PROBLEM: DWC3 USB 3.0 not working on Odroid-XU4 with Exynos 5422

[Michael Niewöhner]

Hi Vivek,
On Di, 2016-10-04 at 17:32 +0530, Vivek Gautam wrote:
> Hi Michael,
> 
> 
> On Tue, Oct 4, 2016 at 4:28 PM, Michael Niewöhner <linux at mniewoehner.de> wrote:
> 
> > 
> > > 
> > > > 
> > > > > 
> > > > > > 
> > > > > > > 
> > > > > > > [1.] One line summary of the problem:
> > > > > > > DWC3 USB 3.0 not working on Odroid-XU4 with Exynos 5422
> > > > > > > 
> > > > > > > [2.] Full description of the problem/report:
> > > > > > > No usb 3.0 devices are being detected when attached while USB 2.0
> > > > > > > devices work on the same port.
> > > > > > > USB 3.0 works after applying patches [9.1] and [9.2], but seems
> > > > > > > to be
> > > > > > > buggy. The usb hub is redetected every time an usb device is
> > > > > > > attached.
> 
> [snip]
> 
> > 
> > > 
> > > > 
> > > > > 
> > > > > > 
> > > > > > > 
> > > > > > > > 
> > > > > > > > [9.] Other notes, patches, fixes, workarounds:
> > > > > > > > [9.1] https://lkml.org/lkml/2014/4/28/234
> > > > > > > > [9.2] https://lkml.org/lkml/2015/2/2/259
> > > 
> > > These patches are required to get USB super-speed working on Exynos5420/5800.
> > > But they did not make to upstream. There was resistance on adding new
> > > phy_calibrate()
> > > callback.
> > > 
> > > Without these patches the Exynos5420/5800 will enumerate all
> > > super-speed capable devices
> > > as high-speed devices.
> > > Last time we checked with exynos542x smdk boards and peach-* boards,
> > > we could get the
> > > Super - speed devices working. I have not tested odroid anytime so
> > > don't have much idea about the
> > > its intricacies.
> > > I guess Anand was able to use these patches to get his kernel working in past.
> > 
> > 
> > The patches don't work anymore with 4.8-rc* / 4.8. They worked - but very
> > unstable - with 4.7.
> > 
> > One more problem appeared since one of the 4.8-RCs: reboot hangs when the dwc3
> > module is loaded. If I unload it before reboot / shutdown everything is fine.
> > 
> > 
> > > 
> > > 
> > > When you have a downstream on-board usb hub, ideally it should be able
> > > to detect the devices
> > > and not reset everytime you connect a new device (like you mentioned earlier).
> > > There can be two possible reasons why the hub keeps getting reset ever
> > > after applying the above
> > > mentioned patches:
> > > 1) the clock rates are not proper.
> > > 2) the regulator load setting is not enough to drive the hub.
> > > 
> > > Anand, can you please point Michael to an older kernel with which you
> > > could test usb on odroid successfully ?
> > > You can compare the clocks with an older version and see if there'a
> > > any difference.
> > > 
> > > Any possibility of any other framework (such as, bus-freq) trimming
> > > down the clock - rates ?
> > 
> > 
> > ################################
> > # v4.7.5
> > ################################
> > 
> > $ cat /sys/kernel/debug/clk/clk_summary | grep usb
> >  sclk_usbh20_scan_clk                     0            0   480000000          0
> >  sclk_usbh20                              0            0    48000
> > 000          0
> >     mout_usbd300                          1            1    24000000          0
> >        dout_usbd300                       0            0    24000000          0
> >           sclk_usbd300
> >                  0            0    24000000          0
> >        dout_usbphy300                     1            1    24000000          0
> >           sclk_usbphy300                  4            4    24000
> > 000          0
> >     mout_usbd301                          1            1    24000000          0
> >        dout_usbd301                       0            0    24000000          0
> >           sclk_usbd301
> >                  0            0    24000000          0
> >        dout_usbphy301                     1            1    24000000          0
> >           sclk_usbphy301                  3            3    24000
> > 000          0
> >                          usbd301           1            1   100000000
> >                          usbd300           1            1   100000000
> > 
> > usbh20           3            3   100000000          0
> 
> > 
> > 
> > ################################
> > # v4.8.0
> > ################################
> > 
> > $ cat /sys/kernel/debug/clk/clk_summary | grep usb
> >  sclk_usbh20_scan_clk                     0            0   480000000          0
> >  sclk_usbh20                              0            0    48000000
> >         0
> >     mout_usbd300                          1            1    24000000          0
> >        dout_usbd300                       0            0    24000000          0
> >           sclk_usbd300
> >             0            0    24000000          0
> >        dout_usbphy300                     1            1    24000000          0
> >           sclk_usbphy300                  4            4    24000000
> >         0
> >     mout_usbd301                          1            1    24000000          0
> >        dout_usbd301                       0            0    24000000          0
> >           sclk_usbd301
> >             0            0    24000000          0
> >        dout_usbphy301                     1            1    24000000          0
> >           sclk_usbphy301                  3            3    24000000
> >         0
> >                          usbd301           1            1   100000000
> 
> This clock should have been 200MHz.
> 
> > 
> >                          usbd300           1            1   100000000
> >                          usbh2
> > 0           3            3   100000000          0
> > 
> > $ cat /sys/kernel/debug/usb/devices
> > <<system hangs>>
> > 
> 
> The clocks are same across working/non-working.
> Is it possible to bisect the commit that's causing hang for 4.8x ?


[c499ff71ff2a281366c6ec7a904c547d806cbcd1] usb: dwc3: core: re-factor init and exit paths
This patch causes both the hang on reboot and the lsusb hang.


> 
> Adding few of the folks from Samsung who can test dwc3 usb on smdk/peach boards.
> +Alim, Pankaj
> 
> Hi Alim, Pankaj,
> can you please give a try with 4.8 kernel on peach/smdk542x board and
> see if dwc3 usb works or not.
> You may need to the patches mentioned in [9.1] and [9.2] mentioned above.
> 
> 
> [snip]
> 
> 
> Thanks
> Vivek
> 

Best regards
Michael