From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Andrzej Siewior Subject: Re: [PATCH] ARM: dts: am33xx: Move the cppi41dma node so it's probed early Date: Wed, 23 Apr 2014 17:31:44 +0200 Message-ID: <5357DCE0.5050204@linutronix.de> References: <1398176371-26468-1-git-send-email-ezequiel@vanguardiasur.com.ar> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1398176371-26468-1-git-send-email-ezequiel-30ULvvUtt6G51wMPkGsGjgyUoB5FGQPZ@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ezequiel Garcia , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: Felipe Balbi , Daniel Mack , =?windows-1252?Q?Guido_Mart=EDnez?= List-Id: devicetree@vger.kernel.org On 04/22/2014 04:19 PM, Ezequiel Garcia wrote: > The DMA controller is needed for the USB controller to be correctly > registered. Therefore, if the DMA node is located at the end an unece= ssary > probe deferral is produced systematically. >=20 > This is easily fixed by moving the node at the beggining of the child= list, > so it's probed first. So you do not change anything except for the order of child nodes. So this should be fine and without a compatibility problem. I added them according to the memory offset so you might want to add a comment why you moved this because Mr. Structured & Organized might noticed this one day and move it back. > Signed-off-by: Ezequiel Garcia > --- > Felipe, Sebastian: >=20 > I cannot see why the cppi41dma node must be placed inside the > "ti,am33xx-usb" compatible node. Tried to move it out > so it's probed just like the edma engine, but the USB doesn't work > properly in that case. >=20 > Can you enlighten me? So If I remember correctly it was a big bag of crap. If you look at the parent node, you notice that it has a ti,hwmods member while the other do not have such a property. According to the manual only the whole IP block as-it has this. It has to be activated if you use one of those devices this includes the two USB-IP cores and the DMA-IP core. I didn't manage to come up with something else except to make one parent node which creates the childs to have a proper relation here. There was also something with parent - child relation in the way musb expected it. I think this was only glue code + musb child node and had nothing to do with the DMA engine. But I am not 100% sure=85 >=20 > In any case, this change is good enough to remove the deferral probe. Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html