On Tue, Jan 3, 2017 at 8:24 PM, Jerry Huang <jerry.huang@xxxxxxx> wrote: > Hi, Rob, > >> -----Original Message----- >> From: Rob Herring [mailto:robh@xxxxxxxxxx] >> Sent: Wednesday, January 04, 2017 5:24 AM >> To: Jerry Huang <jerry.huang@xxxxxxx> >> Cc: balbi@xxxxxxxxxx; mark.rutland@xxxxxxx; catalin.marinas@xxxxxxx; >> will.deacon@xxxxxxx; linux@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; >> linux-usb@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-arm- >> kernel@xxxxxxxxxxxxxxxxxxx >> Subject: Re: [PATCH v3 2/3] USB3/DWC3: Add property "snps, incr-burst- >> type-adjustment" for INCR burst type >> >> On Thu, Dec 22, 2016 at 8:52 PM, Jerry Huang <jerry.huang@xxxxxxx> wrote: >> > Hi, Rob, >> >> -----Original Message----- >> >> From: Rob Herring [mailto:robh@xxxxxxxxxx] >> >> Sent: Friday, December 23, 2016 2:45 AM >> >> To: Jerry Huang <jerry.huang@xxxxxxx> >> >> Cc: balbi@xxxxxxxxxx; mark.rutland@xxxxxxx; catalin.marinas@xxxxxxx; >> >> will.deacon@xxxxxxx; linux@xxxxxxxxxxxxxxx; >> >> devicetree@xxxxxxxxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx; >> >> linux-kernel@xxxxxxxxxxxxxxx; linux-arm- kernel@xxxxxxxxxxxxxxxxxxx >> >> Subject: Re: [PATCH v3 2/3] USB3/DWC3: Add property "snps, >> >> incr-burst- type-adjustment" for INCR burst type >> >> >> >> On Mon, Dec 19, 2016 at 05:25:53PM +0800, Changming Huang wrote: >> >> > New property "snps,incr-burst-type-adjustment = <x>, <y>" for >> >> > USB3.0 >> >> DWC3. >> >> > Field "x": 1/0 - undefined length INCR burst type enable or not; >> >> > Field >> >> > "y": INCR4/INCR8/INCR16/INCR32/INCR64/INCR128/INCR256 burst type. >> >> > >> >> > While enabling undefined length INCR burst type and INCR16 burst >> >> > type, get better write performance on NXP Layerscape platform: >> >> > around 3% improvement (from 364MB/s to 375MB/s). >> >> > >> >> > Signed-off-by: Changming Huang <jerry.huang@xxxxxxx> >> >> > --- >> >> > Changes in v3: >> >> > - add new property for INCR burst in usb node. >> >> > >> >> > Documentation/devicetree/bindings/usb/dwc3.txt | 5 +++++ >> >> > arch/arm/boot/dts/ls1021a.dtsi | 1 + >> >> > arch/arm64/boot/dts/freescale/fsl-ls1043a.dtsi | 3 +++ >> >> > arch/arm64/boot/dts/freescale/fsl-ls2080a.dtsi | 2 ++ >> >> > 4 files changed, 11 insertions(+) >> >> > >> >> > diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt >> >> > b/Documentation/devicetree/bindings/usb/dwc3.txt >> >> > index e3e6983..8c405a3 100644 >> >> > --- a/Documentation/devicetree/bindings/usb/dwc3.txt >> >> > +++ b/Documentation/devicetree/bindings/usb/dwc3.txt >> >> > @@ -55,6 +55,10 @@ Optional properties: >> >> > fladj_30mhz_sdbnd signal is invalid or incorrect. >> >> > >> >> > - <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be >> >> reallocated. >> >> > + - snps,incr-burst-type-adjustment: Value for INCR burst type of >> >> GSBUSCFG0 >> >> > + register, undefined length INCR burst type enable and INCRx type. >> >> > + First field is for undefined length INCR burst type enable or not. >> >> > + Second field is for largest INCRx type enabled. >> >> >> >> Why do you need the first field? Is the 2nd field used if the 1st is 0? >> >> If not, then just use the presence of the property to enable or not. >> > The first field is one switch. >> > When it is 1, means undefined length INCR burst type enabled, we can use >> any length less than or equal to the largest-enabled burst length of >> INCR4/8/16/32/64/128/256. >> > When it is zero, means INCRx burst mode enabled, we can use one fixed >> burst length of 1/4/8/16/32/64/128/256 byte. >> > So, the 2nd field is used if the 1st is 0, we need to select one largest burst >> length the USB controller can support. >> > If we don't want to change the value of this register (use the default value), >> we don't need to add this property to usb node. >> >> Just make this a single value with 0 meaning INCR and 4/8/16/etc being INCRx. > Maybe, I didn't describe it clearly. > According to DWC3 spec, the value "0" of field INCRBrstEna means INCRx burst mode, 1 means INCR burst mode. > Regardless of the value of INCRBrstEna [bit0], we need to modify the other field bit[1,2,3,4,5,6,7] to one INCR burst type for the platform supported. > Ad you mentioned, if we just use a single value with 0 meaning INCR and 4/8/16/etc being INCRx. > I understand totally that when it is none-zero, we can use it for INCR burst mode. > Then, when it is 0, how to select the INCRx value? What I mean is: <no prop> - burst disabled 0 - INCR burst. INCR is undefined length burst IIRC. 4/8/16/etc. - INCR4/INCR8/INCR16/etc. What case does this not cover? Rob -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
