xHCI: count free TRBs on transfer ring
In the past, the room_on_ring() check was implemented by walking all over
the ring, which is wasteful and complicated.
Count the number of free TRBs instead. The free TRBs number should be
updated when enqueue/dequeue pointer is updated, or upon the completion
of a set dequeue pointer command.
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Tested-by: Paul Zimmerman <Paul.Zimmerman@synopsys.com>
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 2337a8e..ea8fc23 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1278,6 +1278,8 @@
u32 cycle_state;
unsigned int stream_id;
unsigned int num_segs;
+ unsigned int num_trbs_free;
+ unsigned int num_trbs_free_temp;
enum xhci_ring_type type;
bool last_td_was_short;
};