From patchwork Tue Mar 19 17:38:15 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Hunter, Jon" X-Patchwork-Id: 2303361 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork2.kernel.org (Postfix) with ESMTP id B7ED9DFB79 for ; Tue, 19 Mar 2013 17:41:45 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UI0V6-00018I-AA; Tue, 19 Mar 2013 17:39:04 +0000 Received: from devils.ext.ti.com ([198.47.26.153]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UI0UT-00012Y-5v for linux-arm-kernel@lists.infradead.org; Tue, 19 Mar 2013 17:38:29 +0000 Received: from dlelxv30.itg.ti.com ([172.17.2.17]) by devils.ext.ti.com (8.13.7/8.13.7) with ESMTP id r2JHcNmZ024719; Tue, 19 Mar 2013 12:38:23 -0500 Received: from DLEE71.ent.ti.com (dlee71.ent.ti.com [157.170.170.114]) by dlelxv30.itg.ti.com (8.13.8/8.13.8) with ESMTP id r2JHcNlq015220; Tue, 19 Mar 2013 12:38:23 -0500 Received: from dlelxv24.itg.ti.com (172.17.1.199) by DLEE71.ent.ti.com (157.170.170.114) with Microsoft SMTP Server id 14.2.342.3; Tue, 19 Mar 2013 12:38:22 -0500 Received: from legion.dal.design.ti.com (legion.dal.design.ti.com [128.247.22.53]) by dlelxv24.itg.ti.com (8.13.8/8.13.8) with ESMTP id r2JHcMM9018319; Tue, 19 Mar 2013 12:38:22 -0500 Received: from localhost (ula0741266.am.dhcp.ti.com [192.157.144.139]) by legion.dal.design.ti.com (8.11.7p1+Sun/8.11.7) with ESMTP id r2JHcMV01782; Tue, 19 Mar 2013 12:38:22 -0500 (CDT) From: Jon Hunter To: Tony Lindgren , Benoit Cousson Subject: [PATCH 1/5] ARM: OMAP: Simplify dmtimer context-loss handling Date: Tue, 19 Mar 2013 12:38:15 -0500 Message-ID: <1363714699-29622-2-git-send-email-jon-hunter@ti.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1363714699-29622-1-git-send-email-jon-hunter@ti.com> References: <1363714699-29622-1-git-send-email-jon-hunter@ti.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130319_133825_486029_02C3CFBC X-CRM114-Status: GOOD ( 14.77 ) X-Spam-Score: -9.4 (---------) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-9.4 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at http://www.dnswl.org/, high trust [198.47.26.153 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -2.5 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: NeilBrown , device-tree , linux-omap , Jon Hunter , linux-arm X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org From: NeilBrown The context loss handling in dmtimer appears to assume that omap_dm_timer_set_load_start() or omap_dm_timer_start() and omap_dm_timer_stop() bracket all interactions. Only the first two restore the context and the last updates the context loss counter. However omap_dm_timer_set_load() or omap_dm_timer_set_match() can reasonably be called outside this bracketing, and the fact that they call omap_dm_timer_enable() / omap_dm_timer_disable() suggest that is expected. So if, after a transition into and out of off-mode which would cause the dm timer to loose all state, omap_dm_timer_set_match() is called before omap_dm_timer_start(), the value read from OMAP_TIMER_CTRL_REG will be 'wrong' and this wrong value will be stored context.tclr so a subsequent omap_dm_timer_start() can fail (As the control register is wrong). Simplify this be doing the restore-from-context in omap_dm_timer_enable() so that whenever the timer is enabled, the context is correct. Also update the ctx_loss_count at the same time as we notice it is wrong - these is no value in delaying this until the omap_dm_timer_disable() as it cannot change while the timer is enabled. Signed-off-by: NeilBrown [jon-hunter@ti.com: minor update to subject and changed variable name] Signed-off-by: Jon Hunter --- arch/arm/plat-omap/dmtimer.c | 32 ++++++++++++-------------------- 1 file changed, 12 insertions(+), 20 deletions(-) diff --git a/arch/arm/plat-omap/dmtimer.c b/arch/arm/plat-omap/dmtimer.c index a0daa2f..5cae1dd 100644 --- a/arch/arm/plat-omap/dmtimer.c +++ b/arch/arm/plat-omap/dmtimer.c @@ -315,7 +315,19 @@ EXPORT_SYMBOL_GPL(omap_dm_timer_free); void omap_dm_timer_enable(struct omap_dm_timer *timer) { + int c; + pm_runtime_get_sync(&timer->pdev->dev); + + if (!(timer->capability & OMAP_TIMER_ALWON)) { + if (timer->get_context_loss_count) { + c = timer->get_context_loss_count(&timer->pdev->dev); + if (c != timer->ctx_loss_count) { + omap_timer_restore_context(timer); + timer->ctx_loss_count = c; + } + } + } } EXPORT_SYMBOL_GPL(omap_dm_timer_enable); @@ -410,13 +422,6 @@ int omap_dm_timer_start(struct omap_dm_timer *timer) omap_dm_timer_enable(timer); - if (!(timer->capability & OMAP_TIMER_ALWON)) { - if (timer->get_context_loss_count && - timer->get_context_loss_count(&timer->pdev->dev) != - timer->ctx_loss_count) - omap_timer_restore_context(timer); - } - l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG); if (!(l & OMAP_TIMER_CTRL_ST)) { l |= OMAP_TIMER_CTRL_ST; @@ -441,12 +446,6 @@ int omap_dm_timer_stop(struct omap_dm_timer *timer) __omap_dm_timer_stop(timer, timer->posted, rate); - if (!(timer->capability & OMAP_TIMER_ALWON)) { - if (timer->get_context_loss_count) - timer->ctx_loss_count = - timer->get_context_loss_count(&timer->pdev->dev); - } - /* * Since the register values are computed and written within * __omap_dm_timer_stop, we need to use read to retrieve the @@ -553,13 +552,6 @@ int omap_dm_timer_set_load_start(struct omap_dm_timer *timer, int autoreload, omap_dm_timer_enable(timer); - if (!(timer->capability & OMAP_TIMER_ALWON)) { - if (timer->get_context_loss_count && - timer->get_context_loss_count(&timer->pdev->dev) != - timer->ctx_loss_count) - omap_timer_restore_context(timer); - } - l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG); if (autoreload) { l |= OMAP_TIMER_CTRL_AR;