123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132 |
- // -*- mode:doc; -*-
- // vim: set syntax=asciidoc:
- [[adding-boards]]
- Adding new embedded boards to OpenADK
- -------------------------------------
- This section covers how support for new embedded boards
- can be integrated into OpenADK.
- First step is to create a board description file in
- target/<arch>/systems with the short name of your embedded board.
- For example you would create following file for Raspberry PI 2 support:
- target/arm/systems/raspberry-pi2
- ---------------------
- config ADK_TARGET_SYSTEM_RASPBERRY_PI2
- bool "Raspberry PI 2"
- select ADK_CPU_CORTEX_A7
- select ADK_TARGET_LITTLE_ENDIAN
- select ADK_TARGET_CPU_WITH_NEON
- select ADK_TARGET_BOARD_BCM28XX
- select ADK_TARGET_WITH_VGA
- select ADK_TARGET_WITH_SERIAL
- select ADK_TARGET_WITH_CPU_FREQ
- select ADK_TARGET_WITH_USB
- select ADK_TARGET_WITH_INPUT
- select ADK_TARGET_WITH_SD
- select ADK_TARGET_WITH_I2C
- select ADK_TARGET_WITH_SPI
- select ADK_TARGET_WITH_SMP
- select ADK_PACKAGE_BCM28XX_BOOTLOADER
- select ADK_TARGET_WITH_ROOT_RW
- select ADK_TARGET_KERNEL_ZIMAGE
- help
- Raspberry PI 2
- ------------------------
- You need to select as a minimum a CPU type and Kernel format.
- If a bootloader is required you also need to select it.
- (ADK_PACKAGE_BCM28XX_BOOTLOADER) If the bootloader does not exist as a package
- in OpenADK, you need to port it first.
- The hardware capabilities are optional. (f.e. ADK_TARGET_WITH_SD), but
- required when you configure the driver configuration later.
- For architectures with a choice for endianess you should select either
- ADK_TARGET_LITTLE_ENDIAN or ADK_TARGET_BIG_ENDIAN.
- If the CPU type like in this example ADK_CPU_CORTEX_A7 is not yet available
- you need to add it to target/config/Config.in.cpu. For optimized code generation
- you should also add ADK_TARGET_GCC_CPU or ADK_TARGET_GCC_ARCH symbol for your CPU
- type. Furthermore you need to decide if your CPU has a MMU, FPU and NPTL support
- in the C library.
- After the creation of the file you can go into the menu based system and
- select your embedded board.
- The second step is to create a Kernel configuration file fragment, which contains
- only the basic support for your board to get serial console access.
- For example the snippet for Raspberry PI 2, the file name must match the embedded board
- name:
- target/arm/kernel/raspberry-pi2
- ------------------------
- CONFIG_ARM=y
- CONFIG_ARCH_BCM2709=y
- CONFIG_BCM2709_DT=y
- CONFIG_PHYS_OFFSET=0
- CONFIG_HAVE_ARM_ARCH_TIMER=y
- CONFIG_FIQ=y
- CONFIG_ATAGS=y
- CONFIG_KUSER_HELPERS=y
- CONFIG_ARM_ERRATA_643719=y
- CONFIG_BCM2708_NOL2CACHE=y
- CONFIG_RASPBERRYPI_FIRMWARE=y
- CONFIG_BRCM_CHAR_DRIVERS=y
- CONFIG_BCM2708_VCHIQ=y
- CONFIG_BCM2708_VCMEM=y
- CONFIG_MAILBOX=y
- CONFIG_BCM2835_MBOX=y
- CONFIG_OF=y
- CONFIG_OF_OVERLAY=y
- CONFIG_CMDLINE_FROM_BOOTLOADER=y
- ------------------------
- If the mainstream kernel from kernel.org does not contain support for your board
- you need to get a working kernel tree and create a patch.
- For example for Raspberry PI 2 we basically use following method to create a patch:
- ------------------------
- git clone https://github.com/raspberrypi/linux.git linux-rpi
- wget https://www.kernel.org/pub/linux/kernel/v3.x/linux-3.18.9.tar.xz
- tar xvf linux-3.18.9.tar.xz
- find linux-3.18.9 linux-rpi -type l -delete
- rm -rf linux-rpi/.git
- diff -Nur linux-3.18.9 linux-rpi > target/arm/bcm28xx/patches/3.18.9/0001-bcm28xx-github.patch
- ------------------------
- Normally you use target/<arch>/<target system>/patches/<kernelversion>/0001-<target-system>.patch.
- In case of Raspberry PI 2 we have a single patch for Raspberry PI and Raspberry PI 2 and use
- the extra board name bcm28xx to describe the family of devices.
- After that you can build the toolchain, kernel and base system and write the resulting
- firmware from firmware/<target system>/ to your device or boot via netboot and NFS.
- If you have some special notes for your embedded board, please add some advise to
- target/<arch>/Makefile. You can add information for the different rootfilesystem types.
- If your system boots up fine to a shell, you can add the driver configuration.
- For example if you add SD card driver support to Raspberry PI 2 you
- would add following to target/linux/config/Config.in.block
- ------------------------
- config ADK_KERNEL_MMC_BCM2835
- bool "SD card support for BCM2835 boards"
- select ADK_KERNEL_SCSI
- select ADK_KERNEL_MMC
- select ADK_KERNEL_MMC_BLOCK
- select ADK_KERNEL_BLK_DEV
- select ADK_KERNEL_BLK_DEV_SD
- select ADK_KERNEL_MMC_SDHCI
- select ADK_KERNEL_MMC_SDHCI_PLTFM
- select ADK_KERNEL_MMC_BCM2835_DMA
- depends on ADK_TARGET_BOARD_BCM28XX
- default y if ADK_TARGET_BOARD_BCM28XX
- default n
- ------------------------
- We use the symbol prefix ADK_KERNEL instead of CONFIG. Otherwise the symbols are
- matching the kernel symbol names.
- Get again into the menu based system, enable the driver you added and recompile.
- If your driver is available as a kernel module use tristate.
|