
|
* Upon a successful return from this function, preemption and local
|
|
* interrupts are disabled, so the caller must not sleep, and is advised
|
|
* to release the hwspinlock as soon as possible.
|
|
*
|
|
* Returns 0 if we successfully locked the hwspinlock, -EBUSY if
|
|
* the hwspinlock was already taken, and -EINVAL if @hwlock is invalid.
|
|
*/
|
|
static inline int hwspin_trylock_irq(struct hwspinlock *hwlock)
|
|
{
|
|
return __hwspin_trylock(hwlock, HWLOCK_IRQ, NULL);
|
|
}
|
|
|
|
/**
|
|
* hwspin_trylock() - attempt to lock a specific hwspinlock
|
|
* @hwlock: an hwspinlock which we want to trylock
|
|
*
|
|
* This function attempts to lock an hwspinlock, and will immediately fail
|
|
* if the hwspinlock is already taken.
|
|
*
|
|
* Upon a successful return from this function, preemption is disabled,
|
|
* so the caller must not sleep, and is advised to release the hwspinlock
|
|
* as soon as possible. This is required in order to minimize remote cores
|
|
* polling on the hardware interconnect.
|
|
*
|
|
* Returns 0 if we successfully locked the hwspinlock, -EBUSY if
|
|
* the hwspinlock was already taken, and -EINVAL if @hwlock is invalid.
|
|
*/
|
|
static inline int hwspin_trylock(struct hwspinlock *hwlock)
|
|
{
|
|
return __hwspin_trylock(hwlock, 0, NULL);
|
|
}
|
|
|
|
/**
|
|
* hwspin_lock_timeout_irqsave() - lock hwspinlock, with timeout, disable irqs
|
|
* @hwlock: the hwspinlock to be locked
|
|
* @to: timeout value in msecs
|
|
* @flags: a pointer to where the caller's interrupt state will be saved at
|
|
*
|
|
* This function locks the underlying @hwlock. If the @hwlock
|
|
* is already taken, the function will busy loop waiting for it to
|
|
* be released, but give up when @timeout msecs have elapsed.
|
|
*
|
|
* Upon a successful return from this function, preemption and local interrupts
|
|
* are disabled (plus previous interrupt state is saved), so the caller must
|
|
* not sleep, and is advised to release the hwspinlock as soon as possible.
|
|
*
|
|
* Returns 0 when the @hwlock was successfully taken, and an appropriate
|
|
* error code otherwise (most notably an -ETIMEDOUT if the @hwlock is still
|
|
* busy after @timeout msecs). The function will never sleep.
|
|
*/
|
|
static inline int hwspin_lock_timeout_irqsave(struct hwspinlock *hwlock,
|
|
unsigned int to, unsigned long *flags)
|
|
{
|
|
return __hwspin_lock_timeout(hwlock, to, HWLOCK_IRQSTATE, flags);
|
|
}
|
|
|
|
/**
|
|
* hwspin_lock_timeout_irq() - lock hwspinlock, with timeout, disable irqs
|
|
* @hwlock: the hwspinlock to be locked
|
|
* @to: timeout value in msecs
|
|
*
|
|
* This function locks the underlying @hwlock. If the @hwlock
|
|
* is already taken, the function will busy loop waiting for it to
|
|
* be released, but give up when @timeout msecs have elapsed.
|
|
*
|
|
* Upon a successful return from this function, preemption and local interrupts
|
|
* are disabled so the caller must not sleep, and is advised to release the
|
|
* hwspinlock as soon as possible.
|
|
*
|
|
* Returns 0 when the @hwlock was successfully taken, and an appropriate
|
|
* error code otherwise (most notably an -ETIMEDOUT if the @hwlock is still
|
|
* busy after @timeout msecs). The function will never sleep.
|
|
*/
|
|
static inline
|
|
int hwspin_lock_timeout_irq(struct hwspinlock *hwlock, unsigned int to)
|
|
{
|
|
return __hwspin_lock_timeout(hwlock, to, HWLOCK_IRQ, NULL);
|
|
}
|
|
|
|
/**
|
|
* hwspin_lock_timeout() - lock an hwspinlock with timeout limit
|
|
* @hwlock: the hwspinlock to be locked
|
|
* @to: timeout value in msecs
|
|
*
|
|
* This function locks the underlying @hwlock. If the @hwlock
|
|
* is already taken, the function will busy loop waiting for it to
|
|
* be released, but give up when @timeout msecs have elapsed.
|
|
*
|
|
* Upon a successful return from this function, preemption is disabled
|
|
* so the caller must not sleep, and is advised to release the hwspinlock
|
|
* as soon as possible.
|
|
* This is required in order to minimize remote cores polling on the
|
|
* hardware interconnect.
|
|
*
|
|
* Returns 0 when the @hwlock was successfully taken, and an appropriate
|
|
* error code otherwise (most notably an -ETIMEDOUT if the @hwlock is still
|
|
* busy after @timeout msecs). The function will never sleep.
|
|
*/
|
|
static inline
|
|
int hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int to)
|
|
{
|
|
return __hwspin_lock_timeout(hwlock, to, 0, NULL);
|
|
}
|
|
|
|
/**
|
|
* hwspin_unlock_irqrestore() - unlock hwspinlock, restore irq state
|
|
* @hwlock: a previously-acquired hwspinlock which we want to unlock
|
|
* @flags: previous caller's interrupt state to restore
|
|
*
|
|
* This function will unlock a specific hwspinlock, enable preemption and
|
|
* restore the previous state of the local interrupts. It should be used
|
|
* to undo, e.g., hwspin_trylock_irqsave().
|
|
*
|
|
* @hwlock must be already locked before calling this function: it is a bug
|
|
* to call unlock on a @hwlock that is already unlocked.
|
|
*/
|
|
static inline void hwspin_unlock_irqrestore(struct hwspinlock *hwlock,
|
|
unsigned long *flags)
|
|
{
|
|
__hwspin_unlock(hwlock, HWLOCK_IRQSTATE, flags);
|
|
}
|
|
|
|
/**
|
|
* hwspin_unlock_irq() - unlock hwspinlock, enable interrupts
|
|
* @hwlock: a previously-acquired hwspinlock which we want to unlock
|
|
*
|
|
* This function will unlock a specific hwspinlock, enable preemption and
|
|
* enable local interrupts. Should be used to undo hwspin_lock_irq().
|
|
*
|
|
* @hwlock must be already locked (e.g. by hwspin_trylock_irq()) before
|
|
* calling this function: it is a bug to call unlock on a @hwlock that is
|
|
* already unlocked.
|
|
*/
|
|
static inline void hwspin_unlock_irq(struct hwspinlock *hwlock)
|
|
{
|
|
__hwspin_unlock(hwlock, HWLOCK_IRQ, NULL);
|
|
}
|
|
|
|
/**
|
|
* hwspin_unlock() - unlock hwspinlock
|
|
* @hwlock: a previously-acquired hwspinlock which we want to unlock
|
|
*
|
|
* This function will unlock a specific hwspinlock and enable preemption
|
|
* back.
|
|
*
|
|
* @hwlock must be already locked (e.g. by hwspin_trylock()) before calling
|
|
* this function: it is a bug to call unlock on a @hwlock that is already
|
|
* unlocked.
|
|
*/
|
|
static inline void hwspin_unlock(struct hwspinlock *hwlock)
|
|
{
|
|
__hwspin_unlock(hwlock, 0, NULL);
|
|
}
|
|
|
|
#endif /* __LINUX_HWSPINLOCK_H */
|