ioat(4): Export the number of available channels

Sponsored by:	EMC / Isilon Storage Division

sys/dev/ioat/ioat.c

@@ -742,6 +742,13 @@ ioat_reset_hw_task(void *ctx, int pending __unused)
 /*
  * User API functions
  */
+unsigned
+ioat_get_nchannels(void)
+{
+
+	return (ioat_channel_index);
+}
+
 bus_dmaengine_t
 ioat_get_dmaengine(uint32_t index, int flags)
 {

sys/dev/ioat/ioat.h

@@ -85,6 +85,8 @@ typedef void *bus_dmaengine_t;
 struct bus_dmadesc;
 typedef void (*bus_dmaengine_callback_t)(void *arg, int error);
 
+unsigned ioat_get_nchannels(void);
+
 /*
  * Called first to acquire a reference to the DMA channel
  *