On Wed, Nov 18, 2015 at 10:16 AM, Andrew Baumann <andrew.baum...@microsoft.com> wrote: > Hi Peter, > > Thanks for your feedback! > > From: Peter Crosthwaite [mailto:crosthwaitepe...@gmail.com] > Sent: Tuesday, 17 November 2015 23:51 >> I haven't looked beyond the diffstat yet, but a top level >> architectural comment, I only see the one file in hw/arm. We are >> promoting the split of board and SoC now as two separate objects. Each >> of the patch series linked above demonstrates this. The BCM SoC would >> be an object in its own right, then the board instantiates the SoC as >> a composite device. > > I understand the rationale here, but is there much value pursuing this for > the Pi? As far as I know, the Pi1/2 SOCs (bcm2835 and 2836) are one-off > designs used only in the Pi. Moreover, the 2836 is basically a copy of the > 2835 with the addition of a new block for a multi-core interrupt controller > and mailboxes, so trying to split those out into two separate SOC definition > files would require either lots of duplication, or a tight coupling between > the two. Finally, there is basically nothing on the board besides the SoC and > RAM (just a USB-Ethernet adapter), so the actual board definition files would > be almost empty. As it is, I've already factored out all the common devices > within hw/arm/raspi.c -- my feeling is that this is a cleaner way to do it > for the Pi. >
So I am looking at some recent news, and there is the RPi Zero which reuses the bcm2835 as a different board. Can't find the schematic yet, but from what I can see, this is a raw SoC (no USB ethernet). With your SoC/board split we should be able pickup the Zero board quite cheaply as follow up work. Regards, Peter >> It is big. Work of this magnitude is generally better managed as >> multiple series (each of multiple patches). A general approach with >> new ARM boards is the first series is the bare minimum needed to get a
