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+.. SPDX-License-Identifier: GPL-2.0+
+.. sectionauthor:: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
+
+QEMU MIPS
+=========
+
+Qemu for MIPS is based on the MIPS Malta board. The built Malta U-Boot
+images can be used for Qemu and on physical hardware. The Malta board
+supports all combinations of Little and Big Endian as well as 32 bit
+and 64 bit.
+
+Limitations & comments
+----------------------
+The memory size for Qemu is hard-coded to 256 MiB. For Malta Little Endian
+targets an extra endianness swapped image named *u-boot-swap.bin* is
+generated and required for Qemu.
+
+Example usage
+-------------
+
+Build for 32 bit, big endian:
+
+.. code-block:: bash
+
+  make malta_defconfig
+  make
+  UBOOT_BIN=u-boot.bin
+  QEMU_BIN=qemu-system-mips
+  QEMU_CPU=24Kc
+
+Build for 32 bit, little endian:
+
+.. code-block:: bash
+
+  make maltael_defconfig
+  make
+  UBOOT_BIN=u-boot-swap.bin
+  QEMU_BIN=qemu-system-mipsel
+  QEMU_CPU=24Kc
+
+Build for 64 bit, big endian:
+
+.. code-block:: bash
+
+  make malta64_defconfig
+  make
+  UBOOT_BIN=u-boot.bin
+  QEMU_BIN=qemu-system-mips64
+  QEMU_CPU=MIPS64R2-generic
+
+Build for 64 bit, little endian:
+
+.. code-block:: bash
+
+  make malta64el_defconfig
+  make
+  UBOOT_BIN=u-boot-swap.bin
+  QEMU_BIN=qemu-system-mips64el
+  QEMU_CPU=MIPS64R2-generic
+
+Generate NOR flash image with U-Boot binary:
+
+.. code-block:: bash
+
+  dd if=/dev/zero bs=1M count=4 | tr '\000' '\377' > pflash.img
+  dd if=${UBOOT_BIN} of=pflash.img conv=notrunc
+
+Start Qemu:
+
+.. code-block:: bash
+
+  mkdir tftproot
+  ${QEMU_BIN} -nographic -cpu ${QEMU_CPU} -m 256 -drive if=pflash,file="$(pwd)/pflash.img",format=raw -netdev user,id=net0,tftp="$(pwd)/tftproot" -device pcnet,netdev=net0
+
+.. code-block:: bash
+
+  U-Boot 2021.04-00963-g60279a2b1d (Apr 21 2021 - 19:54:32 +0200)
+
+  Board: MIPS Malta CoreLV
+  DRAM:  256 MiB
+  Flash: 4 MiB
+  Loading Environment from Flash... *** Warning - bad CRC, using default environment
+
+  In:    serial@3f8
+  Out:   serial@3f8
+  Err:   serial@3f8
+  Net:   pcnet#0
+  IDE:   Bus 0: not available
+  maltael #
+
+How to debug U-Boot
+-------------------
+
+In order to debug U-Boot you need to start qemu with gdb server support (-s)
+and waiting the connection to start the CPU (-S). Start Qemu in the first console:
+
+.. code-block:: bash
+
+  mkdir tftproot
+  ${QEMU_BIN} -s -S -nographic -cpu ${QEMU_CPU} -m 256 -drive if=pflash,file="$(pwd)/pflash.img",format=raw -netdev user,id=net0,tftp="$(pwd)/tftproot" -device pcnet,netdev=net0
+
+In the second console start gdb:
+
+.. code-block:: bash
+
+  gdb-multiarch --eval-command "target remote :1234" u-boot
+
+.. code-block:: bash
+
+  GNU gdb (Ubuntu 9.2-0ubuntu1~20.04) 9.2
+  Copyright (C) 2020 Free Software Foundation, Inc.
+  License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
+  This is free software: you are free to change and redistribute it.
+  There is NO WARRANTY, to the extent permitted by law.
+  Type "show copying" and "show warranty" for details.
+  This GDB was configured as "x86_64-linux-gnu".
+  Type "show configuration" for configuration details.
+  For bug reporting instructions, please see:
+  <http://www.gnu.org/software/gdb/bugs/>.
+  Find the GDB manual and other documentation resources online at:
+      <http://www.gnu.org/software/gdb/documentation/>.
+
+  For help, type "help".
+  Type "apropos word" to search for commands related to "word"...
+  Reading symbols from u-boot...
+  Remote debugging using :1234
+  0xbfc00000 in ?? ()
+  (gdb) c
+  Continuing.