linux-kernel - [PATCH 4.19 046/106] ASoC: use dma_ops of parent device for acp_audio

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Date:   Thu, 24 Jan 2019 20:20:03 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Yu Zhao <yuzhao@...gle.com>,
        Mark Brown <broonie@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 046/106] ASoC: use dma_ops of parent device for acp_audio_dma

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 23aa128bb28d9da69bb1bdb2b70e50128857884a ]

AMD platform device acp_audio_dma can only be created by parent PCI
device driver (drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c). Pass struct
device of the parent to snd_pcm_lib_preallocate_pages() so
dma_alloc_coherent() can use correct dma_ops. Otherwise, it will
use default dma_ops which is nommu_dma_ops on x86_64 even when
IOMMU is enabled and set to non passthrough mode.

Though platform device inherits some dma related fields during its
creation in mfd_add_device(), we can't simply pass its struct device
to snd_pcm_lib_preallocate_pages() because dma_ops is not among the
inherited fields. Even it were, drivers/iommu/amd_iommu.c would
ignore it because get_device_id() doesn't handle platform device.

This change shouldn't give us any trouble even struct device of the
parent becomes null or represents some non PCI device in the future,
because get_dma_ops() correctly handles null struct device or uses
the default dma_ops if struct device doesn't have it set.

Signed-off-by: Yu Zhao <yuzhao@...gle.com>
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 sound/soc/amd/acp-pcm-dma.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sound/soc/amd/acp-pcm-dma.c b/sound/soc/amd/acp-pcm-dma.c
index 3135e9eafd18..7f376b63a166 100644
--- a/sound/soc/amd/acp-pcm-dma.c
+++ b/sound/soc/amd/acp-pcm-dma.c
@@ -1147,18 +1147,21 @@ static int acp_dma_new(struct snd_soc_pcm_runtime *rtd)
 	struct snd_soc_component *component = snd_soc_rtdcom_lookup(rtd,
 								    DRV_NAME);
 	struct audio_drv_data *adata = dev_get_drvdata(component->dev);
+	struct device *parent = component->dev->parent;

 	switch (adata->asic_type) {
 	case CHIP_STONEY:
 		ret = snd_pcm_lib_preallocate_pages_for_all(rtd->pcm,
 							    SNDRV_DMA_TYPE_DEV,
-							    NULL, ST_MIN_BUFFER,
+							    parent,
+							    ST_MIN_BUFFER,
 							    ST_MAX_BUFFER);
 		break;
 	default:
 		ret = snd_pcm_lib_preallocate_pages_for_all(rtd->pcm,
 							    SNDRV_DMA_TYPE_DEV,
-							    NULL, MIN_BUFFER,
+							    parent,
+							    MIN_BUFFER,
 							    MAX_BUFFER);
 		break;
 	}
-- 
2.19.1