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From: Peng Fan <peng.fan@nxp.com>
To: Adam Ford <aford173@gmail.com>,
	linux-spi <linux-spi@vger.kernel.org>,
	dl-linux-imx <linux-imx@nxp.com>,
	Clark Wang <xiaoning.wang@nxp.com>
Cc: Charles Stevens <charles.stevens@logicpd.com>
Subject: RE: ECSPI Slave on i.M8M Mini with DMA
Date: Wed, 30 Jun 2021 09:34:45 +0000	[thread overview]
Message-ID: <DB6PR0402MB27601D0F4FB77F0007EDF0E888019@DB6PR0402MB2760.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <CAHCN7xJ_Cidr5EiBXNi11St9vLFmm=s=K6jdHGJrvCzeQQpqyQ@mail.gmail.com>

> Subject: ECSPI Slave on i.M8M Mini with DMA

Clark may help on this.

Regards,
Peng.

> 
> To the NXP team,
> 
> I noticed the spi-imx driver has a function called spi_imx_can_dma() which
> returns false if the SPI is configured as a slave, so the dma cannot be used in
> slave mode.
> 
> Section 10.1.2.7 "DMA" of the The 8MM Ref manual, Rev 3, shows there are a
> few conditions that can trigger the DMA.  Of them, two are RXFIFO data
> request and RXFIFO full.  The block diagram in that section shows it can
> retrieve data with DMA
> 
> However, in section 10.1.4 "Applications" of the same document, it shows the
> optional DMA configurations are only in the SPI master configuration and not
> the SPI slave configuration.
> 
> The ECSPIx_DMAREG documentation (section 10.1.5.6) states "The ECSPI
> sends out DMA requests when the appropriate FIFO conditions are matched."
> Unfortunately it doesn't explicitly state whether that's only for master or
> available in either master or slave mode.
> 
> Can someone tell me if DMA is available when SPI is configured as a slave?
> 
> thank you,
> 
> adam

  reply	other threads:[~2021-06-30  9:34 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-18 16:58 ECSPI Slave on i.M8M Mini with DMA Adam Ford
2021-06-30  9:34 ` Peng Fan [this message]
2021-07-05  7:16   ` Clark Wang

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