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Re: [RESEND PATCH 3/4] usb: dwc2: assert phy reset when waking up in rk3288 platform

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On 8/24/2016 1:54 AM, Randy Li wrote:
> 
> 
> On 08/24/2016 04:46 AM, John Youn wrote:
>> On 8/21/2016 12:32 PM, Randy Li wrote:
>>> On the rk3288 USB host-only port (the one that's not the OTG-enabled
>>> port) the PHY can get into a bad state when a wakeup is asserted (not
>>> just a wakeup from full system suspend but also a wakeup from
>>> autosuspend).
>>>
>>> We can get the PHY out of its bad state by asserting its "port reset",
>>> but unfortunately that seems to assert a reset onto the USB bus so it
>>> could confuse things if we don't actually deenumerate / reenumerate the
>>> device.
>>>
>>> We can also get the PHY out of its bad state by fully resetting it using
>>> the reset from the CRU (clock reset unit) in chip, which does a more full
>>> reset.  The CRU-based reset appears to actually cause devices on the bus
>>> to be removed and reinserted, which fixes the problem (albeit in a hacky
>>> way).
>>>
>>> It's unfortunate that we need to do a full re-enumeration of devices at
>>> wakeup time, but this is better than alternative of letting the bus get
>>> wedged.
>>>
>>> Signed-off-by: Randy Li <ayaka@soulik.info>
>>> ---
>>>  drivers/usb/dwc2/core_intr.c | 11 +++++++++++
>>>  1 file changed, 11 insertions(+)
>>>
>>> diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
>>> index d85c5c9..f57c48a 100644
>>> --- a/drivers/usb/dwc2/core_intr.c
>>> +++ b/drivers/usb/dwc2/core_intr.c
>>> @@ -345,6 +345,7 @@ static void dwc2_handle_session_req_intr(struct dwc2_hsotg *hsotg)
>>>  static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
>>>  {
>>>  	int ret;
>>> +	struct device_node *np = hsotg->dev->of_node;
>>>
>>>  	/* Clear interrupt */
>>>  	dwc2_writel(GINTSTS_WKUPINT, hsotg->regs + GINTSTS);
>>> @@ -379,6 +380,16 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
>>>  			/* Restart the Phy Clock */
>>>  			pcgcctl &= ~PCGCTL_STOPPCLK;
>>>  			dwc2_writel(pcgcctl, hsotg->regs + PCGCTL);
>>> +
>>> +			/*
>>> +			 * It is a quirk in Rockchip RK3288, causing by
>>> +			 * a hardware bug. This will propagate out and
>>> +			 * eventually we'll re-enumerate the device.
>>> +			 * Not great but the best we can do
>>
>> Remove the trailing whitespaces in this comment.
>>
>> Run scripts/checkpatch.pl to catch these.
> I see.
>>
>>> +			 */
>>> +			if (of_device_is_compatible(np, "rockchip,rk3288-usb"))
>>> +				hsotg->phy->ops->reset(hsotg->phy);
>>> +
>>
>> You should probably check for NULL before calling the reset()
>> callback.
> Sure.
>>
>> Also, I'd rather see a generic quirk property that you set for your
>> platform.
>>
>> Something like "phy_reset_on_wakeup_quirk".
> But Rob Herring want me to implied by the SoC specific compatible 
> string. I agree with him. It is certainly bug in RK3288 platform.
> It is no found no the other platform.

Ok, I missed that before.

Based on the drivers I'm familiar with (like dwc3), you would typically add a
"quirk" anyways.

Felipe,

Do you have some policy or preference on this?

Regards,
John

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[PATCH 3/4] usb: dwc2: assert phy reset when waking up in rk3288 platform Randy Li <ayaka@soulik.info> - 2016-08-20 22:50 +0200
  Re: [PATCH 3/4] usb: dwc2: assert phy reset when waking up in rk3288  platform Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> - 2016-08-20 23:40 +0200
    [PATCH 4/4] ARM: dts: rockchip: Point rk3288 dwc2 usb at the full PHY reset Randy Li <ayaka@soulik.info> - 2016-08-21 10:00 +0200
      Re: [PATCH 4/4] ARM: dts: rockchip: Point rk3288 dwc2 usb at the full  PHY reset Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> - 2016-08-21 13:10 +0200
        Re: [PATCH 4/4] ARM: dts: rockchip: Point rk3288 dwc2 usb at the full  PHY reset ayaka <ayaka@soulik.info> - 2016-08-21 14:30 +0200
          Re: [PATCH 4/4] ARM: dts: rockchip: Point rk3288 dwc2 usb at the full  PHY reset Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> - 2016-08-22 12:40 +0200
    [PATCH 2/4] phy: rockchip-usb: use rockchip_usb_phy_reset to reset phy during wakeup Randy Li <ayaka@soulik.info> - 2016-08-21 10:00 +0200
      Re: [PATCH 2/4] phy: rockchip-usb: use rockchip_usb_phy_reset to  reset phy during wakeup Rob Herring <robh@kernel.org> - 2016-08-23 20:20 +0200
    [PATCH 1/4] phy: Add reset callback Randy Li <ayaka@soulik.info> - 2016-08-21 10:00 +0200
    [PATCH 3/4] usb: dwc2: assert phy reset when waking up in rk3288 platform Randy Li <ayaka@soulik.info> - 2016-08-21 10:00 +0200
    [PATCH 0/4 v5] usb: dwc2: fix the usb host for host port at RK32 Randy Li <ayaka@soulik.info> - 2016-08-21 10:00 +0200
    [RESEND PATCH 4/4] ARM: dts: rockchip: Point rk3288 dwc2 usb at the full PHY reset Randy Li <ayaka@soulik.info> - 2016-08-21 21:40 +0200
    [RESEND PATCH 3/4] usb: dwc2: assert phy reset when waking up in rk3288 platform Randy Li <ayaka@soulik.info> - 2016-08-21 21:40 +0200
      Re: [RESEND PATCH 3/4] usb: dwc2: assert phy reset when waking up in  rk3288 platform John Youn <John.Youn@synopsys.com> - 2016-08-23 22:50 +0200
        Re: [RESEND PATCH 3/4] usb: dwc2: assert phy reset when waking up in  rk3288 platform Randy Li <randy.li@rock-chips.com> - 2016-08-24 11:00 +0200
          Re: [RESEND PATCH 3/4] usb: dwc2: assert phy reset when waking up in  rk3288 platform John Youn <John.Youn@synopsys.com> - 2016-08-25 20:30 +0200
            Re: [RESEND PATCH 3/4] usb: dwc2: assert phy reset when waking up in rk3288 platform Felipe Balbi <felipe.balbi@linux.intel.com> - 2016-08-29 10:00 +0200
              Re: [RESEND PATCH 3/4] usb: dwc2: assert phy reset when waking up in  rk3288 platform John Youn <John.Youn@synopsys.com> - 2016-08-29 20:30 +0200

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