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

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Date:   Wed, 21 Jul 2021 19:42:27 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     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>,
        Abhinav Kumar <abhinavk@...eaurora.org>
Cc:     Kuogee Hsieh <khsieh@...eaurora.org>,
        Tanmay Shah <tanmay@...eaurora.org>,
        Chandan Uddaraju <chandanu@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 5/5] drm/msm/dp: Allow sub-regions to be specified in DT

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>
---
 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))
-- 
2.29.2