| Message ID | 20240110142305.755367-3-nfraprado@collabora.com |
|---|---|
| State | Accepted |
| Commit | 788715b5f21c6455264fe00a1779e61bec407fe2 |
| Headers | show |
| Series | Fixes for hang on MT8195-Tomato during mediatek-cpufreq-hw init | expand |
Il 10/01/24 15:23, Nícolas F. R. A. Prado ha scritto: > 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 <nfraprado@collabora.com> > Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
diff --git a/drivers/cpufreq/mediatek-cpufreq-hw.c b/drivers/cpufreq/mediatek-cpufreq-hw.c index d46afb3c0092..a1aa9385980a 100644 --- a/drivers/cpufreq/mediatek-cpufreq-hw.c +++ b/drivers/cpufreq/mediatek-cpufreq-hw.c @@ -13,6 +13,7 @@ #include <linux/of.h> #include <linux/of_platform.h> #include <linux/platform_device.h> +#include <linux/regulator/consumer.h> #include <linux/slab.h> #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)
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 <nfraprado@collabora.com> --- Changes in v2: - Added this commit drivers/cpufreq/mediatek-cpufreq-hw.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-)