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dmaengine: jz4780: Work around hardware bug on JZ4760 SoCs 

The JZ4760 SoC has a hardware problem with chan0 not enabling properly
if it's enabled before chan1, after a reset (works fine afterwards).
This is worked around in the probe function by just enabling then
disabling chan1.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20211206174259.68133-4-paul@crapouillou.net
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Paul Cercueil 2021-12-06 17:42:56 +00:00 committed by Vinod Koul
parent dafa79a10e
commit b72cbb1ab2
1 changed files with 8 additions and 0 deletions
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8
drivers/dma/dma-jz4780.c
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@ -938,6 +938,14 @@ static int jz4780_dma_probe(struct platform_device *pdev)
jzchan->vchan.desc_free = jz4780_dma_desc_free; jzchan->vchan.desc_free = jz4780_dma_desc_free;
} }
/*
* On JZ4760, chan0 won't enable properly the first time.
* Enabling then disabling chan1 will magically make chan0 work
* correctly.
*/
jz4780_dma_chan_enable(jzdma, 1);
jz4780_dma_chan_disable(jzdma, 1);
ret = platform_get_irq(pdev, 0); ret = platform_get_irq(pdev, 0);
if (ret < 0) if (ret < 0)
goto err_disable_clk; goto err_disable_clk;