From e158a6520a690b98242b9ecb53d25aa639641547 Mon Sep 17 00:00:00 2001 From: Sunil V L Date: Thu, 1 Jun 2023 10:29:10 +0530 Subject: [PATCH] docs/system: riscv: Add pflash usage details MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit pflash devices can be used in virt machine for different purposes like for ROM code or S-mode FW payload. Add a section in the documentation on how to use pflash devices for different purposes. Signed-off-by: Sunil V L Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Alistair Francis Message-Id: <20230601045910.18646-4-sunilvl@ventanamicro.com> Signed-off-by: Alistair Francis --- docs/system/riscv/virt.rst | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/docs/system/riscv/virt.rst b/docs/system/riscv/virt.rst index 4b16e41d7f..b33f45e5b3 100644 --- a/docs/system/riscv/virt.rst +++ b/docs/system/riscv/virt.rst @@ -53,6 +53,37 @@ with the default OpenSBI firmware image as the -bios. It also supports the recommended RISC-V bootflow: U-Boot SPL (M-mode) loads OpenSBI fw_dynamic firmware and U-Boot proper (S-mode), using the standard -bios functionality. +Using flash devices +------------------- + +By default, the first flash device (pflash0) is expected to contain +S-mode firmware code. It can be configured as read-only, with the +second flash device (pflash1) available to store configuration data. + +For example, booting edk2 looks like + +.. code-block:: bash + + $ qemu-system-riscv64 \ + -blockdev node-name=pflash0,driver=file,read-only=on,filename= \ + -blockdev node-name=pflash1,driver=file,filename= \ + -M virt,pflash0=pflash0,pflash1=pflash1 \ + ... other args .... + +For TCG guests only, it is also possible to boot M-mode firmware from +the first flash device (pflash0) by additionally passing ``-bios +none``, as in + +.. code-block:: bash + + $ qemu-system-riscv64 \ + -bios none \ + -blockdev node-name=pflash0,driver=file,read-only=on,filename= \ + -M virt,pflash0=pflash0 \ + ... other args .... + +Firmware images used for pflash must be exactly 32 MiB in size. + Machine-specific options ------------------------ -- 2.11.4.GIT