linux-kernel - Re: [Freedreno] [PATCH 5/5] drm/msm/dp: Allow sub-regions to be specified in DT

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Message-ID: <2d969e35f13b6a5313a901ac8b6dde9e@codeaurora.org>
Date:   Fri, 23 Jul 2021 13:33:07 -0700
From:   abhinavk@...eaurora.org
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Stephen Boyd <swboyd@...omium.org>, devicetree@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org,
        Kuogee Hsieh <khsieh@...eaurora.org>,
        Tanmay Shah <tanmay@...eaurora.org>,
        freedreno@...ts.freedesktop.org,
        Chandan Uddaraju <chandanu@...eaurora.org>
Subject: Re: [Freedreno] [PATCH 5/5] drm/msm/dp: Allow sub-regions to be
 specified in DT

On 2021-07-21 19:42, Bjorn Andersson wrote:
> Not all platforms has P0 at an offset of 0x1000 from the base address,
> so add support for specifying each sub-region in DT. The code falls 
> back
> to the predefined offsets in the case that only a single reg is
> specified, in order to support existing DT.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
The change itself looks good, hence
Reviewed-by: Abhinav Kumar <abhinavk@...eaurora.org>

But as a follow up to this change, can we move the existing DP DT on
sc7180 to this model and then drop this legacy path?

That will clean this up nicely.

> ---
>  drivers/gpu/drm/msm/dp/dp_parser.c | 49 +++++++++++++++++++++++-------
>  1 file changed, 38 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_parser.c
> b/drivers/gpu/drm/msm/dp/dp_parser.c
> index 1a10901ae574..fc8a6452f641 100644
> --- a/drivers/gpu/drm/msm/dp/dp_parser.c
> +++ b/drivers/gpu/drm/msm/dp/dp_parser.c
> @@ -63,18 +63,45 @@ static int dp_parser_ctrl_res(struct dp_parser 
> *parser)
>  		return PTR_ERR(dss->ahb);
>  	}
> 
> -	if (dss->ahb_len < DP_DEFAULT_P0_OFFSET + DP_DEFAULT_P0_SIZE) {
> -		DRM_ERROR("legacy memory region not large enough\n");
> -		return -EINVAL;
> -	}
> +	dss->aux = dp_ioremap(pdev, 1, &dss->aux_len);
> +	if (IS_ERR(dss->aux)) {
> +		/*
> +		 * The initial binding had a single reg, but in order to
> +		 * support variation in the sub-region sizes this was split.
> +		 * dp_ioremap() will fail with -ENODEV here if only a single
> +		 * reg is specified, so fill in the sub-region offsets and
> +		 * lengths based on this single region.
> +		 */
> +		if (PTR_ERR(dss->aux) == -ENODEV) {
> +			if (dss->ahb_len < DP_DEFAULT_P0_OFFSET + DP_DEFAULT_P0_SIZE) {
> +				DRM_ERROR("legacy memory region not large enough\n");
> +				return -EINVAL;
> +			}
> +
> +			dss->ahb_len = DP_DEFAULT_AHB_SIZE;
> +			dss->aux = dss->ahb + DP_DEFAULT_AUX_OFFSET;
> +			dss->aux_len = DP_DEFAULT_AUX_SIZE;
> +			dss->link = dss->ahb + DP_DEFAULT_LINK_OFFSET;
> +			dss->link_len = DP_DEFAULT_LINK_SIZE;
> +			dss->p0 = dss->ahb + DP_DEFAULT_P0_OFFSET;
> +			dss->p0_len = DP_DEFAULT_P0_SIZE;
> +		} else {
> +			DRM_ERROR("unable to remap aux region: %pe\n", dss->aux);
> +			return PTR_ERR(dss->aux);
> +		}
> +	} else {
> +		dss->link = dp_ioremap(pdev, 2, &dss->link_len);
> +		if (IS_ERR(dss->link)) {
> +			DRM_ERROR("unable to remap link region: %pe\n", dss->link);
> +			return PTR_ERR(dss->link);
> +		}
> 
> -	dss->ahb_len = DP_DEFAULT_AHB_SIZE;
> -	dss->aux = dss->ahb + DP_DEFAULT_AUX_OFFSET;
> -	dss->aux_len = DP_DEFAULT_AUX_SIZE;
> -	dss->link = dss->ahb + DP_DEFAULT_LINK_OFFSET;
> -	dss->link_len = DP_DEFAULT_LINK_SIZE;
> -	dss->p0 = dss->ahb + DP_DEFAULT_P0_OFFSET;
> -	dss->p0_len = DP_DEFAULT_P0_SIZE;
> +		dss->p0 = dp_ioremap(pdev, 3, &dss->p0_len);
> +		if (IS_ERR(dss->p0)) {
> +			DRM_ERROR("unable to remap p0 region: %pe\n", dss->p0);
> +			return PTR_ERR(dss->p0);
> +		}
> +	}
> 
>  	io->phy = devm_phy_get(&pdev->dev, "dp");
>  	if (IS_ERR(io->phy))