docs: platform: Describe sifive_fu540 as supported generic platform

The upstream U-Boot/QEMU have been using generic platform for SiFive
HiFive Unleashed board for some time. Let's document sifive_fu540 as
one of the supported targets for "generic" platform.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

docs/platform/generic.md

@@ -47,10 +47,12 @@ RISC-V Platforms Using Generic Platform
 
 * **QEMU RISC-V Virt Machine** (*[qemu_virt.md]*)
 * **Shakti C-class SoC Platform** (*[shakti_cclass.md]*)
+* **SiFive HiFive Unleashed** (*[sifive_fu540.md]*)
 * **Spike** (*[spike.md]*)
 * **T-HEAD C9xx series Processors** (*[thead-c9xx.md]*)
 
 [qemu_virt.md]: qemu_virt.md
 [shakti_cclass.md]: shakti_cclass.md
+[sifive_fu540.md]: sifive_fu540.md
 [spike.md]: spike.md
 [thead-c9xx.md]: thead-c9xx.md

docs/platform/sifive_fu540.md

@@ -8,7 +8,7 @@ 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=generic* parameter to the top level `make` command.
 
 Platform Options
 ----------------
@@ -32,10 +32,10 @@ To use Linux v5.2 (or higher), the pre-built DTB (DT binary) from Linux v5.2
 the compile time option *FW_FDT_PATH*.
 
 ```
-make PLATFORM=sifive/fu540 FW_PAYLOAD_PATH=<linux_build_directory>/arch/riscv/boot/Image
+make PLATFORM=generic 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>
+make PLATFORM=generic FW_PAYLOAD_PATH=<linux_build_directory>/arch/riscv/boot/Image FW_FDT_PATH=<hifive-unleashed-a00.dtb path from Linux kernel>
 ```
 
 **U-Boot Payload**
@@ -45,7 +45,7 @@ sifive_fu540_defconfig configuration and with U-Boot v2020.01, and up to
 v2021.04. sifive_unleashed_defconfig shall be used with v2021.07 or above.
 
 ```
-make PLATFORM=sifive/fu540 FW_PAYLOAD_PATH=<u-boot_build_dir>/u-boot-dtb.bin
+make PLATFORM=generic 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].
@@ -64,7 +64,7 @@ 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
+dd if=build/platform/generic/firmware/fw_payload.bin of=/dev/disk2s1 bs=1024
 ```
 
 In my case, it is the first partition is **disk2s1** that has been formatted
@@ -161,7 +161,7 @@ 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
+make PLATFORM=generic FW_PAYLOAD_PATH=<u-boot_build_dir>/u-boot.bin
 ```
 
 U-Boot v2020.07 release added SPL support to SiFive HiFive Unleashed board,
@@ -179,12 +179,12 @@ 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
+	-bios build/platform/generic/firmware/fw_payload.bin
 ```
 or
 ```
 qemu-system-riscv64 -M sifive_u -m 256M -nographic \
-	-bios build/platform/sifive/fu540/firmware/fw_jump.bin \
+	-bios build/platform/generic/firmware/fw_jump.bin \
 	-kernel <uboot_build_dir>/u-boot.bin
 ```