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List:       linux-omap
Subject:    Re: [PATCH v5 0/3] dmaengine: ti: edma: Polled completion support
From:       Vinod Koul <vkoul () kernel ! org>
Date:       2019-07-29 7:45:54
Message-ID: 20190729073354.GL12733 () vkoul-mobl ! Dlink
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On 29-07-19, 10:22, Peter Ujfalusi wrote:
> Vinod,
> 
> On 29/07/2019 9.42, Vinod Koul wrote:
> > On 16-07-19, 11:26, Peter Ujfalusi wrote:
> >> Hi,
> >>
> >> Changes since v4:
> >> - Split the DMA_COMPLETE and !txstate check as Vinod suggested
> >>
> >> Change since v3:
> >> - fix DMA pointer tracking for memcpy
> >> - completion polling is only done when it is asked by not providing
> >>   DMA_PREP_INTERRUPT for memcpy
> >>
> >> Changes since v2:
> >> - Fix typo in the comment for patch 0
> >>
> >> Changes since v1:
> >> - Cleanup patch for the array register handling
> >> - typo fixed in patch2 commit message
> >>
> >> The code around the array register access was pretty confusing for the first
> >> look, so clean them up first then use the cleaner way in the polled handling.
> >>
> >> When a DMA client driver does not set the DMA_PREP_INTERRUPT because it
> >> does not want to use interrupts for DMA completion or because it can not
> >> rely on DMA interrupts due to executing the memcpy when interrupts are
> >> disabled it will poll the status of the transfer.
> >>
> >> Since we can not tell from any EDMA register that the transfer is
> >> completed, we can only know that the paRAM set has been sent to TPTC for
> >> processing we need to check the residue of the transfer, if it is 0 then
> >> the transfer is completed.
> >>
> >> The polled completion can bve tested by applying:
> >> https://patchwork.kernel.org/patch/10966499/
> >>
> >> Enabling the memcpy for EDMA and run the dmatest with polled = 1.
> >>
> >> Or, enable the EDMA memcpy support and boot up any dra7 family device with
> >> display enabled. The workaround for DMM errata i878 uses polled DMA memcpy.
> > 
> > Applied, thanks. Fixed typo in 2nd patch while at it
> 
> Thank you! I was about to send v6 with the fixed typo.

Simpler typos are ok to fix while applying

-- 
~Vinod
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