To prevent infinite loop when tracking voltage, we calculate the maximum
value for each platform data.
We assume min voltage is 0 and tracking target voltage using
min_volt_shift for each iteration.
The retry_max is 3 times of expeted iteration count.
Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
---
drivers/cpufreq/mediatek-cpufreq.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
index cc44a7a9427a..d4c00237e862 100644
--- a/drivers/cpufreq/mediatek-cpufreq.c
+++ b/drivers/cpufreq/mediatek-cpufreq.c
@@ -86,6 +86,16 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
struct regulator *proc_reg = info->proc_reg;
struct regulator *sram_reg = info->sram_reg;
int pre_vproc, pre_vsram, new_vsram, vsram, vproc, ret;
+ int retry_max;
+
+ /*
+ * We assume min voltage is 0 and tracking target voltage using
+ * min_volt_shift for each iteration.
+ * The retry_max is 3 times of expeted iteration count.
+ */
+ retry_max = 3 * DIV_ROUND_UP(max(info->soc_data->sram_max_volt,
+ info->soc_data->proc_max_volt),
+ info->soc_data->min_volt_shift);
pre_vproc = regulator_get_voltage(proc_reg);
if (pre_vproc < 0) {
@@ -151,6 +161,12 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
pre_vproc = vproc;
pre_vsram = vsram;
+
+ if (--retry_max < 0) {
+ dev_err(info->cpu_dev,
+ "over loop count, failed to set voltage\n");
+ return -EINVAL;
+ }
} while (vproc != new_vproc || vsram != new_vsram);
return 0;
--
2.18.0On Fri, Apr 15, 2022 at 1:59 PM Rex-BC Chen <rex-bc.chen@mediatek.com> wrote:
>
> To prevent infinite loop when tracking voltage, we calculate the maximum
> value for each platform data.
> We assume min voltage is 0 and tracking target voltage using
> min_volt_shift for each iteration.
> The retry_max is 3 times of expeted iteration count.
>
> Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
> ---
> drivers/cpufreq/mediatek-cpufreq.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
> index cc44a7a9427a..d4c00237e862 100644
> --- a/drivers/cpufreq/mediatek-cpufreq.c
> +++ b/drivers/cpufreq/mediatek-cpufreq.c
> @@ -86,6 +86,16 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
> struct regulator *proc_reg = info->proc_reg;
> struct regulator *sram_reg = info->sram_reg;
> int pre_vproc, pre_vsram, new_vsram, vsram, vproc, ret;
> + int retry_max;
> +
> + /*
> + * We assume min voltage is 0 and tracking target voltage using
> + * min_volt_shift for each iteration.
> + * The retry_max is 3 times of expeted iteration count.
> + */
> + retry_max = 3 * DIV_ROUND_UP(max(info->soc_data->sram_max_volt,
> + info->soc_data->proc_max_volt),
> + info->soc_data->min_volt_shift);
mtk_cpufreq_voltage_tracking() will be called very frequently.
retry_max is the same every time mtk_cpufreq_voltage_tracking() is
called. Is it better to calculate before and store in
mtk_cpu_dvfs_info?
>
> pre_vproc = regulator_get_voltage(proc_reg);
> if (pre_vproc < 0) {
> @@ -151,6 +161,12 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
>
> pre_vproc = vproc;
> pre_vsram = vsram;
> +
> + if (--retry_max < 0) {
> + dev_err(info->cpu_dev,
> + "over loop count, failed to set voltage\n");
> + return -EINVAL;
> + }
> } while (vproc != new_vproc || vsram != new_vsram);
>
> return 0;
> --
> 2.18.0
>
Il 15/04/22 08:14, Hsin-Yi Wang ha scritto: > On Fri, Apr 15, 2022 at 1:59 PM Rex-BC Chen <rex-bc.chen@mediatek.com> wrote: >> >> To prevent infinite loop when tracking voltage, we calculate the maximum >> value for each platform data. >> We assume min voltage is 0 and tracking target voltage using >> min_volt_shift for each iteration. >> The retry_max is 3 times of expeted iteration count. >> >> Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com> I'm sorry Rex, but this commit has to be squashed with 09/15, as the logic is that each commit has to be acceptable, and 09/15 is not, without this fix. Besides, as Hsin-Yi suggested, calculating this every time may hit performance, but at the same time I don't want to lose this explicit calculation... >> --- >> drivers/cpufreq/mediatek-cpufreq.c | 16 ++++++++++++++++ >> 1 file changed, 16 insertions(+) >> >> diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c >> index cc44a7a9427a..d4c00237e862 100644 >> --- a/drivers/cpufreq/mediatek-cpufreq.c >> +++ b/drivers/cpufreq/mediatek-cpufreq.c >> @@ -86,6 +86,16 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info, >> struct regulator *proc_reg = info->proc_reg; >> struct regulator *sram_reg = info->sram_reg; >> int pre_vproc, pre_vsram, new_vsram, vsram, vproc, ret; >> + int retry_max; >> + >> + /* >> + * We assume min voltage is 0 and tracking target voltage using >> + * min_volt_shift for each iteration. >> + * The retry_max is 3 times of expeted iteration count. >> + */ >> + retry_max = 3 * DIV_ROUND_UP(max(info->soc_data->sram_max_volt, >> + info->soc_data->proc_max_volt), >> + info->soc_data->min_volt_shift); > > mtk_cpufreq_voltage_tracking() will be called very frequently. > retry_max is the same every time mtk_cpufreq_voltage_tracking() is > called. Is it better to calculate before and store in > mtk_cpu_dvfs_info? > ...so I agree with this solution: perhaps you can add a "vtrack_max" variable to mtk_cpu_dvfs_info as suggested, and fill in that one in function mtk_cpu_dvfs_info_init(), where we effectively initialize all-the-things. Cheers, Angelo
On Fri, 2022-04-15 at 14:24 +0200, AngeloGioacchino Del Regno wrote: > Il 15/04/22 08:14, Hsin-Yi Wang ha scritto: > > On Fri, Apr 15, 2022 at 1:59 PM Rex-BC Chen < > > rex-bc.chen@mediatek.com> wrote: > > > > > > To prevent infinite loop when tracking voltage, we calculate the > > > maximum > > > value for each platform data. > > > We assume min voltage is 0 and tracking target voltage using > > > min_volt_shift for each iteration. > > > The retry_max is 3 times of expeted iteration count. > > > > > > Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com> > > I'm sorry Rex, but this commit has to be squashed with 09/15, as the > logic is > that each commit has to be acceptable, and 09/15 is not, without this > fix. > > Besides, as Hsin-Yi suggested, calculating this every time may hit > performance, > but at the same time I don't want to lose this explicit > calculation... > Hello Angelo, I will squash thius patch into 9/15 and will use info->vtrack_max to record the value in probe function. Thanks! BRs, Rex > > > --- > > > drivers/cpufreq/mediatek-cpufreq.c | 16 ++++++++++++++++ > > > 1 file changed, 16 insertions(+) > > > > > > diff --git a/drivers/cpufreq/mediatek-cpufreq.c > > > b/drivers/cpufreq/mediatek-cpufreq.c > > > index cc44a7a9427a..d4c00237e862 100644 > > > --- a/drivers/cpufreq/mediatek-cpufreq.c > > > +++ b/drivers/cpufreq/mediatek-cpufreq.c > > > @@ -86,6 +86,16 @@ static int mtk_cpufreq_voltage_tracking(struct > > > mtk_cpu_dvfs_info *info, > > > struct regulator *proc_reg = info->proc_reg; > > > struct regulator *sram_reg = info->sram_reg; > > > int pre_vproc, pre_vsram, new_vsram, vsram, vproc, ret; > > > + int retry_max; > > > + > > > + /* > > > + * We assume min voltage is 0 and tracking target voltage > > > using > > > + * min_volt_shift for each iteration. > > > + * The retry_max is 3 times of expeted iteration count. > > > + */ > > > + retry_max = 3 * DIV_ROUND_UP(max(info->soc_data- > > > >sram_max_volt, > > > + info->soc_data- > > > >proc_max_volt), > > > + info->soc_data- > > > >min_volt_shift); > > > > mtk_cpufreq_voltage_tracking() will be called very frequently. > > retry_max is the same every time mtk_cpufreq_voltage_tracking() is > > called. Is it better to calculate before and store in > > mtk_cpu_dvfs_info? > > > > ...so I agree with this solution: perhaps you can add a "vtrack_max" > variable to > mtk_cpu_dvfs_info as suggested, and fill in that one in function > mtk_cpu_dvfs_info_init(), where we effectively initialize all-the- > things. > > Cheers, > Angelo
On Fri, 2022-04-15 at 14:14 +0800, Hsin-Yi Wang wrote:
> On Fri, Apr 15, 2022 at 1:59 PM Rex-BC Chen <rex-bc.chen@mediatek.com
> > wrote:
> >
> > To prevent infinite loop when tracking voltage, we calculate the
> > maximum
> > value for each platform data.
> > We assume min voltage is 0 and tracking target voltage using
> > min_volt_shift for each iteration.
> > The retry_max is 3 times of expeted iteration count.
> >
> > Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
> > ---
> > drivers/cpufreq/mediatek-cpufreq.c | 16 ++++++++++++++++
> > 1 file changed, 16 insertions(+)
> >
> > diff --git a/drivers/cpufreq/mediatek-cpufreq.c
> > b/drivers/cpufreq/mediatek-cpufreq.c
> > index cc44a7a9427a..d4c00237e862 100644
> > --- a/drivers/cpufreq/mediatek-cpufreq.c
> > +++ b/drivers/cpufreq/mediatek-cpufreq.c
> > @@ -86,6 +86,16 @@ static int mtk_cpufreq_voltage_tracking(struct
> > mtk_cpu_dvfs_info *info,
> > struct regulator *proc_reg = info->proc_reg;
> > struct regulator *sram_reg = info->sram_reg;
> > int pre_vproc, pre_vsram, new_vsram, vsram, vproc, ret;
> > + int retry_max;
> > +
> > + /*
> > + * We assume min voltage is 0 and tracking target voltage
> > using
> > + * min_volt_shift for each iteration.
> > + * The retry_max is 3 times of expeted iteration count.
> > + */
> > + retry_max = 3 * DIV_ROUND_UP(max(info->soc_data-
> > >sram_max_volt,
> > + info->soc_data-
> > >proc_max_volt),
> > + info->soc_data-
> > >min_volt_shift);
>
> mtk_cpufreq_voltage_tracking() will be called very frequently.
> retry_max is the same every time mtk_cpufreq_voltage_tracking() is
> called. Is it better to calculate before and store in
> mtk_cpu_dvfs_info?
>
Hello Hsin-Yi,
Thanks for your reviwew.
I will do this in next version.
BRs,
Rex
> >
> > pre_vproc = regulator_get_voltage(proc_reg);
> > if (pre_vproc < 0) {
> > @@ -151,6 +161,12 @@ static int mtk_cpufreq_voltage_tracking(struct
> > mtk_cpu_dvfs_info *info,
> >
> > pre_vproc = vproc;
> > pre_vsram = vsram;
> > +
> > + if (--retry_max < 0) {
> > + dev_err(info->cpu_dev,
> > + "over loop count, failed to set
> > voltage\n");
> > + return -EINVAL;
> > + }
> > } while (vproc != new_vproc || vsram != new_vsram);
> >
> > return 0;
> > --
> > 2.18.0
> >
© 2016 - 2026 Red Hat, Inc.