docs/system: riscv: Add documentation for sifive_u machine
This adds detailed documentation for RISC-V `sifive_u` machine, including the following information: - Supported devices - Hardware configuration information - Boot options - Machine-specific options - Running Linux kernel - Running VxWorks kernel - Running U-Boot, and with an alternate configuration Signed-off-by: Bin Meng <bin.meng@windriver.com> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Message-id: 20210126060007.12904-10-bmeng.cn@gmail.com Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
This commit is contained in:
Bin Meng
Alistair Francis
parent
d6d9896814
commit
01153d2b60
|
|
@ -0,0 +1,336 @@
|
|||
SiFive HiFive Unleashed (``sifive_u``)
|
||||
======================================
|
||||
|
||||
SiFive HiFive Unleashed Development Board is the ultimate RISC-V development
|
||||
board featuring the Freedom U540 multi-core RISC-V processor.
|
||||
|
||||
Supported devices
|
||||
-----------------
|
||||
|
||||
The ``sifive_u`` machine supports the following devices:
|
||||
|
||||
* 1 E51 / E31 core
|
||||
* Up to 4 U54 / U34 cores
|
||||
* Core Level Interruptor (CLINT)
|
||||
* Platform-Level Interrupt Controller (PLIC)
|
||||
* Power, Reset, Clock, Interrupt (PRCI)
|
||||
* L2 Loosely Integrated Memory (L2-LIM)
|
||||
* DDR memory controller
|
||||
* 2 UARTs
|
||||
* 1 GEM Ethernet controller
|
||||
* 1 GPIO controller
|
||||
* 1 One-Time Programmable (OTP) memory with stored serial number
|
||||
* 1 DMA controller
|
||||
* 2 QSPI controllers
|
||||
* 1 ISSI 25WP256 flash
|
||||
* 1 SD card in SPI mode
|
||||
|
||||
Please note the real world HiFive Unleashed board has a fixed configuration of
|
||||
1 E51 core and 4 U54 core combination and the RISC-V core boots in 64-bit mode.
|
||||
With QEMU, one can create a machine with 1 E51 core and up to 4 U54 cores. It
|
||||
is also possible to create a 32-bit variant with the same peripherals except
|
||||
that the RISC-V cores are replaced by the 32-bit ones (E31 and U34), to help
|
||||
testing of 32-bit guest software.
|
||||
|
||||
Hardware configuration information
|
||||
----------------------------------
|
||||
|
||||
The ``sifive_u`` machine automatically generates a device tree blob ("dtb")
|
||||
which it passes to the guest. This provides information about the addresses,
|
||||
interrupt lines and other configuration of the various devices in the system.
|
||||
Guest software should discover the devices that are present in the generated
|
||||
DTB instead of using a DTB for the real hardware, as some of the devices are
|
||||
not modeled by QEMU and trying to access these devices may cause unexpected
|
||||
behavior.
|
||||
|
||||
Boot options
|
||||
------------
|
||||
|
||||
The ``sifive_u`` machine can start using the standard -kernel functionality
|
||||
for loading a Linux kernel, a VxWorks kernel, a modified U-Boot bootloader
|
||||
(S-mode) or ELF executable with the default OpenSBI firmware image as the
|
||||
-bios. It also supports booting the unmodified U-Boot bootloader using the
|
||||
standard -bios functionality.
|
||||
|
||||
Machine-specific options
|
||||
------------------------
|
||||
|
||||
The following machine-specific options are supported:
|
||||
|
||||
- serial=nnn
|
||||
|
||||
The board serial number. When not given, the default serial number 1 is used.
|
||||
|
||||
SiFive reserves the first 1 KiB of the 16 KiB OTP memory for internal use.
|
||||
The current usage is only used to store the serial number of the board at
|
||||
offset 0xfc. U-Boot reads the serial number from the OTP memory, and uses
|
||||
it to generate a unique MAC address to be programmed to the on-chip GEM
|
||||
Ethernet controller. When multiple QEMU ``sifive_u`` machines are created
|
||||
and connected to the same subnet, they all have the same MAC address hence
|
||||
it creates an unusable network. In such scenario, user should give different
|
||||
values to serial= when creating different ``sifive_u`` machines.
|
||||
|
||||
- start-in-flash
|
||||
|
||||
When given, QEMU's ROM codes jump to QSPI memory-mapped flash directly.
|
||||
Otherwise QEMU will jump to DRAM or L2LIM depending on the msel= value.
|
||||
When not given, it defaults to direct DRAM booting.
|
||||
|
||||
- msel=[6|11]
|
||||
|
||||
Mode Select (MSEL[3:0]) pins value, used to control where to boot from.
|
||||
|
||||
The FU540 SoC supports booting from several sources, which are controlled
|
||||
using the Mode Select pins on the chip. Typically, the boot process runs
|
||||
through several stages before it begins execution of user-provided programs.
|
||||
These stages typically include the following:
|
||||
|
||||
1. Zeroth Stage Boot Loader (ZSBL), which is contained in an on-chip mask
|
||||
ROM and provided by QEMU. Note QEMU implemented ROM codes are not the
|
||||
same as what is programmed in the hardware. The QEMU one is a simplified
|
||||
version, but it provides the same functionality as the hardware.
|
||||
2. First Stage Boot Loader (FSBL), which brings up PLLs and DDR memory.
|
||||
This is U-Boot SPL.
|
||||
3. Second Stage Boot Loader (SSBL), which further initializes additional
|
||||
peripherals as needed. This is U-Boot proper combined with an OpenSBI
|
||||
fw_dynamic firmware image.
|
||||
|
||||
msel=6 means FSBL and SSBL are both on the QSPI flash. msel=11 means FSBL
|
||||
and SSBL are both on the SD card.
|
||||
|
||||
Running Linux kernel
|
||||
--------------------
|
||||
|
||||
Linux mainline v5.10 release is tested at the time of writing. To build a
|
||||
Linux mainline kernel that can be booted by the ``sifive_u`` machine in
|
||||
64-bit mode, simply configure the kernel using the defconfig configuration:
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ export ARCH=riscv
|
||||
$ export CROSS_COMPILE=riscv64-linux-
|
||||
$ make defconfig
|
||||
$ make
|
||||
|
||||
To boot the newly built Linux kernel in QEMU with the ``sifive_u`` machine:
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ qemu-system-riscv64 -M sifive_u -smp 5 -m 2G \
|
||||
-display none -serial stdio \
|
||||
-kernel arch/riscv/boot/Image \
|
||||
-initrd /path/to/rootfs.ext4 \
|
||||
-append "root=/dev/ram"
|
||||
|
||||
To build a Linux mainline kernel that can be booted by the ``sifive_u`` machine
|
||||
in 32-bit mode, use the rv32_defconfig configuration. A patch is required to
|
||||
fix the 32-bit boot issue for Linux kernel v5.10.
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ export ARCH=riscv
|
||||
$ export CROSS_COMPILE=riscv64-linux-
|
||||
$ curl https://patchwork.kernel.org/project/linux-riscv/patch/20201219001356.2887782-1-atish.patra@wdc.com/mbox/ > riscv.patch
|
||||
$ git am riscv.patch
|
||||
$ make rv32_defconfig
|
||||
$ make
|
||||
|
||||
Replace ``qemu-system-riscv64`` with ``qemu-system-riscv32`` in the command
|
||||
line above to boot the 32-bit Linux kernel. A rootfs image containing 32-bit
|
||||
applications shall be used in order for kernel to boot to user space.
|
||||
|
||||
Running VxWorks kernel
|
||||
----------------------
|
||||
|
||||
VxWorks 7 SR0650 release is tested at the time of writing. To build a 64-bit
|
||||
VxWorks mainline kernel that can be booted by the ``sifive_u`` machine, simply
|
||||
create a VxWorks source build project based on the sifive_generic BSP, and a
|
||||
VxWorks image project to generate the bootable VxWorks image, by following the
|
||||
BSP documentation instructions.
|
||||
|
||||
A pre-built 64-bit VxWorks 7 image for HiFive Unleashed board is available as
|
||||
part of the VxWorks SDK for testing as well. Instructions to download the SDK:
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ wget https://labs.windriver.com/downloads/wrsdk-vxworks7-sifive-hifive-1.01.tar.bz2
|
||||
$ tar xvf wrsdk-vxworks7-sifive-hifive-1.01.tar.bz2
|
||||
$ ls bsps/sifive_generic_1_0_0_0/uboot/uVxWorks
|
||||
|
||||
To boot the VxWorks kernel in QEMU with the ``sifive_u`` machine, use:
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ qemu-system-riscv64 -M sifive_u -smp 5 -m 2G \
|
||||
-display none -serial stdio \
|
||||
-nic tap,ifname=tap0,script=no,downscript=no \
|
||||
-kernel /path/to/vxWorks \
|
||||
-append "gem(0,0)host:vxWorks h=192.168.200.1 e=192.168.200.2:ffffff00 u=target pw=vxTarget f=0x01"
|
||||
|
||||
It is also possible to test 32-bit VxWorks on the ``sifive_u`` machine. Create
|
||||
a 32-bit project to build the 32-bit VxWorks image, and use exact the same
|
||||
command line options with ``qemu-system-riscv32``.
|
||||
|
||||
Running U-Boot
|
||||
--------------
|
||||
|
||||
U-Boot mainline v2021.01 release is tested at the time of writing. To build a
|
||||
U-Boot mainline bootloader that can be booted by the ``sifive_u`` machine, use
|
||||
the sifive_fu540_defconfig with similar commands as described above for Linux:
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ export CROSS_COMPILE=riscv64-linux-
|
||||
$ export OPENSBI=/path/to/opensbi-riscv64-generic-fw_dynamic.bin
|
||||
$ make sifive_fu540_defconfig
|
||||
|
||||
You will get spl/u-boot-spl.bin and u-boot.itb file in the build tree.
|
||||
|
||||
To start U-Boot using the ``sifive_u`` machine, prepare an SPI flash image, or
|
||||
SD card image that is properly partitioned and populated with correct contents.
|
||||
genimage_ can be used to generate these images.
|
||||
|
||||
A sample configuration file for a 128 MiB SD card image is:
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ cat genimage_sdcard.cfg
|
||||
image sdcard.img {
|
||||
size = 128M
|
||||
|
||||
hdimage {
|
||||
gpt = true
|
||||
}
|
||||
|
||||
partition u-boot-spl {
|
||||
image = "u-boot-spl.bin"
|
||||
offset = 17K
|
||||
partition-type-uuid = 5B193300-FC78-40CD-8002-E86C45580B47
|
||||
}
|
||||
|
||||
partition u-boot {
|
||||
image = "u-boot.itb"
|
||||
offset = 1041K
|
||||
partition-type-uuid = 2E54B353-1271-4842-806F-E436D6AF6985
|
||||
}
|
||||
}
|
||||
|
||||
SPI flash image has slightly different partition offsets, and the size has to
|
||||
be 32 MiB to match the ISSI 25WP256 flash on the real board:
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ cat genimage_spi-nor.cfg
|
||||
image spi-nor.img {
|
||||
size = 32M
|
||||
|
||||
hdimage {
|
||||
gpt = true
|
||||
}
|
||||
|
||||
partition u-boot-spl {
|
||||
image = "u-boot-spl.bin"
|
||||
offset = 20K
|
||||
partition-type-uuid = 5B193300-FC78-40CD-8002-E86C45580B47
|
||||
}
|
||||
|
||||
partition u-boot {
|
||||
image = "u-boot.itb"
|
||||
offset = 1044K
|
||||
partition-type-uuid = 2E54B353-1271-4842-806F-E436D6AF6985
|
||||
}
|
||||
}
|
||||
|
||||
Assume U-Boot binaries are put in the same directory as the config file,
|
||||
we can generate the image by:
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ genimage --config genimage_<boot_src>.cfg --inputpath .
|
||||
|
||||
Boot U-Boot from SD card, by specifying msel=11 and pass the SD card image
|
||||
to QEMU ``sifive_u`` machine:
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ qemu-system-riscv64 -M sifive_u,msel=11 -smp 5 -m 8G \
|
||||
-display none -serial stdio \
|
||||
-bios /path/to/u-boot-spl.bin \
|
||||
-drive file=/path/to/sdcard.img,if=sd
|
||||
|
||||
Changing msel= value to 6, allows booting U-Boot from the SPI flash:
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ qemu-system-riscv64 -M sifive_u,msel=6 -smp 5 -m 8G \
|
||||
-display none -serial stdio \
|
||||
-bios /path/to/u-boot-spl.bin \
|
||||
-drive file=/path/to/spi-nor.img,if=mtd
|
||||
|
||||
Note when testing U-Boot, QEMU automatically generated device tree blob is
|
||||
not used because U-Boot itself embeds device tree blobs for U-Boot SPL and
|
||||
U-Boot proper. Hence the number of cores and size of memory have to match
|
||||
the real hardware, ie: 5 cores (-smp 5) and 8 GiB memory (-m 8G).
|
||||
|
||||
Above use case is to run upstream U-Boot for the SiFive HiFive Unleashed
|
||||
board on QEMU ``sifive_u`` machine out of the box. This allows users to
|
||||
develop and test the recommended RISC-V boot flow with a real world use
|
||||
case: ZSBL (in QEMU) loads U-Boot SPL from SD card or SPI flash to L2LIM,
|
||||
then U-Boot SPL loads the combined payload image of OpenSBI fw_dynamic
|
||||
firmware and U-Boot proper. However sometimes we want to have a quick test
|
||||
of booting U-Boot on QEMU without the needs of preparing the SPI flash or
|
||||
SD card images, an alternate way can be used, which is to create a U-Boot
|
||||
S-mode image by modifying the configuration of U-Boot:
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ make menuconfig
|
||||
|
||||
then manually select the following configuration in U-Boot:
|
||||
|
||||
Device Tree Control > Provider of DTB for DT Control > Prior Stage bootloader DTB
|
||||
|
||||
This lets U-Boot to use the QEMU generated device tree blob. During the build,
|
||||
a build error will be seen below:
|
||||
|
||||
.. code-block:: none
|
||||
|
||||
MKIMAGE u-boot.img
|
||||
./tools/mkimage: Can't open arch/riscv/dts/hifive-unleashed-a00.dtb: No such file or directory
|
||||
./tools/mkimage: failed to build FIT
|
||||
make: *** [Makefile:1440: u-boot.img] Error 1
|
||||
|
||||
The above errors can be safely ignored as we don't run U-Boot SPL under QEMU
|
||||
in this alternate configuration.
|
||||
|
||||
Boot the 64-bit U-Boot S-mode image directly:
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ qemu-system-riscv64 -M sifive_u -smp 5 -m 2G \
|
||||
-display none -serial stdio \
|
||||
-kernel /path/to/u-boot.bin
|
||||
|
||||
It's possible to create a 32-bit U-Boot S-mode image as well.
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ export CROSS_COMPILE=riscv64-linux-
|
||||
$ make sifive_fu540_defconfig
|
||||
$ make menuconfig
|
||||
|
||||
then manually update the following configuration in U-Boot:
|
||||
|
||||
Device Tree Control > Provider of DTB for DT Control > Prior Stage bootloader DTB
|
||||
RISC-V architecture > Base ISA > RV32I
|
||||
Boot images > Text Base > 0x80400000
|
||||
|
||||
Use the same command line options to boot the 32-bit U-Boot S-mode image:
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
$ qemu-system-riscv32 -M sifive_u -smp 5 -m 2G \
|
||||
-display none -serial stdio \
|
||||
-kernel /path/to/u-boot.bin
|
||||
|
||||
.. _genimage: https://github.com/pengutronix/genimage
|
||||
|
|
@ -58,5 +58,15 @@ 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/sifive_u
|
||||
|
||||
RISC-V CPU features
|
||||
-------------------
|
||||
|
|
|
|||
Loading…
Reference in New Issue