0924a423ba
Add documentation for Shakti C reference platform. Signed-off-by: Vijai Kumar K <vijai@behindbytes.com> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-id: 20210412174248.8668-1-vijai@behindbytes.com Signed-off-by: Bin Meng <bmeng.cn@gmail.com> [ Changes from Bin Meng: - Add missing TOC Message-id: 20210430070534.1487242-1-bmeng.cn@gmail.com ] Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
75 lines
3.0 KiB
ReStructuredText
75 lines
3.0 KiB
ReStructuredText
.. _RISC-V-System-emulator:
|
|
|
|
RISC-V System emulator
|
|
======================
|
|
|
|
QEMU can emulate both 32-bit and 64-bit RISC-V CPUs. Use the
|
|
``qemu-system-riscv64`` executable to simulate a 64-bit RISC-V machine,
|
|
``qemu-system-riscv32`` executable to simulate a 32-bit RISC-V machine.
|
|
|
|
QEMU has generally good support for RISC-V guests. It has support for
|
|
several different machines. The reason we support so many is that
|
|
RISC-V hardware is much more widely varying than x86 hardware. RISC-V
|
|
CPUs are generally built into "system-on-chip" (SoC) designs created by
|
|
many different companies with different devices, and these SoCs are
|
|
then built into machines which can vary still further even if they use
|
|
the same SoC.
|
|
|
|
For most boards the CPU type is fixed (matching what the hardware has),
|
|
so typically you don't need to specify the CPU type by hand, except for
|
|
special cases like the ``virt`` board.
|
|
|
|
Choosing a board model
|
|
----------------------
|
|
|
|
For QEMU's RISC-V system emulation, you must specify which board
|
|
model you want to use with the ``-M`` or ``--machine`` option;
|
|
there is no default.
|
|
|
|
Because RISC-V systems differ so much and in fundamental ways, typically
|
|
operating system or firmware images intended to run on one machine
|
|
will not run at all on any other. This is often surprising for new
|
|
users who are used to the x86 world where every system looks like a
|
|
standard PC. (Once the kernel has booted, most user space software
|
|
cares much less about the detail of the hardware.)
|
|
|
|
If you already have a system image or a kernel that works on hardware
|
|
and you want to boot with QEMU, check whether QEMU lists that machine
|
|
in its ``-machine help`` output. If it is listed, then you can probably
|
|
use that board model. If it is not listed, then unfortunately your image
|
|
will almost certainly not boot on QEMU. (You might be able to
|
|
extract the file system and use that with a different kernel which
|
|
boots on a system that QEMU does emulate.)
|
|
|
|
If you don't care about reproducing the idiosyncrasies of a particular
|
|
bit of hardware, such as small amount of RAM, no PCI or other hard
|
|
disk, etc., and just want to run Linux, the best option is to use the
|
|
``virt`` board. This is a platform which doesn't correspond to any
|
|
real hardware and is designed for use in virtual machines. You'll
|
|
need to compile Linux with a suitable configuration for running on
|
|
the ``virt`` board. ``virt`` supports PCI, virtio, recent CPUs and
|
|
large amounts of RAM. It also supports 64-bit CPUs.
|
|
|
|
Board-specific documentation
|
|
----------------------------
|
|
|
|
Unfortunately many of the RISC-V boards QEMU supports are currently
|
|
undocumented; you can get a complete list by running
|
|
``qemu-system-riscv64 --machine help``, or
|
|
``qemu-system-riscv32 --machine help``.
|
|
|
|
..
|
|
This table of contents should be kept sorted alphabetically
|
|
by the title text of each file, which isn't the same ordering
|
|
as an alphabetical sort by filename.
|
|
|
|
.. toctree::
|
|
:maxdepth: 1
|
|
|
|
riscv/microchip-icicle-kit
|
|
riscv/shakti-c
|
|
riscv/sifive_u
|
|
|
|
RISC-V CPU features
|
|
-------------------
|