[PATCH for-7.1] docs/system/loongarch: Update the LoongArch document

[Xiaojuan Yang]

1. Add some information about how to boot the LoongArch virt
machine by uefi bios and linux kernel and how to access the
source code or binary file.
2. Move the explanation of LoongArch system emulation in the
target/loongarch/README to docs/system/loongarch/loongson3.rst


Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
---
 docs/system/loongarch/loongson3.rst | 104 +++++++++++++++++++++++++---
 target/loongarch/README             |  49 +------------
 2 files changed, 97 insertions(+), 56 deletions(-)

diff --git a/docs/system/loongarch/loongson3.rst 
b/docs/system/loongarch/loongson3.rst
index fa3acd01c0..66bcd28030 100644
--- a/docs/system/loongarch/loongson3.rst
+++ b/docs/system/loongarch/loongson3.rst
@@ -15,27 +15,115 @@ The ``virt`` machine supports:
 - Gpex host bridge
 - Ls7a RTC device
 - Ls7a IOAPIC device
-- Ls7a ACPI device
+- ACPI GED device
 - Fw_cfg device
 - PCI/PCIe devices
 - Memory device
-- CPU device. Type: Loongson-3A5000.
+- CPU device. Type: la464-loongarch-cpu.
 
 CPU and machine Type
 --------------------
 
 The ``qemu-system-loongarch64`` provides emulation for virt
 machine. You can specify the machine type ``virt`` and
-cpu type ``Loongson-3A5000``.
+cpu type ``la464-loongarch-cpu``.
 
 Boot options
 ------------
 
-Now the ``virt`` machine can run test program in ELF format and the
-method of compiling is in target/loongarch/README.
+We can boot the LoongArch virt machine by specifying the uefi bios,
+initrd, and linux kernel. And those source codes and binary files
+can be accessed by following steps.
+
+(1) booting command:
+
+.. code-block:: bash
+
+  $ qemu-system-loongarch64 -machine virt -m 4G -cpu la464-loongarch-cpu \
+      -smp 1 -bios QEMU_EFI.fd -kernel vmlinuz.efi -initrd initrd.img \
+      -append "root=/dev/ram rdinit=/sbin/init consol e=ttyS0,115200" \
+      --nographic
+
+Note: The running speed may be a little slow, as the performance of our
+qemu and uefi bios is not perfect, and it is being fixed.
+
+(2) cross compiler tools:
+
+.. code-block:: bash
+
+  wget https://github.com/loongson/build-tools/releases/download/ \
+  2022.05.29/loongarch64-clfs-5.0-cross-tools-gcc-full.tar.xz
+
+  tar -vxf loongarch64-clfs-5.0-cross-tools-gcc-full.tar.xz
+
+(3) qemu compile configure option:
+
+.. code-block:: bash
+
+  ./configure --disable-rdma --disable-pvrdma --prefix=usr \
+              --target-list="loongarch64-softmmu" \
+              --disable-libiscsi --disable-libnfs --disable-libpmem \
+              --disable-glusterfs --enable-libusb --enable-usb-redir \
+              --disable-opengl --disable-xen --enable-spice \
+              --enable-debug --disable-capstone --disable-kvm \
+              --enable-profiler
+  make
+
+(4) uefi bios source code and compile method:
+
+.. code-block:: bash
+
+  git clone https://github.com/loongson/edk2-LoongarchVirt.git
+
+  cd edk2-LoongarchVirt
+
+  git submodule update --init
+
+  export PATH=$YOUR_COMPILER_PATH/bin:$PATH
+
+  export WORKSPACE=`pwd`
+
+  export PACKAGES_PATH=$WORKSPACE/edk2-LoongarchVirt
+
+  export GCC5_LOONGARCH64_PREFIX=loongarch64-unknown-linux-gnu-
+
+  edk2-LoongarchVirt/edksetup.sh
+
+  make -C edk2-LoongarchVirt/BaseTools
+
+  build --buildtarget=DEBUG --tagname=GCC5 --arch=LOONGARCH64  
--platform=OvmfPkg/LoongArchQemu/Loongson.dsc
+
+  build --buildtarget=RELEASE --tagname=GCC5 --arch=LOONGARCH64  
--platform=OvmfPkg/LoongArchQemu/Loongson.dsc
+
+The efi binary file path:
+
+  Build/LoongArchQemu/DEBUG_GCC5/FV/QEMU_EFI.fd
+
+  Build/LoongArchQemu/RELEASE_GCC5/FV/QEMU_EFI.fd
+
+(5) linux kernel source code and compile method:
 
 .. code-block:: bash
 
-  $ qemu-system-loongarch64 -machine virt -m 4G -cpu Loongson-3A5000 \
-      -smp 1 -kernel hello -monitor none -display none \
-      -chardev file,path=hello.out,id=output -serial chardev:output
+  git clone https://github.com/loongson/linux.git
+
+  export PATH=$YOUR_COMPILER_PATH/bin:$PATH
+
+  export LD_LIBRARY_PATH=$YOUR_COMPILER_PATH/lib:$LD_LIBRARY_PATH
+
+  export 
LD_LIBRARY_PATH=$YOUR_COMPILER_PATH/loongarch64-unknown-linux-gnu/lib/:$LD_LIBRARY_PATH
+
+  make ARCH=loongarch CROSS_COMPILE=loongarch64-unknown-linux-gnu- 
loongson3_defconfig
+
+  make ARCH=loongarch CROSS_COMPILE=loongarch64-unknown-linux-gnu-
+
+  make ARCH=loongarch CROSS_COMPILE=loongarch64-unknown-linux-gnu- install
+
+  make ARCH=loongarch CROSS_COMPILE=loongarch64-unknown-linux-gnu- 
modules_install
+
+Note: The branch of linux source code is loongarch-next.
+
+(6) initrd file:
+
+  You can use busybox tool and the linux modules to make a initrd file. Or you 
can access the
+  binary files: https://github.com/yangxiaojuan-loongson/qemu-binary
diff --git a/target/loongarch/README b/target/loongarch/README
index 1823375d04..0b9dc0d40a 100644
--- a/target/loongarch/README
+++ b/target/loongarch/README
@@ -11,54 +11,7 @@
 
 - System emulation
 
-  Mainly emulate a virt 3A5000 board and ls7a bridge that is not exactly the 
same as the host.
-  3A5000 support multiple interrupt cascading while here we just emulate the 
extioi interrupt
-  cascading. LS7A1000 host bridge support multiple devices, such as sata, 
gmac, uart, rtc
-  and so on. But we just realize the rtc. Others use the qemu common devices. 
It does not affect
-  the general use. We also introduced the emulation of devices at 
docs/system/loongarch/virt.rst.
-
-  This version only supports running binary files in ELF format, and does not 
depend on BIOS and kernel file.
-  You can compile the test program with 'make & make check-tcg' and run the 
test case with the following command:
-
-  1. Install LoongArch cross-tools on X86 machines.
-
-    Download cross-tools.
-
-      wget 
https://github.com/loongson/build-tools/releases/download/2022.05.29/loongarch64-clfs-5.0-cross-tools-gcc-full.tar.xz
-
-      tar -vxf loongarch64-clfs-5.0-cross-tools-gcc-full.tar.xz -C /opt
-
-    Config cross-tools env.
-
-      . setenv.sh
-
-      setenv.sh:
-
-          #!/bin/sh
-          set -x
-          CC_PREFIX=/opt/cross-tools
-
-          export PATH=$CC_PREFIX/bin:$PATH
-          export LD_LIBRARY_PATH=$CC_PREFIX/lib:$LD_LIBRARY_PATH
-          export 
LD_LIBRARY_PATH=$CC_PREFIX/loongarch64-unknown-linux-gnu/lib/:$LD_LIBRARY_PATH
-          set +x
-
-  2. Test tests/tcg/multiarch.
-
-    ./configure --disable-rdma --disable-pvrdma --prefix=/usr  \
-            --target-list="loongarch64-softmmu"  \
-            --disable-libiscsi --disable-libnfs --disable-libpmem \
-            --disable-glusterfs --enable-libusb --enable-usb-redir \
-            --disable-opengl --disable-xen --enable-spice --disable-werror \
-            --enable-debug --disable-capstone --disable-kvm --enable-profiler
-
-    cd  build/
-
-    make && make check-tcg
-
-    or
-
-    ./build/qemu-system-loongarch64 -machine virt -m 4G -cpu Loongson-3A5000 
-smp 1 -kernel build/tests/tcg/loongarch64-softmmu/hello -monitor none -display 
none -chardev file,path=hello.out,id=output -serial chardev:output
+  You can reference docs/system/loongarch/loongson3.rst to get the information 
about system emulation of LoongArch.
 
 - Linux-user emulation
 
-- 
2.31.1