Hi Kuan-Wei, On Mon, 5 Jan 2026 at 11:21, Kuan-Wei Chiu <[email protected]> wrote: > > Add support for the QEMU 'virt' machine on the m68k architecture. This > board emulates a generic machine based on the Motorola 68040 CPU > equipped with Goldfish virtual peripherals. > > Introduce the necessary board configuration and initialization > infrastructure. The implementation includes logic to parse the QEMU > bootinfo interface, enabling dynamic detection of system RAM size to > adapt to the virtual machine's configuration. > > Enable the Goldfish TTY driver for serial console output. Additionally, > enable Goldfish RTC and timer drivers to support real-time clock > functionality and nanosecond-resolution delays. Include comprehensive > documentation covering build instructions and usage examples. > > Signed-off-by: Kuan-Wei Chiu <[email protected]> > Tested-by: Daniel Palmer <[email protected]> > --- > Changes in v5: > - Rebase on u-boot/next branch. > - Add 'imply CMD_DM' to TARGET_QEMU_M68K. > > arch/m68k/Kconfig | 9 ++ > board/emulation/qemu-m68k/Kconfig | 12 +++ > board/emulation/qemu-m68k/MAINTAINERS | 8 ++ > board/emulation/qemu-m68k/Makefile | 5 ++ > board/emulation/qemu-m68k/qemu-m68k.c | 115 ++++++++++++++++++++++++++ > configs/qemu-m68k_defconfig | 16 ++++ > doc/board/emulation/index.rst | 1 + > doc/board/emulation/qemu-m68k.rst | 39 +++++++++ > include/configs/qemu-m68k.h | 18 ++++ > 9 files changed, 223 insertions(+) > create mode 100644 board/emulation/qemu-m68k/Kconfig > create mode 100644 board/emulation/qemu-m68k/MAINTAINERS > create mode 100644 board/emulation/qemu-m68k/Makefile > create mode 100644 board/emulation/qemu-m68k/qemu-m68k.c > create mode 100644 configs/qemu-m68k_defconfig > create mode 100644 doc/board/emulation/qemu-m68k.rst > create mode 100644 include/configs/qemu-m68k.h >
Very nice patch. > diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig > index de7c673c376..0cf632729da 100644 > --- a/arch/m68k/Kconfig > +++ b/arch/m68k/Kconfig > @@ -183,6 +183,14 @@ config TARGET_STMARK2 > select CF_DSPI > select M54418 > > +config TARGET_QEMU_M68K > + bool "Support QEMU m68k virt" > + select M68040 > + imply CMD_DM > + help > + This target supports the QEMU m68k virtual machine (-M virt). > + It simulates a Motorola 68040 CPU with Goldfish peripherals. > + > endchoice > > config SYS_CPU > @@ -208,6 +216,7 @@ source "board/freescale/m5329evb/Kconfig" > source "board/freescale/m5373evb/Kconfig" > source "board/sysam/amcore/Kconfig" > source "board/sysam/stmark2/Kconfig" > +source "board/emulation/qemu-m68k/Kconfig" > > config M68K_QEMU > bool "Build with workarounds for incomplete QEMU emulation" > diff --git a/board/emulation/qemu-m68k/Kconfig > b/board/emulation/qemu-m68k/Kconfig > new file mode 100644 > index 00000000000..aae6dfe400f > --- /dev/null > +++ b/board/emulation/qemu-m68k/Kconfig > @@ -0,0 +1,12 @@ > +if TARGET_QEMU_M68K > + > +config SYS_BOARD > + default "qemu-m68k" > + > +config SYS_VENDOR > + default "emulation" > + > +config SYS_CONFIG_NAME > + default "qemu-m68k" > + > +endif > diff --git a/board/emulation/qemu-m68k/MAINTAINERS > b/board/emulation/qemu-m68k/MAINTAINERS > new file mode 100644 > index 00000000000..90414c58465 > --- /dev/null > +++ b/board/emulation/qemu-m68k/MAINTAINERS > @@ -0,0 +1,8 @@ > +QEMU M68K VIRT BOARD > +M: Kuan-Wei Chiu <[email protected]> > +S: Maintained > +F: board/emulation/qemu-m68k/ > +F: board/emulation/common/ > +F: include/configs/qemu-m68k.h > +F: configs/qemu-m68k_defconfig > +F: doc/board/emulation/qemu-m68k.rst > diff --git a/board/emulation/qemu-m68k/Makefile > b/board/emulation/qemu-m68k/Makefile > new file mode 100644 > index 00000000000..5cb2886ff5a > --- /dev/null > +++ b/board/emulation/qemu-m68k/Makefile > @@ -0,0 +1,5 @@ > +# SPDX-License-Identifier: GPL-2.0-or-later > +# > +# Copyright (C) 2025, Kuan-Wei Chiu <[email protected]> > + > +obj-y += qemu-m68k.o > diff --git a/board/emulation/qemu-m68k/qemu-m68k.c > b/board/emulation/qemu-m68k/qemu-m68k.c > new file mode 100644 > index 00000000000..3b911b95343 > --- /dev/null > +++ b/board/emulation/qemu-m68k/qemu-m68k.c > @@ -0,0 +1,115 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * Copyright (C) 2025, Kuan-Wei Chiu <[email protected]> > + */ > + > +#include <asm-generic/sections.h> > +#include <asm/bootinfo.h> > +#include <asm/global_data.h> > +#include <asm/io.h> > +#include <config.h> > +#include <dm/platdata.h> > +#include <goldfish_rtc.h> > +#include <goldfish_timer.h> > +#include <goldfish_tty.h> > +#include <init.h> > +#include <linux/errno.h> > +#include <serial.h> Check header order: https://docs.u-boot.org/en/v2024.01/develop/codingstyle.html#include-files > + > +DECLARE_GLOBAL_DATA_PTR; > + > +/* QEMU Virt Machine Hardware Map */ > +#define VIRT_GF_RTC_MMIO_BASE 0xff007000 > +#define VIRT_GF_TTY_MMIO_BASE 0xff008000 > +#define VIRT_CTRL_MMIO_BASE 0xff009000 > +#define VIRT_CTRL_RESET 0x01 > + Could these move to devicetree? Or perhaps have an overall base + offsets? > +/* > + * Theoretical limit derivation: > + * Max Bootinfo Size (Standard Page) = 4096 bytes > + * Min Record Size (Tag + Size) = 4 bytes > + * Max Records = 4096 / 4 = 1024 > + */ > +#define MAX_BOOTINFO_RECORDS 1024 > + > +int board_early_init_f(void) If you don't need this function, you could disable BOARD_EARLY_INIT_F > +{ > + return 0; > +} > + > +int checkboard(void) > +{ > + puts("Board: QEMU m68k virt\n"); blank line here (and below) > + return 0; > +} > + > +int dram_init(void) > +{ > + struct bi_record *record; > + ulong addr; > + int loops = 0; > + > + /* Default: 16MB */ > + gd->ram_size = 0x01000000; or SZ_16M > + > + /* QEMU places bootinfo after _end, aligned to 2 bytes */ > + addr = (ulong)&_end; > + addr = ALIGN(addr, 2); > + > + record = (struct bi_record *)addr; > + > + if (record->tag != BI_MACHTYPE) > + return 0; > + > + while (record->tag != BI_LAST) { > + if (++loops > MAX_BOOTINFO_RECORDS) > + panic("Bootinfo loop exceeded"); > + if (record->tag == BI_MEMCHUNK) { > + gd->ram_size = record->data[1]; > + break; > + } > + record = (struct bi_record *)((ulong)record + record->size); > + } > + > + return 0; > +} > + > +void reset_cpu(unsigned long addr) > +{ > + writel(VIRT_CTRL_RESET, VIRT_CTRL_MMIO_BASE); > + while (1) > + ; hang()? But if it prints a few characters of the message, you won't want it. BTW this should really be a sysreset driver. > +} > + > +int do_reset(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]) > +{ > + reset_cpu(0); > + return 0; > +} > + > +static const struct goldfish_rtc_plat rtc_plat = { > + .base = (void __iomem *)VIRT_GF_RTC_MMIO_BASE, > +}; > + > +U_BOOT_DRVINFO(goldfish_rtc) = { > + .name = "rtc_goldfish", > + .plat = &rtc_plat, > +}; > + > +static const struct goldfish_timer_plat timer_plat = { > + .base = (void __iomem *)VIRT_GF_RTC_MMIO_BASE, > +}; > + > +U_BOOT_DRVINFO(goldfish_timer) = { > + .name = "goldfish_timer", > + .plat = &timer_plat, > +}; > + > +static const struct goldfish_tty_plat serial_plat = { > + .base = (void __iomem *)VIRT_GF_TTY_MMIO_BASE, > +}; > + > +U_BOOT_DRVINFO(goldfish_serial) = { > + .name = "serial_goldfish", > + .plat = &serial_plat, > +}; This is what device tree is for. It would be trivial to set one up. > diff --git a/configs/qemu-m68k_defconfig b/configs/qemu-m68k_defconfig > new file mode 100644 > index 00000000000..f9294218429 > --- /dev/null > +++ b/configs/qemu-m68k_defconfig > @@ -0,0 +1,16 @@ > +CONFIG_M68K=y > +CONFIG_TEXT_BASE=0x00000000 > +CONFIG_SYS_MALLOC_LEN=0x20000 > +CONFIG_SYS_MALLOC_F_LEN=0x2000 > +CONFIG_SYS_MONITOR_LEN=262144 > +CONFIG_SYS_BOOTM_LEN=0x1000000 > +CONFIG_SYS_LOAD_ADDR=0x00000000 > +CONFIG_TARGET_QEMU_M68K=y > +# CONFIG_DISPLAY_BOARDINFO is not set > +CONFIG_BOARD_EARLY_INIT_F=y > +CONFIG_DM_RTC=y > +CONFIG_RTC_GOLDFISH=y > +CONFIG_DM_SERIAL=y > +CONFIG_SERIAL_GOLDFISH=y > +CONFIG_TIMER=y > +CONFIG_GOLDFISH_TIMER=y > diff --git a/doc/board/emulation/index.rst b/doc/board/emulation/index.rst > index f8908166276..4f7c812d493 100644 > --- a/doc/board/emulation/index.rst > +++ b/doc/board/emulation/index.rst > @@ -15,6 +15,7 @@ Emulation > qemu-sbsa > qemu-x86 > qemu-xtensa > + qemu-m68k > > Also see > > diff --git a/doc/board/emulation/qemu-m68k.rst > b/doc/board/emulation/qemu-m68k.rst > new file mode 100644 > index 00000000000..6c4de54cf6a > --- /dev/null > +++ b/doc/board/emulation/qemu-m68k.rst > @@ -0,0 +1,39 @@ > +.. SPDX-License-Identifier: GPL-2.0-or-later > +.. Copyright (C) 2025, Kuan-Wei Chiu <[email protected]> > + > +QEMU m68k > +========= > + > +QEMU for m68k supports a special 'virt' machine designed for emulation and > +virtualization purposes. This document describes how to run U-Boot under it. > + > +The QEMU virt machine models a generic m68k virtual machine with Goldfish > +interfaces. It supports the Motorola 68040 CPU architecture. > + > +Building U-Boot > +--------------- > +Set the CROSS_COMPILE environment variable to your m68k toolchain, and run: > + > +.. code-block:: bash > + > + export CROSS_COMPILE=m68k-linux-gnu- > + make qemu-m68k_defconfig > + make > + > +Running U-Boot > +-------------- > +The minimal QEMU command line to get U-Boot up and running is: > + > +.. code-block:: bash > + > + qemu-system-m68k -M virt -cpu m68040 -nographic -kernel u-boot > + > +Note that the `-nographic` option is used to redirect the console to stdio, > +which connects to the emulated Goldfish TTY device. > + > +Hardware Support > +---------------- > +The following QEMU virt peripherals are supported in U-Boot: > + > +* Goldfish TTY (Serial Console) > +* Goldfish RTC (Real Time Clock) > diff --git a/include/configs/qemu-m68k.h b/include/configs/qemu-m68k.h > new file mode 100644 > index 00000000000..1d8aa92fe80 > --- /dev/null > +++ b/include/configs/qemu-m68k.h > @@ -0,0 +1,18 @@ > +/* SPDX-License-Identifier: GPL-2.0-or-later */ > +/* > + * Copyright (C) 2025, Kuan-Wei Chiu <[email protected]> > + */ > + > +#ifndef __QEMU_M68K_H > +#define __QEMU_M68K_H > + > +/* Memory Configuration */ > +#define CFG_SYS_SDRAM_BASE 0x00000000 > + > +/* > + * Initial Stack Pointer: > + * Place the stack at 4MB offset to avoid overwriting U-Boot code/data. > + */ > +#define CFG_SYS_INIT_SP_ADDR (CFG_SYS_SDRAM_BASE + 0x400000) > + > +#endif /* __QEMU_M68K_H */ > -- > 2.52.0.358.g0dd7633a29-goog > Regards, Simon
