From patchwork Fri Dec 7 20:26:34 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Hunter, Jon" X-Patchwork-Id: 1851611 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id 414D7400ED for ; Fri, 7 Dec 2012 20:29:21 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1Th4VQ-0001kc-3D; Fri, 07 Dec 2012 20:26:44 +0000 Received: from comal.ext.ti.com ([198.47.26.152]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1Th4VM-0001k3-9A for linux-arm-kernel@lists.infradead.org; Fri, 07 Dec 2012 20:26:41 +0000 Received: from dlelxv30.itg.ti.com ([172.17.2.17]) by comal.ext.ti.com (8.13.7/8.13.7) with ESMTP id qB7KQbLL017678; Fri, 7 Dec 2012 14:26:37 -0600 Received: from DLEE74.ent.ti.com (dlee74.ent.ti.com [157.170.170.8]) by dlelxv30.itg.ti.com (8.13.8/8.13.8) with ESMTP id qB7KQbJ2013979; Fri, 7 Dec 2012 14:26:37 -0600 Received: from dlelxv24.itg.ti.com (172.17.1.199) by DLEE74.ent.ti.com (157.170.170.8) with Microsoft SMTP Server id 14.1.323.3; Fri, 7 Dec 2012 14:26:37 -0600 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 qB7KQb6K016385; Fri, 7 Dec 2012 14:26:37 -0600 Received: from localhost (h113-201.vpn.ti.com [172.24.113.201]) by legion.dal.design.ti.com (8.11.7p1+Sun/8.11.7) with ESMTP id qB7KQaw11709; Fri, 7 Dec 2012 14:26:36 -0600 (CST) From: Jon Hunter To: Paul Walmsley Subject: [PATCH] ARM: OMAP4: Fix EMU clock domain always on Date: Fri, 7 Dec 2012 14:26:34 -0600 Message-ID: <1354911994-20045-1-git-send-email-jon-hunter@ti.com> X-Mailer: git-send-email 1.7.10.4 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20121207_152640_490715_341337F2 X-CRM114-Status: GOOD ( 11.81 ) X-Spam-Score: -7.6 (-------) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-7.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at http://www.dnswl.org/, high trust [198.47.26.152 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -0.7 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: linux-omap , Mike Turquette , Jon Hunter , linux-arm X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Commit d043d87 (ARM: OMAP2+: clockdomain: bypass clockdomain handling when disabling unused clks) skips the decrementing of a clock-domains use count if the clocks use count is zero. However, for OMAP4 devices this is causing the EMU clock-domain to be stuck ON as the use count is not getting decremented correctly. The scenario that leads to this problem is described below ... omap_hwmod_setup_all --> _setup --> clkdm_hwmod_enable --> EMU clock domain usecount = 1 --> _enable_clocks --> clk_enable --> trace_clk_div_div usecount = 1 --> clkdm_hwmod_enable --> EMU clock domain usecount = 2 --> _idle --> _disable_clocks --> clk_disable --> trace_clk_div_div usecount = 0 --> clkdm_hwmod_disable --> skips decrement of EMU clock domain usecount because trace_clk_div_div is 0! --> EMU clock domain usecount = 2 --> clkdm_hwmod_disable --> EMU clock domain usecount = 1 Hence, due to the order that a clocks use count is decremented and the clock domain is disabled, it is possible that the clock domain can have a non-zero use count when the actual clock has a use count of 0. Therefore, we should only bypass the clock-domain handling when both the clock-domain and clock in the clock-domain have a use count of 0 and warn when the clock-domain has a zero use count and the clock has a non-zero use count. Signed-off-by: Jon Hunter --- Based and test on current linux-next tree. This has been boot tested on OMAP2420, OMAP3430 and OMAP4430. I have validated suspend is working on OMAP3430. arch/arm/mach-omap2/clockdomain.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm/mach-omap2/clockdomain.c b/arch/arm/mach-omap2/clockdomain.c index 3848735..0b5452d 100644 --- a/arch/arm/mach-omap2/clockdomain.c +++ b/arch/arm/mach-omap2/clockdomain.c @@ -998,7 +998,8 @@ int clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk) spin_lock_irqsave(&clkdm->lock, flags); /* corner case: disabling unused clocks */ - if (__clk_get_enable_count(clk) == 0) + if ((__clk_get_enable_count(clk) == 0) && + (atomic_read(&clkdm->usecount) == 0)) goto ccd_exit; if (atomic_read(&clkdm->usecount) == 0) {