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[209.132.180.67]) by mx.google.com with ESMTP id 1-v6si13966741plk.308.2018.04.07.20.07.30; Sat, 07 Apr 2018 20:07:30 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=dQEpi18b; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752711AbeDHDH1 (ORCPT + 29 others); Sat, 7 Apr 2018 23:07:27 -0400 Received: from mail-pl0-f66.google.com ([209.85.160.66]:43290 "EHLO mail-pl0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752653AbeDHDHV (ORCPT ); Sat, 7 Apr 2018 23:07:21 -0400 Received: by mail-pl0-f66.google.com with SMTP id a39-v6so3018989pla.10 for ; Sat, 07 Apr 2018 20:07:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :in-reply-to:references; bh=PKhnu+eL7PQiHIcztMn8ouDbNj4UqGk9EvpLyjIbIlo=; b=dQEpi18bTNi27weRdm6Us/2RyCY+YKg7na8j6/nn9+Ke3pVh4eZbm2mgvhvID4TqGf KRn/0ME3NU4ZE2lt80acPKoerYHzts0AMAWS8aZ3a6l1dccun/FNdn/+ZAo2uxeYKzok fMgbLAY4U9pbU8jpXdejZz9akG+TFn+yJ/IBo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:in-reply-to:references; bh=PKhnu+eL7PQiHIcztMn8ouDbNj4UqGk9EvpLyjIbIlo=; b=BNUhh8zK0NXivxN1YDEaOheGI2D5NG1N9Ljdogs+DFjO4ZRR/OVaKKXVKTGDyz/uSi AXAwd4ZHcswIMCbXqFbiNlIVPnjhdU/c5oqV95BCB3PqhLzhCmooaaTEsweqvuA5Rz4m OB5AiyRvQIfU/82vEVVCyWFyi2mJSiKCNy4MTTnw5TO5pFqfWDMibDFzqydhxs1XU37t ZwA5JDMvHoaLZZlhu+4W/OFntJPwyc2aVLryD7nL9gP/po4nnCt9phXMWQdmvIwuoIWl FIhB6KbpBNsTXV4Y2SwFp1tvoL6ru/bFqKLpZBOR7g/pq2xU/cXDOMwYSEPXV3c7F37f AU6A== X-Gm-Message-State: AElRT7EQ0SK4KSw1n6ilnGFfMxDZWCz9u+TrzPUldwbu7g6IFIbkmJXW gYuhfdRx5XV8IwzsG8FNiqLzbg== X-Received: by 2002:a17:902:850b:: with SMTP id bj11-v6mr33775933plb.35.1523156840889; Sat, 07 Apr 2018 20:07:20 -0700 (PDT) Received: from baolinwangubtpc.spreadtrum.com ([117.18.48.82]) by smtp.gmail.com with ESMTPSA id t25sm28279825pfj.187.2018.04.07.20.07.18 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sat, 07 Apr 2018 20:07:20 -0700 (PDT) From: Baolin Wang To: ohad@wizery.com, bjorn.andersson@linaro.org Cc: arnd@arndb.de, broonie@kernel.org, linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org, baolin.wang@linaro.org Subject: [PATCH 2/2] hwspinlock: Introduce one new mode for hwspinlock Date: Sun, 8 Apr 2018 11:06:57 +0800 Message-Id: X-Mailer: git-send-email 1.7.9.5 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- drivers/hwspinlock/hwspinlock_core.c | 34 ++++++++++++++++---- include/linux/hwspinlock.h | 58 ++++++++++++++++++++++++++++++++++ 2 files changed, 85 insertions(+), 7 deletions(-) -- 1.7.9.5 diff --git a/drivers/hwspinlock/hwspinlock_core.c b/drivers/hwspinlock/hwspinlock_core.c index f4a59f5..5278d05 100644 --- a/drivers/hwspinlock/hwspinlock_core.c +++ b/drivers/hwspinlock/hwspinlock_core.c @@ -71,10 +71,16 @@ * 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 @@ -113,6 +119,9 @@ int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags) case HWLOCK_IRQ: ret = spin_trylock_irq(&hwlock->lock); break; + case HWLOCK_RAW: + ret = 1; + break; default: ret = spin_trylock(&hwlock->lock); break; @@ -134,6 +143,9 @@ int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags) case HWLOCK_IRQ: spin_unlock_irq(&hwlock->lock); break; + case HWLOCK_RAW: + /* Nothing to do */ + break; default: spin_unlock(&hwlock->lock); break; @@ -170,9 +182,14 @@ int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags) * 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. * @@ -266,6 +283,9 @@ void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags) case HWLOCK_IRQ: spin_unlock_irq(&hwlock->lock); break; + case HWLOCK_RAW: + /* Nothing to do */ + break; default: spin_unlock(&hwlock->lock); break; diff --git a/include/linux/hwspinlock.h b/include/linux/hwspinlock.h index 859d673..fe450ee 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; @@ -176,6 +177,25 @@ static inline int hwspin_trylock_irq(struct hwspinlock *hwlock) } /** + * 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 * @@ -243,6 +263,29 @@ int hwspin_lock_timeout_irq(struct hwspinlock *hwlock, unsigned int to) } /** + * 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 * @to: timeout value in msecs @@ -302,6 +345,21 @@ static inline void hwspin_unlock_irq(struct hwspinlock *hwlock) } /** + * 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 *