On Sun, 2016-05-08 at 13:44 +0200, Christian Lamparter wrote: > On Sunday, May 08, 2016 08:40:55 PM Benjamin Herrenschmidt wrote: > > > > On Sun, 2016-05-08 at 00:54 +0200, Christian Lamparter via Linuxppc-dev > > wrote: > > > > > > I've been looking in getting the MyBook Live Duo's USB OTG port > > > to function. The SoC is a APM82181. Which has a PowerPC 464 core > > > and related to the supported canyonlands architecture in > > > arch/powerpc/. > > > > > > Currently in -next the dwc2 module doesn't load: > > Smells like the APM implementation is little endian. You might need to > > use a flag to indicate what endian to use instead and set it > > appropriately based on some DT properties. > I tried. As per common-properties[0], I added little-endian; but it has no > effect. I looked in dwc2_driver_probe and found no way of specifying the > endian of the device. It all comes down to the dwc2_readl & dwc2_writel > accessors. These - sadly - have been hardwired to use __raw_readl and > __raw_writel. So, it's always "native-endian". While common-properties > says little-endian should be preferred. Right, I meant, you should produce a patch adding a runtime test inside those functions based on a device-tree property, a bit like we do for some of the HCDs like OHCI, EHCI etc... Cheers, Ben. > > > > > > > > dwc2 4bff80000.usbotg: dwc2_core_reset() HANG! AHB Idle GRSTCTL=80 > > > dwc2 4bff80000.usbotg: Bad value for GSNPSID: 0x0a29544f > > > > > > Looking at the Bad GSNPSID value: 0x0a29544f. It is obvious that > > > this is an endian problem. git finds this patch: > > > > > > commit 95c8bc3609440af5e4a4f760b8680caea7424396 > > > Author: Antti Seppälä <a.seppala@xxxxxxxxx> > > > Date: Thu Aug 20 21:41:07 2015 +0300 > > > > > > usb: dwc2: Use platform endianness when accessing registers > > > > > > This patch is necessary to access dwc2 registers correctly on > > > big-endian > > > systems such as the mips based SoCs made by Lantiq. Then dwc2 can > > > be > > > used to replace ifx-hcd driver for Lantiq platforms found e.g. in > > > OpenWrt. > > > > > > The patch was autogenerated with the following commands: > > > $EDITOR core.h > > > sed -i "s/\/dwc2_readl/g" *.c hcd.h hw.h > > > sed -i "s/\/dwc2_writel/g" *.c hcd.h hw.h > > > > > > Some files were then hand-edited to fix checkpatch.pl warnings > > > about > > > too long lines. > > > > > > which unfortunately, broke the USB-OTG port on the MyBook Live Duo. > > > Reverting to the readl / writel: > > > > > > --- > > > diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h > > > index 3c58d63..c021c1f 100644 > > > --- a/drivers/usb/dwc2/core.h > > > +++ b/drivers/usb/dwc2/core.h > > > @@ -66,7 +66,7 @@ > > > > > > static inline u32 dwc2_readl(const void __iomem *addr) > > > { > > > - u32 value = __raw_readl(addr); > > > + u32 value = readl(addr); > > > > > > /* In order to preserve endianness __raw_* operation is > > > used. Therefore > > > * a barrier is needed to ensure IO access is not re-ordered > > > across > > > @@ -78,7 +78,7 @@ static inline u32 dwc2_readl(const void __iomem > > > *addr) > > > > > > static inline void dwc2_writel(u32 value, void __iomem *addr) > > > { > > > - __raw_writel(value, addr); > > > + writel(value, addr); > > > > > > /* > > > * In order to preserve endianness __raw_* operation is > > > used. Therefore > > > > > > --- > > > > > > restores the dwc-otg port to full working order: > > > dwc2 4bff80000.usbotg: Specified GNPTXFDEP=1024 > 256 > > > dwc2 4bff80000.usbotg: EPs: 3, shared fifos, 2042 entries in SPRAM > > > dwc2 4bff80000.usbotg: DWC OTG Controller > > > dwc2 4bff80000.usbotg: new USB bus registered, assigned bus number 1 > > > dwc2 4bff80000.usbotg: irq 33, io mem 0x00000000 > > > hub 1-0:1.0: USB hub found > > > hub 1-0:1.0: 1 port detected > > > root@mbl:~# usb 1-1: new high-speed USB device number 2 using dwc2 > > > > > > So, what to do? > ^^^ > > Regards, > Christian > > [0] > > -- > 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 -- 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