xhci: rework command timeout and cancellation,

Use one timer to control command timeout.

start/kick the timer every time a command is completed and a
new command is waiting, or a new command is added to a empty list.

If the timer runs out, then tag the current command as "aborted", and
start the xhci command abortion process.

Previously each function that submitted a command had its own timer.
If that command timed out, a new command structure for the
command was created and it was put on a cancel_cmd_list list,
then a pci write to abort the command ring was issued.

when the ring was aborted, it checked if the current command
was the one to be canceled, later when the ring was stopped the
driver got ownership of the TRBs in the command ring,
compared then to the TRBs in the cancel_cmd_list,
and turned them into No-ops.

Now, instead, at timeout we tag the status of the command in the
command queue to be aborted, and start the ring abortion.
Ring abortion stops the command ring and gives control of the
commands to us.
All the aborted commands are now turned into No-ops.

If the ring is already stopped when the command times outs its not possible
to start the ring abortion, in this case the command is turnd to No-op
right away.

All these changes allows us to remove the entire cancel_cmd_list code.

The functions waiting for a command to finish no longer have their own timeouts.
They will wait either until the command completes normally,
or until the whole command abortion is done.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index fde57b09a9bd..2774526449a6 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1295,7 +1295,6 @@ struct xhci_td {
 
 /* command descriptor */
 struct xhci_cd {
-	struct list_head	cancel_cmd_list;
 	struct xhci_command	*command;
 	union xhci_trb		*cmd_trb;
 };
@@ -1480,9 +1479,10 @@ struct xhci_hcd {
 #define CMD_RING_STATE_RUNNING         (1 << 0)
 #define CMD_RING_STATE_ABORTED         (1 << 1)
 #define CMD_RING_STATE_STOPPED         (1 << 2)
-	struct list_head        cancel_cmd_list;
 	struct list_head        cmd_list;
 	unsigned int		cmd_ring_reserved_trbs;
+	struct timer_list	cmd_timer;
+	struct xhci_command	*current_cmd;
 	struct xhci_ring	*event_ring;
 	struct xhci_erst	erst;
 	/* Scratchpad */
@@ -1845,8 +1845,8 @@ void xhci_queue_config_ep_quirk(struct xhci_hcd *xhci,
 		unsigned int slot_id, unsigned int ep_index,
 		struct xhci_dequeue_state *deq_state);
 void xhci_stop_endpoint_command_watchdog(unsigned long arg);
-int xhci_cancel_cmd(struct xhci_hcd *xhci, struct xhci_command *command,
-		union xhci_trb *cmd_trb);
+void xhci_handle_command_timeout(unsigned long data);
+
 void xhci_ring_ep_doorbell(struct xhci_hcd *xhci, unsigned int slot_id,
 		unsigned int ep_index, unsigned int stream_id);
 void xhci_cleanup_command_queue(struct xhci_hcd *xhci);