linux-kernel - Re: [PATCH v10 1/2] usb: dwc2: assert phy reset when waking up in rk3288 platform

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Date:   Sat, 4 Mar 2017 10:56:38 +0800
From:   ayaka <ayaka@...lik.info>
To:     linux-usb@...r.kernel.org
Cc:     John.Youn@...opsys.com, kishon@...com,
        felipe.balbi@...ux.intel.com, mark.rutland@....com,
        devicetree@...r.kernel.org, heiko@...ech.de,
        gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
        robh+dt@...nel.org, randy.li@...k-chips.com
Subject: Re: [PATCH v10 1/2] usb: dwc2: assert phy reset when waking up in
 rk3288 platform

What is wrong with this patch? I have not seen it is merged in 
next-20170303.


On 12/11/2016 11:36 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@...lik.info>
> Acked-by: John Youn <johnyoun@...opsys.com>
> ---
>   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 9548d3e..0cd5896 100644
> --- a/drivers/usb/dwc2/core.h
> +++ b/drivers/usb/dwc2/core.h
> @@ -919,6 +919,7 @@ 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 5b228ba..bf1c029 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 4fc8c60..8ef278e 100644
> --- a/drivers/usb/dwc2/platform.c
> +++ b/drivers/usb/dwc2/platform.c
> @@ -207,6 +207,14 @@ 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;
> @@ -251,6 +259,7 @@ 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);