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

[Abhinav Kumar <quic_abhinavk@quicinc.com>]

On 2/14/2022 2:39 PM, Dmitry Baryshkov wrote:
> 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@linaro.org>
>>>>
>>>> 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?

Yes it seems like 8996 writeback is the only client to use VBIF_NRT. I 
am unable to locate the old codebase to check its usage.

Here since we are talking about eventually using DPU for 8996, even if 
we consider VBIF_NRT into the mix, its only 2.

So I feel we can get rid of the loop and instead just come up with a 
simple if else?

So something like:

if (VBIF_RT)
	vbif = dpu_kms[VBIF_RT].vbif;
else
	vbif = dpu_kms[VBIF_NRT].vbif

I am not foreseeing more vbif clients so far.

We can revisit this in the future if it goes beyond 2.

> 
>>
>>>
>>>>   /**
>>>>    * _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(
>>>
>>>
> 
>