From patchwork Thu Nov 7 20:59:01 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nishanth Menon X-Patchwork-Id: 3154501 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 122B1BEEB2 for ; Thu, 7 Nov 2013 20:59:37 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id DC791204E2 for ; Thu, 7 Nov 2013 20:59:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A7202204C9 for ; Thu, 7 Nov 2013 20:59:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754111Ab3KGU7d (ORCPT ); Thu, 7 Nov 2013 15:59:33 -0500 Received: from bear.ext.ti.com ([192.94.94.41]:51479 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751010Ab3KGU7b (ORCPT ); Thu, 7 Nov 2013 15:59:31 -0500 Received: from dflxv15.itg.ti.com ([128.247.5.124]) by bear.ext.ti.com (8.13.7/8.13.7) with ESMTP id rA7Kx5Ba027343; Thu, 7 Nov 2013 14:59:05 -0600 Received: from DLEE71.ent.ti.com (dlee71.ent.ti.com [157.170.170.114]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id rA7Kx5pE007686; Thu, 7 Nov 2013 14:59:05 -0600 Received: from dlep32.itg.ti.com (157.170.170.100) by DLEE71.ent.ti.com (157.170.170.114) with Microsoft SMTP Server id 14.2.342.3; Thu, 7 Nov 2013 14:59:04 -0600 Received: from localhost (ileax41-snat.itg.ti.com [10.172.224.153]) by dlep32.itg.ti.com (8.14.3/8.13.8) with ESMTP id rA7Kx4NW027476; Thu, 7 Nov 2013 14:59:04 -0600 From: Nishanth Menon To: Tony Lindgren , CC: , , , , Nishanth Menon Subject: [PATCH] ARM: OMAP2+: omap_device: maintain sane runtime pm status around suspend/resume Date: Thu, 7 Nov 2013 14:59:01 -0600 Message-ID: <1383857942-23630-1-git-send-email-nm@ti.com> X-Mailer: git-send-email 1.7.9.5 MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, 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 OMAP device hooks around suspend|resume_noirq ensures that hwmod devices are forced to idle using omap_device_idle/enable as part of the last stage of suspend activity. For a device such as i2c who uses autosuspend, it is possible to enter the suspend path with dev->power.runtime_status = RPM_ACTIVE. As part of the suspend flow, the generic runtime logic would increment it's dev->power.disable_depth to 1. This should prevent further pm_runtime_get_sync from succeeding once the runtime_status has been set to RPM_SUSPENDED. Now, as part of the suspend_noirq handler in omap_device, we force the following: if the device status is !suspended, we force the device to idle using omap_device_idle (clocks are cut etc..). This ensures that from a hardware perspective, the device is "suspended". However, runtime_status is left to be active. *if* an operation is attempted after this point to pm_runtime_get_sync, runtime framework depends on runtime_status to indicate accurately the device status, and since it sees it to be ACTIVE, it assumes the module is functional and returns a non-error value. As a result the user will see pm_runtime_get succeed, however a register access will crash due to the lack of clocks. To prevent this from happening, we should ensure that runtime_status exactly indicates the device status. As a result of this change any further calls to pm_runtime_get* would return -EACCES (since disable_depth is 1). On resume, we restore the clocks and runtime status exactly as we suspended with. Reported-by: J Keerthy Signed-off-by: Nishanth Menon Acked-by: Rajendra Nayak --- patch baseline: V3.12 tag (also applies on linux-next next-20131107 tag) Logs from 3.12 based vendor kernel: Before: http://pastebin.com/m5KxnB7a After: http://pastebin.com/8AfX4e7r The discussion on cpufreq side of the story which triggered this scenario: http://marc.info/?l=linux-pm&m=138263811321921&w=2 Tested on TI vendor kernel (with dt boot): AM335x: evm, BBB, sk, BBW OMAP5uEVM, DRA7-evm arch/arm/mach-omap2/omap_device.c | 16 ++++++++++++++-- arch/arm/mach-omap2/omap_device.h | 1 + 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c index b69dd9a..87ecbb0 100644 --- a/arch/arm/mach-omap2/omap_device.c +++ b/arch/arm/mach-omap2/omap_device.c @@ -621,6 +621,13 @@ static int _od_suspend_noirq(struct device *dev) if (!ret && !pm_runtime_status_suspended(dev)) { if (pm_generic_runtime_suspend(dev) == 0) { + if (!pm_runtime_suspended(dev)) { + /* NOTE: *might* indicate driver race */ + dev_dbg(dev, "%s: Force suspending\n", + __func__); + pm_runtime_set_suspended(dev); + od->flags |= OMAP_DEVICE_SUSPEND_FORCED; + } omap_device_idle(pdev); od->flags |= OMAP_DEVICE_SUSPENDED; } @@ -634,10 +641,15 @@ static int _od_resume_noirq(struct device *dev) struct platform_device *pdev = to_platform_device(dev); struct omap_device *od = to_omap_device(pdev); - if ((od->flags & OMAP_DEVICE_SUSPENDED) && - !pm_runtime_status_suspended(dev)) { + if (od->flags & OMAP_DEVICE_SUSPENDED) { od->flags &= ~OMAP_DEVICE_SUSPENDED; omap_device_enable(pdev); + + if (od->flags & OMAP_DEVICE_SUSPEND_FORCED) { + pm_runtime_set_active(dev); + od->flags &= ~OMAP_DEVICE_SUSPEND_FORCED; + } + pm_generic_runtime_resume(dev); } diff --git a/arch/arm/mach-omap2/omap_device.h b/arch/arm/mach-omap2/omap_device.h index 17ca1ae..45885b0 100644 --- a/arch/arm/mach-omap2/omap_device.h +++ b/arch/arm/mach-omap2/omap_device.h @@ -38,6 +38,7 @@ extern struct dev_pm_domain omap_device_pm_domain; /* omap_device.flags values */ #define OMAP_DEVICE_SUSPENDED BIT(0) +#define OMAP_DEVICE_SUSPEND_FORCED BIT(1) /** * struct omap_device - omap_device wrapper for platform_devices