linux-kernel - Re: [PATCH v4 2/9] soc: qcom: ubwc: add helpers to get programmable values

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Message-ID: <CACu1E7Gpzgg0WKT9EyFO+uJsGCVAcEUG1OkTdhXLpGThTrd=Ww@mail.gmail.com>
Date: Sun, 25 Jan 2026 12:16:37 -0500
From: Connor Abbott <cwabbott0@...il.com>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: Bjorn Andersson <andersson@...nel.org>, Konrad Dybcio <konradybcio@...nel.org>, 
	Rob Clark <robin.clark@....qualcomm.com>, Dmitry Baryshkov <lumag@...nel.org>, 
	Abhinav Kumar <abhinav.kumar@...ux.dev>, Jessica Zhang <jesszhan0024@...il.com>, 
	Sean Paul <sean@...rly.run>, Marijn Suijten <marijn.suijten@...ainline.org>, 
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
	Akhil P Oommen <akhilpo@....qualcomm.com>, Vikash Garodia <vikash.garodia@....qualcomm.com>, 
	Dikshita Agarwal <dikshita.agarwal@....qualcomm.com>, "Bryan O'Donoghue" <bod@...nel.org>, 
	Mauro Carvalho Chehab <mchehab@...nel.org>, Konrad Dybcio <konrad.dybcio@....qualcomm.com>, 
	linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org, 
	linux-media@...r.kernel.org, Wangao Wang <wangao.wang@....qualcomm.com>
Subject: Re: [PATCH v4 2/9] soc: qcom: ubwc: add helpers to get programmable values

On Sun, Jan 25, 2026 at 6:37 AM Dmitry Baryshkov
<dmitry.baryshkov@....qualcomm.com> wrote:
>
> Currently the database stores macrotile_mode in the data. However it
> can be derived from the rest of the data: it should be used for UBWC
> encoding >= 3.0 except for several corner cases (SM8150 and SC8180X).

FWIW, there is a UBWC version 3.1 not currently reflected in the code
which adds the 8-channel macrotile mode. If we just added that and
made SM8150 and SC8180X be 3.1 then we could derive it from the
version.

Connor

>
> The ubwc_bank_spread field seems to be based on the impreside data we
> had for the MDSS and DPU programming. In some cases UBWC engine inside
> the display controller doesn't need to program it, although bank spread
> is to be enabled.
>
> Bank swizzle is also currently stored as is, but it is almost standard
> (banks 1-3 for UBWC 1.0 and 2-3 for other versions), the only exception
> being Lemans (it uses only bank 3).
>
> Add helpers returning values from the config for now. They will be
> rewritten later, in a separate series, but having the helper now
> simplifies refacroring the code later.
>
> Tested-by: Wangao Wang <wangao.wang@....qualcomm.com>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
> ---
>  include/linux/soc/qcom/ubwc.h | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>
> diff --git a/include/linux/soc/qcom/ubwc.h b/include/linux/soc/qcom/ubwc.h
> index 5bdeca18d54d..f5d0e2341261 100644
> --- a/include/linux/soc/qcom/ubwc.h
> +++ b/include/linux/soc/qcom/ubwc.h
> @@ -84,4 +84,19 @@ static inline bool qcom_ubwc_min_acc_length_64b(const struct qcom_ubwc_cfg_data
>                  cfg->ubwc_dec_version == UBWC_3_0);
>  }
>
> +static inline bool qcom_ubwc_macrotile_mode(const struct qcom_ubwc_cfg_data *cfg)
> +{
> +       return cfg->macrotile_mode;
> +}
> +
> +static inline bool qcom_ubwc_bank_spread(const struct qcom_ubwc_cfg_data *cfg)
> +{
> +       return cfg->ubwc_bank_spread;
> +}
> +
> +static inline u32 qcom_ubwc_swizzle(const struct qcom_ubwc_cfg_data *cfg)
> +{
> +       return cfg->ubwc_swizzle;
> +}
> +
>  #endif /* __QCOM_UBWC_H__ */
>
> --
> 2.47.3
>