[PATCH 4.9 40/43] ASoC: intel: atom: Fix breakage for PCM buffer address setup

Sasha Levin
2021-08-24T17:39:15Z

From: Takashi Iwai <tiwai@suse.de>

[ Upstream commit 65ca89c2b12cca0d473f3dd54267568ad3af55cc ]

The commit 2e6b836312a4 ("ASoC: intel: atom: Fix reference to PCM
buffer address") changed the reference of PCM buffer address to
substream->runtime->dma_addr as the buffer address may change
dynamically. However, I forgot that the dma_addr field is still not
set up for the CONTINUOUS buffer type (that this driver uses) yet in
5.14 and earlier kernels, and it resulted in garbage I/O. The problem
will be fixed in 5.15, but we need to address it quickly for now.

The fix is to deduce the address again from the DMA pointer with
virt_to_phys(), but from the right one, substream->runtime->dma_area.

Fixes: 2e6b836312a4 ("ASoC: intel: atom: Fix reference to PCM buffer address")
Reported-and-tested-by: Hans de Goede <hdegoede@redhat.com>
Cc: <stable@vger.kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/2048c6aa-2187-46bd-6772-36a4fb3c5aeb@redhat.com
Link: https://lore.kernel.org/r/20210819152945.8510-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/soc/intel/atom/sst-mfld-platform-pcm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/intel/atom/sst-mfld-platform-pcm.c b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
index 6303b2d3982d..1b6dedfc33e3 100644
--- a/sound/soc/intel/atom/sst-mfld-platform-pcm.c
+++ b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
@@ -135,7 +135,7 @@ static void sst_fill_alloc_params(struct snd_pcm_substream *substream,
snd_pcm_uframes_t period_size;
ssize_t periodbytes;
ssize_t buffer_bytes = snd_pcm_lib_buffer_bytes(substream);
- u32 buffer_addr = substream->runtime->dma_addr;
+ u32 buffer_addr = virt_to_phys(substream->runtime->dma_area);

channels = substream->runtime->channels;
period_size = substream->runtime->period_size;
--
2.30.2