[PATCH v2 04/12] usb: gadget: Set max speed for SSP devices

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A super-speed-plus device may operate at different sublink speeds (e.g.
gen2x2, gen1x2, or gen2x1). If the USB device supports different sublink
speeds at super-speed-plus, set the device to operate at the maximum
number of lanes and sublink speed possible. Introduce gadget ops
udc_set_num_lanes_and_speed to set the lane count and sublink speed for
super-speed-plus capable devices.

Signed-off-by: Thinh Nguyen <thinhn@xxxxxxxxxxxx>
---
 Changes in v2:
 - None

 drivers/usb/gadget/udc/core.c | 24 +++++++++++++++++++-----
 include/linux/usb/gadget.h    |  3 +++
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index 5241603bd008..5fea14cc9dbd 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -1112,12 +1112,26 @@ static inline void usb_gadget_udc_stop(struct usb_udc *udc)
 static inline void usb_gadget_udc_set_speed(struct usb_udc *udc,
 					    enum usb_device_speed speed)
 {
-	if (udc->gadget->ops->udc_set_speed) {
-		enum usb_device_speed s;
+	struct usb_gadget *gadget = udc->gadget;
+	enum usb_device_speed s;
 
-		s = min(speed, udc->gadget->max_speed);
-		udc->gadget->ops->udc_set_speed(udc->gadget, s);
-	}
+	if (speed == USB_SPEED_UNKNOWN)
+		s = gadget->max_speed;
+	else
+		s = min(speed, gadget->max_speed);
+
+	/*
+	 * If the UDC supports super-speed-plus and different sublink speeds,
+	 * then set the gadget to the max possible sublink speed for
+	 * super-speed-plus symmetric lanes.
+	 */
+	if (s == USB_SPEED_SUPER_PLUS &&
+	    gadget->ops->udc_set_num_lanes_and_speed)
+		gadget->ops->udc_set_num_lanes_and_speed(gadget,
+							 gadget->max_num_lanes,
+							 gadget->max_speed_ssid);
+	else if (gadget->ops->udc_set_speed)
+		gadget->ops->udc_set_speed(gadget, s);
 }
 
 /**
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 2ab929eed928..ec4ed17e7bf5 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -322,6 +322,9 @@ struct usb_gadget_ops {
 			struct usb_gadget_driver *);
 	int	(*udc_stop)(struct usb_gadget *);
 	void	(*udc_set_speed)(struct usb_gadget *, enum usb_device_speed);
+	void	(*udc_set_num_lanes_and_speed)(struct usb_gadget *,
+					       unsigned int num_lanes,
+					       unsigned int ssid);
 	struct usb_ep *(*match_ep)(struct usb_gadget *,
 			struct usb_endpoint_descriptor *,
 			struct usb_ss_ep_comp_descriptor *);
-- 
2.11.0





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