[U-Boot] [PATCH v2 1/3] ARM: Tegra: FDT: Add USB EHCI function for T30/T114

Marek Vasut
2013-06-18T11:28:58Z

Dear Thierry Reding,

> On Mon, Jun 17, 2013 at 10:39:12PM +0200, Marek Vasut wrote:
> > Dear Thierry Reding,
> >
> > > On Sun, Jun 16, 2013 at 10:48:45PM +0200, Marek Vasut wrote:
> > > > Dear Thierry Reding,
> > > >
> > > > > On Sat, Jun 15, 2013 at 11:28:25PM +0200, Marek Vasut wrote:
> > > > > > Dear Thierry Reding,
> > > > > >
> > > > > > > On Fri, Jun 14, 2013 at 06:41:40PM +0800, Jim Lin wrote:
> > > > > > > [...]
> > > > > > >
> > > > > > > > diff --git a/board/nvidia/dts/tegra30-beaver.dts
> > > > > > > > b/board/nvidia/dts/tegra30-beaver.dts
> > > > > > >
> > > > > > > [...]
> > > > > > >
> > > > > > > > @@ -68,4 +69,9 @@
> > > > > > > >
> > > > > > > > status = "okay";
> > > > > > > > bus-width = <8>;
> > > > > > > >
> > > > > > > > };
> > > > > > > >
> > > > > > > > +
> > > > > > > > + usb at 7d008000 {
> > > > > > > > + nvidia,vbus-gpio = <&gpio 61 3>; /* PH5,
> > > >
> > > > USB13_VBUS_PULLUP */
> > > >
> > > > > > > This doesn't work for me on Beaver. I need to turn the above
> > > > > > > line into
> > > > > > >
> > > > > > > this:
> > > > > > > nvidia,vbus-gpio = <&gpio 236 0>; /* PDD4 */
> > > > > > >
> > > > > > > PDD4 is the correct GPIO according to the schematics and the
> > > > > > > pin is high-active. Also as far as I can tell, 3 is not a
> > > > > > > meaningful value for the U-Boot GPIO bindings. Only the value
> > > > > > > 1 (low-active) is used.
> > > > > > >
> > > > > > > With that change applied on top of your patches I can see that
> > > > > > > a USB flash drive connected to USB3 is indeed powered. However
> > > > > > > I noticed
> > > > > > >
> > > > > > > something strange. When I try to use USB, I get this:
> > > > > > > Tegra30 (Beaver) # usb start
> > > > > > > (Re)start USB...
> > > > > > > USB0: set_host_mode: GPIO 236 high
> > > > > > > USB EHCI 1.00
> > > > > > > scanning bus 0 for devices... 1 USB Device(s) found
> > > > > > >
> > > > > > > scanning usb for storage devices... 0 Storage Device(s)
> > > > > > > found scanning usb for ethernet devices... 0 Ethernet
> > > > > > > Device(s) found
> > > > > > >
> > > > > > > So no storage device is detected, even though a USB flash drive
> > > > > > > is connected and powered properly. If I repeat the same
> > > > > > > command, however,
> > > > > > >
> > > > > > > the storage device is detected:
> > > > > > > Tegra30 (Beaver) # usb reset
> > > > > > > (Re)start USB...
> > > > > > > USB0: set_host_mode: GPIO 236 high
> > > > > > > USB EHCI 1.00
> > > > > > > scanning bus 0 for devices... 2 USB Device(s) found
> > > > > > >
> > > > > > > scanning usb for storage devices... 1 Storage Device(s)
> > > > > > > found scanning usb for ethernet devices... 0 Ethernet
> > > > > > > Device(s) found
> > > > > > >
> > > > > > > Any idea what might be going on here?
> > > > > >
> > > > > > Try waiting a little after setting the GPIO maybe? The drive
> > > > > > might need some time to settle.
> > > > >
> > > > > I can make it work on the first invocation of "usb start" by adding
> > > > > a rather long mdelay() at the very end of ehci_hcd_init() in the
> > > > > Tegra EHCI driver. The magic value seems to be 853 ms. 852 ms
> > > > > wasn't enough in any of the test runs. 853 ms always worked.
> > > > >
> > > > > However 850+ ms seems like a very long time for the device to
> > > > > settle, and keeping it in the driver probably isn't a good idea.
> > > > > Furthermore I cannot reproduce the same issue with a newer flash
> > > > > drive, which works fine with no additional delays.
> > > >
> > > > Try reverting 020bbcb "usb: hub: Power-cycle on root-hub ports" ...
> > > > there's a thread in the ML that it caused issues.
> > >
> > > I reverted the following two patches:
> > > 0bf796f usb: hub: Parallelize power-cycling of root-hub ports
> > > 020bbcb usb: hub: Power-cycle on root-hub ports
> > >
> > > because it wasn't trivial to revert only 020bbcb alone. However it
> > > didn't change anything regarding the problem I was seeing.
> > >
> > > Thierry
> >
> > Ok, this looks ugly and calls for a bisect. Can you check it ? I'll try
> > to test if USB works for me on some EHCI-enabled device.
>
> I should repeat that things work fine for a more recent flash drive, so
> it doesn't look all that bad. Bisecting will be difficult because the
> patches for Tegra30 haven't been merged upstream yet. Also I can't tell
> for sure if this particular flash driver ever worked as expected since
> I've never tried it before.
>
> Given that I have limited time over the next few weeks, I'll see if I
> can come up with a successful bisection. If I do I'll let you know.

You can try checking 2013.01, I recall merging some usb-storage related changes
after that release.

Best regards,
Marek Vasut