6 files changed, 341 insertions, 0 deletions

diff --git a/sys/conf/files.x86 b/sys/conf/files.x86
index df206b314b38..9976e9cfec5d 100644
--- a/sys/conf/files.x86
+++ b/sys/conf/files.x86
@@ -62,6 +62,7 @@ dev/acpi_support/acpi_wmi_if.m	standard
 dev/agp/agp_amd64.c		optional	agp
 dev/agp/agp_i810.c		optional	agp
 dev/agp/agp_via.c		optional	agp
+dev/amdsmu/amdsmu.c		optional	amdsmu pci
 dev/amdsbwd/amdsbwd.c		optional	amdsbwd
 dev/amdsmn/amdsmn.c		optional	amdsmn | amdtemp
 dev/amdtemp/amdtemp.c		optional	amdtemp
diff --git a/sys/dev/amdsmu/amdsmu.c b/sys/dev/amdsmu/amdsmu.c
new file mode 100644
index 000000000000..84e6c749cca7
--- /dev/null
+++ b/sys/dev/amdsmu/amdsmu.c
@@ -0,0 +1,221 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2025 The FreeBSD Foundation
+ *
+ * This software was developed by Aymeric Wibo <obiwac@freebsd.org>
+ * under sponsorship from the FreeBSD Foundation.
+ */
+
+#include <sys/param.h>
+#include <sys/bus.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+#include <sys/rman.h>
+
+#include <dev/pci/pcivar.h>
+#include <dev/amdsmu/amdsmu.h>
+
+static bool
+amdsmu_match(device_t dev, const struct amdsmu_product **product_out)
+{
+	const uint16_t vendorid = pci_get_vendor(dev);
+	const uint16_t deviceid = pci_get_device(dev);
+
+	for (size_t i = 0; i < nitems(amdsmu_products); i++) {
+		const struct amdsmu_product *prod = &amdsmu_products[i];
+
+		if (vendorid == prod->amdsmu_vendorid &&
+		    deviceid == prod->amdsmu_deviceid) {
+			if (product_out != NULL)
+				*product_out = prod;
+			return (true);
+		}
+	}
+	return (false);
+}
+
+static void
+amdsmu_identify(driver_t *driver, device_t parent)
+{
+	if (device_find_child(parent, "amdsmu", -1) != NULL)
+		return;
+
+	if (amdsmu_match(parent, NULL)) {
+		if (device_add_child(parent, "amdsmu", -1) == NULL)
+			device_printf(parent, "add amdsmu child failed\n");
+	}
+}
+
+static int
+amdsmu_probe(device_t dev)
+{
+	if (resource_disabled("amdsmu", 0))
+		return (ENXIO);
+	if (!amdsmu_match(device_get_parent(dev), NULL))
+		return (ENXIO);
+	device_set_descf(dev, "AMD System Management Unit");
+
+	return (BUS_PROBE_GENERIC);
+}
+
+static enum amdsmu_res
+amdsmu_wait_res(device_t dev)
+{
+	struct amdsmu_softc *sc = device_get_softc(dev);
+	enum amdsmu_res res;
+
+	/*
+	 * The SMU has a response ready for us when the response register is
+	 * set.  Otherwise, we must wait.
+	 */
+	for (size_t i = 0; i < SMU_RES_READ_MAX; i++) {
+		res = amdsmu_read4(sc, SMU_REG_RESPONSE);
+		if (res != SMU_RES_WAIT)
+			return (res);
+		pause_sbt("amdsmu", ustosbt(SMU_RES_READ_PERIOD_US), 0,
+		    C_HARDCLOCK);
+	}
+	device_printf(dev, "timed out waiting for response from SMU\n");
+	return (SMU_RES_WAIT);
+}
+
+static int
+amdsmu_cmd(device_t dev, enum amdsmu_msg msg, uint32_t arg, uint32_t *ret)
+{
+	struct amdsmu_softc *sc = device_get_softc(dev);
+	enum amdsmu_res res;
+
+	/* Wait for SMU to be ready. */
+	if (amdsmu_wait_res(dev) == SMU_RES_WAIT)
+		return (ETIMEDOUT);
+
+	/* Clear previous response. */
+	amdsmu_write4(sc, SMU_REG_RESPONSE, SMU_RES_WAIT);
+
+	/* Write out command to registers. */
+	amdsmu_write4(sc, SMU_REG_MESSAGE, msg);
+	amdsmu_write4(sc, SMU_REG_ARGUMENT, arg);
+
+	/* Wait for SMU response and handle it. */
+	res = amdsmu_wait_res(dev);
+
+	switch (res) {
+	case SMU_RES_WAIT:
+		return (ETIMEDOUT);
+	case SMU_RES_OK:
+		if (ret != NULL)
+			*ret = amdsmu_read4(sc, SMU_REG_ARGUMENT);
+		return (0);
+	case SMU_RES_REJECT_BUSY:
+		device_printf(dev, "SMU is busy\n");
+		return (EBUSY);
+	case SMU_RES_REJECT_PREREQ:
+	case SMU_RES_UNKNOWN:
+	case SMU_RES_FAILED:
+		device_printf(dev, "SMU error: %02x\n", res);
+		return (EIO);
+	}
+
+	return (EINVAL);
+}
+
+static void
+amdsmu_print_vers(device_t dev)
+{
+	uint32_t smu_vers;
+	uint8_t smu_program;
+	uint8_t smu_maj, smu_min, smu_rev;
+
+	if (amdsmu_cmd(dev, SMU_MSG_GETSMUVERSION, 0, &smu_vers) != 0) {
+		device_printf(dev, "failed to get SMU version\n");
+		return;
+	}
+	smu_program = (smu_vers >> 24) & 0xFF;
+	smu_maj = (smu_vers >> 16) & 0xFF;
+	smu_min = (smu_vers >> 8) & 0xFF;
+	smu_rev = smu_vers & 0xFF;
+	device_printf(dev, "SMU version: %d.%d.%d (program %d)\n",
+	    smu_maj, smu_min, smu_rev, smu_program);
+}
+
+static int
+amdsmu_attach(device_t dev)
+{
+	struct amdsmu_softc *sc = device_get_softc(dev);
+	uint32_t physbase_addr_lo, physbase_addr_hi;
+	uint64_t physbase_addr;
+	int rid = 0;
+
+	/*
+	 * Find physical base address for SMU.
+	 * XXX I am a little confused about the masks here.  I'm just copying
+	 * what Linux does in the amd-pmc driver to get the base address.
+	 */
+	pci_write_config(dev, SMU_INDEX_ADDRESS, SMU_PHYSBASE_ADDR_LO, 4);
+	physbase_addr_lo = pci_read_config(dev, SMU_INDEX_DATA, 4) & 0xFFF00000;
+
+	pci_write_config(dev, SMU_INDEX_ADDRESS, SMU_PHYSBASE_ADDR_HI, 4);
+	physbase_addr_hi = pci_read_config(dev, SMU_INDEX_DATA, 4) & 0x0000FFFF;
+
+	physbase_addr = (uint64_t)physbase_addr_hi << 32 | physbase_addr_lo;
+
+	/* Map memory for SMU and its registers. */
+	sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
+	if (sc->res == NULL) {
+		device_printf(dev, "could not allocate resource\n");
+		return (ENXIO);
+	}
+
+	sc->bus_tag = rman_get_bustag(sc->res);
+
+	if (bus_space_map(sc->bus_tag, physbase_addr,
+	    SMU_MEM_SIZE, 0, &sc->smu_space) != 0) {
+		device_printf(dev, "could not map bus space for SMU\n");
+		bus_release_resource(dev, SYS_RES_MEMORY, rid, sc->res);
+		return (ENXIO);
+	}
+	if (bus_space_map(sc->bus_tag, physbase_addr + SMU_REG_SPACE_OFF,
+	    SMU_MEM_SIZE, 0, &sc->reg_space) != 0) {
+		device_printf(dev, "could not map bus space for SMU regs\n");
+		bus_space_unmap(sc->bus_tag, sc->smu_space, SMU_MEM_SIZE);
+		bus_release_resource(dev, SYS_RES_MEMORY, rid, sc->res);
+		return (ENXIO);
+	}
+
+	amdsmu_print_vers(dev);
+	return (0);
+}
+
+static int
+amdsmu_detach(device_t dev)
+{
+	struct amdsmu_softc *sc = device_get_softc(dev);
+	int rid = 0;
+
+	bus_space_unmap(sc->bus_tag, sc->smu_space, SMU_MEM_SIZE);
+	bus_space_unmap(sc->bus_tag, sc->reg_space, SMU_MEM_SIZE);
+
+	bus_release_resource(dev, SYS_RES_MEMORY, rid, sc->res);
+	return (0);
+}
+
+static device_method_t amdsmu_methods[] = {
+	DEVMETHOD(device_identify,	amdsmu_identify),
+	DEVMETHOD(device_probe,		amdsmu_probe),
+	DEVMETHOD(device_attach,	amdsmu_attach),
+	DEVMETHOD(device_detach,	amdsmu_detach),
+	DEVMETHOD_END
+};
+
+static driver_t amdsmu_driver = {
+	"amdsmu",
+	amdsmu_methods,
+	sizeof(struct amdsmu_softc),
+};
+
+DRIVER_MODULE(amdsmu, hostb, amdsmu_driver, NULL, NULL);
+MODULE_VERSION(amdsmu, 1);
+MODULE_DEPEND(amdsmu, amdsmn, 1, 1, 1);
+MODULE_PNP_INFO("U16:vendor;U16:device", pci, amdsmu, amdsmu_products,
+    nitems(amdsmu_products));
diff --git a/sys/dev/amdsmu/amdsmu.h b/sys/dev/amdsmu/amdsmu.h
new file mode 100644
index 000000000000..5e76c8e93062
--- /dev/null
+++ b/sys/dev/amdsmu/amdsmu.h
@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2025 The FreeBSD Foundation
+ *
+ * This software was developed by Aymeric Wibo <obiwac@freebsd.org>
+ * under sponsorship from the FreeBSD Foundation.
+ */
+#ifndef _AMDSMU_H_
+#define	_AMDSMU_H_
+
+#include <sys/types.h>
+#include <machine/bus.h>
+#include <x86/cputypes.h>
+
+#include <dev/amdsmu/amdsmu_reg.h>
+
+#define SMU_RES_READ_PERIOD_US	50
+#define SMU_RES_READ_MAX	20000
+
+static const struct amdsmu_product {
+	uint16_t	amdsmu_vendorid;
+	uint16_t	amdsmu_deviceid;
+} amdsmu_products[] = {
+	{ CPU_VENDOR_AMD,	PCI_DEVICEID_AMD_REMBRANDT_ROOT },
+	{ CPU_VENDOR_AMD,	PCI_DEVICEID_AMD_PHOENIX_ROOT },
+	{ CPU_VENDOR_AMD,	PCI_DEVICEID_AMD_STRIX_POINT_ROOT },
+};
+
+struct amdsmu_softc {
+	struct resource		*res;
+	bus_space_tag_t 	bus_tag;
+
+	bus_space_handle_t	smu_space;
+	bus_space_handle_t	reg_space;
+};
+
+static inline uint32_t
+amdsmu_read4(const struct amdsmu_softc *sc, bus_size_t reg)
+{
+	return (bus_space_read_4(sc->bus_tag, sc->reg_space, reg));
+}
+
+static inline void
+amdsmu_write4(const struct amdsmu_softc *sc, bus_size_t reg, uint32_t val)
+{
+	bus_space_write_4(sc->bus_tag, sc->reg_space, reg, val);
+}
+
+#endif /* _AMDSMU_H_ */
diff --git a/sys/dev/amdsmu/amdsmu_reg.h b/sys/dev/amdsmu/amdsmu_reg.h
new file mode 100644
index 000000000000..5e73cea19028
--- /dev/null
+++ b/sys/dev/amdsmu/amdsmu_reg.h
@@ -0,0 +1,53 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2025 The FreeBSD Foundation
+ *
+ * This software was developed by Aymeric Wibo <obiwac@freebsd.org>
+ * under sponsorship from the FreeBSD Foundation.
+ */
+#ifndef _AMDSMU_REG_H_
+#define	_AMDSMU_REG_H_
+
+/*
+ * TODO These are in common with amdtemp; should we find a way to factor these
+ * out?  Also, there are way more of these.  I couldn't find a centralized place
+ * which lists them though.
+ */
+#define PCI_DEVICEID_AMD_REMBRANDT_ROOT		0x14B5
+#define PCI_DEVICEID_AMD_PHOENIX_ROOT		0x14E8
+#define PCI_DEVICEID_AMD_STRIX_POINT_ROOT	0x14A4
+
+#define SMU_INDEX_ADDRESS	0xB8
+#define SMU_INDEX_DATA		0xBC
+
+#define SMU_PHYSBASE_ADDR_LO	0x13B102E8
+#define SMU_PHYSBASE_ADDR_HI	0x13B102EC
+
+#define SMU_MEM_SIZE		0x1000
+#define SMU_REG_SPACE_OFF	0x10000
+
+#define SMU_REG_MESSAGE		0x538
+#define SMU_REG_RESPONSE	0x980
+#define SMU_REG_ARGUMENT	0x9BC
+
+enum amdsmu_res {
+	SMU_RES_WAIT		= 0x00,
+	SMU_RES_OK		= 0x01,
+	SMU_RES_REJECT_BUSY	= 0xFC,
+	SMU_RES_REJECT_PREREQ	= 0xFD,
+	SMU_RES_UNKNOWN		= 0xFE,
+	SMU_RES_FAILED		= 0xFF,
+};
+
+enum amdsmu_msg {
+	SMU_MSG_GETSMUVERSION		= 0x02,
+	SMU_MSG_LOG_GETDRAM_ADDR_HI	= 0x04,
+	SMU_MSG_LOG_GETDRAM_ADDR_LO	= 0x05,
+	SMU_MSG_LOG_START		= 0x06,
+	SMU_MSG_LOG_RESET		= 0x07,
+	SMU_MSG_LOG_DUMP_DATA		= 0x08,
+	SMU_MSG_GET_SUP_CONSTRAINTS	= 0x09,
+};
+
+#endif /* _AMDSMU_REG_H_ */
diff --git a/sys/modules/Makefile b/sys/modules/Makefile
index 7cb6e2124326..99c9ec9dcd01 100644
--- a/sys/modules/Makefile
+++ b/sys/modules/Makefile
@@ -34,6 +34,7 @@ SUBDIR=	\
 	alq \
 	${_amd_ecc_inject} \
 	${_amdgpio} \
+	${_amdsmu} \
 	${_amdsbwd} \
 	${_amdsmn} \
 	${_amdtemp} \
@@ -772,6 +773,7 @@ _acpi=		acpi
 _aesni=		aesni
 .endif
 _amd_ecc_inject=amd_ecc_inject
+_amdsmu=	amdsmu
 _amdsbwd=	amdsbwd
 _amdsmn=	amdsmn
 _amdtemp=	amdtemp
diff --git a/sys/modules/amdsmu/Makefile b/sys/modules/amdsmu/Makefile
new file mode 100644
index 000000000000..752f57173d61
--- /dev/null
+++ b/sys/modules/amdsmu/Makefile
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2025 The FreeBSD Foundation
+#
+# This software was developed by Aymeric Wibo <obiwac@freebsd.org>
+# under sponsorship from the FreeBSD Foundation.
+
+.PATH: ${SRCTOP}/sys/dev/amdsmu
+
+KMOD=	amdsmu
+SRCS=	amdsmu.c
+SRCS+=	bus_if.h device_if.h pci_if.h
+
+.include <bsd.kmod.mk>