xHCI: add aborting command ring function

Software have to abort command ring and cancel command
when a command is failed or hang. Otherwise, the command
ring will hang up and can't handle the others. An example
of a command that may hang is the Address Device Command,
because waiting for a SET_ADDRESS request to be acknowledged
by a USB device is outside of the xHC's ability to control.

To cancel a command, software will initialize a command
descriptor for the cancel command, and add it into a
cancel_cmd_list of xhci.

Sarah: Fixed missing newline on "Have the command ring been stopped?"
debugging statement.

This patch should be backported to kernels as old as 3.0, that contain
the commit 7ed603ecf8b68ab81f4c83097d3063d43ec73bb8 "xhci: Add an
assertion to check for virt_dev=0 bug." That commit papers over a NULL
pointer dereference, and this patch fixes the underlying issue that
caused the NULL pointer dereference.

Signed-off-by: Elric Fu <elricfu1@gmail.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Tested-by: Miroslav Sabljic <miroslav.sabljic@avl.com>
Cc: stable@vger.kernel.org

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 33f24e9fa766..fdfcebf342e8 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1256,6 +1256,13 @@ struct xhci_td {
         union xhci_trb          *last_trb;
 };
 
+/* command descriptor */
+struct xhci_cd {
+        struct list_head        cancel_cmd_list;
+        struct xhci_command     *command;
+        union xhci_trb          *cmd_trb;
+};
+
 struct xhci_dequeue_state {
         struct xhci_segment *new_deq_seg;
         union xhci_trb *new_deq_ptr;
@@ -1425,6 +1432,7 @@ 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;
         unsigned int            cmd_ring_reserved_trbs;
         struct xhci_ring        *event_ring;
         struct xhci_erst        erst;
@@ -1702,6 +1710,8 @@ static inline void xhci_unregister_plat(void)
 
 /* xHCI host controller glue */
 typedef void (*xhci_get_quirks_t)(struct device *, struct xhci_hcd *);
+int handshake(struct xhci_hcd *xhci, void __iomem *ptr,
+                u32 mask, u32 done, int usec);
 void xhci_quiesce(struct xhci_hcd *xhci);
 int xhci_halt(struct xhci_hcd *xhci);
 int xhci_reset(struct xhci_hcd *xhci);
@@ -1792,6 +1802,8 @@ 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_ring_ep_doorbell(struct xhci_hcd *xhci, unsigned int slot_id,
                 unsigned int ep_index, unsigned int stream_id);