From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Brian Norris <computersforpeace@gmail.com>,
MTD Maling List <linux-mtd@lists.infradead.org>,
Boris BREZILLON <boris.brezillon@free-electrons.com>,
Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
Linux-sh list <linux-sh@vger.kernel.org>,
Magnus Damm <magnus.damm@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Simon Horman <horms@verge.net.au>,
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
Date: Tue, 8 Dec 2015 17:30:02 +0100 [thread overview]
Message-ID: <CAMuHMdVWss6Kz8sVrcUR3a4iJ+Z8D1q1Er6eH_uRMoS5DCN5pw@mail.gmail.com> (raw)
In-Reply-To: <3152458.D3kElfhRW2@wuerfel>
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.
I'll send a patch to update Kconfig.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2015-12-08 16:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-08 15:38 [PATCH] mtd: sh_flctl: pass FIFO as physical address Arnd Bergmann
2015-12-08 16:30 ` Geert Uytterhoeven [this message]
2015-12-10 2:21 ` Brian Norris
2015-12-10 9:02 ` Geert Uytterhoeven
2015-12-10 9:27 ` Arnd Bergmann
2015-12-19 2:27 ` Brian Norris
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