This is a note to let you know that I've just added the patch titled
media: platform: mtk-mdp: Fix mdp_ipi_comm structure alignment
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
media-platform-mtk-mdp-fix-mdp_ipi_comm-structure-al.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2bd97e9ed4ca7142bf0c890546f490d365f1e915
Author: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Date: Thu Jun 23 14:55:46 2022 +0100
media: platform: mtk-mdp: Fix mdp_ipi_comm structure alignment
[ 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@xxxxxxxxxxxxx>
Reviewed-by: Houlong Wei <houlong.wei@xxxxxxxxxxxx>
Reviewed-by: Irui Wang <irui.wang@xxxxxxxxxxxx>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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;
};
/**
