From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 211F02773D3; Mon, 29 Jun 2026 18:37:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782758252; cv=none; b=jBJEFKi1OuqR6MW/jTs/HT3pRT70FddlL5gvjDltL8jbpqF9gTWJV6Gipk/14jbWk4V9i1bINQy0sBU9X4drKbQxwCTjrRkUImM1d/YHrBxl1vWYoeUJjitJgRBRt1y5Bn5vZfA46kclygYFhbvAH/ox9DnI5zM7gN9xANL+q7g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782758252; c=relaxed/simple; bh=U/GD3njGPJZ6cyC69hIyOZoHm8SMjBNpuBG1/Y/igqA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=J9orOMZxyNJ255rR+A9Hyujfkl1AlieH0Urqn5x1r+trNn6Egi32E78DvbYkKa8uZOxRdWHgHD5Y/nDVg9f9JyHe79OZSXbx5ZK77dhbuL5kvG74yVDxuwGCnxelgFs1eY/frr+/ywseAfsI0oBIXxUoiWPfBU8hXqNlzl+O0LU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OCc7RPq7; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OCc7RPq7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 10BED1F000E9; Mon, 29 Jun 2026 18:37:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782758250; bh=XPiPL74SAk+eqBZk4tlvJWkRykwdPpKnj7n4ELAjaCY=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=OCc7RPq7MpD/xjWQlz2RCGwTT16lLKAYQ9WcZgmVoMhM5jZ4MkUQ5IhrqvCoZLSua E5EliCwA3upMoR7bbt5N6jfkrIHfxxmBZTUBkw304ZGoqln7qaqwoF/9dSu0+knBzD hiuh4joLze0JlBVrP7E+y9+bBdf7m2gsJMJHEP9WTBePLfyfmDaVGqTcZEgzOii1dq WFXuICp21eTQtv04ZKABgixnb2URSe9tHcuLXdCdDrhyi+ZcE80UAlpSQaVENlf6wV lpSOEUQl9Zn44rUFqYt2m2msgOWcFi85HcZ1sqALiXMcrsQfNormch4BT0dEPoGtUS W1QBfg0zcizXQ== Message-ID: Date: Mon, 29 Jun 2026 20:37:22 +0200 Precedence: bulk X-Mailing-List: linux-clk@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 5/5] clk: implement sync_state support To: dongxuyang@eswincomputing.com, Brian Masney , Saravana Kannan , Abel Vesa , Maxime Ripard , Michael Turquette , Stephen Boyd , Russell King , Bjorn Andersson , Hans de Goede , Konrad Dybcio , Dmitry Baryshkov Cc: linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, Jens Glathe , Min Lin References: <20260616-clk-sync-state-v2-5-15f82c64d95c@redhat.com> <20260617092538.1098-1-dongxuyang@eswincomputing.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 17/06/2026 11:25, dongxuyang@eswincomputing.com wrote: >> >> The existing support for disabling unused clks runs in the late initcall >> stage, and it has been known for a long time that this is broken since >> it runs too early in the boot up process. It doesn't work for kernel >> modules, and it also doesn't work if all of the consumers haven't fully >> probed yet. Folks have long recommended to boot certain platforms with >> clk_ignore_unused to work around issues with disabling unused clks. >> >> >> Let's go ahead and add a framework-level sync_state callback for the clk >> subsystem. If a driver doesn't have a sync_state callback configured, >> which is the 99+% use case today, then let's set it up to use the >> clk_sync_state() introduced in this commit so that no driver changes >> are needed. >> >> >> At the time of this writing, there are currently only 7 clk drivers that >> implement sync_state, and all are Qualcomm SoCs where they interact with >> the interconnect framework via icc_sync_state(). A shared helper has >> been created for this platform that calls clk_sync_state(). It is >> expected that any new clk drivers that want to implement their own >> sync_state will also need to call clk_sync_state() at the end of their >> custom sync_state callback. >> >> >> There will be several stages of disabling unused clks: >> >> >> - The first phase will be executed at late_initcall and it will only >> disable unused clks that do not have a struct dev. >> - The sync_state callback will be invoked for each clk driver once all >> consumers have probed. >> >> >> This is based on previous attempts by Saravana Kannan and Abel Vesa >> that are linked below. >> >> >> This change was tested on a Thinkpad x13s laptop. >> >> >> [ 0.308051] clk: Disabling unused clocks not associated with a device >> [ 6.541069] qcom_aoss_qmp c300000.power-management: clk: Disabling unused clocks >> [ 6.843310] qcom-qmp-pcie-phy 1c24000.phy: clk: Disabling unused clocks >> [ 7.604556] qcom-qmp-pcie-phy 1c14000.phy: clk: Disabling unused clocks >> [ 8.446161] qcom-qmp-usb-phy 88f1000.phy: clk: Disabling unused clocks >> [ 8.446293] qcom-qmp-usb-phy 88ef000.phy: clk: Disabling unused clocks >> [ 8.546067] qcom-qmp-combo-phy 88eb000.phy: clk: Disabling unused clocks >> [ 8.546203] qcom-qmp-combo-phy 8903000.phy: clk: Disabling unused clocks >> [ 8.546254] qcom-edp-phy aec5a00.phy: clk: Disabling unused clocks >> [ 15.436834] qcom-cpufreq-hw 18591000.cpufreq: clk: Disabling unused clocks >> [ 15.436953] clk-rpmh 18200000.rsc:clock-controller: clk: Disabling unused clocks >> [ 15.723348] qcom-qmp-pcie-phy 1c06000.phy: clk: Disabling unused clocks >> [ 21.063241] q6prm-lpass-clock 3000000.remoteproc:glink-edge:gpr:service@2:clock-controller: clk: Disabling unused clocks >> [ 21.081996] va_macro 3370000.codec: clk: Disabling unused clocks >> [ 21.092740] rx_macro 3200000.rxmacro: clk: Disabling unused clocks >> [ 21.118261] wsa_macro 3240000.codec: clk: Disabling unused clocks >> [ 21.128758] tx_macro 3220000.txmacro: clk: Disabling unused clocks >> >> >> Tested-by: Jens Glathe >> Signed-off-by: Brian Masney >> Link: https://www.youtube.com/watch?v=tXYzM8yLIQA >> Link: https://lore.kernel.org/all/20210407034456.516204-1-saravanak@google.com/ >> Link: https://lore.kernel.org/all/20221227204528.1899863-1-abel.vesa@linaro.org/ >> --- >> drivers/clk/clk.c | 72 ++++++++++++++++++++++++++++++++++++++--------- >> 1 file changed, 59 insertions(+), 13 deletions(-) >> >> >> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c >> index 9cb2b42d1be4..7a15cceec620 100644 >> --- a/drivers/clk/clk.c >> +++ b/drivers/clk/clk.c >> @@ -1442,14 +1442,39 @@ static void clk_core_disable_unprepare(struct clk_core *core) >> clk_core_unprepare_lock(core); >> } >> >> -static void __init clk_unprepare_unused_subtree(struct clk_core *core) >> +/* >> + * Returns true if @core should be skipped during an unused-clock sweep for >> + * @dev. When @dev is NULL the sweep is the global late_initcall pass; when >> + * @dev is non-NULL the sweep is a per-device sync_state pass. >> + */ >> +static bool clk_core_skip_unused(struct clk_core *core, struct device *dev) >> +{ >> + /* >> + * At late_initcall, skip clocks that belong to a device — they will be >> + * handled at sync_state time. >> + */ >> + if (!dev && core->dev) >> + return true; >> + >> + /* When called from sync_state, only process clocks for this device. */ >> + if (dev && core->dev != dev) >> + return true; >> + >> + return false; >> +} >> + >> +static void clk_unprepare_unused_subtree(struct clk_core *core, >> + struct device *dev) >> { >> struct clk_core *child; >> >> lockdep_assert_held(&prepare_lock); >> >> hlist_for_each_entry(child, &core->children, child_node) >> - clk_unprepare_unused_subtree(child); >> + clk_unprepare_unused_subtree(child, dev); >> + >> + if (clk_core_skip_unused(core, dev)) >> + return; >> >> if (core->prepare_count) >> return; >> @@ -1467,7 +1492,8 @@ static void __init clk_unprepare_unused_subtree(struct clk_core *core) >> } >> } >> >> -static void __init clk_disable_unused_subtree(struct clk_core *core) >> +static void clk_disable_unused_subtree(struct clk_core *core, >> + struct device *dev) >> { >> struct clk_core *child; >> unsigned long flags; >> @@ -1475,7 +1501,10 @@ static void __init clk_disable_unused_subtree(struct clk_core *core) >> lockdep_assert_held(&prepare_lock); >> >> hlist_for_each_entry(child, &core->children, child_node) >> - clk_disable_unused_subtree(child); >> + clk_disable_unused_subtree(child, dev); >> + >> + if (clk_core_skip_unused(core, dev)) >> + return; >> >> if (core->flags & CLK_OPS_PARENT_ENABLE) >> clk_core_prepare_enable(core->parent); >> @@ -1508,7 +1537,7 @@ static void __init clk_disable_unused_subtree(struct clk_core *core) >> clk_core_disable_unprepare(core->parent); >> } >> >> -static bool clk_ignore_unused __initdata; >> +static bool clk_ignore_unused; >> static int __init clk_ignore_unused_setup(char *__unused) >> { >> clk_ignore_unused = true; >> @@ -1516,7 +1545,7 @@ static int __init clk_ignore_unused_setup(char *__unused) >> } >> __setup("clk_ignore_unused", clk_ignore_unused_setup); >> >> -static int __init clk_disable_unused(void) >> +static int __clk_disable_unused(struct device *dev) >> { >> struct clk_core *core; >> int ret; >> @@ -1526,7 +1555,10 @@ static int __init clk_disable_unused(void) >> return 0; >> } >> >> - pr_info("clk: Disabling unused clocks\n"); >> + if (dev) >> + dev_info(dev, "clk: Disabling unused clocks\n"); >> + else >> + pr_info("clk: Disabling unused clocks not associated with a device\n"); >> >> ret = clk_pm_runtime_get_all(); >> if (ret) >> @@ -1538,16 +1570,16 @@ static int __init clk_disable_unused(void) >> clk_prepare_lock(); >> >> hlist_for_each_entry(core, &clk_root_list, child_node) >> - clk_disable_unused_subtree(core); >> + clk_disable_unused_subtree(core, dev); >> >> hlist_for_each_entry(core, &clk_orphan_list, child_node) >> - clk_disable_unused_subtree(core); >> + clk_disable_unused_subtree(core, dev); >> >> hlist_for_each_entry(core, &clk_root_list, child_node) >> - clk_unprepare_unused_subtree(core); >> + clk_unprepare_unused_subtree(core, dev); >> >> hlist_for_each_entry(core, &clk_orphan_list, child_node) >> - clk_unprepare_unused_subtree(core); >> + clk_unprepare_unused_subtree(core, dev); >> >> clk_prepare_unlock(); >> >> @@ -1555,11 +1587,16 @@ static int __init clk_disable_unused(void) >> >> return 0; >> } >> + >> +static int __init clk_disable_unused(void) >> +{ >> + return __clk_disable_unused(NULL); >> +} >> late_initcall_sync(clk_disable_unused); >> >> void clk_sync_state(struct device *dev) >> { >> - /* Will fill in */ >> + __clk_disable_unused(dev); >> } >> EXPORT_SYMBOL_GPL(clk_sync_state); >> >> @@ -4345,8 +4382,17 @@ __clk_register(struct device *dev, struct device_node *np, struct clk_hw *hw) >> core->dev = dev; >> clk_pm_runtime_init(core); >> core->of_node = np; >> - if (dev && dev->driver) >> + if (dev && dev->driver) { >> core->owner = dev->driver->owner; >> + >> + /* >> + * If a clk provider sets their own sync_state, then it needs to >> + * also call clk_sync_state(). dev_set_drv_sync_state() won't >> + * overwrite the sync_state callback, and this call will fail >> + * with -EBUSY. >> + */ >> + dev_set_drv_sync_state(dev, clk_sync_state); >> + } >> core->hw = hw; >> core->flags = init->flags; >> core->num_parents = init->num_parents; > > Hi Brian, > > Thank you for the patch set. I tested this in my tree on Sifive HiFive > Premier P550, and it behaved correctly. > > Tested-by: Xuyang Dong # hfp550 If I understand correctly your platform, you tested nothing. You executed no code from common part and no code from the drivers listed here. This is not a real test in such case. When you test code, please actually be sure you execute the tested code. I am afraid the tag is not applicable. Best regards, Krzysztof