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X-Envelope-From: stefanr@s5r6.in-berlin.de
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Date: Tue, 16 Oct 2007 21:49:44 +0200
From: Stefan Richter <stefanr@s5r6.in-berlin.de>
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To: linux1394-devel@lists.sourceforge.net
CC: linux-kernel@vger.kernel.org,
       =?ISO-8859-1?Q?Kristian_H=F8gsberg?= <krh@redhat.com>
Subject: Re: [PATCH corrected] firewire: fw-ohci: fix DMA mapping for ar context
References: <tkrat.2493a847503e3d62@s5r6.in-berlin.de> <4714F652.1060007@s5r6.in-berlin.de> <tkrat.c21e564719351bc6@s5r6.in-berlin.de>
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I wrote:
> The CPU must not touch the buffer after it was DMA-mapped.
> 
> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
> ---
>  drivers/firewire/fw-ohci.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> Index: linux/drivers/firewire/fw-ohci.c
> ===================================================================
> --- linux.orig/drivers/firewire/fw-ohci.c
> +++ linux/drivers/firewire/fw-ohci.c
> @@ -258,6 +258,7 @@ static int ar_context_add_page(struct ar
>  		free_page((unsigned long) ab);
>  		return -ENOMEM;
>  	}
> +	dma_sync_single_for_cpu(dev, ab_bus, PAGE_SIZE, DMA_BIDIRECTIONAL);
>  
>  	memset(&ab->descriptor, 0, sizeof(ab->descriptor));
>  	ab->descriptor.control        = cpu_to_le16(DESCRIPTOR_INPUT_MORE |
> 

This is still not complete:

in ar_context_add_page():
	ctx->last_buffer->descriptor.branch_address = ...;

in ar_context_tasklet():
	dma_unmap_single(ohci->card.device,
		le32_to_cpu(ab->descriptor.data_address) - offset,
		PAGE_SIZE, DMA_BIDIRECTIONAL);

They both access DMA-mapped areas.
-- 
Stefan Richter
-=====-=-=== =-=- =----
http://arcgraph.de/sr/