[PATCH 4/4] ARM: configs: rpi: add and document single barebox-dt-2nd bootloader

[Ahmad Fatoum]

With recent rework, we can install barebox along with all supported
Raspberry Pi device trees to the boot partition and let the VideoCore
take core of passing the correct device tree to barebox. Enable the
relevant option in config and document this briefly.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 Documentation/boards/bcm2835.rst | 6 ++++++
 arch/arm/configs/rpi_defconfig   | 1 +
 2 files changed, 7 insertions(+)

diff --git a/Documentation/boards/bcm2835.rst b/Documentation/boards/bcm2835.rst
index 8af6a09c13db..0b5299a34078 100644
--- a/Documentation/boards/bcm2835.rst
+++ b/Documentation/boards/bcm2835.rst
@@ -14,10 +14,16 @@ Raspberry Pi
      - ``images/barebox-raspberry-pi-1.img`` for the BCM2835/ARM1176JZF-S (Raspberry Pi 1, Raspberry Pi Zero)
      - ``images/barebox-raspberry-pi-2.img`` for the BCM2836/CORTEX-A7 (Raspberry Pi 2)
      - ``images/barebox-raspberry-pi-3.img`` for the BCM2837/CORTEX-A53 (Raspberry Pi 3)
+     - ``images/barebox-raspberry-pi-cm3.img`` for the BCM2837/CORTEX-A53 (Raspberry Pi CM3)
 
      Copy the respective image for your model to your SD card and name it
      ``barebox.img``.
 
+     Alternatively, ``images/barebox-dt-2nd.img`` can be used as single bootloader for all
+     supported 32-bit boards. In this case the device tree supplied by the video core
+     is directly used by barebox to probe. The device trees in ``arch/arm/dts/*.dtb``
+     will need to be renamed for alignment with the naming scheme expected by the videocore.
+
   4. Create a text file ``config.txt`` on the SD card with the following content::
 
          kernel=barebox.img
diff --git a/arch/arm/configs/rpi_defconfig b/arch/arm/configs/rpi_defconfig
index b823a9a3d09b..e0e1497481dc 100644
--- a/arch/arm/configs/rpi_defconfig
+++ b/arch/arm/configs/rpi_defconfig
@@ -3,6 +3,7 @@ CONFIG_MACH_RPI=y
 CONFIG_MACH_RPI2=y
 CONFIG_MACH_RPI3=y
 CONFIG_MACH_RPI_CM3=y
+CONFIG_BOARD_ARM_GENERIC_DT=y
 CONFIG_AEABI=y
 CONFIG_ARM_OPTIMZED_STRING_FUNCTIONS=y
 CONFIG_ARM_UNWIND=y
-- 
2.30.2