linux-kernel - Re: [PATCH v9 1/2] usb: dwc2: assert phy reset when waking up in rk3288 platform

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Date:   Sun, 23 Oct 2016 17:33:23 +0800
From:   ayaka <ayaka@...lik.info>
To:     John Youn <John.Youn@...opsys.com>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>
Cc:     "kishon@...com" <kishon@...com>,
        "felipe.balbi@...ux.intel.com" <felipe.balbi@...ux.intel.com>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "heiko@...ech.de" <heiko@...ech.de>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "randy.li@...k-chips.com" <randy.li@...k-chips.com>
Subject: Re: [PATCH v9 1/2] usb: dwc2: assert phy reset when waking up in
 rk3288 platform



On 10/22/2016 03:27 AM, John Youn wrote:
> On 10/20/2016 11:38 AM, 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@...lik.info>
>> ---
>>   drivers/usb/dwc2/core.h      |  1 +
>>   drivers/usb/dwc2/core_intr.c | 11 +++++++++++
>>   drivers/usb/dwc2/platform.c  |  9 +++++++++
>>   3 files changed, 21 insertions(+)
>>
>> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
>> index 2a21a04..e91ddbc 100644
>> --- a/drivers/usb/dwc2/core.h
>> +++ b/drivers/usb/dwc2/core.h
>> @@ -859,6 +859,7 @@ struct dwc2_hsotg {
>>   	unsigned int ll_hw_enabled:1;
>>   
>>   	struct phy *phy;
>> +	struct work_struct phy_rst_work;
>>   	struct usb_phy *uphy;
>>   	struct dwc2_hsotg_plat *plat;
>>   	struct regulator_bulk_data supplies[ARRAY_SIZE(dwc2_hsotg_supply_names)];
>> diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
>> index d85c5c9..c3d2168 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
>> +			 */
>> +			if (of_device_is_compatible(np, "rockchip,rk3288-usb"))
>> +				schedule_work(&hsotg->phy_rst_work);
>> +
>>   			mod_timer(&hsotg->wkp_timer,
>>   				  jiffies + msecs_to_jiffies(71));
>>   		} else {
>> diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
>> index 8e1728b..65953cf 100644
>> --- a/drivers/usb/dwc2/platform.c
>> +++ b/drivers/usb/dwc2/platform.c
>> @@ -366,6 +366,14 @@ int dwc2_lowlevel_hw_disable(struct dwc2_hsotg *hsotg)
>>   	return ret;
>>   }
>>   
>> +/* Only used to reset usb phy at interrupter runtime */
>> +static void dwc2_reset_phy_work(struct work_struct *data)
>> +{
>> +	struct dwc2_hsotg *hsotg = container_of(data, struct dwc2_hsotg,
>> +			phy_rst_work);
>> +	phy_reset(hsotg->phy);
>> +}
>> +
>>   static int dwc2_lowlevel_hw_init(struct dwc2_hsotg *hsotg)
>>   {
>>   	int i, ret;
>> @@ -410,6 +418,7 @@ static int dwc2_lowlevel_hw_init(struct dwc2_hsotg *hsotg)
>>   			return ret;
>>   		}
>>   	}
>> +	INIT_WORK(&hsotg->phy_rst_work, dwc2_reset_phy_work);
>>   
>>   	if (!hsotg->phy) {
>>   		hsotg->uphy = devm_usb_get_phy(hsotg->dev, USB_PHY_TYPE_USB2);
>>
> Hi Randy,
>
> This fails compile if CONFIG_GENERIC_PHY is disabled. I think you need
> to make a fix to your phy_reset patch first.
In the last time, cac18ecb6f44b11bc303d7afbae3887b27938fa4 have not been 
merged, I though the
[PATCH v8 1/3] phy: Add reset callback for not generic phy have been 
merged before that. when the rebase abandon it.
Should re-send that patch? As the mainline have not been affected, could 
you arrange a squash for it?
>
> Regards,
> John