[PATCH v3] drm/exynos: mixer: configure layers once in mixer_atomic_flush()
Tobias Jakobi
tjakobi at math.uni-bielefeld.de
Wed Sep 28 09:06:43 UTC 2016
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.
>>
>>
>>> 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().
>
> mixer_win_reset function sets registers to default value because mixer device has no reset HW register like vp did.
> So original codes set the registers to default value but you removed them like below,
> - /* reset default layer priority */
> - mixer_reg_write(res, MXR_LAYER_CFG, 0);
>
>
> - /* disable all layers */
> - mixer_reg_writemask(res, MXR_CFG, 0, MXR_CFG_GRP0_ENABLE);
> - mixer_reg_writemask(res, MXR_CFG, 0, MXR_CFG_GRP1_ENABLE);
> - if (test_bit(MXR_BIT_VP_ENABLED, &ctx->flags))
> - mixer_reg_writemask(res, MXR_CFG, 0, MXR_CFG_VP_ENABLE);
>
> and called mixer_cfg_layer function which configures overlay registers as previous plane state but not HW default values.
OK, let me explain you.
The previous code does the following:
- write zero to MXR_LAYER_CFG
- write zero to the GRP0_ENABLE, GRP1_ENABLE and maybe VP_ENABLE bits of
MXR_CFG
A brief note about the MXR_LAYER_CFG register. Only the region [11:0] is
to be manipulated, bits [31:12] should be left zero. The region [11:0]
is the newly introduced mask MXR_LAYER_CFG_MASK.
The new code does the following:
- set active_windows to zero
- issue mixer_cfg_layer(), which now does the following:
- initializes local variables mxr_cfg, mxr_layer_cfg, vp_enable
- iterates over planes
- since no plane is enabled, all three variables above
stay zero
- zero is written to MXR_CFG with writemask MXR_CFG_ENABLE_MASK
- zero is written to MXR_LAYER_CFG with writemask MXR_LAYER_CFG_MASK
So in the end, both the old and the new code write exactly the same
thing into MXR_CFG and MXR_LAYER_CFG.
I hope this clears things up! :-)
> With this patch do you know that how many times mixer_cfg_layer function is called when we requested atomic operation?
For your typical operation, where mixer_{enable,disable}() is not
called, it should now be just once (in mixer_atomic_flush()).
With best wishes,
Tobias
>> 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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>>>>
>>>>
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>>>
>>
>>
>>
>>
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