From: Nícolas F. R. A. Prado Date: Wed, 10 Jan 2024 14:23:02 +0000 (-0300) Subject: cpufreq: mediatek-hw: Wait for CPU supplies before probing X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=788715b5f21c;p=linux.git cpufreq: mediatek-hw: Wait for CPU supplies before probing Before proceeding with the probe and enabling frequency scaling for the CPUs, make sure that all supplies feeding the CPUs have probed. This fixes an issue observed on MT8195-Tomato where if the mediatek-cpufreq-hw driver enabled the hardware (by writing to REG_FREQ_ENABLE) before the SPMI controller driver (spmi-mtk-pmif), behind which lies the big CPU supply, probed the platform would hang shortly after with "rcu: INFO: rcu_preempt detected stalls on CPUs/tasks" being printed in the log. Fixes: 4855e26bcf4d ("cpufreq: mediatek-hw: Add support for CPUFREQ HW") Signed-off-by: Nícolas F. R. A. Prado Reviewed-by: AngeloGioacchino Del Regno Reviewed-by: Matthias Brugger Signed-off-by: Viresh Kumar --- diff --git a/drivers/cpufreq/mediatek-cpufreq-hw.c b/drivers/cpufreq/mediatek-cpufreq-hw.c index d46afb3c00923..a1aa9385980ae 100644 --- a/drivers/cpufreq/mediatek-cpufreq-hw.c +++ b/drivers/cpufreq/mediatek-cpufreq-hw.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #define LUT_MAX_ENTRIES 32U @@ -300,7 +301,23 @@ static struct cpufreq_driver cpufreq_mtk_hw_driver = { static int mtk_cpufreq_hw_driver_probe(struct platform_device *pdev) { const void *data; - int ret; + int ret, cpu; + struct device *cpu_dev; + struct regulator *cpu_reg; + + /* Make sure that all CPU supplies are available before proceeding. */ + for_each_possible_cpu(cpu) { + cpu_dev = get_cpu_device(cpu); + if (!cpu_dev) + return dev_err_probe(&pdev->dev, -EPROBE_DEFER, + "Failed to get cpu%d device\n", cpu); + + cpu_reg = devm_regulator_get_optional(cpu_dev, "cpu"); + if (IS_ERR(cpu_reg)) + return dev_err_probe(&pdev->dev, PTR_ERR(cpu_reg), + "CPU%d regulator get failed\n", cpu); + } + data = of_device_get_match_data(&pdev->dev); if (!data)