From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [PATCH] of/device: Really only set bus DMA mask when appropriate Date: Wed, 7 Nov 2018 12:56:49 +0000 Message-ID: <22cbe798-612f-8c88-90e7-388202f603cf@arm.com> References: <20181107080335.GA24511@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20181107080335.GA24511-jcswGhMUV9g@public.gmane.org> Content-Language: en-GB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Christoph Hellwig Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, aaro.koskinen-X3B1VOXEql0@public.gmane.org, jean-philippe.brucker-5wv7dgnIgG8@public.gmane.org, linux-mips-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, john.stultz-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On 2018-11-07 8:03 am, Christoph Hellwig wrote: > On Tue, Nov 06, 2018 at 11:54:15AM +0000, Robin Murphy wrote: >> of_dma_configure() was *supposed* to be following the same logic as >> acpi_dma_configure() and only setting bus_dma_mask if some range was >> specified by the firmware. However, it seems that subtlety got lost in >> the process of fitting it into the differently-shaped control flow, and >> as a result the force_dma==true case ends up always setting the bus mask >> to the 32-bit default, which is not what anyone wants. >> >> Make sure we only touch it if the DT actually said so. > > This looks good, but I think it could really use a comment as the use > of ret all the way down the function isn't exactly obvious. Fair point. > Let me now if you want this picked up through the OF or DMA trees. I don't mind either way; I figure I'll wait a bit longer to see if Rob has any preference, then resend with the comment and the tags picked up so it can hopefully make rc2. Robin. From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 07 Nov 2018 13:58:11 +0100 (CET) Received: from foss.arm.com ([217.140.101.70]:39626 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23990397AbeKGM4yYwAFp (ORCPT ); Wed, 7 Nov 2018 13:56:54 +0100 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CE85980D; Wed, 7 Nov 2018 04:56:52 -0800 (PST) Received: from [192.168.1.123] (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 046363F5CF; Wed, 7 Nov 2018 04:56:50 -0800 (PST) Subject: Re: [PATCH] of/device: Really only set bus DMA mask when appropriate To: Christoph Hellwig Cc: robh+dt@kernel.org, m.szyprowski@samsung.com, aaro.koskinen@iki.fi, jean-philippe.brucker@arm.com, john.stultz@linaro.org, iommu@lists.linux-foundation.org, devicetree@vger.kernel.org, linux-mips@linux-mips.org, linux-arm-kernel@lists.infradead.org References: <20181107080335.GA24511@lst.de> From: Robin Murphy Message-ID: <22cbe798-612f-8c88-90e7-388202f603cf@arm.com> Date: Wed, 7 Nov 2018 12:56:49 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181107080335.GA24511@lst.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 67131 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: robin.murphy@arm.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips On 2018-11-07 8:03 am, Christoph Hellwig wrote: > On Tue, Nov 06, 2018 at 11:54:15AM +0000, Robin Murphy wrote: >> of_dma_configure() was *supposed* to be following the same logic as >> acpi_dma_configure() and only setting bus_dma_mask if some range was >> specified by the firmware. However, it seems that subtlety got lost in >> the process of fitting it into the differently-shaped control flow, and >> as a result the force_dma==true case ends up always setting the bus mask >> to the 32-bit default, which is not what anyone wants. >> >> Make sure we only touch it if the DT actually said so. > > This looks good, but I think it could really use a comment as the use > of ret all the way down the function isn't exactly obvious. Fair point. > Let me now if you want this picked up through the OF or DMA trees. I don't mind either way; I figure I'll wait a bit longer to see if Rob has any preference, then resend with the comment and the tags picked up so it can hopefully make rc2. Robin. From mboxrd@z Thu Jan 1 00:00:00 1970 From: robin.murphy@arm.com (Robin Murphy) Date: Wed, 7 Nov 2018 12:56:49 +0000 Subject: [PATCH] of/device: Really only set bus DMA mask when appropriate In-Reply-To: <20181107080335.GA24511@lst.de> References: <20181107080335.GA24511@lst.de> Message-ID: <22cbe798-612f-8c88-90e7-388202f603cf@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 2018-11-07 8:03 am, Christoph Hellwig wrote: > On Tue, Nov 06, 2018 at 11:54:15AM +0000, Robin Murphy wrote: >> of_dma_configure() was *supposed* to be following the same logic as >> acpi_dma_configure() and only setting bus_dma_mask if some range was >> specified by the firmware. However, it seems that subtlety got lost in >> the process of fitting it into the differently-shaped control flow, and >> as a result the force_dma==true case ends up always setting the bus mask >> to the 32-bit default, which is not what anyone wants. >> >> Make sure we only touch it if the DT actually said so. > > This looks good, but I think it could really use a comment as the use > of ret all the way down the function isn't exactly obvious. Fair point. > Let me now if you want this picked up through the OF or DMA trees. I don't mind either way; I figure I'll wait a bit longer to see if Rob has any preference, then resend with the comment and the tags picked up so it can hopefully make rc2. Robin.