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Diffstat (limited to 'docs/system/riscv/sifive_u.rst')
| -rw-r--r-- | docs/system/riscv/sifive_u.rst | 77 |
1 files changed, 56 insertions, 21 deletions
diff --git a/docs/system/riscv/sifive_u.rst b/docs/system/riscv/sifive_u.rst index 98e7562..32d0a1b 100644 --- a/docs/system/riscv/sifive_u.rst +++ b/docs/system/riscv/sifive_u.rst @@ -9,21 +9,21 @@ 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 +* 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. @@ -36,12 +36,21 @@ 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. +which it passes to the guest, if there is no ``-dtb`` option. 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. + +If users want to provide their own DTB, they can use the ``-dtb`` option. +These DTBs should have the following requirements: + +* The /cpus node should contain at least one subnode for E51 and the number + of subnodes should match QEMU's ``-smp`` option +* The /memory reg size should match QEMU’s selected ram_size via ``-m`` +* Should contain a node for the CLINT device with a compatible string + "riscv,clint0" if using with OpenSBI BIOS images Boot options ------------ @@ -122,6 +131,32 @@ To boot the newly built Linux kernel in QEMU with the ``sifive_u`` machine: -initrd /path/to/rootfs.ext4 \ -append "root=/dev/ram" +Alternatively, we can use a custom DTB to boot the machine by inserting a CLINT +node in fu540-c000.dtsi in the Linux kernel, + +.. code-block:: none + + clint: clint@2000000 { + compatible = "riscv,clint0"; + interrupts-extended = <&cpu0_intc 3 &cpu0_intc 7 + &cpu1_intc 3 &cpu1_intc 7 + &cpu2_intc 3 &cpu2_intc 7 + &cpu3_intc 3 &cpu3_intc 7 + &cpu4_intc 3 &cpu4_intc 7>; + reg = <0x00 0x2000000 0x00 0x10000>; + }; + +with the following command line options: + +.. code-block:: bash + + $ qemu-system-riscv64 -M sifive_u -smp 5 -m 8G \ + -display none -serial stdio \ + -kernel arch/riscv/boot/Image \ + -dtb arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dtb \ + -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. |