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From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: <vkoul@kernel.org>
Cc: <dmaengine@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<dan.j.williams@intel.com>, <grygorii.strashko@ti.com>,
	<vigneshr@ti.com>
Subject: Re: [PATCH for-next 0/4] dmaengine: ti: k3-udma: Updates for next
Date: Tue, 28 Jan 2020 12:15:42 +0200	[thread overview]
Message-ID: <41c53cc4-fa3e-1ab1-32b8-1d516cda7341@ti.com> (raw)
In-Reply-To: <20200127132111.20464-1-peter.ujfalusi@ti.com>

Vinod,

On 27/01/2020 15.21, Peter Ujfalusi wrote:
> Hi Vinod,
> 
> Based on customer reports we have identified two issues with the UDMA driver:
> 
> TX completion (1st patch):
> The scheduled work based workaround for checking for completion worked well for
> UART, but it had significant impact on SPI performance.
> The underlying issue is coming from the fact that we have split data movement
> architecture.
> In order to know that the transfer is really done we need to check the remote
> end's (PDMA) byte counter.
> 
> RX channel teardown with stale data in PDMA (2nd patch):
> If we try to stop the RX DMA channel (teardown) then PDMA is trying to flush the
> data is might received from a peripheral, but if UDMA does not have a packet to
> use for this draining than it is going to push back on the PDMA and the flush
> will never completes.
> The workaround is to use a dummy descriptor for flush purposes when the channel
> is terminated and we did not have active transfer (no descriptor for UDMA).
> This allows UDMA to drain the data and the teardown can complete.
> 
> The last two patch is to use common code to set up the TR parameters for
> slave_sg, cyclic and memcpy. The setup code is the same as we used for memcpy
> with the change we can handle 4.2GB sg elements and periods in case of cyclic.
> It is also nice that we have single function to do the configuration.

I have marked these patches as for-next as 5.5 was not released yet.
Would it be possible to have these as fixes for 5.6?

Thanks,
- Péter

> 
> Regards,
> Peter
> ---
> Peter Ujfalusi (3):
>   dmaengine: ti: k3-udma: Workaround for RX teardown with stale data in
>     peer
>   dmaengine: ti: k3-udma: Move the TR counter calculation to helper
>     function
>   dmaengine: ti: k3-udma: Use the TR counter helper for slave_sg and
>     cyclic
> 
> Vignesh Raghavendra (1):
>   dmaengine: ti: k3-udma: Use ktime/usleep_range based TX completion
>     check
> 
>  drivers/dma/ti/k3-udma.c | 452 +++++++++++++++++++++++++++++----------
>  1 file changed, 343 insertions(+), 109 deletions(-)
> 

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  parent reply	other threads:[~2020-01-28 10:15 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-27 13:21 [PATCH for-next 0/4] dmaengine: ti: k3-udma: Updates for next Peter Ujfalusi
2020-01-27 13:21 ` [PATCH for-next 1/4] dmaengine: ti: k3-udma: Use ktime/usleep_range based TX completion check Peter Ujfalusi
2020-01-28 11:48   ` Vinod Koul
2020-01-28 12:05     ` Vignesh Raghavendra
2020-01-28 12:44       ` Vinod Koul
2020-02-11 10:13         ` Peter Ujfalusi
2020-01-27 13:21 ` [PATCH for-next 2/4] dmaengine: ti: k3-udma: Workaround for RX teardown with stale data in peer Peter Ujfalusi
2020-01-27 13:21 ` [PATCH for-next 3/4] dmaengine: ti: k3-udma: Move the TR counter calculation to helper function Peter Ujfalusi
2020-01-27 13:21 ` [PATCH for-next 4/4] dmaengine: ti: k3-udma: Use the TR counter helper for slave_sg and cyclic Peter Ujfalusi
2020-01-28 10:15 ` Peter Ujfalusi [this message]
2020-01-28 11:50   ` [PATCH for-next 0/4] dmaengine: ti: k3-udma: Updates for next Vinod Koul
2020-01-28 12:37     ` Peter Ujfalusi
2020-01-30 13:19       ` Peter Ujfalusi

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