[PATCH v3] drm/exynos: mixer: configure layers once in mixer_atomic_flush()

Tobias Jakobi tjakobi at math.uni-bielefeld.de
Wed Sep 28 16:28:30 UTC 2016


Inki Dae wrote:
> 2016-09-28 18:06 GMT+09:00 Tobias Jakobi <tjakobi at math.uni-bielefeld.de>:
>> Hello Inki,
>>
>>
>> Inki Dae wrote:
>>>
>>>
>>> 2016년 09월 28일 09:03에 Tobias Jakobi 이(가) 쓴 글:
>>>> Hey Inki,
>>>>
>>>>
>>>> Inki Dae wrote:
>>>>>
>>>>>
>>>>> 2016년 09월 28일 01:52에 Tobias Jakobi 이(가) 쓴 글:
>>>>>> Hello Andrzej,
>>>>>>
>>>>>>
>>>>>> Andrzej Hajda wrote:
>>>>>>> On 27.09.2016 13:22, Tobias Jakobi wrote:
>>>>>>>> Hello Inki,
>>>>>>>>
>>>>>>>>
>>>>>>>> Inki Dae wrote:
>>>>>>>>> 2016년 09월 26일 20:36에 Tobias Jakobi 이(가) 쓴 글:
>>>>>>>>>> Only manipulate the MXR_CFG and MXR_LAYER_CFG registers once
>>>>>>>>>> in mixer_cfg_layer().
>>>>>>>>>> Trigger this via atomic flush.
>>>>>>>>>>
>>>>>>>>>> Changes in v2:
>>>>>>>>>> - issue mixer_cfg_layer() in mixer_disable()
>>>>>>>>>> - rename fields as suggested by Andrzej
>>>>>>>>>> - added docu to mixer context struct
>>>>>>>>>> - simplify mixer_win_reset() as well
>>>>>>>>>>
>>>>>>>>>> Changes in v3:
>>>>>>>>>> - simplify some conditions as suggested by Inki
>>>>>>>>>> - add docu to mixer_cfg_layer()
>>>>>>>>>> - fold switch statements into a single one
>>>>>>>>>>
>>>>>>>>>> Signed-off-by: Tobias Jakobi <tjakobi at math.uni-bielefeld.de>
>>>>>>>>>> ---
>>>>>>>>>>  drivers/gpu/drm/exynos/exynos_mixer.c | 135 ++++++++++++++++++++++------------
>>>>>>>>>>  drivers/gpu/drm/exynos/regs-mixer.h   |   2 +
>>>>>>>>>>  2 files changed, 92 insertions(+), 45 deletions(-)
>>>>>>>>>>
>>>>>>>>>> diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c
>>>>>>>>>> index 1e78d57..4f06f4d 100644
>>>>>>>>>> --- a/drivers/gpu/drm/exynos/exynos_mixer.c
>>>>>>>>>> +++ b/drivers/gpu/drm/exynos/exynos_mixer.c
>>>>>>>>>> @@ -93,12 +93,25 @@ static const uint32_t vp_formats[] = {
>>>>>>>>>>        DRM_FORMAT_NV21,
>>>>>>>>>>  };
>>>>>>>>>>
>>>>>>>>>> +/*
>>>>>>>>>> + * Mixer context structure.
>>>>>>>>>> + *
>>>>>>>>>> + * @crtc: The HDMI CRTC attached to the mixer.
>>>>>>>>>> + * @planes: Array of plane objects for each of the mixer windows.
>>>>>>>>>> + * @active_windows: Cache of the mixer's hardware state.
>>>>>>>>>> + *       Tracks which mixer windows are active/inactive.
>>>>>>>>>> + * @pipe: The CRTC index.
>>>>>>>>>> + * @flags: Bitfield build from the mixer_flag_bits enumerator.
>>>>>>>>>> + * @mixer_resources: A struct containing registers, clocks, etc.
>>>>>>>>>> + * @mxr_ver: The hardware revision/version of the mixer.
>>>>>>>>>> + */
>>>>>>>>>>  struct mixer_context {
>>>>>>>>>>        struct platform_device *pdev;
>>>>>>>>>>        struct device           *dev;
>>>>>>>>>>        struct drm_device       *drm_dev;
>>>>>>>>>>        struct exynos_drm_crtc  *crtc;
>>>>>>>>>>        struct exynos_drm_plane planes[MIXER_WIN_NR];
>>>>>>>>>> +      unsigned long           active_windows;
>>>>>>>>>>        int                     pipe;
>>>>>>>>>>        unsigned long           flags;
>>>>>>>>>>
>>>>>>>>>> @@ -418,37 +431,70 @@ static void mixer_cfg_rgb_fmt(struct mixer_context *ctx, unsigned int height)
>>>>>>>>>>        mixer_reg_writemask(res, MXR_CFG, val, MXR_CFG_RGB_FMT_MASK);
>>>>>>>>>>  }
>>>>>>>>>>
>>>>>>>>>> -static void mixer_cfg_layer(struct mixer_context *ctx, unsigned int win,
>>>>>>>>>> -                          unsigned int priority, bool enable)
>>>>>>>>>> +/**
>>>>>>>>>> + * mixer_cfg_layer - apply layer configuration to hardware
>>>>>>>>>> + * @ctx: mixer context
>>>>>>>>>> + *
>>>>>>>>>> + * This configures the MXR_CFG and MXR_LAYER_CFG hardware registers
>>>>>>>>>> + * using the 'active_windows' field of the the mixer content, and
>>>>>>>>>> + * the pixel format of the framebuffers associated with the enabled
>>>>>>>>>> + * windows.
>>>>>>>>>> + *
>>>>>>>>>> + * Has to be called under mixer lock.
>>>>>>>>>> + */
>>>>>>>>>> +static void mixer_cfg_layer(struct mixer_context *ctx)
>>>>>>>>>>  {
>>>>>>>>>>        struct mixer_resources *res = &ctx->mixer_res;
>>>>>>>>>> -      u32 val = enable ? ~0 : 0;
>>>>>>>>>> -
>>>>>>>>>> -      switch (win) {
>>>>>>>>>> -      case 0:
>>>>>>>>>> -              mixer_reg_writemask(res, MXR_CFG, val, MXR_CFG_GRP0_ENABLE);
>>>>>>>>>> -              mixer_reg_writemask(res, MXR_LAYER_CFG,
>>>>>>>>>> -                                  MXR_LAYER_CFG_GRP0_VAL(priority),
>>>>>>>>>> -                                  MXR_LAYER_CFG_GRP0_MASK);
>>>>>>>>>> -              break;
>>>>>>>>>> -      case 1:
>>>>>>>>>> -              mixer_reg_writemask(res, MXR_CFG, val, MXR_CFG_GRP1_ENABLE);
>>>>>>>>>> -              mixer_reg_writemask(res, MXR_LAYER_CFG,
>>>>>>>>>> -                                  MXR_LAYER_CFG_GRP1_VAL(priority),
>>>>>>>>>> -                                  MXR_LAYER_CFG_GRP1_MASK);
>>>>>>>>>> +      unsigned int win;
>>>>>>>>>>
>>>>>>>>>> -              break;
>>>>>>>>>> -      case VP_DEFAULT_WIN:
>>>>>>>>>> -              if (test_bit(MXR_BIT_VP_ENABLED, &ctx->flags)) {
>>>>>>>>>> -                      vp_reg_writemask(res, VP_ENABLE, val, VP_ENABLE_ON);
>>>>>>>>>> -                      mixer_reg_writemask(res, MXR_CFG, val,
>>>>>>>>>> -                              MXR_CFG_VP_ENABLE);
>>>>>>>>>> -                      mixer_reg_writemask(res, MXR_LAYER_CFG,
>>>>>>>>>> -                                          MXR_LAYER_CFG_VP_VAL(priority),
>>>>>>>>>> -                                          MXR_LAYER_CFG_VP_MASK);
>>>>>>>>>> +      struct exynos_drm_plane_state *state;
>>>>>>>>>> +      struct drm_framebuffer *fb;
>>>>>>>>>> +      unsigned int priority;
>>>>>>>>>> +      u32 mxr_cfg = 0, mxr_layer_cfg = 0, vp_enable = 0;
>>>>>>>>>> +      bool enable;
>>>>>>>>>> +
>>>>>>>>>> +      for (win = 0; win < MIXER_WIN_NR; ++win) {
>>>>>>>>>> +              state = to_exynos_plane_state(ctx->planes[win].base.state);
>>>>>>>>>> +              fb = state->fb;
>>>>>>>>>> +
>>>>>>>>>> +              priority = state->base.normalized_zpos + 1;
>>>>>>>>>> +              enable = test_bit(win, &ctx->active_windows);
>>>>>>>>>> +
>>>>>>>>>> +              if (!enable)
>>>>>>>>>> +                      continue;
>>>>>>>>>> +
>>>>>>>>>> +              BUG_ON(!fb);
>>>>>>>>>> +
>>>>>>>>>> +              /*
>>>>>>>>>> +               * TODO: Don't enable alpha blending for the bottom window.
>>>>>>>>>> +               */
>>>>>>>>>> +              switch (win) {
>>>>>>>>>> +              case 0:
>>>>>>>>>> +                      mxr_cfg |=  MXR_CFG_GRP0_ENABLE;
>>>>>>>>>> +                      mxr_layer_cfg |= MXR_LAYER_CFG_GRP0_VAL(priority);
>>>>>>>>>> +                      mixer_cfg_gfx_blend(ctx, win, is_alpha_format(fb->pixel_format));
>>>>>>>>>> +                      break;
>>>>>>>>>> +
>>>>>>>>>> +              case 1:
>>>>>>>>>> +                      mxr_cfg |=  MXR_CFG_GRP1_ENABLE;
>>>>>>>>>> +                      mxr_layer_cfg |= MXR_LAYER_CFG_GRP1_VAL(priority);
>>>>>>>>>> +                      mixer_cfg_gfx_blend(ctx, win, is_alpha_format(fb->pixel_format));
>>>>>>>>>> +                      break;
>>>>>>>>>> +
>>>>>>>>>> +              case VP_DEFAULT_WIN:
>>>>>>>>>> +                      vp_enable = VP_ENABLE_ON;
>>>>>>>>>> +                      mxr_cfg |=  MXR_CFG_VP_ENABLE;
>>>>>>>>>> +                      mxr_layer_cfg |= MXR_LAYER_CFG_VP_VAL(priority);
>>>>>>>>>> +                      mixer_cfg_vp_blend(ctx);
>>>>>>>>>> +                      break;
>>>>>>>>>>                }
>>>>>>>>>> -              break;
>>>>>>>>>>        }
>>>>>>>>>> +
>>>>>>>>>> +      if (test_bit(MXR_BIT_VP_ENABLED, &ctx->flags))
>>>>>>>>>> +              vp_reg_writemask(res, VP_ENABLE, vp_enable, VP_ENABLE_ON);
>>>>>>>>>> +
>>>>>>>>>> +      mixer_reg_writemask(res, MXR_CFG, mxr_cfg, MXR_CFG_ENABLE_MASK);
>>>>>>>>>> +      mixer_reg_writemask(res, MXR_LAYER_CFG, mxr_layer_cfg, MXR_LAYER_CFG_MASK);
>>>>>>>>>>  }
>>>>>>>>>>
>>>>>>>>>>  static void mixer_run(struct mixer_context *ctx)
>>>>>>>>>> @@ -478,7 +524,6 @@ static void vp_video_buffer(struct mixer_context *ctx,
>>>>>>>>>>        struct drm_display_mode *mode = &state->base.crtc->state->adjusted_mode;
>>>>>>>>>>        struct mixer_resources *res = &ctx->mixer_res;
>>>>>>>>>>        struct drm_framebuffer *fb = state->fb;
>>>>>>>>>> -      unsigned int priority = state->base.normalized_zpos + 1;
>>>>>>>>>>        unsigned long flags;
>>>>>>>>>>        dma_addr_t luma_addr[2], chroma_addr[2];
>>>>>>>>>>        bool tiled_mode = false;
>>>>>>>>>> @@ -563,8 +608,6 @@ static void vp_video_buffer(struct mixer_context *ctx,
>>>>>>>>>>
>>>>>>>>>>        mixer_cfg_scan(ctx, mode->vdisplay);
>>>>>>>>>>        mixer_cfg_rgb_fmt(ctx, mode->vdisplay);
>>>>>>>>>> -      mixer_cfg_layer(ctx, plane->index, priority, true);
>>>>>>>>>> -      mixer_cfg_vp_blend(ctx);
>>>>>>>>> You removed the function call to set MXR_CFG and MXR_LAYER_CFG registers so what if lagacy set plane ioctl is called by user user space? Where these register are updated?
>>>>>>>> yes, you're right. I completly forgot about the legacy codepaths. Sorry
>>>>>>>> about that!
>>>>>>>
>>>>>>> Are you talking about DRM_IOCTL_MODE_SETPLANE?
>>>>>>> It does not seem to be legacy, or to be more precise it calls
>>>>>>> .update_plane and .disable_plane
>>>>>>> callbacks which in exynos are set as follow:
>>>>>>>     .update_plane    = drm_atomic_helper_update_plane,
>>>>>>>     .disable_plane    = drm_atomic_helper_disable_plane,
>>>>>>>
>>>>>>> So DRM_IOCTL_MODE_SETPLANE calls atomic codepath anyway.
>>>>>> thanks a lot for the heads-up. I can confirm that drm_mode_setplane()
>>>>>> also goes through the atomic path.
>>>>>>
>>>>>> The simplified callstack:
>>>>>> - drm_mode_setplane()
>>>>>>   - __setplane_internal()
>>>>>>     - disable_plane() (set in plane_helper_funcs in exynos_drm_plane.c)
>>>>>>     - update_plane() (same here)
>>>>>
>>>>> Sorry for previous comments not enough.
>>>>>
>>>>> update_plane
>>>>>     ...
>>>>>     - mixer_update_plane
>>>>>             - vp_video_buffer or mixer_graph_buffer
>>>>>
>>>>> However, you removed mixer_cfg_layer call from above functions.
>>>> exactly, because that is the very purpose of this patch.
>>>>
>>>>
>>>>> So my intention was to keep the modifed mixer_cfg_layer call on vp_video_buffer and mixer_grpah_buffer functions.
>>>> That is not my intention. I want to move register manipulation to the
>>>> atomic flush step.
>>>>
>>>>
>>>>> mixer_atomic_flush function is not really proper place to call mixer_cfg_layer function even mixer_win_reset.
>>>> Why do you think so? I think it makes perfect sense to put it there. We
>>>> flush the new configuration to the hardware registers there.
>>>>
>>>>
>>>>> For this I mentioned already at previous my comment,
>>>>> "atomic_flush callback will be used to make sure registers to be updated to the real hardware. So calling mixer_cfg_layer function here wouldn't be reasonable."
>>>> You're confusing me. That is exactly what my patch is doing. It moves
>>>> more of the actual hardware register updating to the atomic flush step.
>>>
>>> Ok, for your understanding, you can check atomic_begin, atomic_flush and update_plane callback functions of exynos_drm_fimd.c.
>>> After that I think we could continue to discuss this. I doesn't really want to tackle you.
>> I'm aware of that code, but it's for the FIMD and not the mixer. So I
>> don't see how it is relevant to the discussion. One could probably do
>> the same thing for the FIMD, i.e. moving more code to the flush step.
>> However I lack the hardware to properly test this, so this would be a
>> bit difficult to work on.
> 
> First, check below descriptions for atomic_begin and atomic_flush callbacks,
> 
> "@atomic_begin:
> ...
> Depending upon hardware this might be vblank
> evasion, blocking updates by setting bits or doing preparatory work
> for e.g. manual update display.
> 
> 
> @atomic_flush:
>  ...
> Depending upon hardware this might include
> checking that vblank evasion was successful, unblocking updates by
> setting bits or setting the GO bit to flush out all updates."
> 
> And for this Mixer device has similar registers to FIMD ones. See the
> below codes,
> 
> static void mixer_vsync_set_update(struct mixer_context *ctx, bool enable)
> {
>  struct mixer_resources *res = &ctx->mixer_res;
>  /* block update on vsync */
>  mixer_reg_writemask(res, MXR_STATUS, enable ?
>    MXR_STATUS_SYNC_ENABLE : 0, MXR_STATUS_SYNC_ENABLE);
>  if (ctx->vp_enabled)
>   vp_reg_write(res, VP_SHADOW_UPDATE, enable ?
>    VP_SHADOW_UPDATE_ENABLE : 0);
> }
> 
> According to the second argument of above function - enable value -,
> this function will do something required by atomic_begin or
> atomic_flush callback.
> And this function is already called by mixer_atomic_begin and
> mixer_atomic_flush functions properly.
I'm aware how the mixer operates. However my code doesn't modify
manipulation of the MXR_STATUS register, update blocking still works the
same as before.


> You are trying to really spread out register setting codes here and
> there with this patch.
> 
Uhm, no? The contrary is true, I consolidate register manipulation. Are
you sure you're reading my patch correctly?

@Andrzej: Maybe you can comment on this?


> Ps. most crtc devices have special registers which block setting
> values to be updated to real hardware after vsync completion to make
> sure for all register setting values to be updated to real hardware
> when they are really ready. So atomic_begin and atomic_flush callbacks
> are used for such purpose.
I'm also aware of this. But this is orthogonal to what my patch want to
achieve.


With best wishes,
Tobias



> 
> Thanks,
> Inki Dae
> 
>>
>>
>> With best wishes,
>> Tobias
>>
>>
>>>>> Also it would be reasonable to remove mixer_cfg_layer function call from mixer_win_reset function.
>>>> Why is that? In mixer_win_reset() we want to apply a default
>>>> configuration to the various registers. Hence we set active_windows to
>>>> zero and call mixer_cfg_layer().
>>>>
>>>>
>>>> With best wishes,
>>>> Tobias
>>>>
>>>>
>>>>
>>>>>> For completeness I've also checked drm_mode_setcrtc(), the other legacy
>>>>>> DRM call that manipulates the primary plane.
>>>>>>
>>>>>> It goes the following route:
>>>>>> - drm_mode_setcrtc
>>>>>>   - drm_mode_set_config_internal()
>>>>>>     - set_config() (set in exynos_crtc_funcs in exynos_drm_crtc.c)
>>>>>>
>>>>>> Also here: .set_config = drm_atomic_helper_set_config
>>>>>>
>>>>>> Both DRM_IOCTL_MODE_SETPLANE and DRM_IOCTL_MODE_CRTC go the atomic
>>>>>> route, so the patch is fine this way.
>>>>>>
>>>>>> @Inki: Can you still queue this up for 4.9.y?
>>>>>>
>>>>>>
>>>>>> With best wishes,
>>>>>> Tobias
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> Regards
>>>>>>> Andrzej
>>>>>>>
>>>>>>
>>>>>> --
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>>>>>>
>>>>>>
>>>>>>
>>>>> --
>>>>> To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
>>>>> the body of a message to majordomo at vger.kernel.org
>>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>>>
>>>>
>>>>
>>>>
>>>>
>>
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