diff options
| author | Janusz Krzysztofik <jmkrzyszt@gmail.com> | 2018-06-05 19:59:57 +0300 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2018-06-19 07:29:13 +0300 |
| commit | c9bd0946da243a8eb86b44ff613e2c813f9b683b (patch) | |
| tree | 4d4654a69b12de89295c2474a18e8b3e8da9cd71 /drivers/dma | |
| parent | ce397d215ccd07b8ae3f71db689aedb85d56ab40 (diff) | |
| download | linux-c9bd0946da243a8eb86b44ff613e2c813f9b683b.tar.xz | |
dmaengine: ti: omap-dma: Fix OMAP1510 incorrect residue_granularity
Commit 0198d7bb8a0c ("ASoC: omap-mcbsp: Convert to use the sdma-pcm
instead of omap-pcm") resulted in broken audio playback on OMAP1510
(discovered on Amstrad Delta).
When running on OMAP1510, omap-pcm used to obtain DMA offset from
snd_dmaengine_pcm_pointer_no_residue() based on DMA interrupt triggered
software calculations instead of snd_dmaengine_pcm_pointer() which
depended on residue value calculated from omap_dma_get_src_pos().
Similar code path is still available in now used
sound/soc/soc-generic-dmaengine-pcm.c but it is not triggered.
It was verified already before that omap_get_dma_src_pos() from
arch/arm/plat-omap/dma.c didn't work correctly for OMAP1510 - see
commit 1bdd7419910c ("ASoC: OMAP: fix OMAP1510 broken PCM pointer
callback") for details. Apparently the same applies to its successor,
omap_dma_get_src_pos() from drivers/dma/ti/omap-dma.c.
On the other hand, snd_dmaengine_pcm_pointer_no_residue() is described
as depreciated and discouraged for use in new drivers because of its
unreliable accuracy. However, it seems the only working option for
OPAM1510 now, as long as a software calculated residue is not
implemented as OMAP1510 fallback in omap-dma.
Using snd_dmaengine_pcm_pointer_no_residue() code path instead of
snd_dmaengine_pcm_pointer() in sound/soc/soc-generic-dmaengine-pcm.c
can be triggered in two ways:
- by passing pcm->flags |= SND_DMAENGINE_PCM_FLAG_NO_RESIDUE from
sound/soc/omap/sdma-pcm.c,
- by passing dma_caps.residue_granularity =
DMA_RESIDUE_GRANULARITY_DESCRIPTOR from DMA engine.
Let's do the latter.
Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/ti/omap-dma.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c index 9b5ca8691f27..a4a931ddf6f6 100644 --- a/drivers/dma/ti/omap-dma.c +++ b/drivers/dma/ti/omap-dma.c @@ -1485,7 +1485,11 @@ static int omap_dma_probe(struct platform_device *pdev) od->ddev.src_addr_widths = OMAP_DMA_BUSWIDTHS; od->ddev.dst_addr_widths = OMAP_DMA_BUSWIDTHS; od->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV); - od->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; + if (__dma_omap15xx(od->plat->dma_attr)) + od->ddev.residue_granularity = + DMA_RESIDUE_GRANULARITY_DESCRIPTOR; + else + od->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; od->ddev.max_burst = SZ_16M - 1; /* CCEN: 24bit unsigned */ od->ddev.dev = &pdev->dev; INIT_LIST_HEAD(&od->ddev.channels); |