linux-kernel - [PATCH v3 03/14] drm/sun4i: Remove obsolete references to PHYS

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Date:   Sun, 24 Apr 2022 11:26:21 -0500
From:   Samuel Holland <samuel@...lland.org>
To:     Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Maxime Ripard <mripard@...nel.org>
Cc:     Samuel Holland <samuel@...lland.org>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org,
        dri-devel@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-sunxi@...ts.linux.dev
Subject: [PATCH v3 03/14] drm/sun4i: Remove obsolete references to PHYS_OFFSET

commit b4bdc4fbf8d0 ("soc: sunxi: Deal with the MBUS DMA offsets in a
central place") added a platform device notifier that sets the DMA
offset for all of the display engine frontend and backend devices.

The code applying the offset to DMA buffer physical addresses was then
removed from the backend driver in commit 756668ba682e ("drm/sun4i:
backend: Remove the MBUS quirks"), but the code subtracting PHYS_OFFSET
was left in the frontend driver.

As a result, the offset was applied twice in the frontend driver. This
likely went unnoticed because it only affects specific configurations
(scaling or certain pixel formats) where the frontend is used, on boards
with both one of these older SoCs and more than 1 GB of DRAM.

In addition, the references to PHYS_OFFSET prevent compiling the driver
on architectures where PHYS_OFFSET is not defined.

Fixes: b4bdc4fbf8d0 ("soc: sunxi: Deal with the MBUS DMA offsets in a central place")
Reviewed-by: Jernej Skrabec <jernej.skrabec@...il.com>
Signed-off-by: Samuel Holland <samuel@...lland.org>
---

(no changes since v1)

 drivers/gpu/drm/sun4i/sun4i_frontend.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun4i_frontend.c b/drivers/gpu/drm/sun4i/sun4i_frontend.c
index 56ae38389db0..462fae73eae9 100644
--- a/drivers/gpu/drm/sun4i/sun4i_frontend.c
+++ b/drivers/gpu/drm/sun4i/sun4i_frontend.c
@@ -222,13 +222,11 @@ void sun4i_frontend_update_buffer(struct sun4i_frontend *frontend,
 
 	/* Set the physical address of the buffer in memory */
 	paddr = drm_fb_cma_get_gem_addr(fb, state, 0);
-	paddr -= PHYS_OFFSET;
 	DRM_DEBUG_DRIVER("Setting buffer #0 address to %pad\n", &paddr);
 	regmap_write(frontend->regs, SUN4I_FRONTEND_BUF_ADDR0_REG, paddr);
 
 	if (fb->format->num_planes > 1) {
 		paddr = drm_fb_cma_get_gem_addr(fb, state, swap ? 2 : 1);
-		paddr -= PHYS_OFFSET;
 		DRM_DEBUG_DRIVER("Setting buffer #1 address to %pad\n", &paddr);
 		regmap_write(frontend->regs, SUN4I_FRONTEND_BUF_ADDR1_REG,
 			     paddr);
@@ -236,7 +234,6 @@ void sun4i_frontend_update_buffer(struct sun4i_frontend *frontend,
 
 	if (fb->format->num_planes > 2) {
 		paddr = drm_fb_cma_get_gem_addr(fb, state, swap ? 1 : 2);
-		paddr -= PHYS_OFFSET;
 		DRM_DEBUG_DRIVER("Setting buffer #2 address to %pad\n", &paddr);
 		regmap_write(frontend->regs, SUN4I_FRONTEND_BUF_ADDR2_REG,
 			     paddr);
-- 
2.35.1