[PATCH v4 2/2] m68k: virt: Switch to qemu-virt-ctrl driver

Kuan-Wei Chiu
2026-04-12T21:20:16Z

Register the "qemu-virt-ctrl" platform device during board
initialization to utilize the new generic power/reset driver.

Consequently, remove the legacy reset and power-off implementations
specific to the virt machine. The platform's mach_reset callback is
updated to call do_kernel_restart(), bridging the legacy m68k reboot
path to the generic kernel restart handler framework for this machine.

To prevent any regressions in reboot or power-off functionality when
the driver is not built-in, explicitly select POWER_RESET and
POWER_RESET_QEMU_VIRT_CTRL for the VIRT machine in Kconfig.machine.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
arch/m68k/Kconfig.machine | 2 ++
arch/m68k/virt/config.c | 42 +--------------------------------------
arch/m68k/virt/platform.c | 20 ++++++++++++++++---
3 files changed, 20 insertions(+), 44 deletions(-)

diff --git a/arch/m68k/Kconfig.machine b/arch/m68k/Kconfig.machine
index de39f23b180e..624e6b27f394 100644
--- a/arch/m68k/Kconfig.machine
+++ b/arch/m68k/Kconfig.machine
@@ -133,6 +133,8 @@ config VIRT
select GOLDFISH_TIMER
select GOLDFISH_TTY
select M68040
+ select POWER_RESET
+ select POWER_RESET_QEMU_VIRT_CTRL
select RTC_CLASS
select RTC_DRV_GOLDFISH
select TTY
diff --git a/arch/m68k/virt/config.c b/arch/m68k/virt/config.c
index 632ba200ad42..b338e2a8da6a 100644
--- a/arch/m68k/virt/config.c
+++ b/arch/m68k/virt/config.c
@@ -13,18 +13,6 @@

struct virt_booter_data virt_bi_data;

-#define VIRT_CTRL_REG_FEATURES 0x00
-#define VIRT_CTRL_REG_CMD 0x04
-
-static struct resource ctrlres;
-
-enum {
- CMD_NOOP,
- CMD_RESET,
- CMD_HALT,
- CMD_PANIC,
-};
-
static void virt_get_model(char *str)
{
/* str is 80 characters long */
@@ -33,25 +21,9 @@ static void virt_get_model(char *str)
(u8)(virt_bi_data.qemu_version >> 16),
(u8)(virt_bi_data.qemu_version >> 8));
}
-
-static void virt_halt(void)
-{
- void __iomem *base = (void __iomem *)virt_bi_data.ctrl.mmio;
-
- iowrite32be(CMD_HALT, base + VIRT_CTRL_REG_CMD);
- local_irq_disable();
- while (1)
- ;
-}
-
static void virt_reset(void)
{
- void __iomem *base = (void __iomem *)virt_bi_data.ctrl.mmio;
-
- iowrite32be(CMD_RESET, base + VIRT_CTRL_REG_CMD);
- local_irq_disable();
- while (1)
- ;
+ do_kernel_restart(NULL);
}

/*
@@ -113,20 +85,8 @@ void __init config_virt(void)
virt_bi_data.tty.mmio);
setup_earlycon(earlycon);

- ctrlres = (struct resource)
- DEFINE_RES_MEM_NAMED(virt_bi_data.ctrl.mmio, 0x100,
- "virtctrl");
-
- if (request_resource(&iomem_resource, &ctrlres)) {
- pr_err("Cannot allocate virt controller resource\n");
- return;
- }
-
mach_init_IRQ = virt_init_IRQ;
mach_sched_init = virt_sched_init;
mach_get_model = virt_get_model;
mach_reset = virt_reset;
- mach_halt = virt_halt;
-
- register_platform_power_off(virt_halt);
}
diff --git a/arch/m68k/virt/platform.c b/arch/m68k/virt/platform.c
index 1560c4140ab9..764f556b4b32 100644
--- a/arch/m68k/virt/platform.c
+++ b/arch/m68k/virt/platform.c
@@ -30,7 +30,10 @@ static int __init virt_platform_init(void)
DEFINE_RES_MEM(virt_bi_data.rtc.mmio + 0x1000, 0x1000),
DEFINE_RES_IRQ(virt_bi_data.rtc.irq + 1),
};
- struct platform_device *pdev1, *pdev2;
+ const struct resource virt_ctrl_res[] = {
+ DEFINE_RES_MEM(virt_bi_data.ctrl.mmio, 0x100),
+ };
+ struct platform_device *pdev1, *pdev2, *pdev3;
struct platform_device *pdevs[VIRTIO_BUS_NB];
unsigned int i;
int ret = 0;
@@ -57,19 +60,30 @@ static int __init virt_platform_init(void)
goto err_unregister_tty;
}

+ pdev3 = platform_device_register_simple("qemu-virt-ctrl",
+ PLATFORM_DEVID_NONE,
+ virt_ctrl_res,
+ ARRAY_SIZE(virt_ctrl_res));
+ if (IS_ERR(pdev3)) {
+ ret = PTR_ERR(pdev3);
+ goto err_unregister_rtc;
+ }
+
for (i = 0; i < VIRTIO_BUS_NB; i++) {
pdevs[i] = virt_virtio_init(i);
if (IS_ERR(pdevs[i])) {
ret = PTR_ERR(pdevs[i]);
- goto err_unregister_rtc_virtio;
+ goto err_unregister_virtio;
}
}

return 0;

-err_unregister_rtc_virtio:
+err_unregister_virtio:
while (i > 0)
platform_device_unregister(pdevs[--i]);
+ platform_device_unregister(pdev3);
+err_unregister_rtc:
platform_device_unregister(pdev2);
err_unregister_tty:
platform_device_unregister(pdev1);
--
2.53.0.1213.gd9a14994de-goog