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Date: Wed, 11 Mar 2009 13:11:44 +0100
From: Matteo Fortini <matteo.fortini@mta.it>
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To: linux-ppc list <linuxppc-dev@ozlabs.org>
Subject: MPC512x DMA to PCI dev
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Hi all,
I'm trying to send some data through DMA from a memory buffer to a PCI 
video card VRAM.

While I got that I need to alloc the src buffer through 
dma_alloc_coherent, I don't understand which address I should give as 
the dst address.

I tried both the mapped hw address and an address received from 
pci_map_single, but even if the DMA transfer completes "correctly", I 
have the wrong data in the VRAM in the end.

I read about all the PCI DMA manuals, but it seems they are for letting 
some external DMA device on the PCI bus read/write from/to the main memory.

How do you do that?

Thanks,
Matteo