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media: platform: mtk-mdp: Fix mdp_ipi_comm structure alignment

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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@collabora.com>
Reviewed-by: Houlong Wei <houlong.wei@mediatek.com>
Reviewed-by: Irui Wang <irui.wang@mediatek.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
This commit is contained in:
AngeloGioacchino Del Regno 2022-06-23 14:55:46 +01:00 committed by Mauro Carvalho Chehab
parent b813aa3dc6
commit ab14c99c03
1 changed files with 2 additions and 0 deletions
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2
drivers/media/platform/mediatek/mdp/mtk_mdp_ipi.h
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@ -40,12 +40,14 @@ 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;
};
/**