usb: xhci: move debug capabilities from trb_in_td() to handle_tx_event()

Function trb_in_td() currently includes debug capabilities that are
triggered when its debug argument is set to true. The only consumer of
these debug capabilities is handle_tx_event(), which calls trb_in_td()
twice, once for its primary functionality and a second time solely for
debugging purposes if the first call returns 'NULL'.

This approach is inefficient and can lead to confusion, as trb_in_td()
executes the same code with identical arguments twice, differing only in
the debug output during the second execution.

To enhance clarity and efficiency, move the debug capabilities out of
trb_in_td() and integrates them directly into handle_tx_event().
This change reduces the argument count of trb_in_td() and ensures that
debug steps are executed only when necessary, streamlining the function's
operation.

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20250306144954.3507700-12-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Epicurius

drivers/usb/host/xhci-ring.c

@@ -281,8 +281,7 @@ static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring,
  * If the suspect DMA address is a TRB in this TD, this function returns that
  * TRB's segment. Otherwise it returns 0.
  */
-static struct xhci_segment *trb_in_td(struct xhci_hcd *xhci, struct xhci_td *td,
-				      dma_addr_t suspect_dma, bool debug)
+static struct xhci_segment *trb_in_td(struct xhci_td *td, dma_addr_t suspect_dma)
 {
 	dma_addr_t start_dma;
 	dma_addr_t end_seg_dma;
@@ -301,15 +300,6 @@ static struct xhci_segment *trb_in_td(struct xhci_hcd *xhci, struct xhci_td *td,
 		/* If the end TRB isn't in this segment, this is set to 0 */
 		end_trb_dma = xhci_trb_virt_to_dma(cur_seg, td->end_trb);
 
-		if (debug)
-			xhci_warn(xhci,
-				"Looking for event-dma %016llx trb-start %016llx trb-end %016llx seg-start %016llx seg-end %016llx\n",
-				(unsigned long long)suspect_dma,
-				(unsigned long long)start_dma,
-				(unsigned long long)end_trb_dma,
-				(unsigned long long)cur_seg->dma,
-				(unsigned long long)end_seg_dma);
-
 		if (end_trb_dma > 0) {
 			/* The end TRB is in this segment, so suspect should be here */
 			if (start_dma <= end_trb_dma) {
@@ -1075,7 +1065,7 @@ static int xhci_invalidate_cancelled_tds(struct xhci_virt_ep *ep)
 					 td->urb->stream_id);
 		hw_deq &= ~0xf;
 
-		if (td->cancel_status == TD_HALTED || trb_in_td(xhci, td, hw_deq, false)) {
+		if (td->cancel_status == TD_HALTED || trb_in_td(td, hw_deq)) {
 			switch (td->cancel_status) {
 			case TD_CLEARED: /* TD is already no-op */
 			case TD_CLEARING_CACHE: /* set TR deq command already queued */
@@ -1165,7 +1155,7 @@ static struct xhci_td *find_halted_td(struct xhci_virt_ep *ep)
 		hw_deq = xhci_get_hw_deq(ep->xhci, ep->vdev, ep->ep_index, 0);
 		hw_deq &= ~0xf;
 		td = list_first_entry(&ep->ring->td_list, struct xhci_td, td_list);
-		if (trb_in_td(ep->xhci, td, hw_deq, false))
+		if (trb_in_td(td, hw_deq))
 			return td;
 	}
 	return NULL;
@@ -2800,7 +2790,7 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 	 */
 	td = list_first_entry_or_null(&ep_ring->td_list, struct xhci_td, td_list);
 
-	if (td && td->error_mid_td && !trb_in_td(xhci, td, ep_trb_dma, false)) {
+	if (td && td->error_mid_td && !trb_in_td(td, ep_trb_dma)) {
 		xhci_dbg(xhci, "Missing TD completion event after mid TD error\n");
 		xhci_dequeue_td(xhci, td, ep_ring, td->status);
 	}
@@ -2833,7 +2823,7 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 				      td_list);
 
 		/* Is this a TRB in the currently executing TD? */
-		ep_seg = trb_in_td(xhci, td, ep_trb_dma, false);
+		ep_seg = trb_in_td(td, ep_trb_dma);
 
 		if (!ep_seg) {
 
@@ -2893,12 +2883,7 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 			}
 
 			/* HC is busted, give up! */
-			xhci_err(xhci,
-				 "ERROR Transfer event TRB DMA ptr not part of current TD ep_index %d comp_code %u\n",
-				 ep_index, trb_comp_code);
-			trb_in_td(xhci, td, ep_trb_dma, true);
-
-			return -ESHUTDOWN;
+			goto debug_finding_td;
 		}
 
 		if (ep->skip) {
@@ -2955,6 +2940,17 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 
 	return 0;
 
+debug_finding_td:
+	xhci_err(xhci, "Event dma %pad for ep %d status %d not part of TD at %016llx - %016llx\n",
+		 &ep_trb_dma, ep_index, trb_comp_code,
+		 (unsigned long long)xhci_trb_virt_to_dma(td->start_seg, td->start_trb),
+		 (unsigned long long)xhci_trb_virt_to_dma(td->end_seg, td->end_trb));
+
+	xhci_for_each_ring_seg(ep_ring->first_seg, ep_seg)
+		xhci_warn(xhci, "Ring seg %u dma %pad\n", ep_seg->num, &ep_seg->dma);
+
+	return -ESHUTDOWN;
+
 err_out:
 	xhci_err(xhci, "@%016llx %08x %08x %08x %08x\n",
 		 (unsigned long long) xhci_trb_virt_to_dma(