firmware: scmi: Add i.MX95 SCMI CPU Protocol

This protocol allows an agent to start, stop a CPU or set reset vector.
It is used to manage auxiliary CPUs in an LM (e.g. additional cores in an
AP cluster).

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Alice Guo <alice.guo@nxp.com>

drivers/firmware/scmi/vendors/imx/Kconfig

@@ -1,3 +1,11 @@
+config IMX_SM_CPU
+	bool "Enable i.MX System Manager CPU API"
+	depends on ARCH_IMX9 && SCMI_FIRMWARE
+	select SCMI_ID_VENDOR_82
+	help
+	  If you say Y here to enable i.MX System Manager CPU
+	  API to work on some NXP i.MX processors.
+
 config IMX_SM_LMM
 	bool "Enable i.MX System Manager Logical Machine API"
 	depends on ARCH_IMX9 && SCMI_FIRMWARE

drivers/firmware/scmi/vendors/imx/Makefile

@@ -4,4 +4,5 @@
 # SPDX-License-Identifier:      GPL-2.0+
 #
 
+obj-$(CONFIG_IMX_SM_CPU) += imx-sm-cpu.o
 obj-$(CONFIG_IMX_SM_LMM) += imx-sm-lmm.o

drivers/firmware/scmi/vendors/imx/imx-sm-cpu.c

@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * i.MX SCMI CPU protocol
+ *
+ * Copyright 2025 NXP
+ */
+
+#include <compiler.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <misc.h>
+#include <scmi_agent.h>
+#include <scmi_agent-uclass.h>
+#include <scmi_protocols.h>
+#include <scmi_nxp_protocols.h>
+
+enum scmi_imx_cpu_protocol_cmd {
+	SCMI_IMX_CPU_ATTRIBUTES	= 0x3,
+	SCMI_IMX_CPU_START = 0x4,
+	SCMI_IMX_CPU_STOP = 0x5,
+	SCMI_IMX_CPU_RESET_VECTOR_SET = 0x6,
+	SCMI_IMX_CPU_INFO_GET = 0xC,
+};
+
+struct scmi_imx_cpu_priv {
+	u32 nr_cpu;
+};
+
+struct scmi_imx_cpu_reset_vector_set_in {
+	__le32 cpuid;
+#define	CPU_VEC_FLAGS_RESUME	BIT(31)
+#define	CPU_VEC_FLAGS_START	BIT(30)
+#define	CPU_VEC_FLAGS_BOOT	BIT(29)
+	__le32 flags;
+	__le32 resetvectorlow;
+	__le32 resetvectorhigh;
+};
+
+struct scmi_imx_cpu_info_get_out {
+	__le32 status;
+#define	CPU_RUN_MODE_START	0
+#define	CPU_RUN_MODE_HOLD	1
+#define	CPU_RUN_MODE_STOP	2
+#define	CPU_RUN_MODE_SLEEP	3
+	__le32 runmode;
+	__le32 sleepmode;
+	__le32 resetvectorlow;
+	__le32 resetvectorhigh;
+};
+
+int scmi_imx_cpu_start(struct udevice *dev, u32 cpuid, bool start)
+{
+	s32 status;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_VENDOR_82,
+		.message_id = SCMI_IMX_CPU_STOP,
+		.in_msg = (u8 *)&cpuid,
+		.in_msg_sz = sizeof(cpuid),
+		.out_msg = (u8 *)&status,
+		.out_msg_sz = sizeof(status),
+	};
+	int ret;
+
+	if (!dev)
+		return -EINVAL;
+
+	if (start)
+		msg.message_id = SCMI_IMX_CPU_START;
+
+	ret = devm_scmi_process_msg(dev, &msg);
+	if (ret)
+		return ret;
+
+	if (status)
+		return scmi_to_linux_errno(status);
+
+	return 0;
+}
+
+int scmi_imx_cpu_reset_vector_set(struct udevice *dev, u32 cpuid, u32 flags, u64 vector,
+				  bool start, bool boot, bool resume)
+{
+	struct scmi_imx_cpu_reset_vector_set_in in;
+	s32 status;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_VENDOR_82,
+		.message_id = SCMI_IMX_CPU_RESET_VECTOR_SET,
+		.in_msg = (u8 *)&in,
+		.in_msg_sz = sizeof(in),
+		.out_msg = (u8 *)&status,
+		.out_msg_sz = sizeof(status),
+	};
+	int ret;
+
+	if (!dev)
+		return -EINVAL;
+
+	in.cpuid = cpu_to_le32(cpuid);
+	in.flags = cpu_to_le32(0);
+	if (start)
+		in.flags |= CPU_VEC_FLAGS_START;
+	if (boot)
+		in.flags |= CPU_VEC_FLAGS_BOOT;
+	if (resume)
+		in.flags |= CPU_VEC_FLAGS_RESUME;
+	in.resetvectorlow = cpu_to_le32(lower_32_bits(vector));
+	in.resetvectorhigh = cpu_to_le32(upper_32_bits(vector));
+
+	ret = devm_scmi_process_msg(dev, &msg);
+	if (ret)
+		return ret;
+
+	if (status)
+		return scmi_to_linux_errno(status);
+
+	return 0;
+}
+
+int scmi_imx_cpu_started(struct udevice *dev, u32 cpuid, bool *started)
+{
+	struct scmi_imx_cpu_info_get_out out;
+	u32 mode;
+	s32 status;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_VENDOR_82,
+		.message_id = SCMI_IMX_CPU_INFO_GET,
+		.in_msg = (u8 *)&cpuid,
+		.in_msg_sz = sizeof(cpuid),
+		.out_msg = (u8 *)&out,
+		.out_msg_sz = sizeof(out),
+	};
+	int ret;
+
+	if (!dev)
+		return -EINVAL;
+
+	ret = devm_scmi_process_msg(dev, &msg);
+	if (ret)
+		return ret;
+
+	status = cpu_to_le32(out.status);
+	if (status)
+		return scmi_to_linux_errno(status);
+
+	mode = le32_to_cpu(out.runmode);
+	if (mode == CPU_RUN_MODE_START || mode == CPU_RUN_MODE_SLEEP)
+		*started = true;
+
+	return 0;
+}
+
+static int scmi_imx_cpu_probe(struct udevice *dev)
+{
+	int ret;
+
+	ret = devm_scmi_of_get_channel(dev);
+	if (ret) {
+		dev_err(dev, "failed to get channel (%d)\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+U_BOOT_DRIVER(scmi_imx_cpu) = {
+	.name = "scmi_imx_cpu",
+	.id = UCLASS_SCMI_BASE,
+	.probe = scmi_imx_cpu_probe,
+	.priv_auto = sizeof(struct scmi_imx_cpu_priv),
+};
+
+static struct scmi_proto_match match[] = {
+	{ .proto_id = SCMI_PROTOCOL_ID_VENDOR_82},
+	{ /* Sentinel */ }
+};
+
+U_BOOT_SCMI_PROTO_DRIVER(scmi_imx_cpu, match);

include/scmi_nxp_protocols.h

@@ -10,6 +10,7 @@
 #include <linux/bitops.h>
 
 #define SCMI_PROTOCOL_ID_IMX_LMM	0x80
+#define SCMI_PROTOCOL_ID_IMX_CPU	0x82
 #define SCMI_PROTOCOL_ID_IMX_MISC	0x84
 
 #define SCMI_PAYLOAD_LEN	100
@@ -95,4 +96,27 @@ static inline int scmi_imx_lmm_shutdown(struct udevice *dev, u32 lmid, bool flag
 	return -EOPNOTSUPP;
 }
 #endif
+
+#if IS_ENABLED(CONFIG_IMX_SM_CPU)
+int scmi_imx_cpu_started(struct udevice *dev, u32 cpuid, bool *started);
+int scmi_imx_cpu_reset_vector_set(struct udevice *dev, u32 cpuid, u32 flags, u64 vector,
+				  bool start, bool boot, bool resume);
+int scmi_imx_cpu_start(struct udevice *dev, u32 cpuid, bool start);
+#else
+static inline int scmi_imx_cpu_started(struct udevice *dev, u32 cpuid, bool *started)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int scmi_imx_cpu_reset_vector_set(struct udevice *dev, u32 cpuid, u32 flags,
+						u64 vector, bool start, bool boot, bool resume)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int scmi_imx_cpu_start(struct udevice *dev, u32 cpuid, bool start)
+{
+	return -EOPNOTSUPP;
+}
+#endif
 #endif