ASoC: rsnd: Enable IPMMU v2

commit 4821d914fe747 ("ASoC: rsnd: use dma_sync_single_for_xxx() for
IOMMU") (= v1) which have been already reverted had supported IPMMU
support on rsnd driver.
Because memory allocating timing and DMAEngine access timing were
different, it used continuous memory and called dma map function by
itself.

OTOH, it is using DMA descriptor mode (= DMA cyclic mode), thus, there
was timing conflict between DMA sync/unsync and DMA transfer starting,
and it maked sound noise.

This patch supports IPMMU with coherent memory, and, it uses Audio DMAC
dev for allocating memory by snd_pcm_lib_preallocate_pages_for_all() to
indicate memory area to IPMMU.
One note is that Playback/Capture need each paired Audio DMAC dev.
Because of this, we need to keep each paired Audio DMAC dev when probing,
and use it when allocating each memory for IPMMU.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/sound/soc/sh/rcar/dma.c b/sound/soc/sh/rcar/dma.c
index 32ac97be26f1..ef82b94d038b 100644
--- a/sound/soc/sh/rcar/dma.c
+++ b/sound/soc/sh/rcar/dma.c
@@ -253,6 +253,13 @@ static int rsnd_dmaen_attach(struct rsnd_dai_stream *io,
 		return -EAGAIN;
 	}
 
+	/*
+	 * use it for IPMMU if needed
+	 * see
+	 *	rsnd_preallocate_pages()
+	 */
+	io->dmac_dev = chan->device->dev;
+
 	dma_release_channel(chan);
 
 	dmac->dmaen_num++;