Q: resource range for SBus oddity

[Marcel Moolenaar]

Gang,

I'm playing with uart(4) on Jake's u2, which has 2 zs(4) devices
attached to sbus.

A GENERIC kernel gives me the following:
	:
zs0: <Zilog Z8530> mem 0x1100000-0x1100003 irq 2024 on sbus0
zstty0: <ttya> on zs0
zstty0: console 9600,8,n,1,-
zstty1: <ttyb> on zs0
sbus0: <zs>, type serial (no driver attached)
	:

A kernel with uart(4) yields currently (it's a WIP):
	:
puc0: <Zilog Z8530 dual channel SCC> mem 0x1100000-0x1100003 irq 2024 on sbus0
uart0: <Zilog Z8530 dual channel SCC> on puc0
uart0: console
uart1: <Zilog Z8530 dual channel SCC> on puc0
puc1: <Zilog Z8530 dual channel SCC> mem 0x1000000-0x1000003 irq 2024 on sbus0
uart2: <Zilog Z8530 dual channel SCC> on puc1
uart3: <Zilog Z8530 dual channel SCC> on puc1
	:

As you can see, the memory I/O resource is 4 bytes wide. However,
the channel A registers on the z8530 chip are at offsets 4
(control) and 6 (data). This lies outside the reserved range.

I would think that with 2 channels and 2 addressable registers
per channel we would be using offsets 0-3.

Question: Is there an implied multiplication or division factor?

-- 
 Marcel Moolenaar	  USPA: A-39004		 marcel at xcllnt.net