[PATCH] MTD: atmel_nand: Add DMA support to access Nandflash

Xu, Hong Hong.Xu at atmel.com
Mon Jan 17 20:43:45 EST 2011


Hi Ryan,
> -----Original Message-----
> From: Ryan Mallon [mailto:ryan at bluewatersys.com]
> Sent: Tuesday, January 18, 2011 6:42 AM
> To: Xu, Hong
> Cc: linux-mtd at lists.infradead.org; linux-arm-kernel at lists.infradead.org;
> linux-kernel at vger.kernel.org; jamie at jamieiles.com; jacmet at sunsite.dk;
> Ferre, Nicolas
> Subject: Re: [PATCH] MTD: atmel_nand: Add DMA support to access Nandflash
> 
> root at snapper:~$ dmesg | grep -i dma
> [    0.850000] atmel_nand atmel_nand: Failed to request DMA channel
> [    0.860000] atmel_nand atmel_nand: No DMA support for NAND access.
> [    1.530000] at_hdmac at_hdmac: Atmel AHB DMA Controller ( cpy slave ),
> 8 channels
> 
> 
> It looks like the registration for the DMA controller happens after the
> NAND driver probe and so the request is failing. I had a quick look, but
> I can't see anything that would change this in more recent kernels. Any
> ideas?
> 
You got the point. A [Git Pull] has been sent, see
http://article.gmane.org/gmane.linux.kernel/1088240/match=dmaengine+update

In this patch, subsys_initcall will be used so DMA engine will be initialized before NAND driver.
Thanks.

BR,
Hong



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