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Date: Wed, 5 Dec 2007 03:59:35 +0300
From: Vitaly Bordug <vitb@kernel.crashing.org>
To: Arnd Bergmann <arnd@arndb.de>
Subject: Re: ucc_uart: add support for Freescale QUICCEngine UART
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Cc: linuxppc-dev@ozlabs.org, Timur Tabi <timur@freescale.com>
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On Wed, 5 Dec 2007 00:56:39 +0100
Arnd Bergmann wrote:

> On Wednesday 05 December 2007, Timur Tabi wrote:
> > Arnd Bergmann wrote:
> >=20
> > > You can argue that the QS is really a DMA device, but in that
> > > case you should convert the driver to use the DMA mapping
> > > interfaces correctly, which I would consider overkill.
> >=20
> > I'm confused. =C2=A0I'm already calling dma_alloc_coherent() and getting
> > a dma_addr_t back. =C2=A0Why do I need to use mapping functions to
> > convert between virtual and physical/bus addresses?
>=20
> No, I'm sorry but I'm the one who was confused. The problem I saw was
> that you return something offset from "bd_phys" as a dma_addr_t. This
> would be a lot easier if you had called it bd_bus or bd_dma instead
> of bd_phys, but your code looks absolutely correct upon closer
> inspection.
>=20
Adding my 2 cents, we already have very similar thing in cpm_uart driver...

> 	Arnd <><
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--=20
Sincerely, Vitaly