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hwspinlock updates for v4.18 

In addition to migrating the files to use SPDX license headers this
 introduces the ability for clients to operate a hwlock without the
 framework taking any additional locks.
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Merge tag 'hwlock-v4.18' of git://github.com/andersson/remoteproc

Pull hwspinlock updates from Bjorn Andersson:
 "In addition to migrating the files to use SPDX license headers this
  introduces the ability for clients to operate a hwlock without the
  framework taking any additional locks"

* tag 'hwlock-v4.18' of git://github.com/andersson/remoteproc:
  hwspinlock/u8500: Switch to SPDX license identifier
  hwspinlock: sprd: Switch to SPDX license identifier
  hwspinlock/sirf: Switch to SPDX license identifier
  hwspinlock: qcom: Switch to SPDX license identifier
  hwspinlock/omap: Switch to SPDX license identifier
  hwspinlock/core: Switch to SPDX license identifier
  hwspinlock: Introduce one new mode for hwspinlock
  hwspinlock: Convert to use 'switch' statement
This commit is contained in:
Linus Torvalds 2018-06-11 12:09:19 -07:00
parent d2b2250c3e e759176c7f
commit 6f75edeadd
9 changed files with 118 additions and 81 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/hwspinlock/Kconfig
View File

@ -1,3 +1,4 @@
# SPDX-License-Identifier: GPL-2.0
#
# Generic HWSPINLOCK framework
#

77
drivers/hwspinlock/hwspinlock_core.c
View File

@ -1,18 +1,10 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Hardware spinlock framework
*
* 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.
*/
#define pr_fmt(fmt) "%s: " fmt, __func__
@ -71,10 +63,16 @@ static DEFINE_MUTEX(hwspinlock_tree_lock);
* 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 (and possibly
* interrupts) 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.
* Caution: If the mode is HWLOCK_RAW, that means user must protect the routine
* of getting hardware lock with mutex or spinlock. Since in some scenarios,
* user need some time-consuming or sleepable operations under the hardware
* lock, they need one sleepable lock (like mutex) to protect the operations.
*
* If the mode is not HWLOCK_RAW, upon a successful return from this function,
* preemption (and possibly interrupts) 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.
*
* The user decides whether local interrupts are disabled or not, and if yes,
* whether he wants their previous state to be saved. It is up to the user
@ -106,12 +104,20 @@ int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
* problems with hwspinlock usage (e.g. scheduler checks like
* 'scheduling while atomic' etc.)
*/
if (mode == HWLOCK_IRQSTATE)
switch (mode) {
case HWLOCK_IRQSTATE:
ret = spin_trylock_irqsave(&hwlock->lock, *flags);
else if (mode == HWLOCK_IRQ)
break;
case HWLOCK_IRQ:
ret = spin_trylock_irq(&hwlock->lock);
else
break;
case HWLOCK_RAW:
ret = 1;
break;
default:
ret = spin_trylock(&hwlock->lock);
break;
}
/* is lock already taken by another context on the local cpu ? */
if (!ret)
@ -122,12 +128,20 @@ int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
/* if hwlock is already taken, undo spin_trylock_* and exit */
if (!ret) {
if (mode == HWLOCK_IRQSTATE)
switch (mode) {
case HWLOCK_IRQSTATE:
spin_unlock_irqrestore(&hwlock->lock, *flags);
else if (mode == HWLOCK_IRQ)
break;
case HWLOCK_IRQ:
spin_unlock_irq(&hwlock->lock);
else
break;
case HWLOCK_RAW:
/* Nothing to do */
break;
default:
spin_unlock(&hwlock->lock);
break;
}
return -EBUSY;
}
@ -160,9 +174,14 @@ EXPORT_SYMBOL_GPL(__hwspin_trylock);
* is already taken, the function will busy loop waiting for it to
* be released, but give up after @timeout msecs have elapsed.
*
* Upon a successful return from this function, preemption is disabled
* (and possibly local interrupts, too), so the caller must not sleep,
* and is advised to release the hwspinlock as soon as possible.
* Caution: If the mode is HWLOCK_RAW, that means user must protect the routine
* of getting hardware lock with mutex or spinlock. Since in some scenarios,
* user need some time-consuming or sleepable operations under the hardware
* lock, they need one sleepable lock (like mutex) to protect the operations.
*
* If the mode is not HWLOCK_RAW, upon a successful return from this function,
* preemption is disabled (and possibly local interrupts, too), 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.
*
@ -249,12 +268,20 @@ void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
hwlock->bank->ops->unlock(hwlock);
/* Undo the spin_trylock{_irq, _irqsave} called while locking */
if (mode == HWLOCK_IRQSTATE)
switch (mode) {
case HWLOCK_IRQSTATE:
spin_unlock_irqrestore(&hwlock->lock, *flags);
else if (mode == HWLOCK_IRQ)
break;
case HWLOCK_IRQ:
spin_unlock_irq(&hwlock->lock);
else
break;
case HWLOCK_RAW:
/* Nothing to do */
break;
default:
spin_unlock(&hwlock->lock);
break;
}
}
EXPORT_SYMBOL_GPL(__hwspin_unlock);

10
drivers/hwspinlock/hwspinlock_internal.h
View File

@ -1,18 +1,10 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Hardware spinlocks internal 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 __HWSPINLOCK_HWSPINLOCK_H

10
drivers/hwspinlock/omap_hwspinlock.c
View File

@ -1,3 +1,4 @@
// SPDX-License-Identifier: GPL-2.0
/*
* OMAP hardware spinlock driver
*
@ -6,15 +7,6 @@
* Contact: Simon Que <sque@ti.com>
* Hari Kanigeri <h-kanigeri2@ti.com>
* 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.
*/
#include <linux/kernel.h>

10
drivers/hwspinlock/qcom_hwspinlock.c
View File

@ -1,15 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2013, The Linux Foundation. All rights reserved.
* Copyright (c) 2015, Sony Mobile Communications AB
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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.
*/
#include <linux/hwspinlock.h>

3
drivers/hwspinlock/sirf_hwspinlock.c
View File

@ -1,9 +1,8 @@
// SPDX-License-Identifier: GPL-2.0
/*
* SIRF hardware spinlock driver
*
* Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company.
*
* Licensed under GPLv2.
*/
#include <linux/kernel.h>

10
drivers/hwspinlock/sprd_hwspinlock.c
View File

@ -1,15 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Spreadtrum hardware spinlock driver
* Copyright (C) 2017 Spreadtrum - http://www.spreadtrum.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.
*/
#include <linux/bitops.h>

10
drivers/hwspinlock/u8500_hsem.c
View File

@ -1,3 +1,4 @@
// SPDX-License-Identifier: GPL-2.0
/*
* u8500 HWSEM driver
*
@ -10,15 +11,6 @@
* Simon Que <sque@ti.com>
* Hari Kanigeri <h-kanigeri2@ti.com>
* 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.
*/
#include <linux/module.h>

68
include/linux/hwspinlock.h
View File

@ -1,18 +1,10 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* 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
@ -24,6 +16,7 @@
/* hwspinlock mode argument */
#define HWLOCK_IRQSTATE 0x01 /* Disable interrupts, save state */
#define HWLOCK_IRQ 0x02 /* Disable interrupts, don't save state */
#define HWLOCK_RAW 0x03
struct device;
struct device_node;
@ -175,6 +168,25 @@ static inline int hwspin_trylock_irq(struct hwspinlock *hwlock)
return __hwspin_trylock(hwlock, HWLOCK_IRQ, NULL);
}
/**
* hwspin_trylock_raw() - 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.
*
* Caution: User must protect the routine of getting hardware lock with mutex
* or spinlock to avoid dead-lock, that will let user can do some time-consuming
* or sleepable operations under the hardware lock.
*
* 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_raw(struct hwspinlock *hwlock)
{
return __hwspin_trylock(hwlock, HWLOCK_RAW, NULL);
}
/**
* hwspin_trylock() - attempt to lock a specific hwspinlock
* @hwlock: an hwspinlock which we want to trylock
@ -242,6 +254,29 @@ int hwspin_lock_timeout_irq(struct hwspinlock *hwlock, unsigned int to)
return __hwspin_lock_timeout(hwlock, to, HWLOCK_IRQ, NULL);
}
/**
* hwspin_lock_timeout_raw() - 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.
*
* Caution: User must protect the routine of getting hardware lock with mutex
* or spinlock to avoid dead-lock, that will let user can do some time-consuming
* or sleepable operations under the hardware lock.
*
* 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_raw(struct hwspinlock *hwlock, unsigned int to)
{
return __hwspin_lock_timeout(hwlock, to, HWLOCK_RAW, NULL);
}
/**
* hwspin_lock_timeout() - lock an hwspinlock with timeout limit
* @hwlock: the hwspinlock to be locked
@ -301,6 +336,21 @@ static inline void hwspin_unlock_irq(struct hwspinlock *hwlock)
__hwspin_unlock(hwlock, HWLOCK_IRQ, NULL);
}
/**
* hwspin_unlock_raw() - unlock hwspinlock
* @hwlock: a previously-acquired hwspinlock which we want to unlock
*
* This function will unlock a specific hwspinlock.
*
* @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_raw(struct hwspinlock *hwlock)
{
__hwspin_unlock(hwlock, HWLOCK_RAW, NULL);
}
/**
* hwspin_unlock() - unlock hwspinlock
* @hwlock: a previously-acquired hwspinlock which we want to unlock