From mboxrd@z Thu Jan 1 00:00:00 1970 From: shawn.lin@rock-chips.com (Shawn Lin) Date: Wed, 17 Aug 2016 16:11:03 +0800 Subject: [PATCH 1/3] dt/bindings: arm-pl330: add description of arm,pl330-periph-burst In-Reply-To: <1d42542f-c43c-5c4b-01b7-ba0ca085004a@rock-chips.com> References: <1470365602-32586-1-git-send-email-shawn.lin@rock-chips.com> <1470365602-32586-2-git-send-email-shawn.lin@rock-chips.com> <20160805033410.GJ9681@localhost> <0df0ab4f-0032-6487-2c30-b1ccd7d9ae62@metafoo.de> <1d42542f-c43c-5c4b-01b7-ba0ca085004a@rock-chips.com> Message-ID: <55e596a0-4176-4277-40cc-1d26763a8be0@rock-chips.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, Vinod and Lars-Peter Ping.. Any better idea to share :) On 2016/8/9 17:12, Shawn Lin wrote: > Hi Lars-Peter, > > ? 2016/8/9 16:39, Lars-Peter Clausen ??: >> On 08/05/2016 09:25 AM, Shawn Lin wrote: >>> Hi Vinod, >>> >>> ? 2016/8/5 11:34, Vinod Koul ??: >>>> On Fri, Aug 05, 2016 at 10:53:20AM +0800, Shawn Lin wrote: >>>>> This patch adds the "arm,pl330-periph-burst" for arm-pl330 to >>>>> support busrt mode. >>>> >>>> why should this be DT property. Only reason I can think of if some hw >>>> versions support this and some won't. >>> >>> yes, if we want to support burst mode, both of the master(pl330) and >>> client(several peripherals) should implement it, otherwise it will >>> be broken when enabling. >> >> As you said, it is up to the consumer peripheral whether it supports >> BURST, >> SINGLE or both. So this is a per client property, but you specify this >> as a >> a global property on the producer side. > > Thanks for comment. > > yup, but what is the proper way to add it ? :) > > > a) If pl330 support BURST as well as all the peripherals, we could > enable it. > > b) If pl300 support BURST, but all the peripherals don't support it, > we could not enable it. > > c) If pl300 support BURST, but not all the peripherals support it, > we also could not enable it. > > the burst feature of peripheral IP may be vendor-specific, but the > common driver for this peripheral are used for many many vendors which > means we could not check all of this info. It's very likely to break > them... I couldn't figure out how many upstreamed peripheral drivers > who are using pl300 either. > > So this check should be done by all this vendors but we could make > sure we don't break them before they check a), b), c), right? > > >> >> >> >> > > -- Best Regards Shawn Lin