From patchwork Fri May 1 17:06:32 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lina Iyer X-Patchwork-Id: 6311971 X-Patchwork-Delegate: agross@codeaurora.org Return-Path: X-Original-To: patchwork-linux-arm-msm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 8BDB4BEEE1 for ; Fri, 1 May 2015 17:07:37 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A5B092043C for ; Fri, 1 May 2015 17:07:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AD0982042B for ; Fri, 1 May 2015 17:07:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752066AbbEARHA (ORCPT ); Fri, 1 May 2015 13:07:00 -0400 Received: from mail-ig0-f171.google.com ([209.85.213.171]:35330 "EHLO mail-ig0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752059AbbEARG7 (ORCPT ); Fri, 1 May 2015 13:06:59 -0400 Received: by igbyr2 with SMTP id yr2so43620837igb.0 for ; Fri, 01 May 2015 10:06:59 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=bs9Dx67EI7zNCfqaEaU1N9pKlaGbqCMHKicmfqqNJXk=; b=gxwRBQR7rwDjNOTgwXwh/8u7zfg+GJaNZGk7/qRdLX909BskzjvoM6XxWWvZEDJ8zF WSh+6TsNAs7HcWxgvX4XtBANGjet7/7o1CTsvB7aF5IsSmoq9NG+8a7WHTbZEZXUQ+gz F5xw/U+/qP09k1CN0KNygAt0Ex79M4H71cmmZD2dkuzUOzSSYg9ALIf6t4PM+JfTvDES gjY49aBkozCh3KABeTN2XrzjwUyanKZCgAtwUksm4LTzNDsn36cSRTomAc2arU0Fuse8 eXFMfFbjF9aBgrYOTff35bXSsIrM9LFtbEHPbVITk875n+pHN5CHow3w8IUWana5CdZb 0XFQ== X-Gm-Message-State: ALoCoQmmjUz7Mn6zJ32d12QeV+6BOG5lqyDVHWxhtiegfrQS3NZnuJwV3DQRgv35q2BCU7Jwpa7I X-Received: by 10.50.66.230 with SMTP id i6mr11740244igt.22.1430500019295; Fri, 01 May 2015 10:06:59 -0700 (PDT) Received: from localhost.localdomain (c-24-8-37-141.hsd1.co.comcast.net. [24.8.37.141]) by mx.google.com with ESMTPSA id t41sm3869172ioe.5.2015.05.01.10.06.58 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 01 May 2015 10:06:58 -0700 (PDT) From: Lina Iyer To: ohad@wizery.com, s-anna@ti.com, Bjorn.Andersson@sonymobile.com, agross@codeaurora.org Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, galak@codeaurora.org, jhugo@codeaurora.org, Lina Iyer , Bjorn Andersson Subject: [PATCH] hwspinlock: qcom: Lock #7 is special lock, uses dynamic proc_id Date: Fri, 1 May 2015 11:06:32 -0600 Message-Id: <1430499992-47944-1-git-send-email-lina.iyer@linaro.org> X-Mailer: git-send-email 2.1.4 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Hwspinlocks are widely used between processors in an SoC, and also between elevation levels within in the same processor. QCOM SoC's use hwspinlock to serialize entry into a low power mode when the context switches from Linux to secure monitor. Lock #7 has been assigned for this purpose. In order to differentiate between one cpu core holding a lock while another cpu is contending for the same lock, the proc id written into the lock is (128 + cpu id). This makes it unique value among the cpu cores and therefore when a core locks the hwspinlock, other cores would wait for the lock to be released since they would have a different proc id. This value is specific for the lock #7 only. Cc: Jeffrey Hugo Cc: Bjorn Andersson Cc: Andy Gross Signed-off-by: Lina Iyer --- drivers/hwspinlock/qcom_hwspinlock.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/hwspinlock/qcom_hwspinlock.c b/drivers/hwspinlock/qcom_hwspinlock.c index 93b62e0..043c62c 100644 --- a/drivers/hwspinlock/qcom_hwspinlock.c +++ b/drivers/hwspinlock/qcom_hwspinlock.c @@ -25,16 +25,26 @@ #include "hwspinlock_internal.h" -#define QCOM_MUTEX_APPS_PROC_ID 1 -#define QCOM_MUTEX_NUM_LOCKS 32 +#define QCOM_MUTEX_APPS_PROC_ID 1 +#define QCOM_MUTEX_CPUIDLE_OFFSET 128 +#define QCOM_CPUIDLE_LOCK 7 +#define QCOM_MUTEX_NUM_LOCKS 32 + +static inline u32 __qcom_get_proc_id(struct hwspinlock *lock) +{ + return hwspin_lock_get_id(lock) == QCOM_CPUIDLE_LOCK ? + (QCOM_MUTEX_CPUIDLE_OFFSET + smp_processor_id()) : + QCOM_MUTEX_APPS_PROC_ID; +} static int qcom_hwspinlock_trylock(struct hwspinlock *lock) { struct regmap_field *field = lock->priv; u32 lock_owner; int ret; + u32 proc_id = __qcom_get_proc_id(lock); - ret = regmap_field_write(field, QCOM_MUTEX_APPS_PROC_ID); + ret = regmap_field_write(field, proc_id); if (ret) return ret; @@ -42,7 +52,7 @@ static int qcom_hwspinlock_trylock(struct hwspinlock *lock) if (ret) return ret; - return lock_owner == QCOM_MUTEX_APPS_PROC_ID; + return lock_owner == proc_id; } static void qcom_hwspinlock_unlock(struct hwspinlock *lock) @@ -57,7 +67,7 @@ static void qcom_hwspinlock_unlock(struct hwspinlock *lock) return; } - if (lock_owner != QCOM_MUTEX_APPS_PROC_ID) { + if (lock_owner != __qcom_get_proc_id(lock)) { pr_err("%s: spinlock not owned by us (actual owner is %d)\n", __func__, lock_owner); }