platform: Drop qemu/sifive_u support

With QEMU v4.2 RISC-V changes to improve the emulation fidelity
of 'sifive_u' machine, OpenSBI v0.4 / U-Boot v2019.10 / Linux
kernel v5.3 images built for the SiFive HiFive Unleashed board
can be used out of the box without any special hack. Hence there
is no need for us to continue supporting such a special target in
OpenSBI. Going forward, sifive/fu540 platform can be used on both
real hardware and QEMU 'sifive_u' machine.

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

4 files changed, 8 insertions, 76 deletions

diff --git a/docs/firmware/fw_jump.md b/docs/firmware/fw_jump.md
index 21161b0..4faaf50 100644
--- a/docs/firmware/fw_jump.md
+++ b/docs/firmware/fw_jump.md
@@ -44,9 +44,8 @@ follows:
 *FW_JUMP* Example
 -----------------
 
-The *[qemu/virt]* and *[qemu/sifive_u]* platforms illustrate how to configure
-and use a *FW_JUMP* firmware. Detailed information regarding these platforms
-can be found in the platform documentation files.
+The *[qemu/virt]* platform illustrates how to configure and use a *FW_JUMP*
+firmware. Detailed information regarding these platforms can be found in the
+platform documentation files.
 
 [qemu/virt]: ../platform/qemu_virt.md
-[qemu/sifive_u]: ../platform/qemu_sifive_u.md
diff --git a/docs/firmware/fw_payload.md b/docs/firmware/fw_payload.md
index 1efe765..3fb3ffc 100644
--- a/docs/firmware/fw_payload.md
+++ b/docs/firmware/fw_payload.md
@@ -79,12 +79,11 @@ file. The parameters currently defined are as follows:
 *FW_PAYLOAD* Example
 --------------------
 
-The *[qemu/virt]* and *[qemu/sifive_u]* platforms illustrate how to configure
-and use a *FW_PAYLOAD* firmware. Detailed information regarding these platforms
-can be found in the platform documentation files.
+The *[qemu/virt]* platforms illustrate how to configure and use a *FW_PAYLOAD*
+firmware. Detailed information regarding these platforms can be found in the
+platform documentation files.
 
 The *kendryte/k210* platform also enables a build of a *FW_PAYLOAD* using an
 internally defined device tree file (*FW_PAYLOAD_FDT*).
 
 [qemu/virt]: ../platform/qemu_virt.md
-[qemu/sifive_u]: ../platform/qemu_sifive_u.md
diff --git a/docs/platform/platform.md b/docs/platform/platform.md
index 17cbfb8..d977646 100644
--- a/docs/platform/platform.md
+++ b/docs/platform/platform.md
@@ -8,14 +8,9 @@ OpenSBI currently supports the following virtual and hardware platforms:
   development and tests. More details on this platform can be found in the
   file *[qemu_virt.md]*.
 
-* **QEMU SiFive Unleashed Machine**: Platform support for the *sifive_u* QEMU
-  virtual RISC-V machine. This is an emulation machine of the HiFive Unleashed
-  board by SiFive. More details on this platform can be found in the file
-  *[qemu_sifive_u.md]*.
-
 * **SiFive FU540 SoC**: Platform support for SiFive FU540 SoC used on the
-  HiFive Unleashed board. This platform is very similar to the *QEMU sifive_u*
-  platform. More details on this platform can be found in the file
+  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
@@ -35,7 +30,6 @@ template files for implementing support for a new platform. The *object.mk*,
 facilitate the implementation.
 
 [qemu_virt.md]: qemu_virt.md
-[qemu_sifive_u.md]: qemu_sifive_u.md
 [sifive_fu540.md]: sifive_fu540.md
 [ariane-fpga.md]: ariane-fpga.md
 [andes_ae350.md]: andes-ae350.md
diff --git a/docs/platform/qemu_sifive_u.md b/docs/platform/qemu_sifive_u.md
deleted file mode 100644
index b5c4f0e..0000000
--- a/docs/platform/qemu_sifive_u.md
+++ /dev/null
@@ -1,60 +0,0 @@
-QEMU SiFive Unleashed Machine Platform
-======================================
-
-The **QEMU SiFive Unleashed Machine** is an emulation of the SiFive Unleashed
-platform.
-
-To build this platform specific library and firmwares, provide the
-*PLATFORM=qemu/sifive_u* parameter to the top level `make` command line.
-
-Note with QEMU v4.2 release, the QEMU *sifive_u* machine has been updated to
-closely match the SiFive HiFive Unleashed hardware and can therefore run the
-same firmware as what gets loaded onto the board, and OpenSBI's *qemu/sifive_u*
-platform should only be used with QEMU v4.1 release or before.
-
-The special *qemu/sifive_u* platform support will be dropped in the future
-OpenSBI release.
-
-Platform Options
-----------------
-
-The *QEMU SiFive Unleashed Machine* platform does not have any platform specific
-options.
-
-Executing on QEMU RISC-V 64-bit
--------------------------------
-
-**No Payload Case**
-
-Build:
-```
-make PLATFORM=qemu/sifive_u
-```
-
-Run:
-```
-qemu-system-riscv64 -M sifive_u -m 256M -display none -serial stdio \
-	-kernel build/platform/qemu/sifive_u/firmware/fw_payload.elf
-```
-
-**U-Boot as a Payload**
-
-Note: the command line examples here assume that U-Boot was compiled using
-the `sifive_fu540_defconfig` configuration.
-
-Build:
-```
-make PLATFORM=qemu/sifive_u FW_PAYLOAD_PATH=<uboot_build_directory>/u-boot.bin
-```
-
-Run:
-```
-qemu-system-riscv64 -M sifive_u -m 256M -display none -serial stdio \
-	-kernel build/platform/qemu/sifive_u/firmware/fw_payload.elf
-```
-or
-```
-qemu-system-riscv64 -M sifive_u -m 256M -display none -serial stdio \
-	-kernel build/platform/qemu/sifive_u/firmware/fw_jump.elf \
-	-device loader,file=<uboot_build_directory>/u-boot.bin,addr=0x80200000
-```