Re: [Freedreno] [PATCH v5 6/6] drm/msm/dpu: move VBIF blocks handling to dpu_rm

[Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>]

On 15/02/2022 01:04, Abhinav Kumar wrote:
> On 2/14/2022 12:56 PM, Dmitry Baryshkov wrote:
> > On 14/02/2022 22:53, Abhinav Kumar wrote:
> > > On 1/21/2022 1:06 PM, Dmitry Baryshkov wrote:
> > > > Move handling of VBIF blocks into dpu_rm. This serves the purpose of
> > > > unification of handling of all hardware blocks inside the DPU driver.
> > > > This removes hand-coded loops in dpu_vbif (which look for necessary 
> > > > VBIF
> > > > instance by looping through the dpu_kms->hw_vbif and comparing
> > > > vbif_idx).
> > > >
> > > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> > >
> > > I have a slightly different idea about this. Let me know what you think.
> > >
> > > VBIF is a bus interface for the dpu to fetch from. I am not sure if 
> > > pulling it in the RM is right because its not a dedicated HW block like
> > > the others in the RM.
> >
> > It's not a hardware block, but a it's still a hardware resource 
> > (hardware instance). It is described in the hw catalog. Thus I 
> > suggested moving it to dpu_rm.
> >
> > As you have seen, from my previous iterations of this patchset, I 
> > tried   to move things out of dpu_rm. After some hacking, I saw that 
> > having alloc/free loops in several places seems like a worse idea. So 
> > I moved dpu_hw_intf back to dpu_rm and then moved dpu_hw_vbif to 
> > dpu_rm too.
> Actually for some reason, I only see two revs here:
>
> https://patchwork.freedesktop.org/series/99175/#rev1

Yeah, I'm not sure why patchwork created new series rather than new 
revision.

> Hence, I didnt check the previous patchsets from patchwork to see the 
> evolution.

https://patchwork.freedesktop.org/patch/464353/


> > > But, I agree with your problem statement of hand-coded loops.
> > >
> > > So instead, why dont you just have a helper in the dpu_vbif.c to get
> > > you the vbif hw for the passed index like, maybe something like this?
> > >
> > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_vbif.c
> > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_vbif.c
> > > @@ -11,6 +11,19 @@
> > >   #include "dpu_hw_vbif.h"
> > >   #include "dpu_trace.h"
> > >
> > > +static dpu_hw_vbif *dpu_vbif_get_hw(struct dpu_kms *dpu_kms, u32 
> > > vbif_idx)
> > > +{
> > > +       int i;
> > > +
> > > +       for (i = 0; i < ARRAY_SIZE(dpu_kms->hw_vbif); i++) {
> > > +               if (dpu_kms->hw_vbif[i] &&
> > > +                               dpu_kms->hw_vbif[i]->idx == vbif_idx)
> > > +                       vbif = dpu_kms->hw_vbif[i];
> > > +       }
> > > +
> > > +       return vbif;
> > > +}
> > > +
> >
> > You see, this code still bears an idea of looping through hw_vbif 
> > entries looking for the correct one (we can directly access 
> > hw_vbif[idx - VBIF_0] instead).
> >
> > And also the alloc/destroy loops are very similar to rm ones, but are 
> > working against the array in dpu_kms.
> >
> > One of the previous iterations had neearly the same idea as yours 
> > patch proposes, but I later abandoned this idea.
> >
> > I'm trying to place common code nearby, so that there is a less chance 
> > of an error.
>
> This loop is being used to find the vbif matching the index only in two 
> places today dpu_vbif_set_ot_limit and dpu_vbif_set_qos_remap.

Here I was talking about the loops to allocate and destroy VBIFs.

> Today and from whatever I see even in downstream (which has support for 
> more newer chipsets), there is only one VBIF
> instance in the catalog and always with the index 0.

When should we use VBIF_NRT? Judging from the _NRT suffix I thought that 
it's used for WB2, but it doesn't seem to be true.

> So to be honest, even that loop is an overkill today because the index 
> seems to be always 0 and there is only one instance so the loop seems to 
> break out at the first occurrence.

It's always better to remove a loop rather than to break from it.

> Thats why I was wondering whether moving VBIF to RM is an overkill for 
> this and just the simple cleanup i was suggesting was enough as that 
> loop itself is an overkill today for one instance of vbif.

Then we might as well drop an array and just leave a single vbif_0.

Just checked downstream device trees. 8996 declares two VBIFs. It looks 
like it's the only user of VBIF_1. Any comments? What would we loose for 
(possible) 8996 support in DPU if we drop VBIF_1 / VBIF_NRT support?

> > >   /**
> > >    * _dpu_vbif_wait_for_xin_halt - wait for the xin to halt
> > >    * @vbif:      Pointer to hardware vbif driver
> > > @@ -156,11 +169,7 @@ void dpu_vbif_set_ot_limit(struct dpu_kms *dpu_kms,
> > >
> > >          mdp = dpu_kms->hw_mdp;
> > >
> > > -       for (i = 0; i < ARRAY_SIZE(dpu_kms->hw_vbif); i++) {
> > > -               if (dpu_kms->hw_vbif[i] &&
> > > -                               dpu_kms->hw_vbif[i]->idx == 
> > > params->vbif_idx)
> > > -                       vbif = dpu_kms->hw_vbif[i];
> > > -       }
> > > +       vbif = dpu_vbif_get_hw(dpu_kms, params->vbif_idx);
> > >
> > >          if (!vbif || !mdp) {
> > >                  DRM_DEBUG_ATOMIC("invalid arguments vbif %d mdp %d\n",
> > > @@ -216,13 +225,7 @@ void dpu_vbif_set_qos_remap(struct dpu_kms 
> > > *dpu_kms,
> > >          }
> > >          mdp = dpu_kms->hw_mdp;
> > >
> > > -       for (i = 0; i < ARRAY_SIZE(dpu_kms->hw_vbif); i++) {
> > > -               if (dpu_kms->hw_vbif[i] &&
> > > -                               dpu_kms->hw_vbif[i]->idx == 
> > > params->vbif_idx) {
> > > -                       vbif = dpu_kms->hw_vbif[i];
> > > -                       break;
> > > -               }
> > > -       }
> > > +       vbif = dpu_vbif_get_hw(params->vbif_idx);
> > >
> > >
> > >
> > > > ---
> > > >   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_vbif.h |  1 +
> > > >   drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c     | 28 
> > > > +--------------------
> > > >   drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h     |  1 -
> > > >   drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c      | 19 ++++++++++++++
> > > >   drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h      | 12 +++++++++
> > > >   drivers/gpu/drm/msm/disp/dpu1/dpu_vbif.c    | 26 ++++++-------------
> > > >   6 files changed, 40 insertions(+), 47 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_vbif.h 
> > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_vbif.h
> > > > index 6417aa28d32c..895e86dabcb6 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_vbif.h
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_vbif.h
> > > > @@ -8,6 +8,7 @@
> > > >   #include "dpu_hw_catalog.h"
> > > >   #include "dpu_hw_mdss.h"
> > > >   #include "dpu_hw_util.h"
> > > > +#include "dpu_hw_blk.h"
> > > >   struct dpu_hw_vbif;
> > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c 
> > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > > > index 47fe11a84a77..4a1983d8561b 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > > > @@ -782,8 +782,6 @@ static long dpu_kms_round_pixclk(struct msm_kms 
> > > > *kms, unsigned long rate,
> > > >   static void _dpu_kms_hw_destroy(struct dpu_kms *dpu_kms)
> > > >   {
> > > > -    int i;
> > > > -
> > > >       if (dpu_kms->hw_intr)
> > > >           dpu_hw_intr_destroy(dpu_kms->hw_intr);
> > > >       dpu_kms->hw_intr = NULL;
> > > > @@ -791,15 +789,6 @@ static void _dpu_kms_hw_destroy(struct dpu_kms 
> > > > *dpu_kms)
> > > >       /* safe to call these more than once during shutdown */
> > > >       _dpu_kms_mmu_destroy(dpu_kms);
> > > > -    if (dpu_kms->catalog) {
> > > > -        for (i = 0; i < dpu_kms->catalog->vbif_count; i++) {
> > > > -            u32 vbif_idx = dpu_kms->catalog->vbif[i].id;
> > > > -
> > > > -            if ((vbif_idx < VBIF_MAX) && dpu_kms->hw_vbif[vbif_idx])
> > > > -                dpu_hw_vbif_destroy(dpu_kms->hw_vbif[vbif_idx]);
> > > > -        }
> > > > -    }
> > > > -
> > > >       if (dpu_kms->rm_init)
> > > >           dpu_rm_destroy(&dpu_kms->rm);
> > > >       dpu_kms->rm_init = false;
> > > > @@ -1027,7 +1016,7 @@ static int dpu_kms_hw_init(struct msm_kms *kms)
> > > >   {
> > > >       struct dpu_kms *dpu_kms;
> > > >       struct drm_device *dev;
> > > > -    int i, rc = -EINVAL;
> > > > +    int rc = -EINVAL;
> > > >       if (!kms) {
> > > >           DPU_ERROR("invalid kms\n");
> > > > @@ -1116,21 +1105,6 @@ static int dpu_kms_hw_init(struct msm_kms *kms)
> > > >           goto power_error;
> > > >       }
> > > > -    for (i = 0; i < dpu_kms->catalog->vbif_count; i++) {
> > > > -        u32 vbif_idx = dpu_kms->catalog->vbif[i].id;
> > > > -
> > > > -        dpu_kms->hw_vbif[i] = dpu_hw_vbif_init(vbif_idx,
> > > > -                dpu_kms->vbif[vbif_idx], dpu_kms->catalog);
> > > > -        if (IS_ERR_OR_NULL(dpu_kms->hw_vbif[vbif_idx])) {
> > > > -            rc = PTR_ERR(dpu_kms->hw_vbif[vbif_idx]);
> > > > -            if (!dpu_kms->hw_vbif[vbif_idx])
> > > > -                rc = -EINVAL;
> > > > -            DPU_ERROR("failed to init vbif %d: %d\n", vbif_idx, rc);
> > > > -            dpu_kms->hw_vbif[vbif_idx] = NULL;
> > > > -            goto power_error;
> > > > -        }
> > > > -    }
> > > > -
> > > >       rc = dpu_core_perf_init(&dpu_kms->perf, dev, dpu_kms->catalog,
> > > >               _dpu_kms_get_clk(dpu_kms, "core"));
> > > >       if (rc) {
> > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h 
> > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> > > > index 3f518c809e33..b96c901483ae 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> > > > @@ -105,7 +105,6 @@ struct dpu_kms {
> > > >       struct dpu_rm rm;
> > > >       bool rm_init;
> > > > -    struct dpu_hw_vbif *hw_vbif[VBIF_MAX];
> > > >       struct dpu_hw_mdp *hw_mdp;
> > > >       bool has_danger_ctrl;
> > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c 
> > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
> > > > index 7497538adae1..6d49666c4e77 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
> > > > @@ -76,6 +76,8 @@ int dpu_rm_destroy(struct dpu_rm *rm)
> > > >       }
> > > >       for (i = 0; i < ARRAY_SIZE(rm->hw_intf); i++)
> > > >           dpu_hw_intf_destroy(rm->hw_intf[i]);
> > > > +    for (i = 0; i < ARRAY_SIZE(rm->hw_vbif); i++)
> > > > +        dpu_hw_vbif_destroy(rm->hw_vbif[i]);
> > > >       return 0;
> > > >   }
> > > > @@ -210,6 +212,23 @@ int dpu_rm_init(struct dpu_rm *rm,
> > > >           rm->dspp_blks[dspp->id - DSPP_0] = &hw->base;
> > > >       }
> > > > +    for (i = 0; i < cat->vbif_count; i++) {
> > > > +        struct dpu_hw_vbif *hw;
> > > > +        const struct dpu_vbif_cfg *vbif = &cat->vbif[i];
> > > > +
> > > > +        if (vbif->id < VBIF_0 || vbif->id >= VBIF_MAX) {
> > > > +            DPU_ERROR("skip vbif %d with invalid id\n", vbif->id);
> > > > +            continue;
> > > > +        }
> > > > +        hw = dpu_hw_vbif_init(vbif->id, mmio, cat);
> > > > +        if (IS_ERR(hw)) {
> > > > +            rc = PTR_ERR(hw);
> > > > +            DPU_ERROR("failed vbif object creation: err %d\n", rc);
> > > > +            goto fail;
> > > > +        }
> > > > +        rm->hw_vbif[vbif->id - VBIF_0] = hw;
> > > > +    }
> > > > +
> > > >       return 0;
> > > >   fail:
> > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h 
> > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h
> > > > index 9b13200a050a..a15977bdceeb 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h
> > > > @@ -20,6 +20,7 @@ struct dpu_global_state;
> > > >    * @ctl_blks: array of ctl hardware resources
> > > >    * @hw_intf: array of intf hardware resources
> > > >    * @dspp_blks: array of dspp hardware resources
> > > > + * @hw_vbif: array of vbif hardware resources
> > > >    */
> > > >   struct dpu_rm {
> > > >       struct dpu_hw_blk *pingpong_blks[PINGPONG_MAX - PINGPONG_0];
> > > > @@ -28,6 +29,7 @@ struct dpu_rm {
> > > >       struct dpu_hw_intf *hw_intf[INTF_MAX - INTF_0];
> > > >       struct dpu_hw_blk *dspp_blks[DSPP_MAX - DSPP_0];
> > > >       struct dpu_hw_blk *merge_3d_blks[MERGE_3D_MAX - MERGE_3D_0];
> > > > +    struct dpu_hw_vbif *hw_vbif[VBIF_MAX - VBIF_0];
> > > >   };
> > > >   /**
> > > > @@ -95,5 +97,15 @@ static inline struct dpu_hw_intf 
> > > > *dpu_rm_get_intf(struct dpu_rm *rm, enum dpu_in
> > > >       return rm->hw_intf[intf_idx - INTF_0];
> > > >   }
> > > > +/**
> > > > + * dpu_rm_get_vbif - Return a struct dpu_hw_vbif instance given 
> > > > it's index.
> > > > + * @rm: DPU Resource Manager handle
> > > > + * @vbif_idx: VBIF's index
> > > > + */
> > > > +static inline struct dpu_hw_vbif *dpu_rm_get_vbif(struct dpu_rm 
> > > > *rm, enum dpu_vbif vbif_idx)
> > > > +{
> > > > +    return rm->hw_vbif[vbif_idx - VBIF_0];
> > > > +}
> > > > +
> > > >   #endif /* __DPU_RM_H__ */
> > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_vbif.c 
> > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_vbif.c
> > > > index 21d20373eb8b..00ac2aa81651 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_vbif.c
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_vbif.c
> > > > @@ -152,15 +152,10 @@ void dpu_vbif_set_ot_limit(struct dpu_kms 
> > > > *dpu_kms,
> > > >       struct dpu_hw_mdp *mdp;
> > > >       bool forced_on = false;
> > > >       u32 ot_lim;
> > > > -    int ret, i;
> > > > +    int ret;
> > > >       mdp = dpu_kms->hw_mdp;
> > > > -
> > > > -    for (i = 0; i < ARRAY_SIZE(dpu_kms->hw_vbif); i++) {
> > > > -        if (dpu_kms->hw_vbif[i] &&
> > > > -                dpu_kms->hw_vbif[i]->idx == params->vbif_idx)
> > > > -            vbif = dpu_kms->hw_vbif[i];
> > > > -    }
> > > > +    vbif = dpu_rm_get_vbif(&dpu_kms->rm, params->vbif_idx);
> > > >       if (!vbif || !mdp) {
> > > >           DRM_DEBUG_ATOMIC("invalid arguments vbif %d mdp %d\n",
> > > > @@ -216,14 +211,7 @@ void dpu_vbif_set_qos_remap(struct dpu_kms 
> > > > *dpu_kms,
> > > >       }
> > > >       mdp = dpu_kms->hw_mdp;
> > > > -    for (i = 0; i < ARRAY_SIZE(dpu_kms->hw_vbif); i++) {
> > > > -        if (dpu_kms->hw_vbif[i] &&
> > > > -                dpu_kms->hw_vbif[i]->idx == params->vbif_idx) {
> > > > -            vbif = dpu_kms->hw_vbif[i];
> > > > -            break;
> > > > -        }
> > > > -    }
> > > > -
> > > > +    vbif = dpu_rm_get_vbif(&dpu_kms->rm, params->vbif_idx);
> > > >       if (!vbif || !vbif->cap) {
> > > >           DPU_ERROR("invalid vbif %d\n", params->vbif_idx);
> > > >           return;
> > > > @@ -261,8 +249,8 @@ void dpu_vbif_clear_errors(struct dpu_kms *dpu_kms)
> > > >       struct dpu_hw_vbif *vbif;
> > > >       u32 i, pnd, src;
> > > > -    for (i = 0; i < ARRAY_SIZE(dpu_kms->hw_vbif); i++) {
> > > > -        vbif = dpu_kms->hw_vbif[i];
> > > > +    for (i = VBIF_0; i < VBIF_MAX; i++) {
> > > > +        vbif = dpu_rm_get_vbif(&dpu_kms->rm, i);
> > > >           if (vbif && vbif->ops.clear_errors) {
> > > >               vbif->ops.clear_errors(vbif, &pnd, &src);
> > > >               if (pnd || src) {
> > > > @@ -278,8 +266,8 @@ void dpu_vbif_init_memtypes(struct dpu_kms 
> > > > *dpu_kms)
> > > >       struct dpu_hw_vbif *vbif;
> > > >       int i, j;
> > > > -    for (i = 0; i < ARRAY_SIZE(dpu_kms->hw_vbif); i++) {
> > > > -        vbif = dpu_kms->hw_vbif[i];
> > > > +    for (i = VBIF_0; i < VBIF_MAX; i++) {
> > > > +        vbif = dpu_rm_get_vbif(&dpu_kms->rm, i);
> > > >           if (vbif && vbif->cap && vbif->ops.set_mem_type) {
> > > >               for (j = 0; j < vbif->cap->memtype_count; j++)
> > > >                   vbif->ops.set_mem_type(


--
With best wishes
Dmitry