Hi

Op 16-04-2021 om 00:23 schreef Thinh Nguyen:

Thinh Nguyen wrote:

quoted

From: Yu Chen <chenyu56@huawei.com>
From: John Stultz <redacted>

According to the programming guide, to switch mode for DRD controller,
the driver needs to do the following.

To switch from device to host:
1. Reset controller with GCTL.CoreSoftReset
2. Set GCTL.PrtCapDir(host mode)
3. Reset the host with USBCMD.HCRESET
4. Then follow up with the initializing host registers sequence

To switch from host to device:
1. Reset controller with GCTL.CoreSoftReset
2. Set GCTL.PrtCapDir(device mode)
3. Reset the device with DCTL.CSftRst
4. Then follow up with the initializing registers sequence

Currently we're missing step 1) to do GCTL.CoreSoftReset and step 3) of
switching from host to device. John Stult reported a lockup issue seen
with HiKey960 platform without these steps[1]. Similar issue is observed
with Ferry's testing platform[2].

So, apply the required steps along with some fixes to Yu Chen's and John
Stultz's version. The main fixes to their versions are the missing wait
for clocks synchronization before clearing GCTL.CoreSoftReset and only
apply DCTL.CSftRst when switching from host to device.

[1] https://urldefense.com/v3/__https://lore.kernel.org/linux-usb/20210108015115.27920-1-john.stultz@linaro.org/__;!!A4F2R9G_pg!PW9Jbs4wv4a_zKGgZHN0FYrIpfecPX0Ouq9V3d16Yz-9-GSHqZWsfBAF-WkeqLhzN4i3$
[2] https://urldefense.com/v3/__https://lore.kernel.org/linux-usb/0ba7a6ba-e6a7-9cd4-0695-64fc927e01f1@gmail.com/__;!!A4F2R9G_pg!PW9Jbs4wv4a_zKGgZHN0FYrIpfecPX0Ouq9V3d16Yz-9-GSHqZWsfBAF-WkeqGeZStt4$

Cc: Andy Shevchenko <redacted>
Cc: Ferry Toth <redacted>
Cc: Wesley Cheng <redacted>
Cc: <redacted>
Fixes: 41ce1456e1db ("usb: dwc3: core: make dwc3_set_mode() work properly")
Signed-off-by: Yu Chen <chenyu56@huawei.com>
Signed-off-by: John Stultz <redacted>
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
---
Changes in v3:
- Check if the desired mode is OTG, then keep the old flow
- Remove condition for OTG support only since the device can still be
   configured DRD host/device mode only
- Remove redundant hw_mode check since __dwc3_set_mode() only applies when
   hw_mode is DRD
Changes in v2:
- Initialize mutex per device and not as global mutex.
- Add additional checks for DRD only mode

  drivers/usb/dwc3/core.c | 27 +++++++++++++++++++++++++++
  drivers/usb/dwc3/core.h |  5 +++++
  2 files changed, 32 insertions(+)

Hi John,

If possible, can you run a test with this version on your platform?

Thanks,
Thinh

I tested this on edison-arduino with this patch on top of usb-next 
(5.12-rc7 + "increase BESL baseline to 6" to prevent throttling").

On this platform there is a physical switch to switch roles. With this 
patch I find:

- switch to host mode always works fine

- switch to gadget mode I need to flip the switch 3x (gadget-host-gadget).

An error message appears on the gadget side "dwc3 dwc3.0.auto: timed out 
waiting for SETUP phase" appears, but then the device connects to my PC, 
no throttling.

- alternatively I can switch to gadget 1x and then unplug/replug the cable.

No error message and connects fine.

- if I flip the switch only once, on the PC side I get:

    kernel: usb 1-5: new high-speed USB device number 18 using xhci_hcd
    kernel: usb 1-5: New USB device found, idVendor=1d6b,
    idProduct=0104, bcdDevice= 1.00 kernel: usb 1-5: New USB device
    strings: Mfr=1, Product=2, SerialNumber=3 kernel: usb 1-5: Product:
    USBArmory Gadget kernel: usb 1-5: Manufacturer: USBArmory kernel:
    usb 1-5: SerialNumber: 0123456789abcdef kernel: usb 1-5: can't set
    config #1, error -110

Then if I wait long enough on the gadget side I get:

    root@yuna:~# ifconfig

    usb0: flags=-28605<UP,BROADCAST,RUNNING,MULTICAST,DYNAMIC> mtu 1500
    inet 169.254.119.239 netmask 255.255.0.0 broadcast 169.254.255.255
    inet6 fe80::a8bb:ccff:fedd:eef1 prefixlen 64 scopeid 0x20<link>
    ether aa:bb:cc:dd:ee:f1 txqueuelen 1000 (Ethernet) RX packets 490424
    bytes 735146578 (701.0 MiB) RX errors 0 dropped 191 overruns 0 frame
    0 TX packets 35279 bytes 2532746 (2.4 MiB) TX errors 0 dropped 0
    overruns 0 carrier 0 collisions 0

(correct would be: inet 10.42.0.221 netmask 255.255.255.0 broadcast 
10.42.0.255)

So much improved now, but it seems I am still missing something on plug.