L3 Bus Driver
-------------

The structure of the driver is as follows:

	+----------+	+----------+	+----------+
	| client 1 |	| client 2 |	| client 3 |
	+-----^----+	+----^-----+	+----^-----+
	      |		     |               |
	+-----v--------------v---------------v-----+
	|                                          |
	+-----^-------+              +-------^-----+
	      |	      |     core     |       |
	+-----v----+  |	             |  +----v-----+
	| device   |  |	             |  | device   |
	| driver 1 |  |              |	| driver 2 |
	+-----^----+  |              |  +----^-----+
	      |	      |	  services   |       |
	+-----v-------+              +-------v-----+
	|                                          |
	+-----------------^----^-------------------+
			  |    |
			  |  +-v---------+
			  |  | algorithm |
			  |  |  driver   |
			  |  +-v---------+
			  |    |
			+-v----v-+
			|  bus   |
			| driver |
			+--------+

Clients talk to the core to attach device drivers and bus adapters, and
to instruct device drivers to perform actions.  Device drivers then talk
to the core to perform L3 bus transactions via the algorithm driver and
ultimately bus driver.