Signed-off-by: Chao Liu <[email protected]> --- MAINTAINERS | 1 + docs/system/riscv/k230.rst | 113 +++++++++++++++++++++++++++++++++++ docs/system/target-riscv.rst | 1 + 3 files changed, 115 insertions(+) create mode 100644 docs/system/riscv/k230.rst
diff --git a/MAINTAINERS b/MAINTAINERS index e7e3ed0c5c..6a752b1a0a 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1784,6 +1784,7 @@ K230 Machines M: Chao Liu <[email protected]> L: [email protected] S: Maintained +F: docs/system/riscv/k230.rst F: hw/riscv/k230.c F: hw/watchdog/k230_wdt.c F: include/hw/riscv/k230.h diff --git a/docs/system/riscv/k230.rst b/docs/system/riscv/k230.rst new file mode 100644 index 0000000000..cea8202e55 --- /dev/null +++ b/docs/system/riscv/k230.rst @@ -0,0 +1,113 @@ +Kendryte K230 virt reference platform (``k230``) +========================================================================== +The ``k230`` machine is compatible with the Kendryte K230 SDK. + +The K230 is a chip from the AIoT SoC series made by Kendryte ® — a part of +Canaan Inc. It uses a brand-new multi-heterogeneous unit accelerated computing +structure. + +This chip has 2 RISC-V computing cores and a new-generation KPU (Knowledge +Process Unit) smart computing unit. + +For more information, see <https://www.kendryte.com/en/proDetail/230> + +Supported devices +----------------- +The ``k230`` machine supports the following devices: + +* 1 c908 cores (little core) +* Core Local Interruptor (CLINT) +* Platform-Level Interrupt Controller (PLIC) +* 2 K230 Watchdog Timer +* 5 UART + +Boot options +------------ +The ``k230`` machine supports K230 SDK boot through M-mode U-Boot, which then +starts OpenSBI/Linux with ``bootm``. It also supports direct Linux boot. + +K230 SDK Linux kernels use T-HEAD C9xx private MAEE page table attributes. QEMU +does not implement MAEE in the generic RISC-V MMU, so such kernels need to be +built with standard RISC-V PTE bits before they can boot under QEMU. + +Running +------- + +Direct Linux boot +~~~~~~~~~~~~~~~~~ + +This flow lets QEMU load OpenSBI, Linux, initrd, and DTB directly, without +running SDK U-Boot. The Linux Image must be rebuilt with standard RISC-V PTE +bits before running under QEMU. + +.. code-block:: bash + + $ SDK=k230_sdk/output/k230_canmv_defconfig + $ qemu-system-riscv64 -machine k230 \ + -kernel "$SDK/images/little-core/Image" \ + -dtb "/tmp/user-k230-qemu.dtb" \ + -initrd "$SDK/images/little-core/rootfs.cpio.gz" \ + -append "console=ttyS0,115200 earlycon=sbi cma=0" \ + -nographic + +Direct boot uses the SDK little-core RAM layout for OpenSBI at +``0x08000000``, Linux at ``0x08200000``, and the DTB at ``0x0a000000``. The +initrd is placed by QEMU's generic RISC-V boot helper, and QEMU writes the +initrd range and kernel command line into ``/chosen``. The DTB passed with +``-dtb`` should be derived from ``$SDK/images/little-core/k230.dtb`` and must +describe that initrd location as usable memory and disable any devices that are +not emulated by this machine. + +U-Boot boot +~~~~~~~~~~~ + +This flow starts SDK U-Boot in M-mode with ``-bios``. Until the SDK storage +path is modeled, place OpenSBI, Linux, initrd, and DTB in RAM with loader +devices and run ``bootm`` manually. The Linux Image must be rebuilt with +standard RISC-V PTE bits before running under QEMU. + +.. code-block:: bash + + $ SDK=k230_sdk/output/k230_canmv_defconfig + $ IMAGE=$SDK/images/little-core/Image + $ INITRD=$SDK/images/little-core/rootfs.cpio.gz + $ DTB=$SDK/images/little-core/k230.dtb + $ FWJUMP_UIMAGE=/tmp/k230-fw-jump.uImage + $ INITRD_END=$(printf "0x%x" $((0x0a100000 + $(stat -c %s "$INITRD")))) + $ "$SDK/little/buildroot-ext/host/bin/mkimage" \ + -A riscv -O linux -T kernel -C none \ + -a 0x8000000 -e 0x8000000 -n opensbi \ + -d "$SDK/images/little-core/fw_jump.bin" "$FWJUMP_UIMAGE" + $ qemu-system-riscv64 -machine k230 \ + -bios "$SDK/little/uboot/u-boot" \ + -device loader,file="$FWJUMP_UIMAGE",addr=0xc100000,force-raw=on \ + -device loader,file="$IMAGE",addr=0x8200000,force-raw=on \ + -device loader,file="$INITRD",addr=0xa100000,force-raw=on \ + -device loader,file="$DTB",addr=0xa000000,force-raw=on \ + -nographic + +The loader addresses mirror the SDK ``k230_canmv_defconfig`` output. Read the +U-Boot addresses from the generated environment, and read the Linux RAM base +from the generated ``hw/k230.dts.txt``. This replaces the SDK storage and +decompression steps. + +Press Enter to stop autoboot. At the U-Boot prompt, run these commands: + +.. code-block:: bash + + K230# setenv bootargs console=ttyS0,115200 earlycon=sbi cma=0 + K230# fdt addr 0xa000000 + K230# fdt resize 8192 + K230# fdt set /chosen linux,initrd-start <0x0 0xa100000> + K230# fdt set /chosen linux,initrd-end <0x0 ${INITRD_END}> + K230# fdt set /soc/sdhci0@91580000 status disabled + K230# fdt set /soc/sdhci1@91581000 status disabled + K230# bootm 0xc100000 - 0xa000000 + +Use ``setenv`` so ``bootm`` writes the kernel command line into +``/chosen/bootargs``. The ``fdt`` commands select the loaded DTB, add space for +edits, describe the initrd range in ``/chosen``, and disable SDHCI nodes because +this machine does not emulate those controllers yet. Replace ``${INITRD_END}`` +with the host-calculated value above when typing the command. ``cma=0`` avoids +the SDK kernel reserving too much of the little-core memory window for initramfs +boot. diff --git a/docs/system/target-riscv.rst b/docs/system/target-riscv.rst index 3ad5d1ddaf..b0b2f9584f 100644 --- a/docs/system/target-riscv.rst +++ b/docs/system/target-riscv.rst @@ -66,6 +66,7 @@ undocumented; you can get a complete list by running .. toctree:: :maxdepth: 1 + riscv/k230 riscv/microblaze-v-generic riscv/microchip-icicle-kit riscv/mips
