[PATCH 11/15] usb: xhci: move debug capabilities from trb_in_td() to handle_tx_event()

Mathias Nyman
2025-03-06T14:49:44Z

From: Niklas Neronin <niklas.neronin@linux.intel.com>

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>
---
drivers/usb/host/xhci-ring.c | 38 ++++++++++++++++--------------------
1 file changed, 17 insertions(+), 21 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 8c7258afb6bf..c2e15a27338b 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/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(
--
2.43.0