From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Wahren Subject: Re: [PATCH v2 2/4] usb: dwc2: Add binding for AHB burst Date: Thu, 17 Nov 2016 16:35:10 +0100 Message-ID: <633e5a10-1ea0-48c7-a5b7-a5ff2625e759@i2se.com> References: <7fa1c1c4d703c435d698cdf140c9d43163347f1d.1479339900.git.johnyoun@synopsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <7fa1c1c4d703c435d698cdf140c9d43163347f1d.1479339900.git.johnyoun-HKixBCOQz3hWk0Htik3J/w@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: John Youn , Felipe Balbi , linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rob Herring , Mark Rutland Cc: Christian Lamparter List-Id: devicetree@vger.kernel.org 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"). Stefan -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html