linux-kernel - RE: [PATCH] usb: dwc2: add bus suspend/resume for dwc2

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Date:	Fri, 31 Oct 2014 17:58:13 +0000
From:	Paul Zimmerman <Paul.Zimmerman@...opsys.com>
To:	Kever Yang <kever.yang@...k-chips.com>
CC:	Dinh Nguyen <dinguyen@...nsource.altera.com>,
	Felipe Balbi <balbi@...com>,
	"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
	"cf@...k-chips.com" <cf@...k-chips.com>,
	"lyz@...k-chips.com" <lyz@...k-chips.com>,
	"wulf@...k-chips.com" <wulf@...k-chips.com>,
	"jwerner@...omium.org" <jwerner@...omium.org>,
	"linux-rockchip@...ts.infradead.org" 
	<linux-rockchip@...ts.infradead.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] usb: dwc2: add bus suspend/resume for dwc2

> From: Kever Yang [mailto:kever.yang@...il.com] On Behalf Of Kever Yang
> Sent: Friday, October 31, 2014 7:03 AM
> 
> This patch adds suspend/resume for dwc2 hcd controller.
> 
> Signed-off-by: Kever Yang <kever.yang@...k-chips.com>
> ---
> 
>  drivers/usb/dwc2/hcd.c | 74 ++++++++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 63 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
> index fa49c72..df68449 100644
> --- a/drivers/usb/dwc2/hcd.c
> +++ b/drivers/usb/dwc2/hcd.c
> @@ -1473,6 +1473,29 @@ static void dwc2_port_suspend(struct dwc2_hsotg *hsotg, u16 windex)
>  	}
>  }
> 
> +static void dwc2_port_resume(struct dwc2_hsotg *hsotg)
> +{
> +	u32 hprt0;
> +
> +	/* After clear the Stop PHY clock bit, we should wait for a moment
> +	 * for PLL work stable with clock output.
> +	 */
> +	writel(0, hsotg->regs + PCGCTL);
> +	usleep_range(2000, 4000);
> +
> +	hprt0 = dwc2_read_hprt0(hsotg);
> +	hprt0 |= HPRT0_RES;
> +	writel(hprt0, hsotg->regs + HPRT0);
> +	hprt0 &= ~HPRT0_SUSP;
> +	/* according to USB2.0 Spec 7.1.7.7, the host most send the resume
> +	 * signal for at least 20ms
> +	 */
> +	usleep_range(20000, 25000);
> +
> +	hprt0 &= ~HPRT0_RES;
> +	writel(hprt0, hsotg->regs + HPRT0);
> +}
> +
>  /* Handles hub class-specific requests */
>  static int dwc2_hcd_hub_control(struct dwc2_hsotg *hsotg, u16 typereq,
>  				u16 wvalue, u16 windex, char *buf, u16 wlength)
> @@ -1518,17 +1541,7 @@ static int dwc2_hcd_hub_control(struct dwc2_hsotg *hsotg, u16 typereq,
>  		case USB_PORT_FEAT_SUSPEND:
>  			dev_dbg(hsotg->dev,
>  				"ClearPortFeature USB_PORT_FEAT_SUSPEND\n");
> -			writel(0, hsotg->regs + PCGCTL);
> -			usleep_range(20000, 40000);
> -
> -			hprt0 = dwc2_read_hprt0(hsotg);
> -			hprt0 |= HPRT0_RES;
> -			writel(hprt0, hsotg->regs + HPRT0);
> -			hprt0 &= ~HPRT0_SUSP;
> -			usleep_range(100000, 150000);
> -
> -			hprt0 &= ~HPRT0_RES;
> -			writel(hprt0, hsotg->regs + HPRT0);
> +			dwc2_port_resume(hsotg);
>  			break;
> 
>  		case USB_PORT_FEAT_POWER:
> @@ -2301,6 +2314,42 @@ static void _dwc2_hcd_stop(struct usb_hcd *hcd)
>  	usleep_range(1000, 3000);
>  }
> 
> +static int _dwc2_hcd_suspend(struct usb_hcd *hcd)
> +{
> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
> +	u32 hprt0;
> +
> +	if (hsotg->op_state != OTG_STATE_B_HOST)
> +		return 0;
> +
> +	if (hsotg->lx_state != DWC2_L0)
> +		return 0;
> +
> +	hprt0 = dwc2_read_hprt0(hsotg);
> +	if (hprt0 & HPRT0_CONNSTS)
> +		dwc2_port_suspend(hsotg, 1);
> +
> +	return 0;
> +}
> +
> +static int _dwc2_hcd_resume(struct usb_hcd *hcd)
> +{
> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
> +	u32 hprt0;
> +
> +	if (hsotg->op_state != OTG_STATE_B_HOST)
> +		return 0;
> +
> +	if (hsotg->lx_state != DWC2_L2)
> +		return 0;
> +
> +	hprt0 = dwc2_read_hprt0(hsotg);
> +	if ((hprt0 | HPRT0_CONNSTS) && (hprt0 | HPRT0_SUSP))

This isn't right, the condition will always be true.

Per your previous email, you are not able to test this because your
platform does not support suspend/resume yet, is that right? I don't
want to apply any untested patches to the driver.

-- 
Paul

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