From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757372AbcIGKdN (ORCPT ); Wed, 7 Sep 2016 06:33:13 -0400 Received: from foss.arm.com ([217.140.101.70]:46602 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757353AbcIGKdI (ORCPT ); Wed, 7 Sep 2016 06:33:08 -0400 Subject: Re: [PATCH] usb: dwc3: host: inherit dma configuration from parent dev To: Peter Chen , Arnd Bergmann References: <5844875.KucAoPMrXi@wuerfel> <20160907063313.GA13903@b29397-desktop> <12021424.cItk3A7CfE@wuerfel> <20160907095549.GD13903@b29397-desktop> Cc: Felipe Balbi , Grygorii Strashko , Russell King - ARM Linux , Catalin Marinas , Yoshihiro Shimoda , "linux-usb@vger.kernel.org" , Sekhar Nori , lkml , Stuart Yoder , Scott Wood , David Fisher , "Thang Q. Nguyen" , Leo Li , Greg Kroah-Hartman , Alan Stern , "linux-arm-kernel@lists.infradead.org" , Lorenzo Pieralisi From: Robin Murphy Message-ID: <75ca65eb-e8c4-bc3f-e00b-b0cba46d28c6@arm.com> Date: Wed, 7 Sep 2016 11:33:03 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20160907095549.GD13903@b29397-desktop> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/09/16 10:55, Peter Chen wrote: [...] >> Regarding the DMA configuration that you mention in ci_hdrc_add_device(), >> I think we should replace >> >> pdev->dev.dma_mask = dev->dma_mask; >> pdev->dev.dma_parms = dev->dma_parms; >> dma_set_coherent_mask(&pdev->dev, dev->coherent_dma_mask); >> >> with of_dma_configure(), which has the chance to configure more than >> just those three, as the dma API might look into different aspects: >> >> - iommu specific configuration >> - cache coherency information >> - bus type >> - dma offset >> - dma_map_ops pointer >> >> We try to handle everything in of_dma_configure() at configuration >> time, and that would be the place to add anything else that we might >> need in the future. >> > > Yes, I agree with you, but just like Felipe mentioned, we also need to > consider PCI device, can we do something like gpiod_get_index does? Are > there any similar APIs like of_dma_configure for ACPI? Not yet, but Lorenzo has one in progress[1], primarily for the sake of abstracting away the IOMMU configuration. Robin. [1]:http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1209911.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: robin.murphy@arm.com (Robin Murphy) Date: Wed, 7 Sep 2016 11:33:03 +0100 Subject: [PATCH] usb: dwc3: host: inherit dma configuration from parent dev In-Reply-To: <20160907095549.GD13903@b29397-desktop> References: <5844875.KucAoPMrXi@wuerfel> <20160907063313.GA13903@b29397-desktop> <12021424.cItk3A7CfE@wuerfel> <20160907095549.GD13903@b29397-desktop> Message-ID: <75ca65eb-e8c4-bc3f-e00b-b0cba46d28c6@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 07/09/16 10:55, Peter Chen wrote: [...] >> Regarding the DMA configuration that you mention in ci_hdrc_add_device(), >> I think we should replace >> >> pdev->dev.dma_mask = dev->dma_mask; >> pdev->dev.dma_parms = dev->dma_parms; >> dma_set_coherent_mask(&pdev->dev, dev->coherent_dma_mask); >> >> with of_dma_configure(), which has the chance to configure more than >> just those three, as the dma API might look into different aspects: >> >> - iommu specific configuration >> - cache coherency information >> - bus type >> - dma offset >> - dma_map_ops pointer >> >> We try to handle everything in of_dma_configure() at configuration >> time, and that would be the place to add anything else that we might >> need in the future. >> > > Yes, I agree with you, but just like Felipe mentioned, we also need to > consider PCI device, can we do something like gpiod_get_index does? Are > there any similar APIs like of_dma_configure for ACPI? Not yet, but Lorenzo has one in progress[1], primarily for the sake of abstracting away the IOMMU configuration. Robin. [1]:http://www.mail-archive.com/linux-kernel at vger.kernel.org/msg1209911.html