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https://github.com/brain-hackers/u-boot-brain
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On all Pis so far, the VC FW provides a short stub to set up the ARM CPU
before entering the kernel (a/k/a U-Boot for us). This feature is not
currently supported by the VC FW when booting in 64-bit mode. However,
this feature will likely appear in the near future, and this U-Boot port
assumes that such a feature is in place. Without that feature, or a
temporary workaround described below, U-Boot will not boot.
Once the VC FW does provide the ARM stub, u-boot.bin built for rpi_3 can
be used drectly as kernel7.img, in the same way as any other RPi port. The
following config.txt is required:
# Fix mini UART input frequency, and setup/enable up the UART.
# Without this option, U-Boot will not boot, even if you don't care
# about the serial console. This option will always be required for
# all RPi3 use-cases, unless the PL011 UART is used, which is not
# yet supported by rpi_3* builds of U-Boot.
enable_uart=1
# Boot in AArch64 (64-bit) mode.
# It is possible that a future VC FW will remove the need for this
# option, instead auto-setting 32-/64-bit mode based on the "kernel"
# filename present on the SD card.
arm_control=0x200
Prior to the VC FW providing the ARM boot stub, you can use the following
steps to build an equivalent stub into the U-Boot binary:
git clone https://github.com/swarren/rpi-3-aarch64-demo.git \
../rpi-3-aarch64-demo
(cd ../rpi-3-aarch64-demo && ./build.sh)
Build U-Boot for rpi_3 in the usual way
cat ../rpi-3-aarch64-demo/armstub64.bin u-boot.bin > u-boot.bin.stubbed
Use u-boot.bin.stubbed as kernel7.img on the Pi SD card.
In this case, the following additional entries are required in config.txt:
# Tell the FW to load the kernel image at address 0, the reset vector.
kernel_old=1
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
99 lines
2.7 KiB
Plaintext
99 lines
2.7 KiB
Plaintext
config BCM2835
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bool "Broadcom BCM2835 SoC support"
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depends on ARCH_BCM283X
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config BCM2836
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bool "Broadcom BCM2836 SoC support"
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depends on ARCH_BCM283X
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config BCM2837
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bool "Broadcom BCM2837 SoC support"
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depends on ARCH_BCM283X
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menu "Broadcom BCM283X family"
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depends on ARCH_BCM283X
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choice
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prompt "Broadcom BCM283X board select"
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optional
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config TARGET_RPI
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bool "Raspberry Pi (all BCM2835 variants)"
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help
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Support for all ARM1176-/BCM2835-based Raspberry Pi variants, such as
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the A, A+, B, B+, Compute Module, and Zero. This option cannot
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support BCM2836/BCM2837-based Raspberry Pis such as the RPi 2 and
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RPi 3 due to different peripheral address maps.
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This option creates a build targetting the ARM1176 ISA.
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select BCM2835
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select CPU_ARM1176
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config TARGET_RPI_2
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bool "Raspberry Pi 2"
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help
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Support for all BCM2836-based Raspberry Pi variants, such as
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the RPi 2 model B.
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This option also supports BCM2837-based variants such as the RPi 3
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Model B, when run in 32-bit mode, provided you have configured the
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VideoCore firmware to select the PL011 UART for the console by:
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a) config.txt should contain dtoverlay=pi3-miniuart-bt.
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b) You should run the following to tell the VC FW to process DT when
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booting, and copy u-boot.bin.img (rather than u-boot.bin) to the SD
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card as the kernel image:
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path/to/kernel/scripts/mkknlimg --dtok u-boot.bin u-boot.bin.img
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This works as of firmware.git commit 046effa13ebc "firmware:
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arm_loader: emmc clock depends on core clock See:
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https://github.com/raspberrypi/firmware/issues/572".
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This option creates a build targetting the ARMv7/AArch32 ISA.
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select ARMV7_LPAE
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select BCM2836
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select CPU_V7
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config TARGET_RPI_3_32B
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bool "Raspberry Pi 3 32-bit build"
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help
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Support for all BCM2837-based Raspberry Pi variants, such as
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the RPi 3 model B, in AArch32 (32-bit) mode.
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This option assumes the VideoCore firmware is configured to use the
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mini UART (rather than PL011) for the serial console. This is the
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default on the RPi 3. To enable the UART console, the following non-
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default option must be present in config.txt: enable_uart=1.
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This option creates a build targetting the ARMv7/AArch32 ISA.
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select ARMV7_LPAE
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select BCM2837
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select CPU_V7
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config TARGET_RPI_3
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bool "Raspberry Pi 3 64-bit build"
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select ARM64
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select BCM2837
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endchoice
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config SYS_BOARD
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default "rpi" if TARGET_RPI
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default "rpi_2" if TARGET_RPI_2
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default "rpi_3_32b" if TARGET_RPI_3_32B
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default "rpi_3" if TARGET_RPI_3
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config SYS_VENDOR
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default "raspberrypi"
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config SYS_SOC
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default "bcm283x"
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config SYS_CONFIG_NAME
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default "rpi" if TARGET_RPI
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default "rpi_2" if TARGET_RPI_2
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default "rpi_3_32b" if TARGET_RPI_3_32B
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default "rpi_3" if TARGET_RPI_3
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endmenu
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