Hi Simon, On Mon, Jan 05, 2026 at 04:30:31PM -0700, Simon Glass wrote: > 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.
Thanks. :) > > > 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 I will sort root headers and directory headers separately in v6. > > > + > > +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? I will remove these macros. I plan to extract the bootinfo parsing logic into a helper and call it in board_early_init_f to get addresses dynamically. > > > +/* > > + * 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 Ack. > > > +{ > > + return 0; > > +} > > + > > +int checkboard(void) > > +{ > > + puts("Board: QEMU m68k virt\n"); > > blank line here (and below) Ack. > > > + return 0; > > +} > > + > > +int dram_init(void) > > +{ > > + struct bi_record *record; > > + ulong addr; > > + int loops = 0; > > + > > + /* Default: 16MB */ > > + gd->ram_size = 0x01000000; > > or SZ_16M Ack. > > > + > > + /* 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. I will add a sysreset driver for this in v6. > > > +} > > + > > +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. Based on the discussion in patch #3, I plan to stick with the current approach. Regards, Kuan-Wei > > > 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
