| Message ID | 20220415055916.28350-11-rex-bc.chen@mediatek.com |
|---|---|
| State | New |
| Headers | show |
| Series | cpufreq: mediatek: Cleanup and support MT8183 and MT8186 | expand |
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 > >
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
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;
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(+)