From patchwork Wed Nov 2 17:07:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephen Boyd X-Patchwork-Id: 620891 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7DFD3C43217 for ; Wed, 2 Nov 2022 17:07:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231144AbiKBRHY (ORCPT ); Wed, 2 Nov 2022 13:07:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33964 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230505AbiKBRHW (ORCPT ); Wed, 2 Nov 2022 13:07:22 -0400 Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7987212754 for ; Wed, 2 Nov 2022 10:07:20 -0700 (PDT) Received: by mail-pl1-x630.google.com with SMTP id d24so17175728pls.4 for ; Wed, 02 Nov 2022 10:07:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=z60DP3IMVx0PgF9XoRWoSbcT5zhGjG4qF0GcGyDN/6s=; b=dvi2lMLG9DYOkxlDlG+HeXOP5KkxvRZBS+MOB8MTFmsk3QF8Lh/Ro4/mVsgpL3Aunr AsMjm0RamScqgwwyFA7tgIy3o0mrT6S911XO3cuvQmMZ1Ok5Zq7sB18wZ7vyTZJPD+2r qMw+fBY8W8hCAM2urjRUmMSa98yJwipB6d+Xc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=z60DP3IMVx0PgF9XoRWoSbcT5zhGjG4qF0GcGyDN/6s=; b=F7LZVHUt4R1xgfwlWT+deF21B7RzpGFFqFsW19tRmP9QKcm+PIWc9k+dOY7cadc4H/ bl9rpJifIqoQ2mvSYg+MMFS5FzE0eOSTtIEvgcvd1VGBm1meNtIO/own4rxjSP8bv5bn y8jt50NzNiSwo0+qcD0mcrk2u4UuVUur04B0ixbE/MMnrV9CmbkyKqXYCT5fxDLfxgrx lpvrC4NYEn+lwPkvvGEBcFCpXo6vpGrLJffoA8UqmgFZtyqmSORIhv63H91QmJeygEv2 EsVCgya2KWTIirmB1aYXDVEuNWQfl68rXRSkpsCCar9NcuudqqFx64VJS3f/40h+uJUZ dGCA== X-Gm-Message-State: ACrzQf0vu067yV+gW4s4EMV4p55s1pkBLtiXG+oMIk4GwHiRoqd3a0p2 ncP32D1bpH75haPhVdIAQbOGUw== X-Google-Smtp-Source: AMsMyM6AKNnkgiRFAAD+XCA6VVUXb4HIYP5FrlTYKEIt8bl3YKcjm6xD5pfY3uA8JhL9icd3Hx4X4A== X-Received: by 2002:a17:902:dac3:b0:186:a437:f4b8 with SMTP id q3-20020a170902dac300b00186a437f4b8mr25604701plx.70.1667408839962; Wed, 02 Nov 2022 10:07:19 -0700 (PDT) Received: from smtp.gmail.com ([2620:15c:11a:201:4437:8d79:dd1:7eb8]) by smtp.gmail.com with ESMTPSA id j6-20020a17090a2a8600b002137d3da760sm1685034pjd.39.2022.11.02.10.07.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Nov 2022 10:07:19 -0700 (PDT) From: Stephen Boyd To: Michael Turquette , Stephen Boyd Cc: linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, patches@lists.linux.dev, Andy Gross , Bjorn Andersson , Konrad Dybcio , linux-arm-msm@vger.kernel.org, Dmitry Baryshkov , Johan Hovold , Ulf Hansson , Taniya Das , Satya Priya , Douglas Anderson , Matthias Kaehlcke Subject: [PATCH v2] clk: qcom: gdsc: Remove direct runtime PM calls Date: Wed, 2 Nov 2022 10:07:17 -0700 Message-Id: <20221102170717.1262547-1-swboyd@chromium.org> X-Mailer: git-send-email 2.38.1.273.g43a17bfeac-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org We shouldn't be calling runtime PM APIs from within the genpd enable/disable path for a couple reasons. First, this causes an AA lockdep splat because genpd can call into genpd code again while holding the genpd lock. WARNING: possible recursive locking detected 5.19.0-rc2-lockdep+ #7 Not tainted -------------------------------------------- kworker/2:1/49 is trying to acquire lock: ffffffeea0370788 (&genpd->mlock){+.+.}-{3:3}, at: genpd_lock_mtx+0x24/0x30 but task is already holding lock: ffffffeea03710a8 (&genpd->mlock){+.+.}-{3:3}, at: genpd_lock_mtx+0x24/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&genpd->mlock); lock(&genpd->mlock); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by kworker/2:1/49: #0: 74ffff80811a5748 ((wq_completion)pm){+.+.}-{0:0}, at: process_one_work+0x320/0x5fc #1: ffffffc008537cf8 ((work_completion)(&genpd->power_off_work)){+.+.}-{0:0}, at: process_one_work+0x354/0x5fc #2: ffffffeea03710a8 (&genpd->mlock){+.+.}-{3:3}, at: genpd_lock_mtx+0x24/0x30 stack backtrace: CPU: 2 PID: 49 Comm: kworker/2:1 Not tainted 5.19.0-rc2-lockdep+ #7 Hardware name: Google Lazor (rev3 - 8) with KB Backlight (DT) Workqueue: pm genpd_power_off_work_fn Call trace: dump_backtrace+0x1a0/0x200 show_stack+0x24/0x30 dump_stack_lvl+0x7c/0xa0 dump_stack+0x18/0x44 __lock_acquire+0xb38/0x3634 lock_acquire+0x180/0x2d4 __mutex_lock_common+0x118/0xe30 mutex_lock_nested+0x70/0x7c genpd_lock_mtx+0x24/0x30 genpd_runtime_suspend+0x2f0/0x414 __rpm_callback+0xdc/0x1b8 rpm_callback+0x4c/0xcc rpm_suspend+0x21c/0x5f0 rpm_idle+0x17c/0x1e0 __pm_runtime_idle+0x78/0xcc gdsc_disable+0x24c/0x26c _genpd_power_off+0xd4/0x1c4 genpd_power_off+0x2d8/0x41c genpd_power_off_work_fn+0x60/0x94 process_one_work+0x398/0x5fc worker_thread+0x42c/0x6c4 kthread+0x194/0x1b4 ret_from_fork+0x10/0x20 Second, this confuses runtime PM on CoachZ for the camera devices by causing the camera clock controller's runtime PM usage_count to go negative after resuming from suspend. This is because runtime PM is being used on the clock controller while runtime PM is disabled for the device. The reason for the negative count is because a GDSC is represented as a genpd and each genpd that is attached to a device is resumed during the noirq phase of system wide suspend/resume (see the noirq suspend ops assignment in pm_genpd_init() for more details). The camera GDSCs are attached to camera devices with the 'power-domains' property in DT. Every device has runtime PM disabled in the late system suspend phase via __device_suspend_late(). Runtime PM is not usable until runtime PM is enabled in device_resume_early(). The noirq phases run after the 'late' and before the 'early' phase of suspend/resume. When the genpds are resumed in genpd_resume_noirq(), we call down into gdsc_enable() that calls pm_runtime_resume_and_get() and that returns -EACCES to indicate failure to resume because runtime PM is disabled for all devices. Upon closer inspection, calling runtime PM APIs like this in the GDSC driver doesn't make sense. It was intended to make sure the GDSC for the clock controller providing other GDSCs was enabled, specifically the MMCX GDSC for the display clk controller on SM8250 (sm8250-dispcc), so that GDSC register accesses succeeded. That will already happen because we make the 'dev->pm_domain' a parent domain of each GDSC we register in gdsc_register() via pm_genpd_add_subdomain(). When any of these GDSCs are accessed, we'll enable the parent domain (in this specific case MMCX). We also remove any getting of runtime PM during registration, because when a genpd is registered it increments the count on the parent if the genpd itself is already enabled. And finally, the runtime PM state of the clk controller registering the GDSC shouldn't matter to the subdomain setup. Therefore we always assign 'dev' unconditionally so when GDSCs are removed we properly unlink the GDSC from the clk controller's pm_domain. Cc: Dmitry Baryshkov Cc: Johan Hovold Cc: Ulf Hansson Cc: Taniya Das Cc: Satya Priya Cc: Douglas Anderson Cc: Matthias Kaehlcke Reported-by: Stephen Boyd Fixes: 1b771839de05 ("clk: qcom: gdsc: enable optional power domain support") Signed-off-by: Stephen Boyd --- Changes from v1 (https://lore.kernel.org/r/20221101233421.997149-1-swboyd@chromium.org): * Fix ret thinko * Update kerneldoc on 'dev' member drivers/clk/qcom/gdsc.c | 62 +++++------------------------------------ drivers/clk/qcom/gdsc.h | 2 +- 2 files changed, 8 insertions(+), 56 deletions(-) base-commit: 9abf2313adc1ca1b6180c508c25f22f9395cc780 diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c index 7cf5e130e92f..36d44eec03b6 100644 --- a/drivers/clk/qcom/gdsc.c +++ b/drivers/clk/qcom/gdsc.c @@ -11,7 +11,6 @@ #include #include #include -#include #include #include #include @@ -56,22 +55,6 @@ enum gdsc_status { GDSC_ON }; -static int gdsc_pm_runtime_get(struct gdsc *sc) -{ - if (!sc->dev) - return 0; - - return pm_runtime_resume_and_get(sc->dev); -} - -static int gdsc_pm_runtime_put(struct gdsc *sc) -{ - if (!sc->dev) - return 0; - - return pm_runtime_put_sync(sc->dev); -} - /* Returns 1 if GDSC status is status, 0 if not, and < 0 on error */ static int gdsc_check_status(struct gdsc *sc, enum gdsc_status status) { @@ -271,8 +254,9 @@ static void gdsc_retain_ff_on(struct gdsc *sc) regmap_update_bits(sc->regmap, sc->gdscr, mask, mask); } -static int _gdsc_enable(struct gdsc *sc) +static int gdsc_enable(struct generic_pm_domain *domain) { + struct gdsc *sc = domain_to_gdsc(domain); int ret; if (sc->pwrsts == PWRSTS_ON) @@ -328,22 +312,11 @@ static int _gdsc_enable(struct gdsc *sc) return 0; } -static int gdsc_enable(struct generic_pm_domain *domain) +static int gdsc_disable(struct generic_pm_domain *domain) { struct gdsc *sc = domain_to_gdsc(domain); int ret; - ret = gdsc_pm_runtime_get(sc); - if (ret) - return ret; - - return _gdsc_enable(sc); -} - -static int _gdsc_disable(struct gdsc *sc) -{ - int ret; - if (sc->pwrsts == PWRSTS_ON) return gdsc_assert_reset(sc); @@ -388,18 +361,6 @@ static int _gdsc_disable(struct gdsc *sc) return 0; } -static int gdsc_disable(struct generic_pm_domain *domain) -{ - struct gdsc *sc = domain_to_gdsc(domain); - int ret; - - ret = _gdsc_disable(sc); - - gdsc_pm_runtime_put(sc); - - return ret; -} - static int gdsc_init(struct gdsc *sc) { u32 mask, val; @@ -447,11 +408,6 @@ static int gdsc_init(struct gdsc *sc) return ret; } - /* ...and the power-domain */ - ret = gdsc_pm_runtime_get(sc); - if (ret) - goto err_disable_supply; - /* * Votable GDSCs can be ON due to Vote from other masters. * If a Votable GDSC is ON, make sure we have a Vote. @@ -459,14 +415,14 @@ static int gdsc_init(struct gdsc *sc) if (sc->flags & VOTABLE) { ret = gdsc_update_collapse_bit(sc, false); if (ret) - goto err_put_rpm; + goto err_disable_supply; } /* Turn on HW trigger mode if supported */ if (sc->flags & HW_CTRL) { ret = gdsc_hwctrl(sc, true); if (ret < 0) - goto err_put_rpm; + goto err_disable_supply; } /* @@ -496,13 +452,10 @@ static int gdsc_init(struct gdsc *sc) ret = pm_genpd_init(&sc->pd, NULL, !on); if (ret) - goto err_put_rpm; + goto err_disable_supply; return 0; -err_put_rpm: - if (on) - gdsc_pm_runtime_put(sc); err_disable_supply: if (on && sc->rsupply) regulator_disable(sc->rsupply); @@ -541,8 +494,7 @@ int gdsc_register(struct gdsc_desc *desc, for (i = 0; i < num; i++) { if (!scs[i]) continue; - if (pm_runtime_enabled(dev)) - scs[i]->dev = dev; + scs[i]->dev = dev; scs[i]->regmap = regmap; scs[i]->rcdev = rcdev; ret = gdsc_init(scs[i]); diff --git a/drivers/clk/qcom/gdsc.h b/drivers/clk/qcom/gdsc.h index 981a12c8502d..47de72834a85 100644 --- a/drivers/clk/qcom/gdsc.h +++ b/drivers/clk/qcom/gdsc.h @@ -30,7 +30,7 @@ struct reset_controller_dev; * @resets: ids of resets associated with this gdsc * @reset_count: number of @resets * @rcdev: reset controller - * @dev: the device holding the GDSC, used for pm_runtime calls + * @dev: the device providing the GDSC */ struct gdsc { struct generic_pm_domain pd;