usb: dwc3: gadget: Handle TRB index 0 when full or empty (361572b5) · Commits · 戴 / test

drivers/usb/dwc3/gadget.c

+22 −6

Original line number	Diff line number	Diff line
		@@ -842,6 +842,25 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
		trace_dwc3_prepare_trb(dep, trb);
		}

		/**
		* dwc3_ep_prev_trb() - Returns the previous TRB in the ring
		* @dep: The endpoint with the TRB ring
		* @index: The index of the current TRB in the ring
		*
		* Returns the TRB prior to the one pointed to by the index. If the
		* index is 0, we will wrap backwards, skip the link TRB, and return
		* the one just before that.
		*/
		static struct dwc3_trb dwc3_ep_prev_trb(struct dwc3_ep dep, u8 index)
		{
		if (!index)
		index = DWC3_TRB_NUM - 2;
		else
		index = dep->trb_enqueue - 1;

		return &dep->trb_pool[index];
		}

		static u32 dwc3_calc_trbs_left(struct dwc3_ep *dep)
		{
		struct dwc3_trb *tmp;
		@@ -855,12 +874,9 @@ static u32 dwc3_calc_trbs_left(struct dwc3_ep *dep)
		* more transfers in our ring.
		*/
		if (dep->trb_enqueue == dep->trb_dequeue) {
		/* If we're full, enqueue/dequeue are > 0 */
		if (dep->trb_enqueue) {
		tmp = &dep->trb_pool[dep->trb_enqueue - 1];
		tmp = dwc3_ep_prev_trb(dep, dep->trb_enqueue);
		if (tmp->ctrl & DWC3_TRB_CTRL_HWO)
		return 0;
		}

		return DWC3_TRB_NUM - 1;
		}