Commit b3fe55196f for qemu.org
commit b3fe55196f080e113129065dc19896e5cac8a3cc
Author: Chao Liu <chao.liu.zevorn@gmail.com>
Date: Fri Jun 12 15:04:08 2026 +0800
docs/system/riscv: add documentation for k230 machine
Signed-off-by: Chao Liu <chao.liu.zevorn@gmail.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <81d2e2fa42ecabf638f841321cf36cee8f10af01.1781246408.git.chao.liu@processmission.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 44654b5798..4fc073b7ee 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1790,6 +1790,7 @@ K230 Machines
M: Chao Liu <chao.liu.zevorn@gmail.com>
L: qemu-riscv@nongnu.org
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 afd86ca2ba..896f14e78b 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