[RFC 1/4] drm/msm/dpu: introduce a wb_idx to be used for writeback interfaces

Dmitry Baryshkov dmitry.baryshkov at linaro.org
Fri Apr 22 00:22:58 UTC 2022


On Fri, 22 Apr 2022 at 02:07, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
>
> Hi Dmitry
>
> Thanks for the review.
>
> One question below.
>
> On 4/21/2022 3:40 PM, Dmitry Baryshkov wrote:
> > On 21/04/2022 23:48, Abhinav Kumar wrote:
> >> Using intf_idx even for writeback interfaces is confusing
> >> because intf_idx is of type enum dpu_intf but the index used
> >> for writeback is of type enum dpu_wb.
> >>
> >> In addition, this makes it easier to separately check the
> >> availability of the two as its possible that there are boards
> >> which don't have any physical display connected but can still
> >> work in writeback mode.
> >>
> >> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
> >
> > Looks good, two minor issues bellow.
> >
> > With them fixed, I'd even squash this patch into the corresponding patch
> > of the previous patchset.
> >
> >> ---
> >>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c      | 62
> >> +++++++++++++-----------
> >>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h |  4 ++
> >>   drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h           |  2 +-
> >>   3 files changed, 40 insertions(+), 28 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >> index 9c12841..054d7e4 100644
> >> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >> @@ -962,7 +962,6 @@ static void
> >> dpu_encoder_virt_atomic_mode_set(struct drm_encoder *drm_enc,
> >>       struct dpu_hw_blk *hw_dsc[MAX_CHANNELS_PER_ENC];
> >>       int num_lm, num_ctl, num_pp, num_dsc;
> >>       unsigned int dsc_mask = 0;
> >> -    enum dpu_hw_blk_type blk_type;
> >>       int i;
> >>       if (!drm_enc) {
> >> @@ -1044,17 +1043,11 @@ static void
> >> dpu_encoder_virt_atomic_mode_set(struct drm_encoder *drm_enc,
> >>           phys->hw_pp = dpu_enc->hw_pp[i];
> >>           phys->hw_ctl = to_dpu_hw_ctl(hw_ctl[i]);
> >> -        if (dpu_encoder_get_intf_mode(&dpu_enc->base) ==
> >> INTF_MODE_WB_LINE)
> >> -            blk_type = DPU_HW_BLK_WB;
> >> -        else
> >> -            blk_type = DPU_HW_BLK_INTF;
> >> +        if (phys->intf_idx >= INTF_0 && phys->intf_idx < INTF_MAX)
> >> +            phys->hw_intf = dpu_rm_get_intf(&dpu_kms->rm,
> >> phys->intf_idx);
> >> -        if (phys->intf_idx >= INTF_0 && phys->intf_idx < INTF_MAX) {
> >> -            if (blk_type == DPU_HW_BLK_INTF)
> >> -                phys->hw_intf = dpu_rm_get_intf(&dpu_kms->rm,
> >> phys->intf_idx);
> >> -            else if (blk_type == DPU_HW_BLK_WB)
> >> -                phys->hw_wb = dpu_rm_get_wb(&dpu_kms->rm,
> >> phys->intf_idx);
> >> -        }
> >> +        if (phys->wb_idx >= WB_0 && phys->wb_idx < WB_MAX)
> >> +            phys->hw_wb = dpu_rm_get_wb(&dpu_kms->rm, phys->wb_idx);
> >
> > We also need a check for if (phus->hw_intf && phys->hw_wb) HERE
>
> So there is an error if
>
> 1) Neither wb NOR intf are present
> 2) Both wb AND intf are present for the physical encoder?
>
> The second check is okay for now to add but considering concurrent
> writeback then that wouldn't assumption be wrong since both physical and
> wb interfaces can go with the same encoder?

To the same encoder, but not to the same physical encoder. Here we
check the phys_enc parameters.

>
> >
> >>           if (!phys->hw_intf && !phys->hw_wb) {
> >>               DPU_ERROR_ENC(dpu_enc,
> >> @@ -1201,7 +1194,7 @@ static void dpu_encoder_virt_disable(struct
> >> drm_encoder *drm_enc)
> >>       mutex_unlock(&dpu_enc->enc_lock);
> >>   }
> >> -static enum dpu_intf dpu_encoder_get_intf_or_wb(struct dpu_mdss_cfg
> >> *catalog,
> >> +static enum dpu_intf dpu_encoder_get_intf(struct dpu_mdss_cfg *catalog,
> >>           enum dpu_intf_type type, u32 controller_id)
> >>   {
> >>       int i = 0;
> >> @@ -1213,16 +1206,28 @@ static enum dpu_intf
> >> dpu_encoder_get_intf_or_wb(struct dpu_mdss_cfg *catalog,
> >>                   return catalog->intf[i].id;
> >>               }
> >>           }
> >> -    } else {
> >> -        for (i = 0; i < catalog->wb_count; i++) {
> >> -            if (catalog->wb[i].id == controller_id)
> >> -                return catalog->wb[i].id;
> >> -        }
> >>       }
> >>       return INTF_MAX;
> >>   }
> >> +static enum dpu_wb dpu_encoder_get_wb(struct dpu_mdss_cfg *catalog,
> >> +        enum dpu_intf_type type, u32 controller_id)
> >> +{
> >> +    int i = 0;
> >> +
> >> +    if (type != INTF_WB)
> >> +        goto end;
> >> +
> >> +    for (i = 0; i < catalog->wb_count; i++) {
> >> +        if (catalog->wb[i].id == controller_id)
> >> +            return catalog->wb[i].id;
> >> +    }
> >> +
> >> +end:
> >> +    return WB_MAX;
> >
> > I'd return INTF_NONE/WB_NONE if the interface or WB unit was not found.
> ack, i guess in that case even the places checking the return value of
> this function need to be changed.

Yes, of course.

> >
> >> +}
> >> +
> >>   static void dpu_encoder_vblank_callback(struct drm_encoder *drm_enc,
> >>           struct dpu_encoder_phys *phy_enc)
> >>   {
> >> @@ -2249,18 +2254,21 @@ static int dpu_encoder_setup_display(struct
> >> dpu_encoder_virt *dpu_enc,
> >>           DPU_DEBUG("h_tile_instance %d = %d, split_role %d\n",
> >>                   i, controller_id, phys_params.split_role);
> >> -        /*
> >> -         * FIXME: have separate intf_idx and wb_idx to avoid using
> >> -         * enum dpu_intf type for wb_idx and also to be able to
> >> -         * not bail out when there is no intf for boards which dont
> >> -         * have a display connected to them.
> >> -         * Having a valid wb_idx but not a intf_idx can be a valid
> >> -         * combination moving forward.
> >> -         */
> >> -        phys_params.intf_idx =
> >> dpu_encoder_get_intf_or_wb(dpu_kms->catalog,
> >> +        phys_params.intf_idx = dpu_encoder_get_intf(dpu_kms->catalog,
> >>                                                       intf_type,
> >>                                                       controller_id);
> >> -        if (phys_params.intf_idx == INTF_MAX) {
> >> +
> >> +        phys_params.wb_idx = dpu_encoder_get_wb(dpu_kms->catalog,
> >> +                intf_type, controller_id);
> >> +        /*
> >> +         * For boards which have no physical displays, having no
> >> interface
> >> +         * is fine because it can still be used with just writeback.
> >> +         * If we try without a display on a board which uses a DPU in
> >> which
> >> +         * writeback is not supported, then this will still fail as
> >> it will not
> >> +         * find any writeback in the catalog.
> >> +         */
> >> +        if ((phys_params.intf_idx == INTF_MAX) &&
> >> +                (phys_params.wb_idx == WB_MAX)) {
> >>               DPU_ERROR_ENC(dpu_enc, "could not get intf or wb: type
> >> %d, id %d\n",
> >>                             intf_type, controller_id);
> >>               ret = -EINVAL;
> >> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
> >> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
> >> index 04d037e..f2af07d 100644
> >> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
> >> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
> >> @@ -181,6 +181,7 @@ enum dpu_intr_idx {
> >>    * @split_role:        Role to play in a split-panel configuration
> >>    * @intf_mode:        Interface mode
> >>    * @intf_idx:        Interface index on dpu hardware
> >> + * @wb_idx:            Writeback index on dpu hardware
> >>    * @enc_spinlock:    Virtual-Encoder-Wide Spin Lock for IRQ purposes
> >>    * @enable_state:    Enable state tracking
> >>    * @vblank_refcount:    Reference count of vblank request
> >> @@ -209,6 +210,7 @@ struct dpu_encoder_phys {
> >>       enum dpu_enc_split_role split_role;
> >>       enum dpu_intf_mode intf_mode;
> >>       enum dpu_intf intf_idx;
> >> +    enum dpu_wb wb_idx;
> >>       spinlock_t *enc_spinlock;
> >>       enum dpu_enc_enable_state enable_state;
> >>       atomic_t vblank_refcount;
> >> @@ -275,6 +277,7 @@ struct dpu_encoder_phys_cmd {
> >>    * @parent_ops:        Callbacks exposed by the parent to the phys_enc
> >>    * @split_role:        Role to play in a split-panel configuration
> >>    * @intf_idx:        Interface index this phys_enc will control
> >> + * @wb_idx:            Writeback index this phys_enc will control
> >>    * @enc_spinlock:    Virtual-Encoder-Wide Spin Lock for IRQ purposes
> >>    */
> >>   struct dpu_enc_phys_init_params {
> >> @@ -283,6 +286,7 @@ struct dpu_enc_phys_init_params {
> >>       const struct dpu_encoder_virt_ops *parent_ops;
> >>       enum dpu_enc_split_role split_role;
> >>       enum dpu_intf intf_idx;
> >> +    enum dpu_wb wb_idx;
> >>       spinlock_t *enc_spinlock;
> >>   };
> >> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h
> >> b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h
> >> index ba82e54..2f34a31 100644
> >> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h
> >> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h
> >> @@ -103,7 +103,7 @@ static inline struct dpu_hw_intf
> >> *dpu_rm_get_intf(struct dpu_rm *rm, enum dpu_in
> >>    * @rm: DPU Resource Manager handle
> >>    * @wb_idx: WB index
> >>    */
> >> -static inline struct dpu_hw_wb *dpu_rm_get_wb(struct dpu_rm *rm, enum
> >> dpu_intf wb_idx)
> >> +static inline struct dpu_hw_wb *dpu_rm_get_wb(struct dpu_rm *rm, enum
> >> dpu_wb wb_idx)
> >>   {
> >>       return rm->hw_wb[wb_idx - WB_0];
> >>   }
> >
> >



-- 
With best wishes
Dmitry


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