ARM: rpi_b: detect board revision

Detect the board revision early during boot, and print the decoded
model name.

Eventually, this information can be used for tasks such as:
- Allowing/preventing USB device mode; some models have a USB device on-
  board so only host mode makes sense. Others connect the SoC directly
  to the USB connector, so device-mode might make sense.
- The on-board USB hub/Ethernet requires different GPIOs to enable it,
  although luckily the default appears to be fine so far.
- The compute module contains an on-board eMMC device, so we could store
  the environment there. Other models use an SD card and so don't support
  saving the environment (unless we store it in a file on the FAT boot
  partition...)

Set $fdtfile based on this information. At present, the mainline Linux
kernel doesn't contain a separate DTB for most models, but I hope that
will change soon.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

1 files changed, 0 insertions, 1 deletions

diff --git a/include/configs/rpi_b.h b/include/configs/rpi_b.h
index 41e975f..4874c51 100644
--- a/include/configs/rpi_b.h
+++ b/include/configs/rpi_b.h
@@ -175,7 +175,6 @@
 	"pxefile_addr_r=0x00100000\0" \
 	"kernel_addr_r=0x01000000\0" \
 	"fdt_addr_r=0x02000000\0" \
-	"fdtfile=bcm2835-rpi-b.dtb\0" \
 	"ramdisk_addr_r=0x02100000\0" \
 
 #define BOOT_TARGET_DEVICES(func) \