From 6165dcb55f0ab4b2a241e49859ce6262157887e7 Mon Sep 17 00:00:00 2001 From: Bin Meng Date: Tue, 6 Jul 2021 17:50:45 +0800 Subject: [PATCH] docs/system: riscv: Update Microchip Icicle Kit for direct kernel boot This adds a new section in the documentation to demonstrate how to use the new direct kernel boot feature for Microchip Icicle Kit, other than the HSS bootflow, using an upstream U-Boot v2021.07 image as an example. It also updates the truth table to have a new '-dtb' column which is required by direct kernel boot. Signed-off-by: Bin Meng Reviewed-by: Alistair Francis Message-id: 20210706095045.1917913-1-bmeng.cn@gmail.com Signed-off-by: Alistair Francis --- docs/system/riscv/microchip-icicle-kit.rst | 54 ++++++++++++++++++++++++++---- 1 file changed, 47 insertions(+), 7 deletions(-) diff --git a/docs/system/riscv/microchip-icicle-kit.rst b/docs/system/riscv/microchip-icicle-kit.rst index 54ced661e3..817d2aec9c 100644 --- a/docs/system/riscv/microchip-icicle-kit.rst +++ b/docs/system/riscv/microchip-icicle-kit.rst @@ -47,13 +47,13 @@ The user provided DTB should have the following requirements: QEMU follows below truth table to select which payload to execute: -===== ========== ======= --bios -kernel payload -===== ========== ======= - N N HSS - Y don't care HSS - N Y kernel -===== ========== ======= +===== ========== ========== ======= +-bios -kernel -dtb payload +===== ========== ========== ======= + N N don't care HSS + Y don't care don't care HSS + N Y Y kernel +===== ========== ========== ======= The memory is set to 1537 MiB by default which is the minimum required high memory size by HSS. A sanity check on ram size is performed in the machine @@ -106,4 +106,44 @@ HSS output is on the first serial port (stdio) and U-Boot outputs on the second serial port. U-Boot will automatically load the Linux kernel from the SD card image. +Direct Kernel Boot +------------------ + +Sometimes we just want to test booting a new kernel, and transforming the +kernel image to the format required by the HSS bootflow is tedious. We can +use '-kernel' for direct kernel booting just like other RISC-V machines do. + +In this mode, the OpenSBI fw_dynamic BIOS image for 'generic' platform is +used to boot an S-mode payload like U-Boot or OS kernel directly. + +For example, the following commands show building a U-Boot image from U-Boot +mainline v2021.07 for the Microchip Icicle Kit board: + +.. code-block:: bash + + $ export CROSS_COMPILE=riscv64-linux- + $ make microchip_mpfs_icicle_defconfig + +Then we can boot the machine by: + +.. code-block:: bash + + $ qemu-system-riscv64 -M microchip-icicle-kit -smp 5 -m 2G \ + -sd path/to/sdcard.img \ + -nic user,model=cadence_gem \ + -nic tap,ifname=tap,model=cadence_gem,script=no \ + -display none -serial stdio \ + -kernel path/to/u-boot/build/dir/u-boot.bin \ + -dtb path/to/u-boot/build/dir/u-boot.dtb + +CAVEATS: + +* Check the "stdout-path" property in the /chosen node in the DTB to determine + which serial port is used for the serial console, e.g.: if the console is set + to the second serial port, change to use "-serial null -serial stdio". +* The default U-Boot configuration uses CONFIG_OF_SEPARATE hence the ELF image + ``u-boot`` cannot be passed to "-kernel" as it does not contain the DTB hence + ``u-boot.bin`` has to be used which does contain one. To use the ELF image, + we need to change to CONFIG_OF_EMBED or CONFIG_OF_PRIOR_STAGE. + .. _HSS: https://github.com/polarfire-soc/hart-software-services -- 2.11.0