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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jernej Skrabec <jernej.skrabec@gmail.com>,
        Samuel Holland <samuel@sholland.org>,
        Maxime Ripard <maxime@cerno.tech>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 109/177] drm/sun4i: Remove obsolete references to PHYS_OFFSET
Date:   Wed,  4 May 2022 18:45:02 +0200
Message-Id: <20220504153102.988331294@linuxfoundation.org>
In-Reply-To: <20220504153053.873100034@linuxfoundation.org>
References: <20220504153053.873100034@linuxfoundation.org>
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From: Samuel Holland <samuel@sholland.org>

[ Upstream commit dc3ae06c5f2170d879ff58696f629d8c3868aec3 ]

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@gmail.com>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220424162633.12369-4-samuel@sholland.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 edb60ae0a9b7..faecc2935039 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