11 files changed, 736 insertions, 0 deletions
diff --git a/roms/opensbi/docs/platform/andes-ae350.md b/roms/opensbi/docs/platform/andes-ae350.md
new file mode 100644
index 000000000..46889a1f1
--- /dev/null
+++ b/roms/opensbi/docs/platform/andes-ae350.md
@@ -0,0 +1,30 @@
+Andes AE350 SoC Platform
+========================
+The AE350 AXI/AHB-based platform N25(F)/NX25(F)/D25F/A25/AX25 CPU with level-one
+memories,interrupt controller, debug module, AXI and AHB Bus Matrix Controller,
+AXI-to-AHB Bridge and a collection of fundamentalAHB/APB bus IP components
+pre-integrated together as a system design.The high-quality and configurable
+AHB/APB IPs suites a majority embedded systems, and the verified platform serves
+as a starting point to jump start SoC designs.
+
+To build platform specific library and firmwares, provide the
+*PLATFORM=andes/ae350* parameter to the top level make command.
+
+Platform Options
+----------------
+
+The Andes AE350 platform does not have any platform-specific options.
+
+Building Andes AE350 Platform
+-----------------------------
+
+To use Linux v5.2 should be used to build Andes AE350 OpenSBI binaries by using
+the compile time option FW_FDT_PATH.
+
+AE350's dts is included in https://github.com/andestech/linux/tree/ast-v3_2_0-release-public
+
+**Linux Kernel Payload**
+
+```
+make PLATFORM=andes/ae350 FW_PAYLOAD_PATH=<linux_build_directory>/arch/riscv/boot/Image FW_FDT_PATH=<ae350.dtb path>
+```
diff --git a/roms/opensbi/docs/platform/fpga-ariane.md b/roms/opensbi/docs/platform/fpga-ariane.md
new file mode 100644
index 000000000..f95001fb3
--- /dev/null
+++ b/roms/opensbi/docs/platform/fpga-ariane.md
@@ -0,0 +1,38 @@
+Ariane FPGA SoC Platform
+========================
+Ariane is a 6-stage, single issue, in-order CPU which implements the 64-bit
+RISC-V instruction set. The Ariane FPGA development platform is based on FPGA
+SoC (which currently supports only Genesys 2 board) and is capable of running
+Linux.
+
+The FPGA SoC currently contains the following peripherals:
+- DDR3 memory controller
+- SPI controller to conncet to an SDCard
+- Ethernet controller
+- JTAG port (see debugging section below)
+- Bootrom containing zero stage bootloader and device tree.
+
+To build platform specific library and firmwares, provide the
+*PLATFORM=fpga/ariane* parameter to the top level `make` command.
+
+Platform Options
+----------------
+
+The *Ariane FPGA* platform does not have any platform-specific options.
+
+Building Ariane FPGA Platform
+-----------------------------
+
+**Linux Kernel Payload**
+
+```
+make PLATFORM=fpga/ariane FW_PAYLOAD_PATH=<linux_build_directory>/arch/riscv/boot/Image
+```
+
+Booting Ariane FPGA Platform
+----------------------------
+
+**Linux Kernel Payload**
+
+As Linux kernel image is embedded in the OpenSBI firmware binary, Ariane will
+directly boot into Linux directly after powered on.
diff --git a/roms/opensbi/docs/platform/fpga-openpiton.md b/roms/opensbi/docs/platform/fpga-openpiton.md
new file mode 100644
index 000000000..7861a197c
--- /dev/null
+++ b/roms/opensbi/docs/platform/fpga-openpiton.md
@@ -0,0 +1,33 @@
+OpenPiton FPGA SoC Platform
+========================
+OpenPiton is the world's first open source, general purpose, multithreaded
+manycore processor. It is a tiled manycore framework scalable from one to
+1/2 billion cores. Currently, OpenPiton supports the 64bit Ariane RISC-V
+processor from ETH Zurich. To this end, Ariane has been equipped with a
+different L1 cache subsystem that follows a write-through protocol and that has
+support for cache invalidations and atomics.
+
+To build platform specific library and firmwares, provide the
+*PLATFORM=fpga/openpiton* parameter to the top level `make` command.
+
+Platform Options
+----------------
+
+The *OpenPiton* platform does not have any platform-specific options.
+
+Building Ariane FPGA Platform
+-----------------------------
+
+**Linux Kernel Payload**
+
+```
+make PLATFORM=fpga/openpiton FW_PAYLOAD_PATH=<linux_build_directory>/arch/riscv/boot/Image
+```
+
+Booting Ariane FPGA Platform
+----------------------------
+
+**Linux Kernel Payload**
+
+As Linux kernel image is embedded in the OpenSBI firmware binary, Ariane will
+directly boot into Linux directly after powered on.
diff --git a/roms/opensbi/docs/platform/generic.md b/roms/opensbi/docs/platform/generic.md
new file mode 100644
index 000000000..f1f7f6424
--- /dev/null
+++ b/roms/opensbi/docs/platform/generic.md
@@ -0,0 +1,54 @@
+Generic Platform
+================
+
+The **Generic** platform is a flattened device tree (FDT) based platform
+where all platform specific functionality is provided based on FDT passed
+by previous booting stage. The **Generic** platform allows us to use same
+OpenSBI firmware binaries on various emulators, simulators, FPGAs, and
+boards.
+
+By default, the generic FDT platform makes following assumptions:
+
+1. platform FW_TEXT_START is 0x80000000
+2. platform features are default
+3. platform stack size is default
+4. platform has no quirks or work-arounds
+
+The above assumptions (except 1) can be overridden by adding special platform
+callbacks which will be called based on FDT root node compatible string.
+
+Users of the generic FDT platform will have to ensure that:
+
+1. Various FDT based drivers under lib/utils directory are upto date
+   based on their platform requirements
+2. The FDT passed by previous booting stage has DT compatible strings and
+   DT properties in sync with the FDT based drivers under lib/utils directory
+3. The FDT must have "stdout-path" DT property in the "/chosen" DT node when
+   a platform has multiple serial ports or consoles
+4. On multi-HART platform, the FDT must have a DT node for IPI device and
+   lib/utils/ipi directory must have corresponding FDT based IPI driver
+5. The FDT must have a DT node for timer device and lib/utils/timer directory
+   must have corresponding FDT based timer driver
+
+To build the platform-specific library and firmware images, provide the
+*PLATFORM=generic* parameter to the top level `make` command.
+
+For custom FW_TEXT_START, we can build the platform-specific library and
+firmware images by passing *PLATFORM=generic FW_TEXT_START=<custom_text_start>*
+parameter to the top level `make` command.
+
+Platform Options
+----------------
+
+The *Generic* platform does not have any platform-specific options.
+
+RISC-V Platforms Using Generic Platform
+---------------------------------------
+
+* **QEMU RISC-V Virt Machine** (*[qemu_virt.md]*)
+* **Spike** (*[spike.md]*)
+* **Shakti C-class SoC Platform** (*[shakti_cclass.md]*)
+
+[qemu_virt.md]: qemu_virt.md
+[spike.md]: spike.md
+[shakti_cclass.md]: shakti_cclass.md
diff --git a/roms/opensbi/docs/platform/nuclei_ux600.md b/roms/opensbi/docs/platform/nuclei_ux600.md
new file mode 100644
index 000000000..273b6b438
--- /dev/null
+++ b/roms/opensbi/docs/platform/nuclei_ux600.md
@@ -0,0 +1,22 @@
+
+Nuclei UX600 Platform
+=====================
+
+The **Nuclei UX600** is a 64-bit RISC-V Core which is capable of running Linux.
+
+> Nuclei UX600: single core, pipeline as single-issue and 6~9 variable stages, in-order dispatch and out-of-order write-back, running up to >1.2GHz
+
+To build the platform-specific library and firmware images, provide the
+*PLATFORM=nuclei/ux600* parameter to the top level `make` command.
+
+Platform Options
+----------------
+
+The *Nuclei UX600* platform does not have any platform-specific options.
+
+Building Nuclei UX600 Platform
+------------------------------
+
+```
+make PLATFORM=nuclei/ux600 clean all
+```
diff --git a/roms/opensbi/docs/platform/platform.md b/roms/opensbi/docs/platform/platform.md
new file mode 100644
index 000000000..7f4706813
--- /dev/null
+++ b/roms/opensbi/docs/platform/platform.md
@@ -0,0 +1,59 @@
+OpenSBI Supported Platforms
+===========================
+
+OpenSBI currently supports the following virtual and hardware platforms:
+
+* **Generic**: Flattened device tree (FDT) based platform where platform
+  specific functionality is provided based on the FDT passed by previous
+  booting stage. More details on this platform can be found in the file
+  *[generic.md]*.
+
+* **QEMU RISC-V Virt Machine**: Platform support for the QEMU *virt* virtual
+  RISC-V machine. This virtual machine is intended for RISC-V software
+  development and tests. More details on this platform can be found in the
+  file *[qemu_virt.md]*.
+
+* **SiFive FU540 SoC**: Platform support for SiFive FU540 SoC used on the
+  HiFive Unleashed board, as well as the *sifive_u* QEMU virtual RISC-V
+  machine. More details on this platform can be found in the file
+  *[sifive_fu540.md]*.
+
+* **Kendryte K210 SoC**: Platform support for the Kendryte K210 SoC used on
+  boards such as the Kendryte KD233 or the Sipeed MAIX Dock.
+
+* **Ariane FPGA SoC**: Platform support for the Ariane FPGA SoC used on
+  Genesys 2 board. More details on this platform can be found in the file
+  *[fpga-ariane.md]*.
+
+* **Andes AE350 SoC**: Platform support for the Andes's SoC (AE350). More
+  details on this platform can be found in the file *[andes-ae350.md]*.
+
+* **T-HEAD C910**: Platform support for the T-HEAD C910 Processor. More
+  details on this platform can be found in the file *[thead-c910.md]*.
+
+* **Spike**: Platform support for the Spike emulator. More
+  details on this platform can be found in the file *[spike.md]*.
+
+* **OpenPiton FPGA SoC**: Platform support OpenPiton research platform based
+  on ariane core. More details on this platform can be found in the file
+  *[fpga_openpiton.md]*.
+
+* **Shakti C-class SoC Platform**: Platform support for Shakti C-class
+  processor based SOCs. More details on this platform can be found in the
+  file *[shakti_cclass.md]*.
+
+The code for these supported platforms can be used as example to implement
+support for other platforms. The *platform/template* directory also provides
+template files for implementing support for a new platform. The *object.mk*,
+*config.mk* and *platform.c* template files provides enough comments to
+facilitate the implementation.
+
+[generic.md]: generic.md
+[qemu_virt.md]: qemu_virt.md
+[sifive_fu540.md]: sifive_fu540.md
+[fpga-ariane.md]: fpga-ariane.md
+[andes-ae350.md]: andes-ae350.md
+[thead-c910.md]: thead-c910.md
+[spike.md]: spike.md
+[fpga_openpiton.md]: fpga_openpiton.md
+[shakti_cclass.md]: shakti_cclass.md
diff --git a/roms/opensbi/docs/platform/qemu_virt.md b/roms/opensbi/docs/platform/qemu_virt.md
new file mode 100644
index 000000000..27771485c
--- /dev/null
+++ b/roms/opensbi/docs/platform/qemu_virt.md
@@ -0,0 +1,149 @@
+QEMU RISC-V Virt Machine Platform
+=================================
+
+The **QEMU RISC-V Virt Machine** is a virtual platform created for RISC-V
+software development and testing. It is also referred to as
+*QEMU RISC-V VirtIO machine* because it uses VirtIO devices for network,
+storage, and other types of IO.
+
+To build the platform-specific library and firmware images, provide the
+*PLATFORM=generic* parameter to the top level `make` command.
+
+Platform Options
+----------------
+
+The *QEMU RISC-V Virt Machine* platform does not have any platform-specific
+options.
+
+Execution on QEMU RISC-V 64-bit
+-------------------------------
+
+**No Payload Case**
+
+Build:
+```
+make PLATFORM=generic
+```
+
+Run:
+```
+qemu-system-riscv64 -M virt -m 256M -nographic \
+	-bios build/platform/generic/firmware/fw_payload.bin
+```
+
+**U-Boot Payload**
+
+Note: the command line examples here assume that U-Boot was compiled using
+the `qemu-riscv64_smode_defconfig` configuration.
+
+Build:
+```
+make PLATFORM=generic FW_PAYLOAD_PATH=<uboot_build_directory>/u-boot.bin
+```
+
+Run:
+```
+qemu-system-riscv64 -M virt -m 256M -nographic \
+	-bios build/platform/generic/firmware/fw_payload.elf
+```
+or
+```
+qemu-system-riscv64 -M virt -m 256M -nographic \
+	-bios build/platform/generic/firmware/fw_jump.bin \
+	-kernel <uboot_build_directory>/u-boot.bin
+```
+
+**Linux Kernel Payload**
+
+Note: We assume that the Linux kernel is compiled using
+*arch/riscv/configs/defconfig*.
+
+Build:
+```
+make PLATFORM=generic FW_PAYLOAD_PATH=<linux_build_directory>/arch/riscv/boot/Image
+```
+
+Run:
+```
+qemu-system-riscv64 -M virt -m 256M -nographic \
+	-bios build/platform/generic/firmware/fw_payload.elf \
+	-drive file=<path_to_linux_rootfs>,format=raw,id=hd0 \
+	-device virtio-blk-device,drive=hd0 \
+	-append "root=/dev/vda rw console=ttyS0"
+```
+or
+```
+qemu-system-riscv64 -M virt -m 256M -nographic \
+	-bios build/platform/generic/firmware/fw_jump.bin \
+	-kernel <linux_build_directory>/arch/riscv/boot/Image \
+	-drive file=<path_to_linux_rootfs>,format=raw,id=hd0 \
+	-device virtio-blk-device,drive=hd0 \
+	-append "root=/dev/vda rw console=ttyS0"
+```
+
+
+Execution on QEMU RISC-V 32-bit
+-------------------------------
+
+**No Payload Case**
+
+Build:
+```
+make PLATFORM=generic PLATFORM_RISCV_XLEN=32
+```
+
+Run:
+```
+qemu-system-riscv32 -M virt -m 256M -nographic \
+	-bios build/platform/generic/firmware/fw_payload.bin
+```
+
+**U-Boot Payload**
+
+Note: the command line examples here assume that U-Boot was compiled using
+the `qemu-riscv32_smode_defconfig` configuration.
+
+Build:
+```
+make PLATFORM=generic PLATFORM_RISCV_XLEN=32 FW_PAYLOAD_PATH=<uboot_build_directory>/u-boot.bin
+```
+
+Run:
+```
+qemu-system-riscv32 -M virt -m 256M -nographic \
+	-bios build/platform/generic/firmware/fw_payload.elf
+```
+or
+```
+qemu-system-riscv32 -M virt -m 256M -nographic \
+	-bios build/platform/generic/firmware/fw_jump.bin \
+	-kernel <uboot_build_directory>/u-boot.bin
+```
+
+**Linux Kernel Payload**
+
+Note: We assume that the Linux kernel is compiled using
+*arch/riscv/configs/rv32_defconfig*.
+
+Build:
+```
+make PLATFORM=generic PLATFORM_RISCV_XLEN=32 FW_PAYLOAD_PATH=<linux_build_directory>/arch/riscv/boot/Image
+```
+
+Run:
+```
+qemu-system-riscv32 -M virt -m 256M -nographic \
+	-bios build/platform/generic/firmware/fw_payload.elf \
+	-drive file=<path_to_linux_rootfs>,format=raw,id=hd0 \
+	-device virtio-blk-device,drive=hd0 \
+	-append "root=/dev/vda rw console=ttyS0"
+```
+or
+```
+qemu-system-riscv32 -M virt -m 256M -nographic \
+	-bios build/platform/generic/firmware/fw_jump.bin \
+	-kernel <linux_build_directory>/arch/riscv/boot/Image \
+	-drive file=<path_to_linux_rootfs>,format=raw,id=hd0 \
+	-device virtio-blk-device,drive=hd0 \
+	-append "root=/dev/vda rw console=ttyS0"
+```
diff --git a/roms/opensbi/docs/platform/shakti_cclass.md b/roms/opensbi/docs/platform/shakti_cclass.md
new file mode 100644
index 000000000..05c9b3a4c
--- /dev/null
+++ b/roms/opensbi/docs/platform/shakti_cclass.md
@@ -0,0 +1,33 @@
+Shakti C-class SoC Platform
+===========================
+C-Class is a member of the SHAKTI family of processors from
+Indian Institute of Technology - Madras (IIT-M).
+
+It is an extremely configurable and commercial-grade 5-stage
+in-order core supporting the standard RV64GCSUN ISA extensions.
+
+For more details, refer:
+* https://gitlab.com/shaktiproject/cores/c-class/blob/master/README.md
+* https://c-class.readthedocs.io/en/latest
+* https://shakti.org.in
+
+Platform Options
+----------------
+
+The *Shakti C-class SoC* platform does not have any platform-specific
+options.
+
+Building Shakti C-class Platform
+--------------------------------
+
+**Linux Kernel Payload**
+
+```
+make PLATFORM=generic FW_PAYLOAD_PATH=<linux_build_directory>/arch/riscv/boot/Image FW_FDT_PATH=<shakti.dtb path>
+```
+
+**Test Payload**
+
+```
+make PLATFORM=generic FW_FDT_PATH=<shakti.dtb path>
+```
diff --git a/roms/opensbi/docs/platform/sifive_fu540.md b/roms/opensbi/docs/platform/sifive_fu540.md
new file mode 100644
index 000000000..b4d3c6051
--- /dev/null
+++ b/roms/opensbi/docs/platform/sifive_fu540.md
@@ -0,0 +1,195 @@
+SiFive FU540 SoC Platform
+=========================
+The FU540-C000 is the world’s first 4+1 64-bit RISC-V SoC from SiFive.
+The HiFive Unleashed development platform is based on FU540-C000 and capable
+of running Linux.
+
+With QEMU v4.2 or above release, the 'sifive_u' machine can be used to test
+OpenSBI image built for the real hardware as well.
+
+To build platform specific library and firmwares, provide the
+*PLATFORM=sifive/fu540* parameter to the top level `make` command.
+
+Platform Options
+----------------
+
+The *SiFive FU540 SoC* platform does not have any platform-specific
+options.
+
+Building SiFive Fu540 Platform
+------------------------------
+
+In order to boot SMP Linux in U-Boot, Linux v5.1 (or higher) and latest
+U-Boot v2020.01 (or higher) should be used.
+
+**Linux Kernel Payload**
+
+The HiFive Unleashed device tree(DT) is merged in Linux v5.2 release. This
+DT (device tree) is not backward compatible with the DT passed from FSBL.
+
+To use Linux v5.2 (or higher), the pre-built DTB (DT binary) from Linux v5.2
+(or higher) should be used to build SiFive FU540 OpenSBI binaries by using
+the compile time option *FW_FDT_PATH*.
+
+```
+make PLATFORM=sifive/fu540 FW_PAYLOAD_PATH=<linux_build_directory>/arch/riscv/boot/Image
+or
+(For Linux v5.2 or higher)
+make PLATFORM=sifive/fu540 FW_PAYLOAD_PATH=<linux_build_directory>/arch/riscv/boot/Image FW_FDT_PATH=<hifive-unleashed-a00.dtb path from Linux kernel>
+```
+
+**U-Boot Payload**
+
+The command-line example here assumes that U-Boot was compiled using the
+sifive_fu540_defconfig configuration and with U-Boot v2020.01, and up to
+v2020.07-rc3.
+
+```
+make PLATFORM=sifive/fu540 FW_PAYLOAD_PATH=<u-boot_build_dir>/u-boot-dtb.bin
+```
+For U-Boot v2020.07-rc4 or later releases, SPL support was added in U-Boot.
+Please refer to the detailed U-Boot booting guide available at [U-Boot].
+
+Flashing the OpenSBI firmware binary to storage media:
+------------------------------------------------------
+The first stage boot loader ([FSBL]) expects the storage media to have a GPT
+partition table. It tries to look for a partition with following GUID to load
+the next stage boot loader (OpenSBI in this case).
+
+```
+2E54B353-1271-4842-806F-E436D6AF6985
+```
+
+That's why the generated firmware binary in above steps should be copied to
+the partition of the sdcard with above GUID.
+
+```
+dd if=build/platform/sifive/fu540/firmware/fw_payload.bin of=/dev/disk2s1 bs=1024
+```
+
+In my case, it is the first partition is **disk2s1** that has been formatted
+with the above specified GUID.
+
+In case of a brand new sdcard, it should be formatted with below partition
+tables as described here.
+
+```
+sgdisk --clear                                                               \
+       --new=1:2048:67583  --change-name=1:bootloader --typecode=1:2E54B353-1271-4842-806F-E436D6AF6985   \
+       --new=2:264192:     --change-name=2:root       --typecode=2:0FC63DAF-8483-4772-8E79-3D69D8477DE4 \
+       ${DISK}
+```
+
+Booting SiFive Fu540 Platform
+-----------------------------
+
+**Linux Kernel Payload**
+
+As Linux kernel image is embedded in the OpenSBI firmware binary, HiFive
+Unleashed will directly boot into Linux directly after powered on.
+
+**U-Boot Payload**
+
+As U-Boot image is used as payload, HiFive Unleashed will boot into a U-Boot
+prompt. U-Boot tftp boot method can be used to load kernel image in U-Boot
+prompt. Here are the steps do a tftpboot.
+
+1. Set the ip address of the board.
+```
+setenv ipaddr <ipaddr of the board>
+```
+2. Set the tftpboot server IP.
+```
+setenv serverip <ipaddr of the tftp server>
+```
+3. Set the network gateway address.
+```
+setenv gatewayip <ipaddress of the network gateway>
+```
+4. Load the Linux kernel image from the tftp server.
+```
+tftpboot ${kernel_addr_r} <Image path in tftpboot directory>
+```
+5. Load the ramdisk image from the tftp server. This is only required if
+ramdisk is loaded from tftp server. This step is optional, if rootfs is
+already part of the kernel or loaded from an external storage by kernel.
+```
+tftpboot ${ramdisk_addr_r} <ramdisk path in tftpboot directory>
+```
+6. Load the pre-compiled device tree via tftpboot.
+```
+tftpboot ${fdt_addr_r} <hifive-unleashed-a00.dtb path in tftpboot directory>
+```
+7. Set the boot command-line arguments.
+```
+setenv bootargs "root=<root partition> rw console=ttySIF0 earlycon=sbi"
+```
+(Note: root partition should point to
+** /dev/ram ** - If a ramdisk is used
+** root=/dev/mmcblk0pX ** - If a rootfs is already on some other partition
+of sdcard)
+8. Now boot into Linux.
+```
+booti ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr_r}
+or
+(If ramdisk is not loaded from network)
+booti ${kernel_addr_r} - ${fdt_addr_r}
+```
+
+**U-Boot & Linux Kernel as a single payload**
+
+At U-Boot prompt execute the following boot command to boot Linux.
+
+```
+booti ${kernel_addr_r} - ${fdt_addr_r}
+```
+
+QEMU Specific Instructions
+--------------------------
+If you want to test OpenSBI with QEMU 'sifive_u' machine, please follow the
+same instructions above, with the exception of not passing FW_FDT_PATH.
+
+This is because QEMU generates a device tree blob on the fly based on the
+command line parameters and it's compatible with the one used in the upstream
+Linux kernel.
+
+When U-Boot v2020.01 (or higher) is used as the payload, as the SiFive FU540
+DTB for the real hardware is embedded in U-Boot binary itself, due to the same
+reason above, we need to switch the U-Boot sifive_fu540_defconfig configuration
+from **CONFIG_OF_SEPARATE** to **CONFIG_OF_PRIOR_STAGE** so that U-Boot uses the
+DTB generated by QEMU, and u-boot.bin should be used as the payload image, like:
+
+```
+make PLATFORM=sifive/fu540 FW_PAYLOAD_PATH=<u-boot_build_dir>/u-boot.bin
+```
+
+U-Boot v2020.07 release added SPL support to SiFive HiFive Unleashed board,
+hence a build error will be seen after you switch to **CONFIG_OF_PRIOR_STAGE**.
+
+```
+./tools/mkimage: Can't open arch/riscv/dts/hifive-unleashed-a00.dtb: No such file or directory
+./tools/mkimage: failed to build FIT
+Makefile:1402: recipe for target 'u-boot.img' failed
+make: *** [u-boot.img] Error 1
+```
+
+The above errors can be safely ignored as we don't run U-Boot SPL under QEMU.
+
+Run:
+```
+qemu-system-riscv64 -M sifive_u -m 256M -nographic \
+	-bios build/platform/sifive/fu540/firmware/fw_payload.bin
+```
+or
+```
+qemu-system-riscv64 -M sifive_u -m 256M -nographic \
+	-bios build/platform/sifive/fu540/firmware/fw_jump.bin \
+	-kernel <uboot_build_dir>/u-boot.bin
+```
+
+While the real hardware operates at the 64-bit mode, it's possible for QEMU to
+test the 32-bit OpenSBI firmware. This can be helpful for testing 32-bit SiFive
+specific drivers.
+
+[U-Boot]: https://gitlab.denx.de/u-boot/u-boot/blob/master/doc/board/sifive/fu540.rst
+[FSBL]: https://github.com/sifive/freedom-u540-c000-bootloader
diff --git a/roms/opensbi/docs/platform/spike.md b/roms/opensbi/docs/platform/spike.md
new file mode 100644
index 000000000..79e2eb2b0
--- /dev/null
+++ b/roms/opensbi/docs/platform/spike.md
@@ -0,0 +1,89 @@
+Spike Simulator Platform
+========================
+
+The **Spike** is a RISC-V ISA simulator which implements a functional model
+of one or more RISC-V harts. The **Spike** compatible virtual platform is
+also available on QEMU. In fact, we can use same OpenSBI firmware binaries
+on **Spike** simulator and QEMU Spike machine.
+
+For more details, refer [Spike on GitHub](https://github.com/riscv/riscv-isa-sim)
+
+To build the platform-specific library and firmware images, provide the
+*PLATFORM=generic* parameter to the top level `make` command.
+
+Platform Options
+----------------
+
+The *Spike* platform does not have any platform-specific options.
+
+Execution on Spike Simulator
+----------------------------
+
+**No Payload Case**
+
+Build:
+```
+make PLATFORM=generic
+```
+
+Run:
+```
+spike build/platform/generic/firmware/fw_payload.elf
+```
+
+**Linux Kernel Payload**
+
+Note: We assume that the Linux kernel is compiled using
+*arch/riscv/configs/defconfig*.
+
+Build:
+```
+make PLATFORM=generic FW_PAYLOAD_PATH=<linux_build_directory>/arch/riscv/boot/Image
+```
+
+Run:
+```
+spike --initrd <path_to_cpio_ramdisk> build/platform/generic/firmware/fw_payload.elf
+```
+
+Execution on QEMU RISC-V 64-bit
+-------------------------------
+
+**No Payload Case**
+
+Build:
+```
+make PLATFORM=generic
+```
+
+Run:
+```
+qemu-system-riscv64 -M spike -m 256M -nographic \
+	-bios build/platform/generic/firmware/fw_payload.elf
+```
+
+**Linux Kernel Payload**
+
+Note: We assume that the Linux kernel is compiled using
+*arch/riscv/configs/defconfig*.
+
+Build:
+```
+make PLATFORM=generic FW_PAYLOAD_PATH=<linux_build_directory>/arch/riscv/boot/Image
+```
+
+Run:
+```
+qemu-system-riscv64 -M spike -m 256M -nographic \
+	-bios build/platform/generic/firmware/fw_payload.elf \
+	-initrd <path_to_cpio_ramdisk> \
+	-append "root=/dev/ram rw console=hvc0 earlycon=sbi"
+```
+or
+```
+qemu-system-riscv64 -M spike -m 256M -nographic \
+	-bios build/platform/generic/firmware/fw_jump.elf \
+	-kernel <linux_build_directory>/arch/riscv/boot/Image \
+	-initrd <path_to_cpio_ramdisk> \
+	-append "root=/dev/ram rw console=hvc0 earlycon=sbi"
+```
diff --git a/roms/opensbi/docs/platform/thead-c910.md b/roms/opensbi/docs/platform/thead-c910.md
new file mode 100644
index 000000000..786b47d03
--- /dev/null
+++ b/roms/opensbi/docs/platform/thead-c910.md
@@ -0,0 +1,34 @@
+T-HEAD C910 Processor
+=====================
+C910 is a 12-stage, 3 issues, 8 executions, out-of-order 64-bit RISC-V CPU which
+supports 16 cores, runs with 2.5GHz, and is capable of running Linux.
+
+To build platform specific library and firmwares, provide the
+*PLATFORM=thead/c910* parameter to the top level make command.
+
+Platform Options
+----------------
+
+The *T-HEAD C910* platform does not have any platform-specific options.
+
+Building T-HEAD C910 Platform
+-----------------------------
+
+```
+make PLATFORM=thead/c910
+```
+
+Booting T-HEAD C910 Platform
+----------------------------
+
+**No Payload**
+
+As there's no payload, you may download vmlinux or u-boot to FW_JUMP_ADDR which
+specified in config.mk or compile commands with GDB. And the execution flow will
+turn to vmlinux or u-boot when opensbi ends.
+
+**Linux Kernel Payload**
+
+You can also choose to use Linux kernel as payload by enabling FW_PAYLOAD=y
+along with specifying FW_PAYLOAD_OFFSET. The kernel image will be embedded in
+the OPENSBI firmware binary, T-head will directly boot into Linux after OpenSBI.