misleading sbdata0 description

[bcstrongx]

Just need a simple clarification here. In the description for sbdata0 I see this:

`Writes to this register start the following:

1. Set sbbusy.
2. Perform a bus write of the new value of sbdata to sbaddress.
3. If the write succeeded and sbautoincrement is set, increment sbaddress.
4. Clear sbbusy.`

Number 2 seems to suggest that the value in register sbdata is copied to register sbaddress. It should probably be more explicit that the value in sbdata is written to the address held in sbaddress. Immediately following the text above is a better explanation, see 3a:

`Reads from this register start the following:

1. "Return" the data.
2. Set sbbusy.
3. If sbreadondata is set:
   a. Perform a system bus read from the address contained in sbaddress, placing the result in
   sbdata.
   b. If sbautoincrement is set and the read was successful, increment sbaddress.
4. Clear sbbusy.`

[pdonahue-ventana]

The wording isn't great but I think that it's probably understood that "bus write ... to sbaddress" doesn't mean that sbaddress must have a memory-mapped address, that the DM must know what that address is, and that the DM must perform a write of that register via the system bus (rather than just doing it directly).

I'm OK with changing it to something like "Perform a system bus write to the address contained in sbaddress with the data that is being written to sbdata." If that causes any problems with respect to ratification schedule then I think that we should leave it alone.