usb: ci_udc: don't assume QTDs are adjacent when transmitting ZLPs
Fix ci_ep_submit_next_request()'s ZLP transmission code to explicitly
call ci_get_qtd() to find the address of the other QTD to use. This
will allow us to correctly align each QTD individually in the future,
which may involve leaving a gap between the QTDs.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
diff --git a/drivers/usb/gadget/ci_udc.c b/drivers/usb/gadget/ci_udc.c
index 8ba6048..4115cd5 100644
--- a/drivers/usb/gadget/ci_udc.c
+++ b/drivers/usb/gadget/ci_udc.c
@@ -404,10 +404,11 @@
* only 1 is used at a time since either an IN or an OUT but
* not both is queued. For an IN transaction, item currently
* points at the second of these items, so we know that we
- * can use (item - 1) to transmit the extra zero-length packet
+ * can use the other to transmit the extra zero-length packet.
*/
- item->next = (unsigned)(item - 1);
- item--;
+ struct ept_queue_item *other_item = ci_get_qtd(num, 0);
+ item->next = (unsigned)other_item;
+ item = other_item;
item->info = INFO_ACTIVE;
}