From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian Norris Date: Thu, 10 Dec 2015 02:21:46 +0000 Subject: Re: [PATCH] mtd: sh_flctl: pass FIFO as physical address Message-Id: <20151210022146.GH144338@google.com> List-Id: References: <3152458.D3kElfhRW2@wuerfel> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-arm-kernel@lists.infradead.org On Tue, Dec 08, 2015 at 05:30:02PM +0100, Geert Uytterhoeven wrote: > On Tue, Dec 8, 2015 at 4:38 PM, Arnd Bergmann 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