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From: Peter Ujfalusi <>
To: Vinod Koul <>
Cc: <>, <>,
Subject: Re: [PATCH v5 0/3] dmaengine: ti: edma: Polled completion support
Date: Mon, 29 Jul 2019 10:22:42 +0300
Message-ID: <> (raw)
In-Reply-To: <20190729064209.GF12733@vkoul-mobl.Dlink>


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:
>> 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.

- Péter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

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Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-16  8:26 Peter Ujfalusi
2019-07-16  8:26 ` [PATCH v5 1/3] dmaengine: ti: edma: Clean up the 2x32bit array register accesses Peter Ujfalusi
2019-07-16  8:26 ` [PATCH v5 2/3] dmaengine: ti: edma: Correct the residue calculation (fix for memcpy) Peter Ujfalusi
2019-07-25 13:46   ` Vinod Koul
2019-07-16  8:26 ` [PATCH v5 3/3] dmaengine: ti: edma: Support for polled (memcpy) completion Peter Ujfalusi
2019-07-29  6:42 ` [PATCH v5 0/3] dmaengine: ti: edma: Polled completion support Vinod Koul
2019-07-29  7:22   ` Peter Ujfalusi [this message]
2019-07-29  7:33     ` Vinod Koul
2019-07-29  7:24   ` Peter Ujfalusi
2019-07-29  7:33     ` Vinod Koul

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