soc: mips: add Qemu Malta support

The MIPS Malta is an ATX form factor evaluation board made by MIPS
Technologies. Malta board is the most popular platform for MIPS
full-system emulation.

See https://www.linux-mips.org/wiki/MIPS_Malta for details.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Remy Luisant <remy@luisant.ca>

CODEOWNERS

@@ -70,6 +70,7 @@
 /arch/nios2/                              @nashif
 /arch/posix/                              @aescolar @daor-oti
 /arch/riscv/                              @kgugala @pgielda
+/soc/mips/                                @frantony
 /soc/posix/                               @aescolar @daor-oti
 /soc/riscv/                               @kgugala @pgielda
 /soc/riscv/openisa*/                      @dleach02

cmake/emu/qemu.cmake

@@ -2,6 +2,12 @@
 
 if("${ARCH}" STREQUAL "x86")
   set_ifndef(QEMU_binary_suffix i386)
+elseif("${ARCH}" STREQUAL "mips")
+  if(CONFIG_BIG_ENDIAN)
+    set_ifndef(QEMU_binary_suffix mips)
+  else()
+    set_ifndef(QEMU_binary_suffix mipsel)
+  endif()
 elseif(DEFINED QEMU_ARCH)
   set_ifndef(QEMU_binary_suffix ${QEMU_ARCH})
 else()

soc/mips/CMakeLists.txt

@@ -0,0 +1,5 @@
+if(SOC_FAMILY)
+  add_subdirectory(${SOC_FAMILY})
+else()
+  add_subdirectory(${SOC_NAME})
+endif()

soc/mips/qemu_malta/CMakeLists.txt

@@ -0,0 +1,17 @@
+# Copyright (c) 2020, 2021 Antony Pavlov <antonynpavlov@gmail.com>
+#
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_compile_options(
+  -mips32
+  ${TOOLCHAIN_C_FLAGS}
+)
+
+zephyr_sources(
+  vector.S
+)
+
+zephyr_ld_options(
+  -mips32
+  ${TOOLCHAIN_LD_FLAGS}
+)

soc/mips/qemu_malta/Kconfig.defconfig

@@ -0,0 +1,16 @@
+# Copyright (c) 2020 Antony Pavlov <antonynpavlov@gmail.com>
+#
+# SPDX-License-Identifier: Apache-2.0
+
+if SOC_QEMU_MALTA
+
+config SOC
+	default "qemu_malta"
+
+config SYS_CLOCK_HW_CYCLES_PER_SEC
+	default 200000000
+
+config NUM_IRQS
+	default 8
+
+endif # SOC_QEMU_MALTA

soc/mips/qemu_malta/Kconfig.soc

@@ -0,0 +1,7 @@
+# Copyright (c) 2020 Antony Pavlov <antonynpavlov@gmail.com>
+#
+# SPDX-License-Identifier: Apache-2.0
+
+config SOC_QEMU_MALTA
+	bool "MIPS Qemu Malta implementation"
+	select MIPS

soc/mips/qemu_malta/linker.ld

@@ -0,0 +1,7 @@
+/*
+ * Copyright (c) 2020 Antony Pavlov <antonynpavlov@gmail.com>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <arch/mips/linker.ld>

soc/mips/qemu_malta/soc.h

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2020, 2021 Antony Pavlov <antonynpavlov@gmail.com>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef __QEMU_MALTA_SOC_H__
+#define __QEMU_MALTA_SOC_H__
+
+#define MIPS_MACHINE_TIMER_IRQ      7  /* Machine Timer Interrupt */
+
+#endif /* __QEMU_MALTA_SOC_H__ */

soc/mips/qemu_malta/vector.S

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2021 Antony Pavlov <antonynpavlov@gmail.com>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <toolchain.h>
+#include <mips/regdef.h>
+
+/* Imports */
+GTEXT(__initialize)
+
+/* Exports */
+GTEXT(__start)
+
+SECTION_FUNC(vectors, __start)
+	/* Call into Zephyr initialization. */
+	la v0, __initialize
+	jal v0