From 1e6c06a7e88c251d8a30271ad5206fbd967a4576 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Sun, 8 Apr 2018 11:06:57 +0800 Subject: hwspinlock: Introduce one new mode for hwspinlock In some scenarios, user need do some time-consuming or sleepable operations under the hardware spinlock protection for synchronization between the multiple subsystems. For example, there is one PMIC efuse on Spreadtrum platform, which need to be accessed under one hardware lock. But during the hardware lock protection, the efuse operation is time-consuming to almost 5 ms, so we can not disable the interrupts or preemption so long in this case. Thus we can introduce one new mode to indicate that we just acquire the hardware lock and do not disable interrupts or preemption, meanwhile we should force user to protect the hardware lock with mutex or spinlock to avoid dead-lock. Signed-off-by: Baolin Wang Signed-off-by: Bjorn Andersson --- include/linux/hwspinlock.h | 58 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) (limited to 'include/linux') diff --git a/include/linux/hwspinlock.h b/include/linux/hwspinlock.h index 859d673d98c8..fe450ee58d55 100644 --- a/include/linux/hwspinlock.h +++ b/include/linux/hwspinlock.h @@ -24,6 +24,7 @@ /* 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 +176,25 @@ 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 +262,29 @@ 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 +344,21 @@ 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 -- cgit From eebba71e1cb4f3464645c4b106f8ccc31bc5cd11 Mon Sep 17 00:00:00 2001 From: Suman Anna Date: Fri, 11 May 2018 12:03:16 -0500 Subject: hwspinlock/core: Switch to SPDX license identifier Use the appropriate SPDX license identifier in the Hwspinlock core driver source files and drop the previous boilerplate license text. Signed-off-by: Suman Anna Signed-off-by: Bjorn Andersson --- drivers/hwspinlock/Kconfig | 1 + drivers/hwspinlock/hwspinlock_core.c | 10 +--------- drivers/hwspinlock/hwspinlock_internal.h | 10 +--------- include/linux/hwspinlock.h | 10 +--------- 4 files changed, 4 insertions(+), 27 deletions(-) (limited to 'include/linux') diff --git a/drivers/hwspinlock/Kconfig b/drivers/hwspinlock/Kconfig index f0f467983960..e895d29500ee 100644 --- a/drivers/hwspinlock/Kconfig +++ b/drivers/hwspinlock/Kconfig @@ -1,3 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0 # # Generic HWSPINLOCK framework # diff --git a/drivers/hwspinlock/hwspinlock_core.c b/drivers/hwspinlock/hwspinlock_core.c index 5278d0560a4a..d16e6a3d38e8 100644 --- a/drivers/hwspinlock/hwspinlock_core.c +++ b/drivers/hwspinlock/hwspinlock_core.c @@ -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 - * - * 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__ diff --git a/drivers/hwspinlock/hwspinlock_internal.h b/drivers/hwspinlock/hwspinlock_internal.h index d26f78b8f214..9eb6bd020dc7 100644 --- a/drivers/hwspinlock/hwspinlock_internal.h +++ b/drivers/hwspinlock/hwspinlock_internal.h @@ -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 - * - * 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 diff --git a/include/linux/hwspinlock.h b/include/linux/hwspinlock.h index fe450ee58d55..57537e67b468 100644 --- a/include/linux/hwspinlock.h +++ b/include/linux/hwspinlock.h @@ -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 - * - * 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 -- cgit