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Date: Wed, 9 Dec 2015 18:21:46 -0800
From: Brian Norris <computersforpeace@gmail.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
        MTD Maling List <linux-mtd@lists.infradead.org>,
        Boris BREZILLON <boris.brezillon@free-electrons.com>,
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        Frans Klaver <fransklaver@gmail.com>,
        David Woodhouse <dwmw2@infradead.org>,
        "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] mtd: sh_flctl: pass FIFO as physical address
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On Tue, Dec 08, 2015 at 05:30:02PM +0100, Geert Uytterhoeven wrote:
> On Tue, Dec 8, 2015 at 4:38 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> > By convention, the FIFO address we pass using dmaengine_slave_config
> > is a physical address in the form that is understood by the DMA
> > engine, as a dma_addr_t, phys_addr_t or resource_size_t.
> >
> > The sh_flctl driver however passes a virtual __iomem address that
> > gets cast to dma_addr_t in the slave driver. This happens to work
> > on shmobile because that platform sets up an identity mapping for
> > its MMIO regions, but such code is not portable to other platforms,
> > and prevents us from ever changing the platform mapping or reusing
> > the driver on other architectures like ARM64 that might not have the
> > mapping.
> 
> Note that since the removal of (ARM) sh7367/sh7377/sh7372 support, this
> driver is used on SH only.

It's still available as COMPILE_TEST, so it's still worth fixing.

But really, does anyone use this driver any more?

Brian