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From: Serge Semin <Sergey.Semin@baikalelectronics.ru>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Serge Semin <fancer.lancer@gmail.com>,
	Mark Brown <broonie@kernel.org>,
	Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
	Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>,
	Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>,
	Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>,
	Peter Ujfalusi <peter.ujfalusi@ti.com>,
	Feng Tang <feng.tang@intel.com>, Vinod Koul <vkoul@kernel.org>,
	<linux-spi@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/8] spi: dw-dma: Move DMA transfers submission to the channels prep methods
Date: Fri, 31 Jul 2020 15:46:46 +0300
Message-ID: <20200731124646.2bngx5mgtwrgctzi@mobilestation> (raw)
In-Reply-To: <20200731091528.GI3703480@smile.fi.intel.com>

On Fri, Jul 31, 2020 at 12:15:28PM +0300, Andy Shevchenko wrote:
> On Fri, Jul 31, 2020 at 10:59:49AM +0300, Serge Semin wrote:
> > Indeed we can freely move the dmaengine_submit() method invocation and the
> > Tx and Rx busy flag setting into the DMA Tx/Rx prepare methods. By doing
> > so first we implement another preparation before adding the one-by-one DMA
> > SG entries transmission, second we now have the dma_async_tx_descriptor
> > descriptor used locally only in the new DMA transfers submitition methods,
> > which makes the code less complex with no passing around the DMA Tx
> > descriptors, third we make the generic transfer method more readable, where
> > now the functionality of submission, execution and wait procedures is
> > transparently split up instead of having a preparation, intermixed
> > submission/execution and wait procedures. While at it we also add the
> > dmaengine_submit() return value test. It has been unnecessary for
> > DW DMAC, but should be done to support the generic DMA interface.
> > 
> > Note since the DMA channels preparation methods are now responsible for
> > the DMA transactions submission, we also rename them to
> > dw_spi_dma_submit_{tx,rx}().
> 
> ...
> 
> > +	cookie = dmaengine_submit(txdesc);
> > +	ret = dma_submit_error(cookie);
> > +	if (!ret)
> 

> Use traditional pattern
> 	if (ret)
> 		return ret;
> 
> Same for below.

Ok.

> 
> > +		set_bit(TX_BUSY, &dws->dma_chan_busy);
> > +
> > +	return ret;
> 
> ...
> 

> > -	if (!xfer->rx_buf)
> > -		return NULL;
> 
> This seems not related.

I moved it to the upper level for the methods better maintainability.

-Sergey

> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
> 

  reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-31  7:59 [PATCH 0/8] spi: dw-dma: Add max SG entries burst capability support Serge Semin
2020-07-31  7:59 ` [PATCH 1/8] spi: dw-dma: Set DMA Level registers on init Serge Semin
2020-07-31  7:59 ` [PATCH 2/8] spi: dw-dma: Fail DMA-based transfer if no Tx-buffer specified Serge Semin
2020-07-31  7:59 ` [PATCH 3/8] spi: dw-dma: Configure the DMA channels in dma_setup Serge Semin
2020-07-31  9:16   ` Andy Shevchenko
2020-07-31 12:32     ` Serge Semin
2020-07-31  7:59 ` [PATCH 4/8] spi: dw-dma: Move DMA transfers submission to the channels prep methods Serge Semin
2020-07-31  9:15   ` Andy Shevchenko
2020-07-31 12:46     ` Serge Semin [this message]
2020-07-31  7:59 ` [PATCH 5/8] spi: dw-dma: Detach DMA transfer into a dedicated method Serge Semin
2020-07-31  7:59 ` [PATCH 6/8] spi: dw-dma: Move DMAC register cleanup to DMA transfer method Serge Semin
2020-07-31  7:59 ` [PATCH 7/8] spi: dw-dma: Pass exact data to the DMA submit and wait methods Serge Semin
2020-07-31  7:59 ` [PATCH 8/8] spi: dw-dma: Add one-by-one SG list entries transfer Serge Semin
2020-07-31  9:26 ` [PATCH 0/8] spi: dw-dma: Add max SG entries burst capability support Andy Shevchenko
2020-07-31 12:59   ` Serge Semin
2020-08-04 21:14     ` Mark Brown
2020-08-05 11:31       ` Vinod Koul

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