Re: [PATCH v4 3/8] usb: common: otg-fsm: add HNP polling support

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On Thu, Mar 19, 2015 at 11:11:20AM +0800, Li Jun wrote:
> Adds HNP polling timer when transits to host state, the OTG status request
> will be sent to peripheral after timeout, if host request flag is set, it will
> switch to peripheral state, otherwise it will repeat HNP polling every 1.5s and
> maintain the current session.

Signed-off-by: Peter Chen <peter.chen@xxxxxxxxxxxxx>

> 
> Signed-off-by: Li Jun <jun.li@xxxxxxxxxxxxx>
> ---
>  drivers/usb/common/usb-otg-fsm.c |   92 ++++++++++++++++++++++++++++++++++++++
>  include/linux/usb/otg-fsm.h      |   13 ++++++
>  2 files changed, 105 insertions(+)
> 
> diff --git a/drivers/usb/common/usb-otg-fsm.c b/drivers/usb/common/usb-otg-fsm.c
> index 61d538a..6f0d40b 100644
> --- a/drivers/usb/common/usb-otg-fsm.c
> +++ b/drivers/usb/common/usb-otg-fsm.c
> @@ -78,6 +78,8 @@ static void otg_leave_state(struct otg_fsm *fsm, enum usb_otg_state old_state)
>  		fsm->b_srp_done = 0;
>  		break;
>  	case OTG_STATE_B_PERIPHERAL:
> +		if (fsm->otg->gadget)
> +			fsm->otg->gadget->host_request_flag = 0;
>  		break;
>  	case OTG_STATE_B_WAIT_ACON:
>  		otg_del_timer(fsm, B_ASE0_BRST);
> @@ -107,6 +109,8 @@ static void otg_leave_state(struct otg_fsm *fsm, enum usb_otg_state old_state)
>  	case OTG_STATE_A_PERIPHERAL:
>  		otg_del_timer(fsm, A_BIDL_ADIS);
>  		fsm->a_bidl_adis_tmout = 0;
> +		if (fsm->otg->gadget)
> +			fsm->otg->gadget->host_request_flag = 0;
>  		break;
>  	case OTG_STATE_A_WAIT_VFALL:
>  		otg_del_timer(fsm, A_WAIT_VFALL);
> @@ -120,6 +124,92 @@ static void otg_leave_state(struct otg_fsm *fsm, enum usb_otg_state old_state)
>  	}
>  }
>  
> +static void otg_hnp_polling_work(struct work_struct *work)
> +{
> +	struct otg_fsm *fsm = container_of(to_delayed_work(work),
> +				struct otg_fsm, hnp_polling_work);
> +	struct usb_device *udev;
> +	u8 host_req_flag;
> +	enum usb_otg_state state = fsm->otg->state;
> +	struct usb_otg_descriptor *desc = NULL;
> +	int retval;
> +
> +	if (state != OTG_STATE_A_HOST && state != OTG_STATE_B_HOST)
> +		return;
> +
> +	udev = usb_hub_find_child(fsm->otg->host->root_hub, 1);
> +	if (!udev) {
> +		dev_err(fsm->otg->host->controller,
> +			"no usb dev connected, can't start HNP polling\n");
> +		return;
> +	}
> +
> +	/* Check if it's a HNP capable OTG device */
> +	retval = __usb_get_extra_descriptor(udev->rawdescriptors[0],
> +			le16_to_cpu(udev->config[0].desc.wTotalLength),
> +						USB_DT_OTG, (void **) &desc);
> +	if (retval || !(desc->bmAttributes & USB_OTG_HNP))
> +		return;
> +
> +	/* Get host request flag from connected USB device */
> +	retval = usb_control_msg(udev,
> +				usb_rcvctrlpipe(udev, 0),
> +				USB_REQ_GET_STATUS,
> +				USB_DIR_IN | USB_RECIP_DEVICE,
> +				0,
> +				OTG_STS_SELECTOR,
> +				&host_req_flag,
> +				1,
> +				USB_CTRL_GET_TIMEOUT);
> +	if (retval != 1) {
> +		dev_err(&udev->dev, "Get one byte OTG status failed\n");
> +		return;
> +	}
> +
> +	if (host_req_flag == 0) {
> +		/* Continue HNP polling */
> +		schedule_delayed_work(&fsm->hnp_polling_work,
> +					msecs_to_jiffies(T_HOST_REQ_POLL));
> +		return;
> +	} else if (host_req_flag != HOST_REQUEST_FLAG) {
> +		dev_err(&udev->dev, "host request flag %d is invalid\n",
> +							host_req_flag);
> +		return;
> +	}
> +
> +	/* Host request flag is set */
> +	if (state == OTG_STATE_A_HOST) {
> +		/* Set b_hnp_enable */
> +		if (!fsm->otg->host->b_hnp_enable) {
> +			retval = usb_control_msg(udev,
> +					usb_sndctrlpipe(udev, 0),
> +					USB_REQ_SET_FEATURE, 0,
> +					USB_DEVICE_B_HNP_ENABLE,
> +					0, NULL, 0,
> +					USB_CTRL_SET_TIMEOUT);
> +			if (retval < 0) {
> +				dev_err(&udev->dev,
> +					"can't enable HNP %d\n", retval);
> +				return;
> +			}
> +			fsm->otg->host->b_hnp_enable = 1;
> +		}
> +
> +		fsm->a_bus_req = 0;
> +	} else if (state == OTG_STATE_B_HOST) {
> +		fsm->b_bus_req = 0;
> +	}
> +
> +	otg_statemachine(fsm);
> +}
> +
> +static void otg_start_hnp_polling(struct otg_fsm *fsm)
> +{
> +	INIT_DELAYED_WORK(&fsm->hnp_polling_work, otg_hnp_polling_work);
> +	schedule_delayed_work(&fsm->hnp_polling_work,
> +					msecs_to_jiffies(T_HOST_REQ_POLL));
> +}
> +
>  /* Called when entering a state */
>  static int otg_set_state(struct otg_fsm *fsm, enum usb_otg_state new_state)
>  {
> @@ -169,6 +259,7 @@ static int otg_set_state(struct otg_fsm *fsm, enum usb_otg_state new_state)
>  		otg_set_protocol(fsm, PROTO_HOST);
>  		usb_bus_start_enum(fsm->otg->host,
>  				fsm->otg->host->otg_port);
> +		otg_start_hnp_polling(fsm);
>  		break;
>  	case OTG_STATE_A_IDLE:
>  		otg_drv_vbus(fsm, 0);
> @@ -203,6 +294,7 @@ static int otg_set_state(struct otg_fsm *fsm, enum usb_otg_state new_state)
>  		 */
>  		if (!fsm->a_bus_req || fsm->a_suspend_req_inf)
>  			otg_add_timer(fsm, A_WAIT_ENUM);
> +		otg_start_hnp_polling(fsm);
>  		break;
>  	case OTG_STATE_A_SUSPEND:
>  		otg_drv_vbus(fsm, 1);
> diff --git a/include/linux/usb/otg-fsm.h b/include/linux/usb/otg-fsm.h
> index f728f18..2bea252 100644
> --- a/include/linux/usb/otg-fsm.h
> +++ b/include/linux/usb/otg-fsm.h
> @@ -40,6 +40,18 @@
>  #define PROTO_HOST	(1)
>  #define PROTO_GADGET	(2)
>  
> +#define OTG_STS_SELECTOR        0xF000	/* OTG status selector, according to
> +					 * OTG and EH 2.0 Chapter 6.2.3
> +					 * Table:6-4
> +					 */
> +
> +#define HOST_REQUEST_FLAG       1	/* Host request flag, according to
> +					 * OTG and EH 2.0 Charpter 6.2.3
> +					 * Table:6-5
> +					 */
> +
> +#define T_HOST_REQ_POLL         (1500)	/* 1500ms, HNP polling interval */
> +
>  enum otg_fsm_timer {
>  	/* Standard OTG timers */
>  	A_WAIT_VRISE,
> @@ -119,6 +131,7 @@ struct otg_fsm {
>  	/* Current usb protocol used: 0:undefine; 1:host; 2:client */
>  	int protocol;
>  	struct mutex lock;
> +	struct delayed_work hnp_polling_work;
>  };
>  
>  struct otg_fsm_ops {
> -- 
> 1.7.9.5
> 

-- 

Best Regards,
Peter Chen
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