From: Naru Sundar <nsundar@fulcrummicro.com>
To: Liu Dave-r63238 <DaveLiu@freescale.com>
Cc: linuxppc-embedded@ozlabs.org
Subject: Re: ppc85xx DMA
Date: Tue, 6 Jun 2006 14:16:10 -0700 [thread overview]
Message-ID: <20060606211610.GD27078@fulcrummicro.com> (raw)
In-Reply-To: <20060606185548.GB27078@fulcrummicro.com>
To clarify, I am definitely using the physical addresses. virt_to_bus and
virt_to_phys result in the same value. My transfer completes and I see
BCR go back to 0, but I can't manage to actually see any data difference
at the destination side.
The destination address is an ioremapped region that I pass through
virt_to_phys. The src is kmalloc'd memory that has GFP_DMA set.
On Tue, Jun 06, 2006 at 11:55:48AM -0700, Naru Sundar wrote:
> On Tue, Jun 06, 2006 at 09:39:29AM +0800, Liu Dave-r63238 wrote:
> > What is the DMA transfer mode? Is direct or chaining mode?
>
> Direct mode. I fixed an error with my bit ordering for the configuration
> registers, and now the transfer seems to complete, but I don't see any
> actual data showing up in the destination register that I am writing to.
>
> > Did you ioremap the DMA register space?
>
> Yes, I can write the destination address manually. So I am thinking my addresses
> are wrong.
>
> For the source and dest address I used:
>
> dma_map_single(NULL, ptr, len, DMA_TO_DEVICE)
>
> (which effectively does a virt_to_bus on ppc and so should just return to me
> the bus address used by the dma).
>
> -naru
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-embedded
next prev parent reply other threads:[~2006-06-06 21:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-06 1:39 ppc85xx DMA Liu Dave-r63238
2006-06-06 18:55 ` Naru Sundar
2006-06-06 21:16 ` Naru Sundar [this message]
2006-06-06 21:38 ` Naru Sundar
-- strict thread matches above, loose matches on Subject: below --
2006-06-06 0:55 Naru Sundar
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