The firmware running on the bcm2835 SoC's VideoCore CPU determines how
much of the system RAM is available for use by the ARM CPU. Previously,
U-Boot assumed that only 128MB was available, since this was the
smallest value configured by any public firmware. However, we can now
query the actual value at run-time from the firmware using the mbox
property protocol.
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
The Raspberry Pi model B uses the BCM2835 SoC, has 256MB of RAM,
contains an SMSC 9512 USB LAN/Hub chip, and various IO connectors.
For more details, see http://www.raspberrypi.org/.
Various portions (cache enable, MACH_TYPE setup, RAM size limit, stack
relocation to top of RAM) extracted from work by:
Oleksandr Tymoshenko <gonzo@bluezbox.com>.
GPIO driver enablement by Vikram Narayanan <vikram186@gmail.com>.
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Tom Rini <trini@ti.com>
