Hi Kuan-Wei, On Mon, 5 Jan 2026 at 11:20, Kuan-Wei Chiu <[email protected]> wrote: > > 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]> > --- > Changes in v5: > - Rebase on u-boot/next branch. > > 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 efecb213be7..bf85f642a8d 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -1324,6 +1324,12 @@ 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
How about a comment as to what this is? > + > # 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; Eek! > + > + gd = gd_ptr; > + > + gd->malloc_base = base + sizeof(*gd_ptr); > +} > + > +int print_cpuinfo(void) > +{ > + puts("CPU: M68040 (QEMU Virt)\n"); We normally put a blank line before the final return (unless it is the only code in the function). > + 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); Why skip relocation? > +} > + > +/* 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 Is there a Kconfig you could use to group these files? Then it could be enabled if !M680x0 > -- > 2.52.0.358.g0dd7633a29-goog > Regards, Simon
