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Subject: Re: [PATCH] mtd: nand: raw: atmel: add module param to avoid using
 dma
To:     Boris Brezillon <boris.brezillon@bootlin.com>,
        Peter Rosin <peda@axentia.se>
CC:     Tudor Ambarus <tudor.ambarus@microchip.com>,
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        Marek Vasut <marek.vasut@gmail.com>,
        Josh Wu <rainyfeeling@outlook.com>,
        Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>,
        <linux-kernel@vger.kernel.org>, <linux-mtd@lists.infradead.org>,
        Richard Weinberger <richard@nod.at>,
        Brian Norris <computersforpeace@gmail.com>,
        David Woodhouse <dwmw2@infradead.org>,
        <linux-arm-kernel@lists.infradead.org>
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From:   Eugen Hristev <eugen.hristev@microchip.com>
Message-ID: <e3c34fb7-4881-3f49-b43b-1b07a8ab865d@microchip.com>
Date:   Tue, 29 May 2018 18:01:40 +0300
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[...]


> 
> I think you're missing something here. We use the DMA engine in memcpy
> mode (SRAM -> DRAM), not in device mode (dev -> DRAM or DRAM -> dev).
> So there's no dmas prop defined in the DT and there should not be.
> 
> Regards,
> 
> Boris
> 

Ok, so the memcpy SRAM <-> DRAM will hog the transfer between DRAM and 
LCD if my understanding is correct. That's the DMA that Peter wants to 
disable with his patch ?

Then we can then try to force NFC SRAM DMA channels to use just DDR port 
1 or 2 for memcpy ?

I have also received a suggestion to try to increase the porches in 
LCDC_LCDCFG3 .

>>
>>   >> [...]
> 
>