--- user/bsps/bsps-arm.rst | 69 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 68 insertions(+), 1 deletion(-)
diff --git a/user/bsps/bsps-arm.rst b/user/bsps/bsps-arm.rst index eb972c6..e6826cd 100644 --- a/user/bsps/bsps-arm.rst +++ b/user/bsps/bsps-arm.rst @@ -93,7 +93,74 @@ TODO. beagle ====== -TODO. +This BSP supports four variants, `beagleboardorig`, `beagleboardxm`, `beaglebonewhite` +and `beagleboneblack`. The basic hardware initialization is not performed by +the BSP. A boot loader with device tree support must be used to start the BSP, +e.g. U-Boot. + +TODO(These drivers are present but not documented yet): +* Clock driver. +* Network Interface Driver. +* SDcard driver. +* GPIO Driver. +* Console driver. +* PWM Driver. +* RTC driver. + +Boot via U-Boot +--------------- +To boot via uboot, the ELF must be converted to a U-Boot image like below: + +.. code-block:: none + arm-rtems5-objcopy hello.exe -O app.bin + gzip 9 app.bin + mkimage -A arm -O linux -T kernel -a 0x80000000 -e 0x80000000 -n RTEMS -d app.bin.gz rtems-app.img + +Getting the Device Tree Blob +---------------------------- + +The Device Tree Blob(dtb) is needed to load the device tree while starting up +the kernel. Currently the dtb is built using the linux `device-tree-rebasing +<https://git.kernel.org/pub/scm/linux/kernel/git/devicetree/devicetree-rebasing.git/tree/>`_ +repository. + +Writing the uEnv.txt file +------------------------- + +The uEnv.txt file is needed to set any environment variable before the kernel is +loaded. Each line is a u-boot command that the uboot will execute during +starting up. + +Add the following to a file named uEnv.txt: + +.. code-block:: none + setenv bootdelay 5 + uenvcmd=run boot + boot=fatload mmc 0 0x80800000 rtems-app.img ; fatload mmc 0 0x88000000 am335x-boneblack.dtb ; bootm 0x80800000 - 0x88000000 + +I2C Driver +---------- + +This BSP uses the I2C framework and is registered using +``am335x_i2c_bus_register()`` the function prototype is given below: + +.. code-block:: C + int am335x_i2c_bus_register( + const char *bus_path, + uintptr_t register_base, + uint32_t input_clock, + rtems_vector_number irq + ); + +This function is needed only while registering with custom path with custom +values. For registering the `/dev/i2c-0` device, a wrapper function is provided, +``bbb_register_i2c_0()`` similarly ``bbb_register_i2c_1()`` and +``bbb_register_i2c_2()`` are respectively used to register `i2c-1` and `i2c-2`. + +SPI Driver +---------- + +The SPI device `/dev/spi-0` can be registered with ``bbb_register_spi_0()``` csb336 ====== -- 2.20.1 _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
