3 files changed, 57 insertions, 3 deletions

diff --git a/sys/dev/amdsmu/amdsmu.c b/sys/dev/amdsmu/amdsmu.c
index 416f875c6176..9a6873b43517 100644
--- a/sys/dev/amdsmu/amdsmu.c
+++ b/sys/dev/amdsmu/amdsmu.c
@@ -1,7 +1,7 @@
 /*
  * SPDX-License-Identifier: BSD-2-Clause
  *
- * Copyright (c) 2025 The FreeBSD Foundation
+ * Copyright (c) 2025-2026 The FreeBSD Foundation
  *
  * This software was developed by Aymeric Wibo <obiwac@freebsd.org>
  * under sponsorship from the FreeBSD Foundation.
@@ -14,6 +14,13 @@
 #include <sys/rman.h>
 #include <sys/sysctl.h>
 
+#include "opt_acpi.h"
+
+#if defined(DEV_ACPI)
+#include <contrib/dev/acpica/include/acpi.h>
+#include <dev/acpica/acpivar.h>
+#endif
+
 #include <dev/pci/pcivar.h>
 #include <dev/amdsmu/amdsmu.h>
 
@@ -289,6 +296,27 @@ amdsmu_fetch_idlemask(device_t dev)
 	sc->idlemask = amdsmu_read4(sc, SMU_REG_IDLEMASK);
 }
 
+static void
+amdsmu_suspend(device_t dev, enum power_stype stype)
+{
+	if (stype != POWER_STYPE_SUSPEND_TO_IDLE)
+		return;
+	if (amdsmu_cmd(dev, SMU_MSG_SLEEP_HINT, true, NULL) != 0)
+		device_printf(dev, "failed to hint to SMU to enter sleep");
+}
+
+static void
+amdsmu_resume(device_t dev, enum power_stype stype)
+{
+	if (stype != POWER_STYPE_SUSPEND_TO_IDLE)
+		return;
+	if (amdsmu_cmd(dev, SMU_MSG_SLEEP_HINT, false, NULL) != 0)
+		device_printf(dev, "failed to hint to SMU to exit sleep");
+	/* Update metrics after resume. */
+	amdsmu_dump_metrics(dev);
+	amdsmu_fetch_idlemask(dev);
+}
+
 static int
 amdsmu_attach(device_t dev)
 {
@@ -422,6 +450,19 @@ amdsmu_attach(device_t dev)
 	    "value is not documented - only used to help AMD internally debug "
 	    "issues");
 
+#if defined(DEV_ACPI)
+	/*
+	 * Register post device suspend/pre device resume eventhandlers.  We use
+	 * a lower priority for the suspend event as we want this to be called
+	 * after the SPMC suspend hook, and a higher priority for the resume
+	 * event as we want this to be called before the SPMC hook.
+	 */
+	sc->eh_suspend = EVENTHANDLER_REGISTER(acpi_post_dev_suspend,
+	    amdsmu_suspend, dev, -10);
+	sc->eh_resume = EVENTHANDLER_REGISTER(acpi_pre_dev_resume,
+	    amdsmu_resume, dev, 10);
+#endif
+
 	return (0);
 err_dump:
 	bus_space_unmap(sc->bus_tag, sc->reg_space, SMU_MEM_SIZE);
@@ -438,6 +479,11 @@ amdsmu_detach(device_t dev)
 	struct amdsmu_softc *sc = device_get_softc(dev);
 	int rid = 0;
 
+#if defined(DEV_ACPI)
+	EVENTHANDLER_DEREGISTER(acpi_post_dev_suspend, sc->eh_suspend);
+	EVENTHANDLER_DEREGISTER(acpi_pre_dev_resume, sc->eh_resume);
+#endif
+
 	bus_space_unmap(sc->bus_tag, sc->smu_space, SMU_MEM_SIZE);
 	bus_space_unmap(sc->bus_tag, sc->reg_space, SMU_MEM_SIZE);
 
diff --git a/sys/dev/amdsmu/amdsmu.h b/sys/dev/amdsmu/amdsmu.h
index 025887f7fe5a..857fa21cba4e 100644
--- a/sys/dev/amdsmu/amdsmu.h
+++ b/sys/dev/amdsmu/amdsmu.h
@@ -6,11 +6,13 @@
  * This software was developed by Aymeric Wibo <obiwac@freebsd.org>
  * under sponsorship from the FreeBSD Foundation.
  */
+
 #ifndef _AMDSMU_H_
 #define	_AMDSMU_H_
 
 #include <sys/param.h>
 #include <sys/bus.h>
+#include <sys/eventhandler.h>
 #include <sys/kernel.h>
 #include <machine/bus.h>
 #include <x86/cputypes.h>
@@ -60,6 +62,9 @@ struct amdsmu_softc {
 	struct sysctl_ctx_list	*sysctlctx;
 	struct sysctl_oid	*sysctlnode;
 
+	struct eventhandler_entry	*eh_suspend;
+	struct eventhandler_entry	*eh_resume;
+
 	struct resource		*res;
 	bus_space_tag_t 	bus_tag;
 
@@ -72,8 +77,10 @@ struct amdsmu_softc {
 	uint32_t		active_ip_blocks;
 	struct sysctl_oid	*ip_blocks_sysctlnode;
 	size_t			ip_block_count;
-	struct sysctl_oid	*ip_block_sysctlnodes[nitems(amdsmu_ip_blocks_names)];
-	bool			ip_blocks_active[nitems(amdsmu_ip_blocks_names)];
+	struct sysctl_oid	*ip_block_sysctlnodes[
+				    nitems(amdsmu_ip_blocks_names)];
+	bool			ip_blocks_active[
+				    nitems(amdsmu_ip_blocks_names)];
 
 	bus_space_handle_t	metrics_space;
 	struct amdsmu_metrics	metrics;
diff --git a/sys/dev/amdsmu/amdsmu_reg.h b/sys/dev/amdsmu/amdsmu_reg.h
index e685b34e6883..d45fa60941d5 100644
--- a/sys/dev/amdsmu/amdsmu_reg.h
+++ b/sys/dev/amdsmu/amdsmu_reg.h
@@ -45,6 +45,7 @@ enum amdsmu_res {
 
 enum amdsmu_msg {
 	SMU_MSG_GETSMUVERSION		= 0x02,
+	SMU_MSG_SLEEP_HINT		= 0x03,
 	SMU_MSG_LOG_GETDRAM_ADDR_HI	= 0x04,
 	SMU_MSG_LOG_GETDRAM_ADDR_LO	= 0x05,
 	SMU_MSG_LOG_START		= 0x06,