Hi Vinod,
Do you have any comment for this patchset? Lucas and Sascha
acked it and tty patch already merged in.
On 二, 2018-06-26 at 17:04 +0200, Lucas Stach wrote:
> Hi Robin,
>
> I've tested this whole series with the SDMA being used for SPI, UART
> and SSI with no regressions spotted. As this should cover most common
> use-cases, I think this series is good to go in.
>
> Tested-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
>
> Regards,
> Lucas
>
> Am Mittwoch, den 20.06.2018, 00:56 +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 v4:
> > 1. identify lockdep issue which caused by allocate memory with
> > 'GFP_KERNEL', change to 'GFP_NOWAIT' instead so that lockdep
> > ignore check. That also make sense since Audio/uart driver may
> > call dma function after spin_lock_irqsave()...
> > 2. use dma pool instead for bd description allocated,since audio
> > driver may call dma_terminate_all in irq. Please refer to 7/7.
> > 3. remove 7/7 serial patch in v4, since lockdep issued fixed by
> > No.1
> >
> > Change from v3:
> > 1. add two uart patches which impacted by this patchset.
> > 2. unlock 'vc.lock' before cyclic dma callback and lock again
> > after
> > it because some driver such as uart will call
> > dmaengine_tx_status
> > which will acquire 'vc.lock' again and dead lock comes out.
> > 3. remove 'Revert commit' stuff since that patch is not wrong and
> > combine two patch into one patch as Sascha's comment.
> >
> > 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 (6):
> > tty: serial: imx: correct dma cookie status
> > dmaengine: imx-sdma: add virt-dma support
> > dmaengine: imx-sdma: remove useless 'lock' and 'enabled' in
> > 'struct
> > sdma_channel'
> > dmaengine: imx-sdma: remove the maximum limitation for bd numbers
> > dmaengine: imx-sdma: add sdma_transfer_init to decrease code
> > overlap
> > dmaengine: imx-sdma: alloclate bd memory from dma pool
> >
> > 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 | 400 +++++++++++++++++++++++++++------
> > --------------
> > drivers/tty/serial/imx.c | 2 +-
> > 3 files changed, 235 insertions(+), 168 deletions(-)
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