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(-)
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)
--
2.43.0
On 10-01-24, 11:23, Nícolas F. R. A. Prado wrote: > 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> Applied 2/2. Thanks. -- viresh
On 10/01/2024 15:23, Nícolas F. R. A. Prado wrote: > 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: Matthias Brugger <matthias.bgg@gmail.com> > > --- > > Changes in v2: > - Added this commit > > drivers/cpufreq/mediatek-cpufreq-hw.c | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > 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)
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>
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