usb: dwc3: gadget: Report isoc transfer frame number

Implement the new frame_number API to report the isochronous interval
frame number. This patch checks and reports the interval in which the
isoc transfer was transmitted or received via the Isoc-First TRB SOF
number field.
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/core.h

@@ -784,6 +784,7 @@ enum dwc3_link_state {
 #define DWC3_TRB_CTRL_ISP_IMI		BIT(10)
 #define DWC3_TRB_CTRL_IOC		BIT(11)
 #define DWC3_TRB_CTRL_SID_SOFN(n)	(((n) & 0xffff) << 14)
+#define DWC3_TRB_CTRL_GET_SID_SOFN(n)	(((n) & (0xffff << 14)) >> 14)
 
 #define DWC3_TRBCTL_TYPE(n)		((n) & (0x3f << 4))
 #define DWC3_TRBCTL_NORMAL		DWC3_TRB_CTRL_TRBCTL(1)

drivers/usb/dwc3/gadget.c

@@ -2339,6 +2339,19 @@ static int dwc3_gadget_ep_reclaim_completed_trb(struct dwc3_ep *dep,
 	if (chain && (trb->ctrl & DWC3_TRB_CTRL_HWO))
 		trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
 
+	/*
+	 * For isochronous transfers, the first TRB in a service interval must
+	 * have the Isoc-First type. Track and report its interval frame number.
+	 */
+	if (usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
+	    (trb->ctrl & DWC3_TRBCTL_ISOCHRONOUS_FIRST)) {
+		unsigned int frame_number;
+
+		frame_number = DWC3_TRB_CTRL_GET_SID_SOFN(trb->ctrl);
+		frame_number &= ~(dep->interval - 1);
+		req->request.frame_number = frame_number;
+	}
+
 	/*
 	 * If we're dealing with unaligned size OUT transfer, we will be left
 	 * with one TRB pending in the ring. We need to manually clear HWO bit