linux-kernel - Re: [PATCH v2 1/3] drm/msm/mdss: define bitfields for the UBWC

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Message-ID: <bclvvuo3i4icx5kraqsvmpdtokx46pnjmdhliz2mhsmdm256vm@rbkwhkhjvjtc>
Date: Tue, 26 Nov 2024 14:17:51 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Abhinav Kumar <quic_abhinavk@...cinc.com>
Cc: Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>, 
	Marijn Suijten <marijn.suijten@...ainline.org>, Connor Abbott <cwabbott0@...il.com>, 
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, linux-kernel@...r.kernel.org, 
	linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org
Subject: Re: [PATCH v2 1/3] drm/msm/mdss: define bitfields for the
 UBWC_STATIC register

On Mon, Nov 25, 2024 at 06:03:52PM -0800, Abhinav Kumar wrote:
> 
> 
> On 11/22/2024 9:44 PM, Dmitry Baryshkov wrote:
> > Rather than hand-coding UBWC_STATIC value calculation, define
> > corresponding bitfields and use them to setup the register value.
> > 
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> > ---
> >   drivers/gpu/drm/msm/msm_mdss.c                 | 38 +++++++++++++++-----------
> >   drivers/gpu/drm/msm/msm_mdss.h                 |  3 +-
> >   drivers/gpu/drm/msm/registers/display/mdss.xml | 11 +++++++-
> >   3 files changed, 34 insertions(+), 18 deletions(-)
> > 
> 
> <snip>
> 
> > diff --git a/drivers/gpu/drm/msm/registers/display/mdss.xml b/drivers/gpu/drm/msm/registers/display/mdss.xml
> > index ac85caf1575c7908bcf68f0249da38dccf4f07b6..b6f93984928522a35a782cbad9de006eac225725 100644
> > --- a/drivers/gpu/drm/msm/registers/display/mdss.xml
> > +++ b/drivers/gpu/drm/msm/registers/display/mdss.xml
> > @@ -21,7 +21,16 @@ xsi:schemaLocation="https://gitlab.freedesktop.org/freedreno/ rules-fd.xsd">
> >   	<reg32 offset="0x00058" name="UBWC_DEC_HW_VERSION"/>
> > -	<reg32 offset="0x00144" name="UBWC_STATIC"/>
> > +	<reg32 offset="0x00144" name="UBWC_STATIC">
> > +		<bitfield name="UBWC_SWIZZLE" low="0" high="2"/>
> > +		<bitfield name="UBWC_BANK_SPREAD" pos="3"/>
> > +		<!-- high=5 for UBWC < 4.0 -->
> > +		<bitfield name="HIGHEST_BANK_BIT" low="4" high="6"/>
> > +		<bitfield name="UBWC_MIN_ACC_LEN" pos="8"/>
> 
> MIN_ACC_LEN OR MALSIZE has 2 bits , bits 8 and 9.
> 
> But bit 9 is unused today. Hence we were using it as a 1 or 0 today.
> 
> Its unused on all the chipsets I checked. Do you want to continue using the
> same way or correct this?

Let's correct it. I will send next iteration.

-- 
With best wishes
Dmitry