From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: Re: [PATCH v8 1/4] pci:host: APM X-Gene PCIe host controller driver Date: Wed, 17 Sep 2014 17:03:39 +0100 Message-ID: <20140917160337.GA15261@e104818-lin.cambridge.arm.com> References: <1410476266-29426-1-git-send-email-tinamdar@apm.com> <1410476266-29426-2-git-send-email-tinamdar@apm.com> <20140912091816.GU27864@e106497-lin.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-pci-owner@vger.kernel.org To: Tanmay Inamdar Cc: Liviu Dudau , Bjorn Helgaas , Arnd Bergmann , Jason Gunthorpe , "grant.likely@linaro.org" , Rob Herring , Rob Landley , "linux-pci@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "patches@apm.com" , "jcm@redhat.com" List-Id: devicetree@vger.kernel.org On Tue, Sep 16, 2014 at 09:02:11PM +0100, Tanmay Inamdar wrote: > On Fri, Sep 12, 2014 at 2:18 AM, Liviu Dudau wrote: > > On Thu, Sep 11, 2014 at 11:57:43PM +0100, Tanmay Inamdar wrote: > >> This patch adds the AppliedMicro X-Gene SOC PCIe host controller driver. > >> X-Gene PCIe controller supports maximum up to 8 lanes and GEN3 speed. > >> X-Gene SOC supports maximum 5 PCIe ports. > >> > >> Signed-off-by: Tanmay Inamdar > > > > It looks good to me now. You can add if you care: > > > > Reviewed-by: Liviu Dudau > > I will have to send another version of patch as I forgot to add > 'dma-coherent' in device tree entry. > > Secondly I see that setting 'dma-coherent' in device tree node sets > coherent_dma_ops for the root bus but for the endpoint another 'dev' > gets assigned. This causes endpoint to use non-coherent dma apis > causing failure in dma operations. For PCIe, setting dma-coherent in the DT nodes wouldn't have any effect yet. We have of_dma_configure() being called for platform devices but it won't work for PCIe which are probed at run-time (nor for AMBA which require an additional patch). So for arm64 currently we have some hooks in dma-mapping.c to intercept when a device is added to a bus. What I need to do though is check recursively whether the parent (bus) had the 'dma-coherent' property (pointed out by Jon). I think something like this would do (not tested): diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index 4164c5ace9f8..638475378f94 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -316,7 +316,7 @@ static int dma_bus_notifier(struct notifier_block *nb, if (event != BUS_NOTIFY_ADD_DEVICE) return NOTIFY_DONE; - if (of_property_read_bool(dev->of_node, "dma-coherent")) + if (of_dma_is_coherent(dev->of_node)) set_dma_ops(dev, &coherent_swiotlb_dma_ops); return NOTIFY_OK; After this, we need to a bus notifier for PCIe as well. Since I don't think we have an of_node for a PCI device, we would need to check recursively on the parent device rather than the parent node until we find an OF node with the 'dma-coherent' property. -- Catalin