Hi Heinrich, On Fri, Jan 30, 2026 at 12:23:31PM +0100, Heinrich Schuchardt wrote: > Kuan-Wei Chiu <[email protected]> schrieb am Mi., 7. Jan. 2026, 21:19: > > > Introduce a new sysreset driver for the QEMU Virtual System Controller. > > This device is found on QEMU "virt" machines (such as the m68k virt > > target) and provides a mechanism to trigger system reset and power-off > > events. > > > > The driver maps U-Boot sysreset types to the corresponding controller > > commands: > > - SYSRESET_WARM / SYSRESET_COLD -> VIRT_CTRL_CMD_RESET > > - SYSRESET_POWER_OFF -> VIRT_CTRL_CMD_HALT > > > > Signed-off-by: Kuan-Wei Chiu <[email protected]> > > --- > > Changes in v6: > > - Introduce new driver to replace board-file reset implementation. > > > > MAINTAINERS | 6 +++ > > drivers/sysreset/Kconfig | 8 ++++ > > drivers/sysreset/Makefile | 1 + > > drivers/sysreset/sysreset_qemu_virt_ctrl.c | 55 ++++++++++++++++++++++ > > include/qemu_virt_ctrl.h | 13 +++++ > > 5 files changed, 83 insertions(+) > > create mode 100644 drivers/sysreset/sysreset_qemu_virt_ctrl.c > > create mode 100644 include/qemu_virt_ctrl.h > > > > diff --git a/MAINTAINERS b/MAINTAINERS > > index efecb213be7..34081769ecd 100644 > > --- a/MAINTAINERS > > +++ b/MAINTAINERS > > @@ -1598,6 +1598,12 @@ S: Maintained > > T: git https://source.denx.de/u-boot/custodians/u-boot-mpc85xx.git > > F: arch/powerpc/cpu/mpc85xx/ > > > > +QEMU VIRTUAL SYSTEM CONTROLLER > > +M: Kuan-Wei Chiu <[email protected]> > > +S: Maintained > > +F: drivers/sysreset/sysreset_qemu_virt_ctrl.c > > +F: include/qemu_virt_ctrl.h > > + > > RAW NAND > > M: Dario Binacchi <[email protected]> > > M: Michael Trimarchi <[email protected]> > > diff --git a/drivers/sysreset/Kconfig b/drivers/sysreset/Kconfig > > index 0181f6cd581..120e7510f15 100644 > > --- a/drivers/sysreset/Kconfig > > +++ b/drivers/sysreset/Kconfig > > @@ -298,6 +298,14 @@ config SYSRESET_QCOM_PSHOLD > > help > > Add support for the system reboot on Qualcomm SoCs via PSHOLD. > > > > +config SYSRESET_QEMU_VIRT_CTRL > > + bool "QEMU Virtual System Controller support" > > + depends on SYSRESET > > + help > > + Enable support for the QEMU Virtual System Controller. > > + This device is used in QEMU machines (e.g. m68k virt) to trigger > > > > Is this specific to m68k or does it work on all QEMU architectures? If it > works everywhere, I would not mention m68k here.
The virt-ctrl device was originally introduced in qemu for the m68k virt machine, which remains its sole user to date. However, as the implementation resides in hw/misc/virt_ctrl.c, I believe it was designed to be generic and architecture-agnostic from the start. Regards, Kuan-Wei > > On x86 QEMU we currently lack poweroff support. So this would come in handy. > > Best regards > > Heinrich > > + system reset and poweroff events. > > + > > endif > > > > endmenu > > diff --git a/drivers/sysreset/Makefile b/drivers/sysreset/Makefile > > index f5c78b25896..d18a5d52360 100644 > > --- a/drivers/sysreset/Makefile > > +++ b/drivers/sysreset/Makefile > > @@ -32,3 +32,4 @@ obj-$(CONFIG_$(PHASE_)SYSRESET_X86) += sysreset_x86.o > > obj-$(CONFIG_SYSRESET_RAA215300) += sysreset_raa215300.o > > obj-$(CONFIG_SYSRESET_QCOM_PSHOLD) += sysreset_qcom-pshold.o > > obj-$(CONFIG_TARGET_XTFPGA) += sysreset_xtfpga.o > > +obj-$(CONFIG_SYSRESET_QEMU_VIRT_CTRL) += sysreset_qemu_virt_ctrl.o > > diff --git a/drivers/sysreset/sysreset_qemu_virt_ctrl.c > > b/drivers/sysreset/sysreset_qemu_virt_ctrl.c > > new file mode 100644 > > index 00000000000..e7cacc9b6e9 > > --- /dev/null > > +++ b/drivers/sysreset/sysreset_qemu_virt_ctrl.c > > @@ -0,0 +1,55 @@ > > +// SPDX-License-Identifier: GPL-2.0-or-later > > +/* > > + * Copyright (C) 2025, Kuan-Wei Chiu <[email protected]> > > + * > > + * QEMU Virtual System Controller Driver > > + */ > > + > > +#include <dm.h> > > +#include <qemu_virt_ctrl.h> > > +#include <sysreset.h> > > +#include <asm/io.h> > > +#include <linux/err.h> > > + > > +/* Register offsets */ > > +#define VIRT_CTRL_REG_FEATURES 0x00 > > +#define VIRT_CTRL_REG_CMD 0x04 > > + > > +/* Commands */ > > +#define VIRT_CTRL_CMD_NOOP 0x00 > > +#define VIRT_CTRL_CMD_RESET 0x01 > > +#define VIRT_CTRL_CMD_HALT 0x02 > > +#define VIRT_CTRL_CMD_PANIC 0x03 > > + > > +static int qemu_virt_ctrl_request(struct udevice *dev, enum sysreset_t > > type) > > +{ > > + struct qemu_virt_ctrl_plat *plat = dev_get_plat(dev); > > + u32 val; > > + > > + switch (type) { > > + case SYSRESET_WARM: > > + case SYSRESET_COLD: > > + val = VIRT_CTRL_CMD_RESET; > > + break; > > + case SYSRESET_POWER_OFF: > > + val = VIRT_CTRL_CMD_HALT; > > + break; > > + default: > > + return -EPROTONOSUPPORT; > > + } > > + > > + writel(val, plat->reg + VIRT_CTRL_REG_CMD); > > + > > + return -EINPROGRESS; > > +} > > + > > +static struct sysreset_ops qemu_virt_ctrl_ops = { > > + .request = qemu_virt_ctrl_request, > > +}; > > + > > +U_BOOT_DRIVER(sysreset_qemu_virt_ctrl) = { > > + .name = "sysreset_qemu_virt_ctrl", > > + .id = UCLASS_SYSRESET, > > + .ops = &qemu_virt_ctrl_ops, > > + .plat_auto = sizeof(struct qemu_virt_ctrl_plat), > > +}; > > diff --git a/include/qemu_virt_ctrl.h b/include/qemu_virt_ctrl.h > > new file mode 100644 > > index 00000000000..05aad82b767 > > --- /dev/null > > +++ b/include/qemu_virt_ctrl.h > > @@ -0,0 +1,13 @@ > > +/* SPDX-License-Identifier: GPL-2.0-or-later */ > > +/* > > + * Copyright (C) 2025, Kuan-Wei Chiu <[email protected]> > > + */ > > + > > +#ifndef _QEMU_VIRT_CTRL_H_ > > +#define _QEMU_VIRT_CTRL_H_ > > + > > +struct qemu_virt_ctrl_plat { > > + phys_addr_t reg; > > +}; > > + > > +#endif /* _QEMU_VIRT_CTRL_H_ */ > > -- > > 2.52.0.457.g6b5491de43-goog > > > >
