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Message-Id: <20220823080056.265603348@linuxfoundation.org>
Date: Tue, 23 Aug 2022 10:23:52 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com>,
Houlong Wei <houlong.wei@...iatek.com>,
Irui Wang <irui.wang@...iatek.com>,
Hans Verkuil <hverkuil-cisco@...all.nl>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 071/229] media: platform: mtk-mdp: Fix mdp_ipi_comm structure alignment
From: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
[ Upstream commit ab14c99c035da7156a3b66fa171171295bc4b89a ]
The mdp_ipi_comm structure defines a command that is either
PROCESS (start processing) or DEINIT (destroy instance); we
are using this one to send PROCESS or DEINIT commands from Linux
to an MDP instance through a VPU write but, while the first wants
us to stay 4-bytes aligned, the VPU instead requires an 8-bytes
data alignment.
Keeping in mind that these commands are executed immediately
after sending them (hence not chained with others before the
VPU/MDP "actually" start executing), it is fine to simply add
a padding of 4 bytes to this structure: this keeps the same
performance as before, as we're still stack-allocating it,
while avoiding hackery inside of mtk-vpu to ensure alignment
bringing a definitely bigger performance impact.
Fixes: c8eb2d7e8202 ("[media] media: Add Mediatek MDP Driver")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
Reviewed-by: Houlong Wei <houlong.wei@...iatek.com>
Reviewed-by: Irui Wang <irui.wang@...iatek.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@...all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h b/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h
index 78e2cc0dead1..4f4a51dd48e1 100644
--- a/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h
+++ b/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h
@@ -48,12 +48,14 @@ struct mdp_ipi_init {
* @ipi_id : IPI_MDP
* @ap_inst : AP mtk_mdp_vpu address
* @vpu_inst_addr : VPU MDP instance address
+ * @padding : Alignment padding
*/
struct mdp_ipi_comm {
uint32_t msg_id;
uint32_t ipi_id;
uint64_t ap_inst;
uint32_t vpu_inst_addr;
+ uint32_t padding;
};
/**
--
2.35.1
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