[PATCH V2 0/7] riscv: spl: OpenSBI OS boot mode

[Randolph]

Introduce a shortcut boot mode for RISC-V. 

As we know, in ARM architecture has the Falcon mode to do the shortcut
boot to the Linux kernel. (by enabling CONFIG_SPL_OS_BOOT)
ARM Falcon mode boot flow would be as follows:
u-boot SPL -> Linux kernel

But for RISC-V, OpenSBI is required to allows the supervisor to execute
some privileged operations.
The RISC-V Normal boot flow as follows:
u-boot SPL -> OpenSBI -> u-boot proper -> Linux kernel

Quoting the same ideas as ARM's Falcon mode,
OpenSBI OS boot flow as follows:
u-boot SPL -> OpenSBI -> Linux kernel

An important part of OpenSBI OS boot mode is to prepare the device tree. 
A normal U-Boot does FDT fixups when booting Linux. 
For OpenSBI OS boot mode, Linux boots directly from SPL, 
skipping the normal U-Boot. 
The device tree has to be prepared in advance.
The device tree in memory is the one needed for OpenSBI OS boot mode.

The Linux kernel image will also need to be provided for the generation
of the FIT file.

Changes in v2:
- change the order from Patch 3/7 in V1 to Patch 1/7 in V2
- merge the OPENSBI_OS_BOOT related logic into binman.dtsi
- change by suggestions 
- add a new patch to delete the output file when make clean.

Randolph (7):
  spl: riscv: opensbi: change the default os_type as varible
  riscv: kconfig: introduce SPL_LOAD_FIT_OPENSBI_OS_BOOT symbol
  riscv: dts: binman: add condition for opensbi os boot
  Makefile: delete file *.itb when make clean
  spl: riscv: add os type for next booting stage
  andes: config: add riscv falcon mode for ae350 platform
  riscv: spl: andes: Move the DTB in front of kernel

 Makefile                                |  2 +-
 arch/riscv/Kconfig                      |  8 ++++
 arch/riscv/dts/binman.dtsi              | 24 ++++++++++
 board/AndesTech/ae350/ae350.c           | 25 ++++++++++
 common/spl/spl_fit.c                    |  3 +-
 common/spl/spl_opensbi.c                | 31 +++++++++----
 configs/ae350_rv32_falcon_defconfig     | 60 ++++++++++++++++++++++++
 configs/ae350_rv32_falcon_xip_defconfig | 61 +++++++++++++++++++++++++
 configs/ae350_rv64_falcon_defconfig     | 60 ++++++++++++++++++++++++
 configs/ae350_rv64_falcon_xip_defconfig | 61 +++++++++++++++++++++++++
 10 files changed, 323 insertions(+), 12 deletions(-)
 create mode 100644 configs/ae350_rv32_falcon_defconfig
 create mode 100644 configs/ae350_rv32_falcon_xip_defconfig
 create mode 100644 configs/ae350_rv64_falcon_defconfig
 create mode 100644 configs/ae350_rv64_falcon_xip_defconfig

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2.34.1