Hi Lucas,
Thank for your report, I tested it only on SPI, will update to you after try on uart tomorrow.
> 在 2018年6月11日，下午7:01，Lucas Stach <l.stach@xxxxxxxxxxxxxx> 写道：
>
> Hi Robin,
>
> this series breaks serial DMA for me. I wasn't able to dig in deeper
> yet. Please let me know if you can test/reproduce at your side, if not
> I'll try to find some time to collect some more debug info.
>
> Regards,
> Lucas
>
> Am Montag, den 11.06.2018, 22:59 +0800 schrieb Robin Gong:
>> The legacy sdma driver has below limitations or drawbacks:
>> 1. Hardcode the max BDs number as "PAGE_SIZE / sizeof(*)", and alloc
>> one page size for one channel regardless of only few BDs needed
>> most time. But in few cases, the max PAGE_SIZE maybe not enough.
>> 2. One SDMA channel can't stop immediatley once channel disabled which
>> means SDMA interrupt may come in after this channel terminated.There
>> are some patches for this corner case such as commit "2746e2c389f9",
>> but not cover non-cyclic.
>>
>> The common virt-dma overcomes the above limitations. It can alloc bd
>> dynamically and free bd once this tx transfer done. No memory wasted or
>> maximum limititation here, only depends on how many memory can be requested
>> from kernel. For No.2, such issue can be workaround by checking if there
>> is available descript("sdmac->desc") now once the unwanted interrupt
>> coming. At last the common virt-dma is easier for sdma driver maintain.
>>
>> Change from v2:
>> 1. include Sascha's patch to make the main patch easier to review.
>> Thanks Sacha.
>> 2. remove useless 'desc'/'chan' in struct sdma_channe.
>>
>> Change from v1:
>> 1. split v1 patch into 5 patches.
>> 2. remove some unnecessary condition check.
>> 3. remove unnecessary 'pending' list.
>>
>> Robin Gong (5):
>> dmaengine: imx-sdma: add virt-dma support
>> Revert "dmaengine: imx-sdma: fix pagefault when channel is disabled
>> during interrupt"
>> dmaengine: imx-sdma: remove usless lock
>> dmaengine: imx-sdma: remove the maximum limation for bd numbers
>> dmaengine: imx-sdma: add sdma_transfer_init to decrease code overlap
>>
>> drivers/dma/Kconfig | 1 +
>> drivers/dma/imx-sdma.c | 392 ++++++++++++++++++++++++++++---------------------
>> 2 files changed, 227 insertions(+), 166 deletions(-)
>>
>> --
>> 2.7.4
>>
>> Robin Gong (5):
>> dmaengine: imx-sdma: add virt-dma support
>> Revert "dmaengine: imx-sdma: fix pagefault when channel is disabled
>> during interrupt"
>> dmaengine: imx-sdma: remove usless lock
>> dmaengine: imx-sdma: remove the maximum limation for bd numbers
>> dmaengine: imx-sdma: add sdma_transfer_init to decrease code overlap
>>
>> Sascha Hauer (1):
>> dmaengine: imx-sdma: factor out a struct sdma_desc from struct
>> sdma_channel
>>
>> drivers/dma/Kconfig | 1 +
>> drivers/dma/imx-sdma.c | 391 ++++++++++++++++++++++++++++---------------------
>> 2 files changed, 226 insertions(+), 166 deletions(-)
>>
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