On Mon, 25 Jan 2021 22:00:07 PST (-0800), bmeng...@gmail.com wrote:
From: Bin Meng <bin.m...@windriver.com>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.m...@windriver.com> Reviewed-by: Alistair Francis <alistair.fran...@wdc.com> --- Changes in v3: - Convert sifive_u.rst from UTF-8 to ASCII Changes in v2: - Correct several typos in sifive_u.rst - Update doc to mention U-Boot v2021.01 docs/system/riscv/sifive_u.rst | 336 +++++++++++++++++++++++++++++++++ docs/system/target-riscv.rst | 10 + 2 files changed, 346 insertions(+) create mode 100644 docs/system/riscv/sifive_u.rst diff --git a/docs/system/riscv/sifive_u.rst b/docs/system/riscv/sifive_u.rst new file mode 100644 index 0000000000..98e7562848 --- /dev/null +++ b/docs/system/riscv/sifive_u.rst @@ -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.pa...@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 diff --git a/docs/system/target-riscv.rst b/docs/system/target-riscv.rst index 9f4b7586e5..94d99c4c82 100644 --- a/docs/system/target-riscv.rst +++ b/docs/system/target-riscv.rst @@ -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 -------------------
Reviewed-by: Palmer Dabbelt <palmerdabb...@google.com> Thanks!
