Re: [PATCH] drm/msm/dp: add voltage corners voting support base on dp link rate

[khsieh@xxxxxxxxxxxxxx]

On 2020-09-30 09:24, Rajendra Nayak wrote:
> On 9/30/2020 1:54 PM, Stephen Boyd wrote:
> > Quoting Kuogee Hsieh (2020-09-29 10:10:26)
> > > Set link rate by using OPP set rate api so that CX level will be set
> > > accordingly base on the link rate.
> >
> > s/base/based/
> >
> > > Signed-off-by: Kuogee Hsieh <khsieh@xxxxxxxxxxxxxx>
> > > ---
> > > diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c 
> > > b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > > index 2e3e1917351f..e1595d829e04 100644
> > > --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > > +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > > @@ -1849,6 +1853,21 @@ struct dp_ctrl *dp_ctrl_get(struct device 
> > > *dev, struct dp_link *link,
> > >                  return ERR_PTR(-ENOMEM);
> > >          }
> > >   +       ctrl->opp_table = dev_pm_opp_set_clkname(dev, "ctrl_link");
>
> I see that downstream has multiple DP clocks which end up voting on
> CX, we don't have a
> way of associating multiple OPP tables with a device upstream, so
> whats usually done is
> (assuming all the clocks get scaled in lock step, which I assume is
> the case here) we pick
> the clock with the 'highest' CX requirement and associate that with
> the OPP table.
> I haven't looked but I am hoping thats how we have decided to
> associate "ctrl_link" clock
> here?
yes, only ctrl_link use dev_pm_opp_set_rate() to set rate.

> > > +
> > > +       if (IS_ERR(ctrl->opp_table)) {
> > > +               dev_err(dev, "invalid DP OPP table in device 
> > > tree\n");
> > > +               ctrl->opp_table = NULL;
> > > +       } else {
> > > +               /* OPP table is optional */
> > > +               ret = dev_pm_opp_of_add_table(dev);
> > > +               if (ret && ret != -ENODEV) {
> > > +                       dev_err(dev, "add DP OPP table\n");
> >
> > This is debug noise right?
> >
> > > +                       dev_pm_opp_put_clkname(ctrl->opp_table);
> > > +                       ctrl->opp_table = NULL;
> > > +               }
> > > +       }
> > > +
> > >          init_completion(&ctrl->idle_comp);
> > >          init_completion(&ctrl->video_comp);
> > >   @@ -1864,6 +1883,18 @@ struct dp_ctrl *dp_ctrl_get(struct device 
> > > *dev, struct dp_link *link,
> > >          return &ctrl->dp_ctrl;
> > >   }
> > >   -void dp_ctrl_put(struct dp_ctrl *dp_ctrl)
> > > +void dp_ctrl_put(struct device *dev, struct dp_ctrl *dp_ctrl)
> > >   {
> > > +       struct dp_ctrl_private *ctrl;
> > > +
> > > +       if (!dp_ctrl)
> >
> > Can this happen?
> >
> > > +               return;
> > > +
> > > +       ctrl = container_of(dp_ctrl, struct dp_ctrl_private, 
> > > dp_ctrl);
> > > +
> > > +       if (ctrl->opp_table != NULL) {
> >
> > This is usually written as
> >
> > 	if (ctrl->opp_table)
> >
> > > +               dev_pm_opp_of_remove_table(dev);
> > > +               dev_pm_opp_put_clkname(ctrl->opp_table);
> > > +               ctrl->opp_table = NULL;
> > > +       }
> > >   }
> > > diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.h 
> > > b/drivers/gpu/drm/msm/dp/dp_ctrl.h
> > > index f60ba93c8678..19b412a93e02 100644
> > > --- a/drivers/gpu/drm/msm/dp/dp_ctrl.h
> > > +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.h
> > > @@ -31,6 +31,6 @@ struct dp_ctrl *dp_ctrl_get(struct device *dev, 
> > > struct dp_link *link,
> > >                          struct dp_panel *panel, struct drm_dp_aux 
> > > *aux,
> > >                          struct dp_power *power, struct dp_catalog 
> > > *catalog,
> > >                          struct dp_parser *parser);
> > > -void dp_ctrl_put(struct dp_ctrl *dp_ctrl);
> > > +void dp_ctrl_put(struct device *dev, struct dp_ctrl *dp_ctrl);
> >
> > Is 'dev' not inside 'dp_ctrl'?
> >
> > >     #endif /* _DP_CTRL_H_ */
> > > diff --git a/drivers/gpu/drm/msm/dp/dp_power.c 
> > > b/drivers/gpu/drm/msm/dp/dp_power.c
> > > index 17c1fc6a2d44..3d75bf09e38f 100644
> > > --- a/drivers/gpu/drm/msm/dp/dp_power.c
> > > +++ b/drivers/gpu/drm/msm/dp/dp_power.c
> > > @@ -8,12 +8,14 @@
> > >   #include <linux/clk.h>
> > >   #include <linux/clk-provider.h>
> > >   #include <linux/regulator/consumer.h>
> > > +#include <linux/pm_opp.h>
> > >   #include "dp_power.h"
> > >   #include "msm_drv.h"
> > >     struct dp_power_private {
> > >          struct dp_parser *parser;
> > >          struct platform_device *pdev;
> > > +       struct device *dev;
> > >          struct clk *link_clk_src;
> > >          struct clk *pixel_provider;
> > >          struct clk *link_provider;
> > > @@ -148,18 +150,49 @@ static int dp_power_clk_deinit(struct 
> > > dp_power_private *power)
> > >          return 0;
> > >   }
> > >   +static int dp_power_clk_set_link_rate(struct dp_power_private 
> > > *power,
> > > +                       struct dss_clk *clk_arry, int num_clk, int 
> > > enable)
> > > +{
> > > +       u32 rate;
> > > +       int i, rc = 0;
> > > +
> > > +       for (i = 0; i < num_clk; i++) {
> > > +               if (clk_arry[i].clk) {
> > > +                       if (clk_arry[i].type == DSS_CLK_PCLK) {
> > > +                               if (enable)
> > > +                                       rate = clk_arry[i].rate;
> > > +                               else
> > > +                                       rate = 0;
> > > +
> > > +                               rc = dev_pm_opp_set_rate(power->dev, 
> > > rate);
> >
> > Why do we keep going if rc is non-zero?
> >
> > > +                       }
> > > +
> > > +               }
> > > +       }
> > > +       return rc;
> > > +}
> > > +
> > >   static int dp_power_clk_set_rate(struct dp_power_private *power,
> > >                  enum dp_pm_type module, bool enable)
> > >   {
> > >          int rc = 0;
> > >          struct dss_module_power *mp = &power->parser->mp[module];
> > >   -       if (enable) {
> > > -               rc = msm_dss_clk_set_rate(mp->clk_config, 
> > > mp->num_clk);
> > > +       if (module == DP_CTRL_PM) {
> > > +               rc = dp_power_clk_set_link_rate(power, 
> > > mp->clk_config, mp->num_clk, enable);
> > >                  if (rc) {
> > > -                       DRM_ERROR("failed to set clks rate.\n");
> > > +                       DRM_ERROR("failed to set link clks rate.\n");
> > >                          return rc;
> > >                  }
> > > +       } else {
> > > +
> > > +               if (enable) {
> > > +                       rc = msm_dss_clk_set_rate(mp->clk_config, 
> > > mp->num_clk);
> > > +                       if (rc) {
> > > +                               DRM_ERROR("failed to set clks 
> > > rate.\n");
> >
> > Not sure we need the period on these error messages.
> >
> > > +                               return rc;
> > > +                       }
> > > +               }
> > >          }
> > >            rc = msm_dss_enable_clk(mp->clk_config, mp->num_clk, 
> > > enable);
> > >
> > > base-commit: 3c0f462da069af12211901ddf26f7e16e6951d9b
> > > prerequisite-patch-id: a109eaf08147f50149ad661a58122b6745a52445
> >
> > Can you rebase this on Rob's msm-next tree
> > (https://gitlab.freedesktop.org/drm/msm.git) and test? It doesn't 
> > apply
> > for me because I have the dp phy patch from there.
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