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authorSunil V L <sunilvl@ventanamicro.com>2023-06-01 10:29:10 +0530
committerAlistair Francis <alistair.francis@wdc.com>2023-06-13 17:41:01 +1000
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parent13bdfb8b5487ad5f68529a53bff09e8a57482206 (diff)
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docs/system: riscv: Add pflash usage details
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 <sunilvl@ventanamicro.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-Id: <20230601045910.18646-4-sunilvl@ventanamicro.com> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Diffstat (limited to 'docs')
-rw-r--r--docs/system/riscv/virt.rst31
1 files changed, 31 insertions, 0 deletions
diff --git a/docs/system/riscv/virt.rst b/docs/system/riscv/virt.rst
index 4b16e41..b33f45e 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=<edk2_code> \
+ -blockdev node-name=pflash1,driver=file,filename=<edk2_vars> \
+ -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_mode_code> \
+ -M virt,pflash0=pflash0 \
+ ... other args ....
+
+Firmware images used for pflash must be exactly 32 MiB in size.
+
Machine-specific options
------------------------