[PATCH 1/1] usb: dwc3: meson-g12a: fix shared reset control use

[Jerome Brunet]

On Thu 20 Aug 2020 at 20:02, Kevin Hilman <khilman at baylibre.com> wrote:

> Jerome Brunet <jbrunet at baylibre.com> writes:
>
>> On Mon 13 Jul 2020 at 18:05, Dan Robertson <dan at dlrobertson.com> wrote:
>>
>>> The reset is a shared reset line, but reset_control_reset is still used
>>> and reset_control_deassert is not guaranteed to have been called before
>>> the first reset_control_assert call. When suspending the following
>>> warning may be seen:
>>
>> And now the same type of warning maybe seen on boot. This is
>> happening for me on the libretech-cc (s905x - gxl).
>>
>> [    1.863469] ------------[ cut here ]------------
>> [    1.867914] WARNING: CPU: 1 PID: 16 at drivers/reset/core.c:309 reset_control_reset+0x130/0x150
>> [    1.876525] Modules linked in:
>> [    1.879548] CPU: 1 PID: 16 Comm: kworker/1:0 Not tainted 5.9.0-rc1-00167-ga2e4e3a34775 #64
>> [    1.887737] Hardware name: Libre Computer AML-S905X-CC V2 (DT)
>> [    1.893525] Workqueue: events deferred_probe_work_func
>> [    1.898607] pstate: 80000005 (Nzcv daif -PAN -UAO BTYPE=--)
>> [    1.904126] pc : reset_control_reset+0x130/0x150
>> [    1.908700] lr : phy_meson_gxl_usb2_init+0x24/0x70
>> [    1.913439] sp : ffff8000123ebad0
>> [    1.916717] x29: ffff8000123ebad0 x28: 0000000000000000 
>> [    1.921978] x27: ffff00007c4b1ac8 x26: ffff00007c4b1ab0 
>> [    1.927239] x25: ffff00007fc149b0 x24: ffff00007c4b1ab0 
>> [    1.932500] x23: ffff00007cd03800 x22: ffff800011fb9000 
>> [    1.937761] x21: ffff00007c60db08 x20: ffff00007c468a80 
>> [    1.943023] x19: ffff00007c466b00 x18: ffffffffffffffff 
>> [    1.948284] x17: 0000000000000000 x16: 000000000000000e 
>> [    1.953545] x15: ffff800011fb9948 x14: ffffffffffffffff 
>> [    1.958806] x13: ffffffff00000000 x12: ffffffffffffffff 
>> [    1.964068] x11: 0000000000000020 x10: 7f7f7f7f7f7f7f7f 
>> [    1.969329] x9 : 78676f2c32617274 x8 : 0000000000000000 
>> [    1.974590] x7 : ffffffffffffffff x6 : 0000000000000000 
>> [    1.979851] x5 : 0000000000000000 x4 : 0000000000000000 
>> [    1.985112] x3 : 0000000000000000 x2 : ffff8000107aa370 
>> [    1.990374] x1 : 0000000000000001 x0 : 0000000000000001 
>> [    1.995636] Call trace:
>> [    1.998054]  reset_control_reset+0x130/0x150
>> [    2.002279]  phy_meson_gxl_usb2_init+0x24/0x70
>> [    2.006677]  phy_init+0x78/0xd0
>> [    2.009784]  dwc3_meson_g12a_probe+0x2c8/0x560
>> [    2.014182]  platform_drv_probe+0x58/0xa8
>> [    2.018149]  really_probe+0x114/0x3d8
>> [    2.021770]  driver_probe_device+0x5c/0xb8
>> [    2.025824]  __device_attach_driver+0x98/0xb8
>> [    2.030138]  bus_for_each_drv+0x74/0xd8
>> [    2.033933]  __device_attach+0xec/0x148
>> [    2.037726]  device_initial_probe+0x24/0x30
>> [    2.041868]  bus_probe_device+0x9c/0xa8
>> [    2.045663]  deferred_probe_work_func+0x7c/0xb8
>> [    2.050150]  process_one_work+0x1f0/0x4b0
>> [    2.054115]  worker_thread+0x210/0x480
>> [    2.057824]  kthread+0x158/0x160
>> [    2.061017]  ret_from_fork+0x10/0x18
>> [    2.064550] ---[ end trace 94d737efe593c6f6 ]---
>> [    2.069158] phy phy-d0078000.phy.0: phy init failed --> -22
>> [    2.074858] dwc3-meson-g12a: probe of d0078080.usb failed with error -22
>>
>> This breaks USB on this device. reverting the change brings it back.
>
> [...]
>
>> In the meantime, I think this change should be reverted. A warning on
>> suspend seems less critical than a regression breaking USB completly.
>
> Fully agree.
>
> Phillip, can you please revert this patch until the right solution is
> found?  Boot failure is much worse than a suspend warning.

I was asking Philip about the reset API suggestion.
I think the maintainer is Felipe for this change :)

>
> Kevin