[PATCH v4] usb: gadget: f_uvc: add super speed plus transfer support

[Jing Leng <jleng@ambarella.com>]

UVC driver doesn't set ssp_descriptors in struct usb_function,
it doesn't support USB_SPEED_SUPER_PLUS transfer. So we can
refer to USB_SPEED_SUPER to realize the support of
USB_SPEED_SUPER_PLUS.

If users use a USB device controller that speed can be up to
USB_SPEED_SUPER_PLUS (10 Gbps), downgrading to USB_SPEED_SUPER
(5 Gbps) is not a good performance. In addition, it triggers a
warning "configfs-gadget gadget: uvc doesn't hold the descriptors
for current speed".

Signed-off-by: Jing Leng <jleng@ambarella.com>
---
ChangeLog v3->v4:
- Rebase the patch.
- Make email addresses ('From' and 'Signed-off-by') consistent.
ChangeLog v2->v3:
- Modify the title and description of the PATCH
- It is a feature but not a bug
ChangeLog v1->v2:
- Update more detailed description of the PATCH
---
 drivers/usb/gadget/function/f_uvc.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 6e196e06181e..6ffaf594be9d 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -482,6 +482,7 @@ uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed)
 	void *mem;
 
 	switch (speed) {
+	case USB_SPEED_SUPER_PLUS:
 	case USB_SPEED_SUPER:
 		uvc_control_desc = uvc->desc.ss_control;
 		uvc_streaming_cls = uvc->desc.ss_streaming;
@@ -526,7 +527,7 @@ uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed)
 	      + uvc_control_ep.bLength + uvc_control_cs_ep.bLength
 	      + uvc_streaming_intf_alt0.bLength;
 
-	if (speed == USB_SPEED_SUPER) {
+	if (speed == USB_SPEED_SUPER || speed == USB_SPEED_SUPER_PLUS) {
 		bytes += uvc_ss_control_comp.bLength;
 		n_desc = 6;
 	} else {
@@ -570,7 +571,7 @@ uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed)
 	uvc_control_header->baInterfaceNr[0] = uvc->streaming_intf;
 
 	UVC_COPY_DESCRIPTOR(mem, dst, &uvc_control_ep);
-	if (speed == USB_SPEED_SUPER)
+	if (speed == USB_SPEED_SUPER || speed == USB_SPEED_SUPER_PLUS)
 		UVC_COPY_DESCRIPTOR(mem, dst, &uvc_ss_control_comp);
 
 	UVC_COPY_DESCRIPTOR(mem, dst, &uvc_control_cs_ep);
@@ -733,6 +734,15 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 		}
 	}
 
+	if (gadget_is_superspeed_plus(c->cdev->gadget)) {
+		f->ssp_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_SUPER_PLUS);
+		if (IS_ERR(f->ssp_descriptors)) {
+			ret = PTR_ERR(f->ssp_descriptors);
+			f->ssp_descriptors = NULL;
+			goto error;
+		}
+	}
+
 	/* Preallocate control endpoint request. */
 	uvc->control_req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
 	uvc->control_buf = kmalloc(UVC_MAX_REQUEST_SIZE, GFP_KERNEL);
-- 
2.17.1


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