[PATCH 1/4] usb: xhci: refactor trb_in_td() to be static

Niklas Neronin
2025-02-06T10:34:34Z

Relocate trb_in_td() and marks it as static, as it's exclusively utilized
in xhci-ring.c. This adjustment lays the groundwork for future rework of
the function.

The function's logic remains unchanged; only its access specifier is
altered to static and a redundant "else" is removed on line 325
(due to checkpatch.pl complaining).

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
---
drivers/usb/host/xhci-ring.c | 122 +++++++++++++++++------------------
drivers/usb/host/xhci.h | 2 -
2 files changed, 61 insertions(+), 63 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 965bffce301e..467a3abf8f53 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -277,6 +277,67 @@ 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)
+{
+ dma_addr_t start_dma;
+ dma_addr_t end_seg_dma;
+ dma_addr_t end_trb_dma;
+ struct xhci_segment *cur_seg;
+
+ start_dma = xhci_trb_virt_to_dma(td->start_seg, td->start_trb);
+ cur_seg = td->start_seg;
+
+ do {
+ if (start_dma == 0)
+ return NULL;
+ /* We may get an event for a Link TRB in the middle of a TD */
+ end_seg_dma = xhci_trb_virt_to_dma(cur_seg,
+ &cur_seg->trbs[TRBS_PER_SEGMENT - 1]);
+ /* 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) {
+ if (suspect_dma >= start_dma && suspect_dma <= end_trb_dma)
+ return cur_seg;
+ } else {
+ /* Case for one segment with
+ * a TD wrapped around to the top
+ */
+ if ((suspect_dma >= start_dma &&
+ suspect_dma <= end_seg_dma) ||
+ (suspect_dma >= cur_seg->dma &&
+ suspect_dma <= end_trb_dma))
+ return cur_seg;
+ }
+ return NULL;
+ }
+ /* Might still be somewhere in this segment */
+ if (suspect_dma >= start_dma && suspect_dma <= end_seg_dma)
+ return cur_seg;
+
+ cur_seg = cur_seg->next;
+ start_dma = xhci_trb_virt_to_dma(cur_seg, &cur_seg->trbs[0]);
+ } while (cur_seg != td->start_seg);
+
+ return NULL;
+}
+
/*
* Return number of free normal TRBs from enqueue to dequeue pointer on ring.
* Not counting an assumed link TRB at end of each TRBS_PER_SEGMENT sized segment.
@@ -2116,67 +2177,6 @@ static void handle_port_status(struct xhci_hcd *xhci, union xhci_trb *event)
spin_lock(&xhci->lock);
}

-/*
- * If the suspect DMA address is a TRB in this TD, this function returns that
- * TRB's segment. Otherwise it returns 0.
- */
-struct xhci_segment *trb_in_td(struct xhci_hcd *xhci, struct xhci_td *td, dma_addr_t suspect_dma,
- bool debug)
-{
- dma_addr_t start_dma;
- dma_addr_t end_seg_dma;
- dma_addr_t end_trb_dma;
- struct xhci_segment *cur_seg;
-
- start_dma = xhci_trb_virt_to_dma(td->start_seg, td->start_trb);
- cur_seg = td->start_seg;
-
- do {
- if (start_dma == 0)
- return NULL;
- /* We may get an event for a Link TRB in the middle of a TD */
- end_seg_dma = xhci_trb_virt_to_dma(cur_seg,
- &cur_seg->trbs[TRBS_PER_SEGMENT - 1]);
- /* 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) {
- if (suspect_dma >= start_dma && suspect_dma <= end_trb_dma)
- return cur_seg;
- } else {
- /* Case for one segment with
- * a TD wrapped around to the top
- */
- if ((suspect_dma >= start_dma &&
- suspect_dma <= end_seg_dma) ||
- (suspect_dma >= cur_seg->dma &&
- suspect_dma <= end_trb_dma))
- return cur_seg;
- }
- return NULL;
- } else {
- /* Might still be somewhere in this segment */
- if (suspect_dma >= start_dma && suspect_dma <= end_seg_dma)
- return cur_seg;
- }
- cur_seg = cur_seg->next;
- start_dma = xhci_trb_virt_to_dma(cur_seg, &cur_seg->trbs[0]);
- } while (cur_seg != td->start_seg);
-
- return NULL;
-}
-
static void xhci_clear_hub_tt_buffer(struct xhci_hcd *xhci, struct xhci_td *td,
struct xhci_virt_ep *ep)
{
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 8c164340a2c3..d66ad9bd7432 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1884,8 +1884,6 @@ int xhci_set_interrupter_moderation(struct xhci_interrupter *ir,

/* xHCI ring, segment, TRB, and TD functions */
dma_addr_t xhci_trb_virt_to_dma(struct xhci_segment *seg, union xhci_trb *trb);
-struct xhci_segment *trb_in_td(struct xhci_hcd *xhci, struct xhci_td *td,
- dma_addr_t suspect_dma, bool debug);
int xhci_is_vendor_info_code(struct xhci_hcd *xhci, unsigned int trb_comp_code);
void xhci_ring_cmd_db(struct xhci_hcd *xhci);
int xhci_queue_slot_control(struct xhci_hcd *xhci, struct xhci_command *cmd,
--
2.47.2