From: "Marek Behún" <kabel@kernel.org> To: Viresh Kumar <viresh.kumar@linaro.org>, Gregory CLEMENT <gregory.clement@bootlin.com> Cc: "Robert Marko" <robert.marko@sartura.hr>, "Pali Rohár" <pali@kernel.org>, "Tomasz Maciej Nowak" <tmn505@gmail.com>, "Anders Trier Olesen" <anders.trier.olesen@gmail.com>, "Philip Soares" <philips@netisense.com>, linux-pm@vger.kernel.org, "Sebastian Hesselbarth" <sebastian.hesselbarth@gmail.com>, linux-arm-kernel@lists.infradead.org, "Konstantin Porotchkin" <kostap@marvell.com>, nnet <nnet@fastmail.fm>, "Nadav Haklai" <nadavh@marvell.com>, "Marek Behún" <kabel@kernel.org>, "Marek Behún" <kabel@kernel.iorg> Subject: [PATCH] cpufreq: armada-37xx: forbid cpufreq for 1.2 GHz variant Date: Wed, 30 Jun 2021 15:59:42 +0200 [thread overview] Message-ID: <20210630135942.29730-1-kabel@kernel.org> (raw) The 1.2 GHz variant of the Armada 3720 SOC is unstable with DVFS: when the SOC boots, the WTMI firmware sets clocks and AVS values that work correctly with 1.2 GHz CPU frequency, but random crashes occur once cpufreq driver starts scaling. We do not know currently what is the reason: - it may be that the voltage value for L0 for 1.2 GHz variant provided by the vendor in the OTP is simply incorrect when scaling is used, - it may be that some delay is needed somewhere, - it may be something else. The most sane solution now seems to be to simply forbid the cpufreq driver on 1.2 GHz variant. Signed-off-by: Marek Behún <kabel@kernel.iorg> Fixes: 92ce45fb875d ("cpufreq: Add DVFS support for Armada 37xx") --- If someone from Marvell could look into this, it would be great since basically 1.2 GHz variant cannot scale, which is a feature that was claimed to be supported by the SOC. --- drivers/cpufreq/armada-37xx-cpufreq.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/cpufreq/armada-37xx-cpufreq.c b/drivers/cpufreq/armada-37xx-cpufreq.c index 3fc98a3ffd91..1ef3dde9a40b 100644 --- a/drivers/cpufreq/armada-37xx-cpufreq.c +++ b/drivers/cpufreq/armada-37xx-cpufreq.c @@ -104,7 +104,13 @@ struct armada_37xx_dvfs { }; static struct armada_37xx_dvfs armada_37xx_dvfs[] = { +#if 0 + /* + * The cpufreq scaling for 1.2 GHz variant of the SOC is currently + * unstable because we do not know how to configure it properly. + */ {.cpu_freq_max = 1200*1000*1000, .divider = {1, 2, 4, 6} }, +#endif {.cpu_freq_max = 1000*1000*1000, .divider = {1, 2, 4, 5} }, {.cpu_freq_max = 800*1000*1000, .divider = {1, 2, 3, 4} }, {.cpu_freq_max = 600*1000*1000, .divider = {2, 4, 5, 6} }, -- 2.31.1
WARNING: multiple messages have this Message-ID (diff)
From: "Marek Behún" <kabel@kernel.org> To: Viresh Kumar <viresh.kumar@linaro.org>, Gregory CLEMENT <gregory.clement@bootlin.com> Cc: "Robert Marko" <robert.marko@sartura.hr>, "Pali Rohár" <pali@kernel.org>, "Tomasz Maciej Nowak" <tmn505@gmail.com>, "Anders Trier Olesen" <anders.trier.olesen@gmail.com>, "Philip Soares" <philips@netisense.com>, linux-pm@vger.kernel.org, "Sebastian Hesselbarth" <sebastian.hesselbarth@gmail.com>, linux-arm-kernel@lists.infradead.org, "Konstantin Porotchkin" <kostap@marvell.com>, nnet <nnet@fastmail.fm>, "Nadav Haklai" <nadavh@marvell.com>, "Marek Behún" <kabel@kernel.org>, "Marek Behún" <kabel@kernel.iorg> Subject: [PATCH] cpufreq: armada-37xx: forbid cpufreq for 1.2 GHz variant Date: Wed, 30 Jun 2021 15:59:42 +0200 [thread overview] Message-ID: <20210630135942.29730-1-kabel@kernel.org> (raw) The 1.2 GHz variant of the Armada 3720 SOC is unstable with DVFS: when the SOC boots, the WTMI firmware sets clocks and AVS values that work correctly with 1.2 GHz CPU frequency, but random crashes occur once cpufreq driver starts scaling. We do not know currently what is the reason: - it may be that the voltage value for L0 for 1.2 GHz variant provided by the vendor in the OTP is simply incorrect when scaling is used, - it may be that some delay is needed somewhere, - it may be something else. The most sane solution now seems to be to simply forbid the cpufreq driver on 1.2 GHz variant. Signed-off-by: Marek Behún <kabel@kernel.iorg> Fixes: 92ce45fb875d ("cpufreq: Add DVFS support for Armada 37xx") --- If someone from Marvell could look into this, it would be great since basically 1.2 GHz variant cannot scale, which is a feature that was claimed to be supported by the SOC. --- drivers/cpufreq/armada-37xx-cpufreq.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/cpufreq/armada-37xx-cpufreq.c b/drivers/cpufreq/armada-37xx-cpufreq.c index 3fc98a3ffd91..1ef3dde9a40b 100644 --- a/drivers/cpufreq/armada-37xx-cpufreq.c +++ b/drivers/cpufreq/armada-37xx-cpufreq.c @@ -104,7 +104,13 @@ struct armada_37xx_dvfs { }; static struct armada_37xx_dvfs armada_37xx_dvfs[] = { +#if 0 + /* + * The cpufreq scaling for 1.2 GHz variant of the SOC is currently + * unstable because we do not know how to configure it properly. + */ {.cpu_freq_max = 1200*1000*1000, .divider = {1, 2, 4, 6} }, +#endif {.cpu_freq_max = 1000*1000*1000, .divider = {1, 2, 4, 5} }, {.cpu_freq_max = 800*1000*1000, .divider = {1, 2, 3, 4} }, {.cpu_freq_max = 600*1000*1000, .divider = {2, 4, 5, 6} }, -- 2.31.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2021-06-30 14:00 UTC|newest] Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-30 13:59 Marek Behún [this message] 2021-06-30 13:59 ` [PATCH] cpufreq: armada-37xx: forbid cpufreq for 1.2 GHz variant Marek Behún 2021-06-30 14:02 ` Marek Behún 2021-06-30 14:02 ` Marek Behún 2021-06-30 15:22 ` Andrew Lunn 2021-06-30 15:22 ` Andrew Lunn 2021-06-30 22:56 ` [PATCH v2] " Marek Behún 2021-06-30 22:56 ` Marek Behún 2021-07-01 2:05 ` Viresh Kumar 2021-07-01 2:05 ` Viresh Kumar 2021-07-02 16:30 ` Pali Rohár 2021-07-02 16:30 ` Pali Rohár 2021-07-08 14:34 ` Pali Rohár 2021-07-08 14:34 ` Pali Rohár 2021-07-15 19:33 ` Pali Rohár 2021-07-15 19:33 ` Pali Rohár 2021-08-08 19:30 ` Pali Rohár 2021-08-08 19:30 ` Pali Rohár 2021-08-09 4:02 ` Viresh Kumar 2021-08-09 4:02 ` Viresh Kumar 2022-08-01 12:36 ` Pali Rohár 2022-08-01 12:36 ` Pali Rohár 2022-08-01 14:01 ` [EXT] " Elad Nachman 2022-08-01 14:01 ` Elad Nachman 2022-08-01 14:12 ` Pali Rohár 2022-08-01 14:12 ` Pali Rohár 2022-08-01 14:15 ` Elad Nachman 2022-08-01 14:15 ` Elad Nachman 2022-08-01 17:56 ` Pali Rohár 2022-08-01 17:56 ` Pali Rohár [not found] ` <BN9PR18MB42518C761E574D862D30CDA7DB9A9@BN9PR18MB4251.namprd18.prod.outlook.com> 2022-08-02 16:42 ` Robert Marko 2022-08-02 16:42 ` Robert Marko 2022-08-02 16:52 ` Elad Nachman 2022-08-02 16:52 ` Elad Nachman 2022-08-02 16:56 ` Robert Marko 2022-08-02 16:56 ` Robert Marko 2022-08-02 17:17 ` Pali Rohár 2022-08-02 17:17 ` Pali Rohár 2022-08-17 9:40 ` Robert Marko 2022-08-17 9:40 ` Robert Marko 2022-08-17 23:10 ` Pali Rohár 2022-08-17 23:10 ` Pali Rohár 2022-08-18 8:14 ` Robert Marko 2022-08-18 8:14 ` Robert Marko 2022-08-25 21:49 ` Pali Rohár 2022-08-25 21:49 ` Pali Rohár
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