From: =?utf-8?q?Marek_Beh=C3=BAn?= Subject: [PATCH v2] cpufreq: armada-37xx: forbid cpufreq for 1.2 GHz variant Date: Thu, 1 Jul 2021 00:56:01 +0200 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 Fixes: 92ce45fb875d ("cpufreq: Add DVFS support for Armada 37xx") --- drivers/cpufreq/armada-37xx-cpufreq.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/cpufreq/armada-37xx-cpufreq.c +++ b/drivers/cpufreq/armada-37xx-cpufreq.c @@ -102,7 +102,11 @@ struct armada_37xx_dvfs { }; static struct armada_37xx_dvfs armada_37xx_dvfs[] = { - {.cpu_freq_max = 1200*1000*1000, .divider = {1, 2, 4, 6} }, + /* + * 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} }, */ {.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} },