usb: host: xhci: extract xhci_slot_state_string()

By extracting and exposing xhci_slot_state_string() in a header file, we
can re-use it to print Slot Context State from our tracepoints, which
can aid in tracking down problems related to command execution.

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

drivers/usb/host/xhci-dbg.c

@@ -451,19 +451,9 @@ char *xhci_get_slot_state(struct xhci_hcd *xhci,
 		struct xhci_container_ctx *ctx)
 {
 	struct xhci_slot_ctx *slot_ctx = xhci_get_slot_ctx(xhci, ctx);
+	int state = GET_SLOT_STATE(le32_to_cpu(slot_ctx->dev_state));
 
-	switch (GET_SLOT_STATE(le32_to_cpu(slot_ctx->dev_state))) {
-	case SLOT_STATE_ENABLED:
-		return "enabled/disabled";
-	case SLOT_STATE_DEFAULT:
-		return "default";
-	case SLOT_STATE_ADDRESSED:
-		return "addressed";
-	case SLOT_STATE_CONFIGURED:
-		return "configured";
-	default:
-		return "reserved";
-	}
+	return xhci_slot_state_string(state);
 }
 
 static void xhci_dbg_slot_ctx(struct xhci_hcd *xhci, struct xhci_container_ctx *ctx)

drivers/usb/host/xhci.h

@@ -2158,6 +2158,22 @@ static inline struct xhci_ring *xhci_urb_to_transfer_ring(struct xhci_hcd *xhci,
 					urb->stream_id);
 }
 
+static inline char *xhci_slot_state_string(u32 state)
+{
+	switch (state) {
+	case SLOT_STATE_ENABLED:
+		return "enabled/disabled";
+	case SLOT_STATE_DEFAULT:
+		return "default";
+	case SLOT_STATE_ADDRESSED:
+		return "addressed";
+	case SLOT_STATE_CONFIGURED:
+		return "configured";
+	default:
+		return "reserved";
+	}
+}
+
 static inline const char *xhci_decode_trb(u32 field0, u32 field1, u32 field2,
 		u32 field3)
 {