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From: Serge Semin <Sergey.Semin@baikalelectronics.ru>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: 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 3/8] spi: dw-dma: Configure the DMA channels in dma_setup
Date: Fri, 31 Jul 2020 15:32:23 +0300
Message-ID: <20200731123223.kdbbcwabi5b72bem@mobilestation> (raw)
In-Reply-To: <20200731091638.GJ3703480@smile.fi.intel.com>

On Fri, Jul 31, 2020 at 12:16:38PM +0300, Andy Shevchenko wrote:
> On Fri, Jul 31, 2020 at 10:59:48AM +0300, Serge Semin wrote:
> > Mainly this is a preparation patch before adding one-by-one DMA SG entries
> > transmission. But logically the Tx and Rx DMA channels setup should be
> > performed in the dma_setup() callback anyway. So let's move the DMA slave
> > channels src/dst burst lengths, address and address width configuration to
> > the DMA setup stage. While at it make sure the return value of the
> > dmaengine_slave_config() method is checked. It has been unnecessary in
> > case if Dw DMAC is utilized as a DMA engine, since its device_config()
> > callback always returns zero (though it might change in future). But since
> > DW APB SSI driver now supports any DMA back-end we must make sure the
> > DMA device configuration has been successful before proceeding with
> > further setups.
> 
> ...
> 

Part 1:
> > +	if (!xfer->rx_buf)
> > +		return NULL;
> 
> ...
> 

Part 2:
> > +	if (xfer->rx_buf) {
> 
> > +	}
> 
> This looks like a separate change to drop one of them and not hide in the next patch.

Both of these changes are a part of the single alteration introduced to detach two
methods from each other: dw_spi_dma_{config,prepare}_{rx,tx}(). Part 1 is a
statement, which belongs to the method dw_spi_dma_prepare_rx() and is left there
after dw_spi_dma_config_rx() has been detached from it. Part 2 is a logical
part, which must be presented in dw_spi_dma_setup() since we don't need to configure
the Rx DMA channel if rx_buf isn't specified.

Please, read more carefully the commit log. I didn't introduce anything other
than the changes described there.

-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 [this message]
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
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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