From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH] of: Devices with pci_epf_bus_type require DMA configuration Date: Mon, 23 Oct 2017 08:31:13 +0200 Message-ID: <20171023063113.GB16978@lst.de> References: <20171011080041.12918-1-kishon@ti.com> <3599d3e2-d496-eac3-7179-2d1795fc059d@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <3599d3e2-d496-eac3-7179-2d1795fc059d@ti.com> Sender: linux-kernel-owner@vger.kernel.org To: Kishon Vijay Abraham I Cc: Robin Murphy , Christoph Hellwig , Rob Herring , Mark Rutland , Bjorn Helgaas , linux-omap@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, nsekhar@ti.com List-Id: devicetree@vger.kernel.org On Mon, Oct 23, 2017 at 11:13:23AM +0530, Kishon Vijay Abraham I wrote: > EPF devices use EPC devices which in turn use the actual platform device for > configuring the hardware. IMO the devices in one layer shouldn't have to > explicitly use devices in another layer other than using clearly defined API's. > Here platform_device is the bottom later, above which is epc_device and on top > is epf_device. > > The idea is just by doing the initial setup in the framework, the epf driver be > able to use APIs like dma_alloc_coherent using it's own *device* rather than > the EPC's "device". That's a little strange - normally we only call dma_map* routines on the actual physical bus devices.