[PATCH v4 03/68] clk: Move no reparent case into a separate function

[Marek Szyprowski]

On 13.06.2023 13:15, Marek Szyprowski wrote:
> On 05.05.2023 13:25, Maxime Ripard wrote:
>> From: Stephen Boyd <sboyd at kernel.org>
>>
>> We'll need to turn the code in clk_mux_determine_rate_flags() to deal
>> with CLK_SET_RATE_NO_REPARENT into a helper clock drivers will be able
>> to use if they don't want to allow reparenting.
>>
>> Cc: Abel Vesa <abelvesa at kernel.org>
>> Cc: Alessandro Zummo <a.zummo at towertech.it>
>> Cc: Alexandre Belloni <alexandre.belloni at bootlin.com>
>> Cc: Alexandre Torgue <alexandre.torgue at foss.st.com>
>> Cc: "Andreas Färber" <afaerber at suse.de>
>> Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
>> Cc: Baolin Wang <baolin.wang at linux.alibaba.com>
>> Cc: Charles Keepax <ckeepax at opensource.cirrus.com>
>> Cc: Chen-Yu Tsai <wens at csie.org>
>> Cc: Chen-Yu Tsai <wenst at chromium.org>
>> Cc: Chunyan Zhang <zhang.lyra at gmail.com>
>> Cc: Claudiu Beznea <claudiu.beznea at microchip.com>
>> Cc: Daniel Vetter <daniel at ffwll.ch>
>> Cc: David Airlie <airlied at gmail.com>
>> Cc: David Lechner <david at lechnology.com>
>> Cc: Dinh Nguyen <dinguyen at kernel.org>
>> Cc: Fabio Estevam <festevam at gmail.com>
>> Cc: Geert Uytterhoeven <geert+renesas at glider.be>
>> Cc: Jaroslav Kysela <perex at perex.cz>
>> Cc: Jernej Skrabec <jernej.skrabec at gmail.com>
>> Cc: Jonathan Hunter <jonathanh at nvidia.com>
>> Cc: Kishon Vijay Abraham I <kishon at kernel.org>
>> Cc: Liam Girdwood <lgirdwood at gmail.com>
>> Cc: Linus Walleij <linus.walleij at linaro.org>
>> Cc: Luca Ceresoli <luca.ceresoli at bootlin.com>
>> Cc: Manivannan Sadhasivam <mani at kernel.org>
>> Cc: Mark Brown <broonie at kernel.org>
>> Cc: Markus Schneider-Pargmann <msp at baylibre.com>
>> Cc: Max Filippov <jcmvbkbc at gmail.com>
>> Cc: Maxime Coquelin <mcoquelin.stm32 at gmail.com>
>> Cc: Mikko Perttunen <mperttunen at nvidia.com>
>> Cc: Miles Chen <miles.chen at mediatek.com>
>> Cc: Nicolas Ferre <nicolas.ferre at microchip.com>
>> Cc: Orson Zhai <orsonzhai at gmail.com>
>> Cc: Paul Cercueil <paul at crapouillou.net>
>> Cc: Peng Fan <peng.fan at nxp.com>
>> Cc: Peter De Schrijver <pdeschrijver at nvidia.com>
>> Cc: Prashant Gaikwad <pgaikwad at nvidia.com>
>> Cc: Richard Fitzgerald <rf at opensource.cirrus.com>
>> Cc: Samuel Holland <samuel at sholland.org>
>> Cc: Sascha Hauer <s.hauer at pengutronix.de>
>> Cc: Sekhar Nori <nsekhar at ti.com>
>> Cc: Shawn Guo <shawnguo at kernel.org>
>> Cc: Takashi Iwai <tiwai at suse.com>
>> Cc: Thierry Reding <thierry.reding at gmail.com>
>> Cc: Ulf Hansson <ulf.hansson at linaro.org>
>> Cc: Vinod Koul <vkoul at kernel.org>
>> Cc: dri-devel at lists.freedesktop.org
>> Cc: linux-actions at lists.infradead.org
>> Cc: linux-arm-kernel at lists.infradead.org
>> Cc: linux-mips at vger.kernel.org
>> Cc: linux-phy at lists.infradead.org
>> Cc: linux-renesas-soc at vger.kernel.org
>> Cc: linux-rtc at vger.kernel.org
>> Cc: linux-stm32 at st-md-mailman.stormreply.com
>> Cc: linux-sunxi at lists.linux.dev
>> Cc: linux-tegra at vger.kernel.org
>> Cc: NXP Linux Team <linux-imx at nxp.com>
>> Cc: patches at opensource.cirrus.com
>> Cc: Pengutronix Kernel Team <kernel at pengutronix.de>
>> Signed-off-by: Stephen Boyd <sboyd at kernel.org>
>> Signed-off-by: Maxime Ripard <maxime at cerno.tech>
>> ---
>
> This patch landed in today's linux-next as commit 1b4e99fda73f ("clk: 
> Move no reparent case into a separate function"). Unfortunately it 
> causes serious regression of some of my test boards. Namely Exynos3250 
> based boards are so slow after it, that my test scripts fail with a 
> timeout waiting for them to finish booting. I will try to debug this 
> later in the evening to check what has happened that some clocks got 
> very low rate.
>
I just got a few spare minutes, so I decided to take a look into this 
issue. The following change fixed my problem:

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index ffc9f03840b7..7ac9f7a8cb84 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -629,6 +629,7 @@ clk_core_determine_rate_no_reparent(struct clk_hw *hw,
                 best = clk_core_get_rate_nolock(core);
         }

+       req->best_parent_rate = best;
         req->rate = best;

         return 0;

best_parent_rate is still being used somewhere in the code and needs to 
be updated regardless of the CLK_SET_RATE_NO_REPARENT flag.

 > ...

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland