Re: [PATCH v4 4/5] usb: dwc3: Add function suspend and function wakeup support

[Thinh Nguyen]

On Mon, Feb 13, 2023, Elson Roy Serrao wrote:
> USB host sends function suspend and function resume notifications to
> the interface through SET_FEATURE/CLEAR_FEATURE setup packets.
> Add support to handle these packets by delegating the requests to
> composite layer. Also add support to handle function wake notification
> requests to exit from function suspend state.
> 
> Signed-off-by: Elson Roy Serrao <quic_eserrao@xxxxxxxxxxx>
> ---
>  drivers/usb/dwc3/core.h   |  3 +++
>  drivers/usb/dwc3/debug.h  |  2 ++
>  drivers/usb/dwc3/ep0.c    | 12 ++++--------
>  drivers/usb/dwc3/gadget.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 51 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index cc78236..1565b21 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -526,6 +526,7 @@
>  #define DWC3_DGCMD_SET_ENDPOINT_NRDY	0x0c
>  #define DWC3_DGCMD_SET_ENDPOINT_PRIME	0x0d
>  #define DWC3_DGCMD_RUN_SOC_BUS_LOOPBACK	0x10
> +#define DWC3_DGCMD_DEV_NOTIFICATION	0x07
>  
>  #define DWC3_DGCMD_STATUS(n)		(((n) >> 12) & 0x0F)
>  #define DWC3_DGCMD_CMDACT		BIT(10)
> @@ -538,6 +539,8 @@
>  #define DWC3_DGCMDPAR_TX_FIFO			BIT(5)
>  #define DWC3_DGCMDPAR_LOOPBACK_DIS		(0 << 0)
>  #define DWC3_DGCMDPAR_LOOPBACK_ENA		BIT(0)
> +#define DWC3_DGCMDPAR_DN_FUNC_WAKE		BIT(0)
> +#define DWC3_DGCMDPAR_INTF_SEL(n)		((n) << 4)
>  
>  /* Device Endpoint Command Register */
>  #define DWC3_DEPCMD_PARAM_SHIFT		16
> diff --git a/drivers/usb/dwc3/debug.h b/drivers/usb/dwc3/debug.h
> index 8bb2c9e..09d7038 100644
> --- a/drivers/usb/dwc3/debug.h
> +++ b/drivers/usb/dwc3/debug.h
> @@ -72,6 +72,8 @@ dwc3_gadget_generic_cmd_string(u8 cmd)
>  		return "Set Endpoint Prime";
>  	case DWC3_DGCMD_RUN_SOC_BUS_LOOPBACK:
>  		return "Run SoC Bus Loopback Test";
> +	case DWC3_DGCMD_DEV_NOTIFICATION:
> +		return "Device Notification";
>  	default:
>  		return "UNKNOWN";
>  	}
> diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
> index f90fa55..1e7cc15 100644
> --- a/drivers/usb/dwc3/ep0.c
> +++ b/drivers/usb/dwc3/ep0.c
> @@ -30,6 +30,8 @@
>  static void __dwc3_ep0_do_control_status(struct dwc3 *dwc, struct dwc3_ep *dep);
>  static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
>  		struct dwc3_ep *dep, struct dwc3_request *req);
> +static int dwc3_ep0_delegate_req(struct dwc3 *dwc,
> +				 struct usb_ctrlrequest *ctrl);
>  
>  static void dwc3_ep0_prepare_one_trb(struct dwc3_ep *dep,
>  		dma_addr_t buf_dma, u32 len, u32 type, bool chain)
> @@ -368,7 +370,7 @@ static int dwc3_ep0_handle_status(struct dwc3 *dwc,
>  		 * Function Remote Wake Capable	D0
>  		 * Function Remote Wakeup	D1
>  		 */
> -		break;
> +		return dwc3_ep0_delegate_req(dwc, ctrl);
>  
>  	case USB_RECIP_ENDPOINT:
>  		dep = dwc3_wIndex_to_dep(dwc, ctrl->wIndex);
> @@ -514,13 +516,7 @@ static int dwc3_ep0_handle_intf(struct dwc3 *dwc,
>  
>  	switch (wValue) {
>  	case USB_INTRF_FUNC_SUSPEND:
> -		/*
> -		 * REVISIT: Ideally we would enable some low power mode here,
> -		 * however it's unclear what we should be doing here.
> -		 *
> -		 * For now, we're not doing anything, just making sure we return
> -		 * 0 so USB Command Verifier tests pass without any errors.
> -		 */
> +		ret = dwc3_ep0_delegate_req(dwc, ctrl);
>  		break;
>  	default:
>  		ret = -EINVAL;
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index b7fef5d..9905875 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -2391,6 +2391,47 @@ static int dwc3_gadget_wakeup(struct usb_gadget *g)
>  	return ret;
>  }
>  
> +static void dwc3_resume_gadget(struct dwc3 *dwc);
> +
> +static int dwc3_gadget_func_wakeup(struct usb_gadget *g, int intf_id)
> +{
> +	struct  dwc3		*dwc = gadget_to_dwc(g);
> +	unsigned long		flags;
> +	int			ret;
> +	int			link_state;
> +
> +	if (!dwc->wakeup_configured) {
> +		dev_err(dwc->dev, "remote wakeup not configured\n");
> +		return -EINVAL;
> +	}
> +
> +	spin_lock_irqsave(&dwc->lock, flags);
> +	/*
> +	 * If the link is in low power, first bring the link to U0
> +	 * before triggering function remote wakeup.

This should be reword as below:
If the link is in U3, signal for remote wakeup and wait for link to
transition to U0 before sending device notification.

After the above change, you can add my ack:

Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>

Thanks,
Thinh

> +	 */
> +	link_state = dwc3_gadget_get_link_state(dwc);
> +	if (link_state == DWC3_LINK_STATE_U3) {
> +		ret = __dwc3_gadget_wakeup(dwc, false);
> +		if (ret) {
> +			spin_unlock_irqrestore(&dwc->lock, flags);
> +			return -EINVAL;
> +		}
> +		dwc3_resume_gadget(dwc);
> +		dwc->link_state = DWC3_LINK_STATE_U0;
> +	}
> +
> +	ret = dwc3_send_gadget_generic_command(dwc, DWC3_DGCMD_DEV_NOTIFICATION,
> +					       DWC3_DGCMDPAR_DN_FUNC_WAKE |
> +					       DWC3_DGCMDPAR_INTF_SEL(intf_id));
> +	if (ret)
> +		dev_err(dwc->dev, "function remote wakeup failed, ret:%d\n", ret);
> +
> +	spin_unlock_irqrestore(&dwc->lock, flags);
> +
> +	return ret;
> +}
> +
>  static int dwc3_gadget_set_remote_wakeup(struct usb_gadget *g, int set)
>  {
>  	struct dwc3		*dwc = gadget_to_dwc(g);
> @@ -3028,6 +3069,7 @@ static void dwc3_gadget_async_callbacks(struct usb_gadget *g, bool enable)
>  static const struct usb_gadget_ops dwc3_gadget_ops = {
>  	.get_frame		= dwc3_gadget_get_frame,
>  	.wakeup			= dwc3_gadget_wakeup,
> +	.func_wakeup		= dwc3_gadget_func_wakeup,
>  	.set_remote_wakeup	= dwc3_gadget_set_remote_wakeup,
>  	.set_selfpowered	= dwc3_gadget_set_selfpowered,
>  	.pullup			= dwc3_gadget_pullup,
> -- 
> 2.7.4
>