This builds a complete RISC-V cross-compile toolchain for the SiFive Freedom Unleashed U500 SoC. It also builds U-boot and a flattened image tree (FIT) image with a BBL binary, linux kernel, device tree, and ramdisk for the HiFive Unleashed development board.

• Status: Working
• Build dependencies: build-essential git autotools texinfo bison flex libgmp-dev libmpfr-dev libmpc-dev gawk libz-dev libssl-dev
• Additional build deps for QEMU: libglib2.0-dev libpixman-1-dev
• Additional build deps for Spike: device-tree-compiler
• tools require for 'format-boot-loader' target: mtools

• Status: Not supported (Riscv-gnu-toolchain does not build natively)
• Likely to work with native Debian gcc

Checkout this repository. Then you will need to checkout all of the linked submodules using:

git submodule update --recursive --init

This will take some time and require around 7GB of disk space. Some modules may fail because certain dependencies don't have the best git hosting. The only solution is to wait and try again later (or ask someone for a copy of that source repository).

Once the submodules are initialized, run make and the complete toolchain and bbl image will be built. The completed build tree will consume about 14G of disk space.

Once the build of the SDK is complete, there will be a new u-boot FIT image under 'work/image.fit'. This can be copied to the first partition of the MicroSD card, which should be formatted as an MSDOS partition and contain a file called 'uEnv.txt' which contains the default U-boot environment. This file can be edited to change boot behavior. See the inline comments in the file for further information. (The file can be found in conf/uEnv.txt as well)

To boot U-boot, the currently supported method is to set the mode select switches to boot from the SDcard, and have U-boot on an SDcard, which can be formatted and set up with the command:

make DISK=/dev/sdX format-boot-loader

where X is replaced with the device name of the SDcard. Alternatively, to download a pre-built Debian demo image, use the 'format-demo-image' target with the same syntax. You may need to use sudo if you do not have udev rules set.

TODO: document Udev rules to allow this to run without root or sudo

The hifive-unleashed-a00-YYYY-MM-DD.gpt image file can be written to the flash with dd or another similiar tool, or flashed to the SPI flash with flashcp. Running from flash is not (yet) well supported, please file issues and send patches to fix problems.

The mode select switches should be set as follows:

      USB   LED    Mode Select                  Ethernet
 +===|___|==****==+-+-+-+-+-+-+=================|******|===+
 |                | | | | |X| |                 |      |   |
 |                | | | | | | |                 |      |   |
 |        HFXSEL->|X|X|X|X| |X|                 |______|   |
 |                +-+-+-+-+-+-+                            |
 |        RTCSEL-----/ 0 1 2 3 <--MSEL                     |
 |                                                         |

You can boot linux on qemu by running make qemu.

You can boot linux on spike by running make sim. This requires a patch to enable the old serial driver, because the new one which works best on the Freedom Unleashed hardware unfortunately does not work on spike.

The current build process also does not include an initrd with spike, so even if you do boot the kernel it will not have a root filesystem. If you would like to help, please see the qemu code for separate firmware and kernel payload options (commit 16aad29) or add an option to the riscv-pk build to allow a '--with-ramdisk' option, and send a patch or pull request.

diff --git a/conf/linux_defconfig b/conf/linux_defconfig
index cd87340..87b480f 100644
--- a/conf/linux_defconfig
+++ b/conf/linux_defconfig
@@ -53,7 +53,7 @@ CONFIG_SERIAL_8250_CONSOLE=y
 CONFIG_SERIAL_OF_PLATFORM=y
 CONFIG_SERIAL_SIFIVE=y
 CONFIG_SERIAL_SIFIVE_CONSOLE=y
-# CONFIG_HVC_RISCV_SBI is not set
+CONFIG_HVC_RISCV_SBI=y
 CONFIG_VIRTIO_CONSOLE=y
 # CONFIG_HW_RANDOM is not set
 CONFIG_I2C=y