Add support for the Motorola 68040 architecture. Currently, m68k support in U-Boot is primarily focused on ColdFire variants. Introduce the necessary infrastructure to support the classic M680x0 series, specifically targeting the M68040 as emulated by QEMU.
The implementation includes exception vectors, early startup code, and minimal CPU initialization and relocation stubs. It also defines the standard m68k boot information structure used for passing hardware information to the operating system. To ensure compatibility, ColdFire- specific library objects such as cache and interrupt handling are excluded from the build when M68040 is selected. Additionally, apply a specific workaround during the early memory reservation stage. Use a manual loop to clear global data instead of the standard memset() function, as utilizing memset() at this point was observed to cause a hang on the QEMU platform. Signed-off-by: Kuan-Wei Chiu <[email protected]> --- No changes in v4. MAINTAINERS | 6 +++ arch/m68k/Kconfig | 16 +++++++ arch/m68k/Makefile | 1 + arch/m68k/config.mk | 10 ++++- arch/m68k/cpu/m680x0/Makefile | 6 +++ arch/m68k/cpu/m680x0/cpu.c | 72 +++++++++++++++++++++++++++++++ arch/m68k/cpu/m680x0/start.S | 73 ++++++++++++++++++++++++++++++++ arch/m68k/cpu/m680x0/u-boot.lds | 47 ++++++++++++++++++++ arch/m68k/include/asm/bootinfo.h | 31 ++++++++++++++ arch/m68k/lib/Makefile | 9 ++-- 10 files changed, 263 insertions(+), 8 deletions(-) create mode 100644 arch/m68k/cpu/m680x0/Makefile create mode 100644 arch/m68k/cpu/m680x0/cpu.c create mode 100644 arch/m68k/cpu/m680x0/start.S create mode 100644 arch/m68k/cpu/m680x0/u-boot.lds create mode 100644 arch/m68k/include/asm/bootinfo.h diff --git a/MAINTAINERS b/MAINTAINERS index fcc437a53ce..bfb24fa7bd3 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1312,6 +1312,12 @@ F: lib/getopt.c F: test/log/ F: test/py/tests/test_log.py +M680X0 ARCHITECTURE +M: Kuan-Wei Chiu <[email protected]> +S: Maintained +F: arch/m68k/cpu/m680x0/ +F: arch/m68k/include/asm/bootinfo.h + MALI DISPLAY PROCESSORS M: Liviu Dudau <[email protected]> S: Supported diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig index 8ade6f7b9d1..de7c673c376 100644 --- a/arch/m68k/Kconfig +++ b/arch/m68k/Kconfig @@ -56,6 +56,9 @@ config MCF5441x select DM_SERIAL bool +config M680x0 + bool + # processor type config M5208 bool @@ -110,6 +113,10 @@ config M54418 bool select MCF5441x +config M68040 + bool + select M680x0 + # peripherals config CF_DSPI bool @@ -178,6 +185,15 @@ config TARGET_STMARK2 endchoice +config SYS_CPU + string + default "mcf52x2" if MCF52x2 + default "mcf523x" if MCF523x + default "mcf530x" if MCF530x + default "mcf532x" if MCF532x + default "mcf5445x" if MCF5445x + default "m680x0" if M680x0 + source "board/BuS/eb_cpu5282/Kconfig" source "board/cobra5272/Kconfig" source "board/freescale/m5208evbe/Kconfig" diff --git a/arch/m68k/Makefile b/arch/m68k/Makefile index 4a7960bbeb4..bb57cf9ac63 100644 --- a/arch/m68k/Makefile +++ b/arch/m68k/Makefile @@ -17,6 +17,7 @@ cpuflags-$(CONFIG_M5307) := -mcpu=5307 cpuflags-$(CONFIG_MCF5301x) := -mcpu=53015 -fPIC cpuflags-$(CONFIG_MCF532x) := -mcpu=5329 -fPIC cpuflags-$(CONFIG_MCF5441x) := -mcpu=54418 -fPIC +cpuflags-$(CONFIG_M68040) := -mcpu=68040 -fno-pic PLATFORM_CPPFLAGS += $(cpuflags-y) diff --git a/arch/m68k/config.mk b/arch/m68k/config.mk index 643b7d1d35d..458953f9712 100644 --- a/arch/m68k/config.mk +++ b/arch/m68k/config.mk @@ -3,8 +3,14 @@ # (C) Copyright 2000-2002 # Wolfgang Denk, DENX Software Engineering, [email protected]. -PLATFORM_CPPFLAGS += -D__M68K__ -fPIC +PLATFORM_CPPFLAGS += -D__M68K__ +ifneq ($(CONFIG_M680x0),y) +PLATFORM_CPPFLAGS += -fPIC +endif KBUILD_LDFLAGS += -n -pie PLATFORM_RELFLAGS += -ffunction-sections -fdata-sections -PLATFORM_RELFLAGS += -ffixed-d7 -msep-data +PLATFORM_RELFLAGS += -ffixed-d7 +ifneq ($(CONFIG_M680x0),y) +PLATFORM_RELFLAGS += -msep-data +endif LDFLAGS_FINAL += --gc-sections -pie diff --git a/arch/m68k/cpu/m680x0/Makefile b/arch/m68k/cpu/m680x0/Makefile new file mode 100644 index 00000000000..f6e0c9a46c0 --- /dev/null +++ b/arch/m68k/cpu/m680x0/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0-or-later +# +# Copyright (C) 2025, Kuan-Wei Chiu <[email protected]> + +extra-y += start.o +obj-y += cpu.o diff --git a/arch/m68k/cpu/m680x0/cpu.c b/arch/m68k/cpu/m680x0/cpu.c new file mode 100644 index 00000000000..e2974560f4d --- /dev/null +++ b/arch/m68k/cpu/m680x0/cpu.c @@ -0,0 +1,72 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * CPU specific code for m68040 + * + * Copyright (C) 2025, Kuan-Wei Chiu <[email protected]> + */ + +#include <asm/global_data.h> +#include <config.h> +#include <cpu_func.h> +#include <init.h> +#include <linux/types.h> +#include <stdio.h> + +DECLARE_GLOBAL_DATA_PTR; + +void m68k_virt_init_reserve(ulong base) +{ + struct global_data *gd_ptr = (struct global_data *)base; + char *p = (char *)gd_ptr; + unsigned int i; + + /* FIXME: usage of memset() here caused a hang on QEMU m68k virt. */ + for (i = 0; i < sizeof(*gd_ptr); i++) + p[i] = 0; + + gd = gd_ptr; + + gd->malloc_base = base + sizeof(*gd_ptr); +} + +int print_cpuinfo(void) +{ + puts("CPU: M68040 (QEMU Virt)\n"); + return 0; +} + +int get_clocks(void) +{ + return 0; +} + +int cpu_init_r(void) +{ + return 0; +} + +/* + * Relocation Stub + * We skip actual relocation for this QEMU bring-up and jump directly + * to board_init_r. + */ + +void relocate_code(ulong sp, struct global_data *new_gd, ulong relocaddr) +{ + board_init_r(new_gd, relocaddr); +} + +/* Stubs for Standard Facilities (Cache, Interrupts) */ + +int disable_interrupts(void) { return 0; } +void enable_interrupts(void) { return; } +int interrupt_init(void) { return 0; } + +void icache_enable(void) {} +void icache_disable(void) {} +int icache_status(void) { return 0; } +void dcache_enable(void) {} +void dcache_disable(void) {} +int dcache_status(void) { return 0; } +void flush_cache(unsigned long start, unsigned long size) {} +void flush_dcache_range(unsigned long start, unsigned long stop) {} diff --git a/arch/m68k/cpu/m680x0/start.S b/arch/m68k/cpu/m680x0/start.S new file mode 100644 index 00000000000..0802ca1fca2 --- /dev/null +++ b/arch/m68k/cpu/m680x0/start.S @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Startup code for m68040 + * + * Copyright (C) 2025, Kuan-Wei Chiu <[email protected]> + */ + +#include <asm-offsets.h> +#include <config.h> +#include <linux/linkage.h> + +.section .text + +/* + * Vector Table + * m68k uses the first 1KB for the exception vector table. + */ +.balign 4 +.global _vectors +_vectors: + .long CFG_SYS_INIT_SP_ADDR /* 0x00: Initial SP */ + .long _start /* 0x04: Initial PC (Reset) */ + .long _fault /* 0x08: Bus Error */ + .long _fault /* 0x0C: Address Error */ + .long _fault /* 0x10: Illegal Instruction */ + .long _fault /* 0x14: Zero Divide */ + .long _fault /* 0x18: CHK */ + .long _fault /* 0x1C: TRAPV */ + .long _fault /* 0x20: Privilege */ + .long _fault /* 0x24: Trace */ + .long _fault /* 0x28: Line 1010 */ + .long _fault /* 0x2C: Line 1111 */ + .fill 0x400 - (.-_vectors), 1, 0 + +/* + * Entry Point + */ +ENTRY(_start) + /* Disable Interrupts */ + move.w #0x2700, %sr + + /* Setup initial stack pointer */ + move.l #CFG_SYS_INIT_SP_ADDR, %sp + + /* + * Allocate Global Data (GD) + * board_init_f_alloc_reserve(top) returns the new top of stack in %d0 + */ + move.l %sp, -(%sp) + bsr.l board_init_f_alloc_reserve + addq.l #4, %sp + + /* Update Stack Pointer and set GD register */ + move.l %d0, %sp + move.l %d0, %d7 /* %d7 is the gd register */ + + /* Initialize Reserved Memory. */ + move.l %d0, -(%sp) + bsr.l m68k_virt_init_reserve + addq.l #4, %sp + + /* Enter board_init_f(0) */ + clr.l -(%sp) + bsr.l board_init_f + addq.l #4, %sp + + /* Should not return */ +hang: + bra.s hang +ENDPROC(_start) + +_fault: + bra.s _fault diff --git a/arch/m68k/cpu/m680x0/u-boot.lds b/arch/m68k/cpu/m680x0/u-boot.lds new file mode 100644 index 00000000000..ae102c32833 --- /dev/null +++ b/arch/m68k/cpu/m680x0/u-boot.lds @@ -0,0 +1,47 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Linker Script for m68040 + * + * Copyright (C) 2025, Kuan-Wei Chiu <[email protected]> + */ + +OUTPUT_ARCH(m68k) +ENTRY(_start) + +SECTIONS +{ + . = 0x00000000; + __text_start = .; + + .text : + { + arch/m68k/cpu/m680x0/start.o (.text*) + *(.text*) + } + + . = ALIGN(16); + .rodata : { *(.rodata*) } + + . = ALIGN(16); + .data : { *(.data*) } + + . = ALIGN(4); + .u_boot_list : { + KEEP(*(SORT(*u_boot_list*))); + } + + . = ALIGN(4); + __image_copy_end = .; + __init_end = .; + + . = ALIGN(16); + __bss_start = .; + .bss : + { + *(.bss*) + . = ALIGN(16); + } + __bss_end = .; + + _end = .; +} diff --git a/arch/m68k/include/asm/bootinfo.h b/arch/m68k/include/asm/bootinfo.h new file mode 100644 index 00000000000..3d2ec818257 --- /dev/null +++ b/arch/m68k/include/asm/bootinfo.h @@ -0,0 +1,31 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2025, Kuan-Wei Chiu <[email protected]> + * + * Definitions for the m68k bootinfo interface. + */ + +#ifndef _ASM_M68K_BOOTINFO_H +#define _ASM_M68K_BOOTINFO_H + +#ifndef __ASSEMBLY__ + +struct bi_record { + unsigned short tag; /* tag ID */ + unsigned short size; /* size of record (in bytes) */ + unsigned long data[0]; /* data */ +}; + +#endif /* __ASSEMBLY__ */ + +/* Bootinfo Tag IDs */ +#define BI_LAST 0x0000 +#define BI_MACHTYPE 0x0001 +#define BI_CPUTYPE 0x0002 +#define BI_FPUTYPE 0x0003 +#define BI_MMUTYPE 0x0004 +#define BI_MEMCHUNK 0x0005 +#define BI_RAMDISK 0x0006 +#define BI_COMMAND_LINE 0x0007 + +#endif /* _ASM_M68K_BOOTINFO_H */ diff --git a/arch/m68k/lib/Makefile b/arch/m68k/lib/Makefile index 6e1fd938f52..e62de51f260 100644 --- a/arch/m68k/lib/Makefile +++ b/arch/m68k/lib/Makefile @@ -7,10 +7,7 @@ ## if the user asked for it lib-$(CONFIG_USE_PRIVATE_LIBGCC) += lshrdi3.o muldi3.o ashldi3.o ashrdi3.o -obj-y += bdinfo.o obj-$(CONFIG_CMD_BOOTM) += bootm.o -obj-y += cache.o -obj-y += interrupts.o -obj-y += time.o -obj-y += traps.o -obj-y += fec.o +ifndef CONFIG_M680x0 +obj-y += cache.o interrupts.o time.o traps.o bdinfo.o fec.o +endif -- 2.52.0.358.g0dd7633a29-goog
