The available defconfigs for RISC-V QEMU have changed. We now have configurations to compile U-Boot to run in supervisor mode and for U-Boot SPL. Update the QEMU RISC-V documentation to reflect these changes.
Signed-off-by: Lukas Auer lukas.auer@aisec.fraunhofer.de ---
doc/README.qemu-riscv | 56 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 55 insertions(+), 1 deletion(-)
diff --git a/doc/README.qemu-riscv b/doc/README.qemu-riscv index e2e4804917..5688084d36 100644 --- a/doc/README.qemu-riscv +++ b/doc/README.qemu-riscv @@ -7,7 +7,8 @@ U-Boot on QEMU's 'virt' machine on RISC-V
QEMU for RISC-V supports a special 'virt' machine designed for emulation and virtualization purposes. This document describes how to run U-Boot under it. -Both 32-bit 64-bit targets are supported. +Both 32-bit and 64-bit targets are supported, running in either machine or +supervisor mode.
The QEMU virt machine models a generic RISC-V virtual machine with support for the VirtIO standard networking and block storage devices. It has CLINT, PLIC, @@ -27,6 +28,11 @@ Set the CROSS_COMPILE environment variable as usual, and run: make qemu-riscv64_defconfig make
+This will compile U-Boot for machine mode. To build supervisor mode binaries, +use the configurations qemu-riscv32_smode_defconfig and +qemu-riscv64_smode_defconfig instead. Note that U-Boot running in supervisor +mode requires a supervisor binary interface (SBI), such as RISC-V OpenSBI. + Running U-Boot -------------- The minimal QEMU command line to get U-Boot up and running is: @@ -43,4 +49,52 @@ parameter. For example, '-m 2G' creates 2GiB memory for the target, and the memory node in the embedded DTB created by QEMU reflects the new setting.
+For instructions on how to run U-Boot in supervisor mode on QEMU +with OpenSBI, see the documentation available with OpenSBI: + +https://github.com/riscv/opensbi/blob/master/docs/platform/qemu_virt.md + These have been tested in QEMU 3.0.0. + +Running U-Boot SPL +------------------ +In the default SPL configuration, U-Boot SPL starts in machine mode. U-Boot +proper and OpenSBI (FW_DYNAMIC firmware) are bundled as FIT image and made +available to U-Boot SPL. Both are then loaded by U-Boot SPL and the location +of U-Boot proper is passed to OpenSBI. After initialization, U-Boot proper is +started in supervisor mode by OpenSBI. + +OpenSBI must be compiled before compiling U-Boot. Clone the OpenSBI repository +and run the following command. + + git clone https://github.com/riscv/opensbi.git + cd opensbi + make PLATFORM=qemu/virt + +See the OpenSBI documentation for full details: + +https://github.com/riscv/opensbi/blob/master/docs/platform/qemu_virt.md + +To make the FW_DYNAMIC binary (build/platform/qemu/virt/firmware/fw_dynamic.bin) +available to U-Boot, either copy it into the U-Boot root directory or specify +its location with the OPENSBI environment variable. Afterwards, compile U-Boot +with the following commands. + +- For 32-bit RISC-V: + make qemu-riscv32_spl_defconfig + make + +- For 64-bit RISC-V: + make qemu-riscv64_spl_defconfig + make + +The minimal QEMU commands to run U-Boot SPL in both 32-bit and 64-bit +configurations are: + +- For 32-bit RISC-V: + qemu-system-riscv32 -nographic -machine virt -kernel spl/u-boot-spl \ + -device loader,file=u-boot.itb,addr=0x80200000 + +- For 64-bit RISC-V: + qemu-system-riscv64 -nographic -machine virt -kernel spl/u-boot-spl \ + -device loader,file=u-boot.itb,addr=0x80200000