From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Ujfalusi Subject: Re: [PATCH v3 1/7] dmaengine: of_dma: Support for DMA routers Date: Tue, 31 Mar 2015 19:48:03 +0300 Message-ID: <551ACFC3.5020003@ti.com> References: <1427459213-14611-1-git-send-email-peter.ujfalusi@ti.com> <1427459213-14611-2-git-send-email-peter.ujfalusi@ti.com> <201503280244.46961.arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from arroyo.ext.ti.com ([192.94.94.40]:46562 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751741AbbCaQuJ (ORCPT ); Tue, 31 Mar 2015 12:50:09 -0400 In-Reply-To: <201503280244.46961.arnd@arndb.de> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Arnd Bergmann Cc: vinod.koul@intel.com, tony@atomide.com, linux@arm.linux.org.uk, grant.likely@linaro.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, robh+dt@kernel.org, nm@ti.com On 03/28/2015 03:44 AM, Arnd Bergmann wrote: > On Friday 27 March 2015, Peter Ujfalusi wrote: >> +Required property: >> +- dma-device: phandle of the DMA controller. The router is= modifying >> + the DMA requests for this controller. >=20 > This property seems rather specific to the case at hand, I would expe= ct that > one might also see routers like this that are connected to more than = one > dma-device, so maybe make it a list? Yeah, it is intentional from my part. In dra7xx family we actually have two DMA controllers: sDMA and eDMA. T= hey both have identical crossbar up front but you can not choose the DMA re= quest to be routed to either eDMA or sDMA. They are always routed to both and= in the crossbar you select which signal goes to which DMA request of the given controller. At the moment I was not aware of different designs (current and future)= , but it might be possible that a design you described might surface at some = point. =46or sure, the list will complicate things quite a bit it might requir= e different API and callbacks at the end. I need to think about this how = it is going to work best. > It might also be better to name this as 'dma-controllers' or 'dma-mas= ters', > as it is not entirely obvious (without referencing the binding docume= nt) > whether a dma device refers to the slave or the master. I think the 'dma-masters' sounds much better. PS: I'm out of office this week so do not expect v4 before mid next wee= k. --=20 P=E9ter -- To unsubscribe from this list: send the line "unsubscribe linux-omap" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: peter.ujfalusi@ti.com (Peter Ujfalusi) Date: Tue, 31 Mar 2015 19:48:03 +0300 Subject: [PATCH v3 1/7] dmaengine: of_dma: Support for DMA routers In-Reply-To: <201503280244.46961.arnd@arndb.de> References: <1427459213-14611-1-git-send-email-peter.ujfalusi@ti.com> <1427459213-14611-2-git-send-email-peter.ujfalusi@ti.com> <201503280244.46961.arnd@arndb.de> Message-ID: <551ACFC3.5020003@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 03/28/2015 03:44 AM, Arnd Bergmann wrote: > On Friday 27 March 2015, Peter Ujfalusi wrote: >> +Required property: >> +- dma-device: phandle of the DMA controller. The router is modifying >> + the DMA requests for this controller. > > This property seems rather specific to the case at hand, I would expect that > one might also see routers like this that are connected to more than one > dma-device, so maybe make it a list? Yeah, it is intentional from my part. In dra7xx family we actually have two DMA controllers: sDMA and eDMA. They both have identical crossbar up front but you can not choose the DMA request to be routed to either eDMA or sDMA. They are always routed to both and in the crossbar you select which signal goes to which DMA request of the given controller. At the moment I was not aware of different designs (current and future), but it might be possible that a design you described might surface at some point. For sure, the list will complicate things quite a bit it might require different API and callbacks at the end. I need to think about this how it is going to work best. > It might also be better to name this as 'dma-controllers' or 'dma-masters', > as it is not entirely obvious (without referencing the binding document) > whether a dma device refers to the slave or the master. I think the 'dma-masters' sounds much better. PS: I'm out of office this week so do not expect v4 before mid next week. -- P?ter From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932239AbbCaQuM (ORCPT ); Tue, 31 Mar 2015 12:50:12 -0400 Received: from arroyo.ext.ti.com ([192.94.94.40]:46562 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751741AbbCaQuJ (ORCPT ); Tue, 31 Mar 2015 12:50:09 -0400 Message-ID: <551ACFC3.5020003@ti.com> Date: Tue, 31 Mar 2015 19:48:03 +0300 From: Peter Ujfalusi User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Arnd Bergmann CC: , , , , , , , , , , Subject: Re: [PATCH v3 1/7] dmaengine: of_dma: Support for DMA routers References: <1427459213-14611-1-git-send-email-peter.ujfalusi@ti.com> <1427459213-14611-2-git-send-email-peter.ujfalusi@ti.com> <201503280244.46961.arnd@arndb.de> In-Reply-To: <201503280244.46961.arnd@arndb.de> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/28/2015 03:44 AM, Arnd Bergmann wrote: > On Friday 27 March 2015, Peter Ujfalusi wrote: >> +Required property: >> +- dma-device: phandle of the DMA controller. The router is modifying >> + the DMA requests for this controller. > > This property seems rather specific to the case at hand, I would expect that > one might also see routers like this that are connected to more than one > dma-device, so maybe make it a list? Yeah, it is intentional from my part. In dra7xx family we actually have two DMA controllers: sDMA and eDMA. They both have identical crossbar up front but you can not choose the DMA request to be routed to either eDMA or sDMA. They are always routed to both and in the crossbar you select which signal goes to which DMA request of the given controller. At the moment I was not aware of different designs (current and future), but it might be possible that a design you described might surface at some point. For sure, the list will complicate things quite a bit it might require different API and callbacks at the end. I need to think about this how it is going to work best. > It might also be better to name this as 'dma-controllers' or 'dma-masters', > as it is not entirely obvious (without referencing the binding document) > whether a dma device refers to the slave or the master. I think the 'dma-masters' sounds much better. PS: I'm out of office this week so do not expect v4 before mid next week. -- Péter