Add README.nios2 about how to add nios2 boards to u-boot.
Signed-off-by: Thomas Chou thomas@wytron.com.tw Acked-by: Marek Vasut marex@denx.de --- v2 add ref and fix words as suggested by Marek. v3 add a dollar sign before a command. remove u-boot,dm-pre-reloc property. it is not needed now.
doc/README.nios2 | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 doc/README.nios2
diff --git a/doc/README.nios2 b/doc/README.nios2 new file mode 100644 index 0000000..2dab7d1 --- /dev/null +++ b/doc/README.nios2 @@ -0,0 +1,95 @@ +Nios II is a 32-bit embedded-processor architecture designed +specifically for the Altera family of FPGAs. + +Please refer to the link for more information on Nios II, +https://www.altera.com/products/processors/overview.html + +Please refer to the link for Linux port and toolchains, +http://rocketboards.org/foswiki/view/Documentation/NiosIILinuxUserManual + +The Nios II port of u-boot is controlled by device tree. Please check +out doc/README.fdt-control. + +To add a new board/configuration (eg, mysystem) to u-boot, you will need +three files. + +1. The device tree source which describes the hardware, dts file. + arch/nios2/dts/mysystem.dts + +2. Default configuration of Kconfig, defconfig file. + configs/mysystem_defconfig + +3. The legacy board header file. + include/configs/mysystem.h + +The device tree source must be generated from your qsys/sopc design +using the sopc2dts tool. Then modified to fit your configuration. Please +find the sopc2dts download and usage at the wiki, +http://www.alterawiki.com/wiki/Sopc2dts + +$ java -jar sopc2dts.jar --force-altr -i mysystem.sopcinfo -o mysystem.dts + +You will need to add additional properties to the dts. Please find an +example at, arch/nios2/dts/3c120_devboard.dts. + +1. Add "stdout-path=..." property with your serial path to the chosen +node, like this, + chosen { + stdout-path = &jtag_uart; + }; + +2. If you use SPI/EPCS or I2C, you will need to add aliases to number +the sequence of these devices, like this, + aliases { + spi0 = &epcs_controller; + }; + +Next, you will need a default config file. You may start with +nios2-generic_defconfig, modify the options and save it. + +$ make nios2-generic_defconfig +$ make menuconfig +$ make savedefconfig +$ cp defconfig configs/mysystem_defconfig + +You will need to change the names of board header file and device tree, +and select the drivers with menuconfig. + +Nios II architecture ---> + (mysystem) Board header file +Device Tree Control ---> + (mysystem) Default Device Tree for DT control + +There is a selection of "Provider of DTB for DT control" in the Device +Tree Control menu. + +( ) Separate DTB for DT control, will cat the dtb to end of u-boot +binary, output u-boot-dtb.bin. This should be used for production. +If you use boot copier, like EPCS boot copier, make sure the copier +copies all the u-boot-dtb.bin, not just u-boot.bin. + +( ) Embedded DTB for DT control, will include the dtb inside the u-boot +binary. This is handy for development, eg, using gdb or nios2-download. + +The last thing, legacy board header file describes those config options +not covered in Kconfig yet. You may copy it from nios2-generic.h. + +$ cp include/configs/nios2-generic.h include/configs/mysystem.h + +Please change the SDRAM base and size to match your board. The base +should be cached virtual address, for Nios II with MMU it is 0xCxxx_xxxx +to 0xDxxx_xxxx. + +#define CONFIG_SYS_SDRAM_BASE 0xD0000000 +#define CONFIG_SYS_SDRAM_SIZE 0x08000000 + +You will need to change the environment variables location and setting, +too. You may change other configs to fit your board. + +After all these changes, you may build and test. + +$ export CROSS_COMPILE=nios2-elf- (or nios2-linux-gnu-) +$ make mysystem_defconfig +$ make + +Enjoy!