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Date:   Thu, 17 Feb 2022 23:06:26 +0100
From:   Marijn Suijten <marijn.suijten@somainline.org>
To:     Vinod Koul <vkoul@kernel.org>
Cc:     Rob Clark <robdclark@gmail.com>, linux-arm-msm@vger.kernel.org,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Jonathan Marek <jonathan@marek.ca>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Abhinav Kumar <abhinavk@codeaurora.org>,
        Jeffrey Hugo <jeffrey.l.hugo@gmail.com>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        freedreno@lists.freedesktop.org
Subject: Re: [PATCH v3 03/13] drm/msm/disp/dpu1: Add support for DSC in
 pingpong block
Message-ID: <20220217220626.q37mvyzu4ifl7hr4@SoMainline.org>
References: <20211116062256.2417186-1-vkoul@kernel.org>
 <20211116062256.2417186-4-vkoul@kernel.org>
 <20220217215437.gvxmfjgfqzljactz@SoMainline.org>
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In-Reply-To: <20220217215437.gvxmfjgfqzljactz@SoMainline.org>
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Hi Vinod,

I seem to have sent this review to v3 instead of the repost of v4.  It
should still apply the same, hope that's no issue.

- Marijn

On 2022-02-17 22:54:38, Marijn Suijten wrote:
> On 2021-11-16 11:52:46, Vinod Koul wrote:
> > In SDM845, DSC can be enabled by writing to pingpong block registers, so
> > add support for DSC in hw_pp
> 
> Nit: I don't think the ", so add support for DSC in XXX" part in this
> and other commit messages add anything.  You've already stated that in
> the title, the commit body is just extra justification (and can perhaps
> be filled with extra details about the patch contents instead).
> 
> > Reviewed-by: Abhinav Kumar <abhinavk@codeaurora.org>
> > Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > Signed-off-by: Vinod Koul <vkoul@kernel.org>
> > ---
> >  .../gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c   | 32 +++++++++++++++++++
> >  .../gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.h   | 14 ++++++++
> >  2 files changed, 46 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c
> > index 55766c97c4c8..47c6ab6caf95 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c
> > @@ -28,6 +28,9 @@
> >  #define PP_FBC_MODE                     0x034
> >  #define PP_FBC_BUDGET_CTL               0x038
> >  #define PP_FBC_LOSSY_MODE               0x03C
> > +#define PP_DSC_MODE                     0x0a0
> > +#define PP_DCE_DATA_IN_SWAP             0x0ac
> 
> This enum does not seem used here, is it used in another patch?
> 
> > +#define PP_DCE_DATA_OUT_SWAP            0x0c8
> >  
> >  #define PP_DITHER_EN			0x000
> >  #define PP_DITHER_BITDEPTH		0x004
> > @@ -245,6 +248,32 @@ static u32 dpu_hw_pp_get_line_count(struct dpu_hw_pingpong *pp)
> >  	return line;
> >  }
> >  
> > +static int dpu_hw_pp_dsc_enable(struct dpu_hw_pingpong *pp)
> > +{
> > +	struct dpu_hw_blk_reg_map *c = &pp->hw;
> > +
> > +	DPU_REG_WRITE(c, PP_DSC_MODE, 1);
> > +	return 0;
> > +}
> > +
> > +static void dpu_hw_pp_dsc_disable(struct dpu_hw_pingpong *pp)
> > +{
> > +	struct dpu_hw_blk_reg_map *c = &pp->hw;
> > +
> > +	DPU_REG_WRITE(c, PP_DSC_MODE, 0);
> > +}
> > +
> > +static int dpu_hw_pp_setup_dsc(struct dpu_hw_pingpong *pp)
> > +{
> > +	struct dpu_hw_blk_reg_map *pp_c = &pp->hw;
> > +	int data;
> > +
> > +	data = DPU_REG_READ(pp_c, PP_DCE_DATA_OUT_SWAP);
> > +	data |= BIT(18); /* endian flip */
> > +	DPU_REG_WRITE(pp_c, PP_DCE_DATA_OUT_SWAP, data);
> > +	return 0;
> > +}
> > +
> >  static void _setup_pingpong_ops(struct dpu_hw_pingpong *c,
> >  				unsigned long features)
> >  {
> > @@ -256,6 +285,9 @@ static void _setup_pingpong_ops(struct dpu_hw_pingpong *c,
> >  	c->ops.get_autorefresh = dpu_hw_pp_get_autorefresh_config;
> >  	c->ops.poll_timeout_wr_ptr = dpu_hw_pp_poll_timeout_wr_ptr;
> >  	c->ops.get_line_count = dpu_hw_pp_get_line_count;
> > +	c->ops.setup_dsc = dpu_hw_pp_setup_dsc;
> > +	c->ops.enable_dsc = dpu_hw_pp_dsc_enable;
> > +	c->ops.disable_dsc = dpu_hw_pp_dsc_disable;
> >  
> >  	if (test_bit(DPU_PINGPONG_DITHER, &features))
> >  		c->ops.setup_dither = dpu_hw_pp_setup_dither;
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.h
> > index 89d08a715c16..12758468d9ca 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.h
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.h
> > @@ -124,6 +124,20 @@ struct dpu_hw_pingpong_ops {
> >  	 */
> >  	void (*setup_dither)(struct dpu_hw_pingpong *pp,
> >  			struct dpu_hw_dither_cfg *cfg);
> > +	/**
> > +	 * Enable DSC
> > +	 */
> > +	int (*enable_dsc)(struct dpu_hw_pingpong *pp);
> > +
> > +	/**
> > +	 * Disable DSC
> > +	 */
> > +	void (*disable_dsc)(struct dpu_hw_pingpong *pp);
> 
> It looks like most other callbacks in dpu1 use an `enable` function with
> a boolean, instead of having a separate disable function.  That should
> simplify the implementation down to a single ternary-if, too.  Would
> that be desired to use here?
> 
> - Marijn
> 
> > +
> > +	/**
> > +	 * Setup DSC
> > +	 */
> > +	int (*setup_dsc)(struct dpu_hw_pingpong *pp);
> >  };
> >  
> >  struct dpu_hw_merge_3d;
> > -- 
> > 2.31.1
> >