From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arpit Goel Subject: [PATCH 2/2] Convert PowerPC macro spin_event_timeout() to architecture independent macro Date: Tue, 30 Jul 2013 18:08:20 +0530 Message-ID: <1375187900-17582-3-git-send-email-B44344@freescale.com> References: <1375187900-17582-1-git-send-email-B44344@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1375187900-17582-1-git-send-email-B44344@freescale.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: linux@arm.linux.org.uk, takata@linux-m32r.org, philb@gnu.org, geert@linux-m68k.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, linux390@de.ibm.com, davem@davemloft.net, rob.herring@calxeda.com, arnd@arndb.de, sboyd@codeaurora.org, swarren@nvidia.com, john.stultz@linaro.org, jesper.nilsson@axis.com, gregkh@linuxfoundation.org, sam@ravnborg.org Cc: linux-m32r-ja@ml.linux-m32r.org, linux-s390@vger.kernel.org, linux-m68k@vger.kernel.org, linux-m32r@ml.linux-m32r.org, Arpit Goel , linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: linux-m68k@vger.kernel.org This patch ports PowerPC implementation of spin_event_timeout() for generic use. Architecture specific implementation can be added to asm/delay.h, which will override the generic linux implementation. Signed-off-by: Arpit Goel --- include/linux/delay.h | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/include/linux/delay.h b/include/linux/delay.h index a6ecb34..e975994 100644 --- a/include/linux/delay.h +++ b/include/linux/delay.h @@ -52,4 +52,44 @@ static inline void ssleep(unsigned int seconds) msleep(seconds * 1000); } +#ifndef spin_event_timeout +/** + * spin_event_timeout - spin until a condition gets true or a timeout elapses + * @condition: a C expression to evalate + * @timeout: timeout, in microseconds + * @delay: the number of microseconds to delay between each evaluation of + * @condition + * + * The process spins until the condition evaluates to true (non-zero) or the + * timeout elapses. The return value of this macro is the value of + * @condition when the loop terminates. This allows you to determine the cause + * of the loop terminates. If the return value is zero, then you know a + * timeout has occurred. + * + * This primary purpose of this macro is to poll on a hardware register + * until a status bit changes. The timeout ensures that the loop still + * terminates even if the bit never changes. The delay is for devices that + * need a delay in between successive reads. + * + * gcc will optimize out the if-statement if @delay is a constant. + * + * This is copied from PowerPC based spin_event_timeout() implementation + * and modified for generic usecase. + */ +#define spin_event_timeout(condition, timeout, delay) \ +({ \ + typeof(condition) __ret; \ + unsigned long __loops = timeout/USECS_PER_JIFFY; \ + unsigned long __start = jiffies; \ + while (!(__ret = (condition)) && \ + time_before(jiffies, __start + __loops + 1)) \ + if (delay) \ + udelay(delay); \ + else \ + schedule(); \ + if (!__ret) \ + __ret = (condition); \ + __ret; \ +}) +#endif #endif /* defined(_LINUX_DELAY_H) */ -- 1.8.1.4