From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH v2 2/4] usb: dwc2: Add binding for AHB burst Date: Fri, 18 Nov 2016 08:16:08 -0600 Message-ID: <20161118141608.r7jsu7pfc4ztjt33@rob-hp-laptop> References: <7fa1c1c4d703c435d698cdf140c9d43163347f1d.1479339900.git.johnyoun@synopsys.com> <633e5a10-1ea0-48c7-a5b7-a5ff2625e759@i2se.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <633e5a10-1ea0-48c7-a5b7-a5ff2625e759-eS4NqCHxEME@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Stefan Wahren , John Youn Cc: Felipe Balbi , linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Mark Rutland , Christian Lamparter List-Id: devicetree@vger.kernel.org On Thu, Nov 17, 2016 at 04:35:10PM +0100, Stefan Wahren wrote: > Hi John, > > Am 17.11.2016 um 00:47 schrieb John Youn: > > Add the "snps,ahb-burst" binding and read it in. > > > > This property controls which burst type to perform on the AHB bus as a > > master in internal DMA mode. This overrides the legacy param value, > > which we need to keep around for now since several platforms use it. > > > > Some platforms may see better or worse performance based on this > > value. The HAPS platform is one example where all INCRx have worse > > performance than INCR. > > > > Other platforms (such as the Canyonlands board) report that the default > > value causes system hangs. > > > > Signed-off-by: John Youn > > Cc: Christian Lamparter > > --- > > Documentation/devicetree/bindings/usb/dwc2.txt | 2 + > > drivers/usb/dwc2/core.h | 9 +++++ > > drivers/usb/dwc2/params.c | 56 ++++++++++++++++++++++++++ > > 3 files changed, 67 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/usb/dwc2.txt b/Documentation/devicetree/bindings/usb/dwc2.txt > > index 6c7c2bce..9e7b4b4 100644 > > --- a/Documentation/devicetree/bindings/usb/dwc2.txt > > +++ b/Documentation/devicetree/bindings/usb/dwc2.txt > > according to Documentation/devicetree/bindings/submitting-patches.txt > this change should be a separate patch. > > > @@ -26,6 +26,8 @@ Optional properties: > > Refer to phy/phy-bindings.txt for generic phy consumer properties > > - dr_mode: shall be one of "host", "peripheral" and "otg" > > Refer to usb/generic.txt > > +- snps,ahb-burst: specifies the ahb burst length. Valid arguments are: > > + "SINGLE", "INCR", "INCR4", "INCR8", "INCR16". Defaults to "INCR4". > > This doesn't apply in case of the bcm2835. I would prefer this option is > ignored in that case with a dev_warn("snps,ahb-burst is not supported on > this platform"). Also, perhaps you should allow that the compatible string can define the default. Rob -- 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