soc: intel_adsp: rework host IPC using IPC service

This reworks the Intel audio DSP host IPC driver as a backend of
the IPC service. This is the first step to rework IPC in SOF
(Sound Open Firmware) into using a more generic IPC API instead
of a SoC specific one.

For now, it keeps the old interface to maintain usability
as it is going to be a multiple process to rework IPC
over there.

Also, the structure of the new IPC backend resembles
the SoC specific driver to make it easier to compare
between them at this first iteration. Future optimizations
will probably be needed once we start modifying the SOF
side to utilize the IPC interface.

Signed-off-by: Daniel Leung <[email protected]>

Author: dcpleung

include/zephyr/ipc/backends/intel_adsp_host_ipc.h

@@ -0,0 +1,213 @@
+/*
+ * Copyright (c) 2022, 2025 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_IPC_BACKEND_INTEL_ADSP_IPC_H
+#define ZEPHYR_INCLUDE_IPC_BACKEND_INTEL_ADSP_IPC_H
+
+#include <intel_adsp_ipc_devtree.h>
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+#include <zephyr/pm/device.h>
+
+#include <zephyr/ipc/ipc_service_backend.h>
+
+/** Enum on IPC send length argument to indicate IPC message type. */
+enum intel_adsp_send_len {
+	/** Normal IPC message. */
+	INTEL_ADSP_IPC_SEND_MSG,
+
+	/** Synchronous IPC message. */
+	INTEL_ADSP_IPC_SEND_MSG_SYNC,
+
+	/** Emergency IPC message. */
+	INTEL_ADSP_IPC_SEND_MSG_EMERGENCY,
+
+	/** Send a DONE message. */
+	INTEL_ADSP_IPC_SEND_DONE,
+
+	/** Query backend to see if IPC is complete. */
+	INTEL_ADSP_IPC_SEND_IS_COMPLETE,
+};
+
+/** Enum on callback return values. */
+enum intel_adsp_cb_ret {
+	/** Callback return to indicate no issue. Must be 0. */
+	INTEL_ADSP_IPC_CB_RET_OKAY = 0,
+
+	/** Callback return to signal needing external completion. */
+	INTEL_ADSP_IPC_CB_RET_EXT_COMPLETE,
+};
+
+/** Enum on callback length argument to indicate which triggers the callback. */
+enum intel_adsp_cb_len {
+	/** Callback length to indicate this is an IPC message. */
+	INTEL_ADSP_IPC_CB_MSG,
+
+	/** Callback length to indicate this is a DONE message. */
+	INTEL_ADSP_IPC_CB_DONE,
+};
+
+/** Struct for IPC message descriptor. */
+struct intel_adsp_ipc_msg {
+	/** Header specific to platform. */
+	uint32_t data;
+
+	/** Extension specific to platform. */
+	uint32_t ext_data;
+
+	/** Timeout for sending synchronuous message. */
+	k_timeout_t timeout;
+};
+
+#ifdef CONFIG_INTEL_ADSP_IPC_OLD_INTERFACE
+
+/**
+ * @brief Intel ADSP IPC Message Handler Callback.
+ *
+ * This function, once registered via intel_adsp_ipc_set_message_handler(),
+ * is invoked in interrupt context to service messages sent from the
+ * foreign/connected IPC context. The message contents of the TDR and
+ * TDD registers are provided in the data/ext_data argument.
+ *
+ * The function should return true if processing of the message is
+ * complete and return notification to the other side (via the TDA
+ * register) is desired immediately. Returning false means that no
+ * return "DONE" interrupt will occur until intel_adsp_ipc_complete() is
+ * called on this device at some point in the future.
+ *
+ * @note Further messages on the link will not be transmitted or
+ * received while an in-progress message remains incomplete!
+ *
+ * @param dev IPC device.
+ * @param arg Registered argument from intel_adsp_ipc_set_message_handler().
+ * @param data Message data from other side (low bits of TDR register).
+ * @param ext_dat Extended message data (TDD register).
+ * @return true if the message is completely handled.
+ */
+typedef bool (*intel_adsp_ipc_handler_t)(const struct device *dev, void *arg, uint32_t data,
+					 uint32_t ext_data);
+
+/**
+ * @brief Intel ADSP IPC Message Complete Callback.
+ *
+ * This function, once registered via intel_adsp_ipc_set_done_handler(), is
+ * invoked in interrupt context when a "DONE" return interrupt is
+ * received from the other side of the connection (indicating that a
+ * previously sent message is finished processing).
+ *
+ * @note On Intel ADSP hardware the DONE interrupt is transmitted
+ * synchronously with the interrupt being cleared on the remote
+ * device. It is not possible to delay processing. This callback
+ * will still occur, but protocols which rely on notification of
+ * asynchronous command processing will need modification.
+ *
+ * @param dev IPC device.
+ * @param arg Registered argument from intel_adsp_ipc_set_done_handler().
+ * @return True if IPC completion will be done externally, otherwise false.
+ * @note Returning True will cause this API to skip writing IPC registers
+ * signalling IPC message completion and those actions should be done by
+ * external code manually. Returning false from the handler will perform
+ * writing to IPC registers signalling message completion normally by this API.
+ */
+typedef bool (*intel_adsp_ipc_done_t)(const struct device *dev, void *arg);
+
+#endif /* CONFIG_INTEL_ADSP_IPC_OLD_INTERFACE */
+
+#ifdef CONFIG_PM_DEVICE
+typedef int (*intel_adsp_ipc_resume_handler_t)(const struct device *dev, void *arg);
+
+typedef int (*intel_adsp_ipc_suspend_handler_t)(const struct device *dev, void *arg);
+#endif /* CONFIG_PM_DEVICE */
+
+/**
+ * Intel Audio DSP IPC service backend config struct.
+ */
+struct intel_adsp_ipc_config {
+	/** Pointer to hardware register block. */
+	volatile struct intel_adsp_ipc *regs;
+};
+
+/**
+ * Intel Audio DSP IPC service backend data struct.
+ */
+struct intel_adsp_ipc_data {
+	/** Semaphore used to wait for remote acknowledgment of sent message. */
+	struct k_sem sem;
+
+	/** General driver lock. */
+	struct k_spinlock lock;
+
+	/** Pending TX acknowlegement. */
+	bool tx_ack_pending;
+
+	/** Pointer to endpoint configuration. */
+	const struct ipc_ept_cfg *ept_cfg;
+
+#ifdef CONFIG_INTEL_ADSP_IPC_OLD_INTERFACE
+	/** Callback for message handler. */
+	intel_adsp_ipc_handler_t handle_message;
+
+	/** Argument for message handler callback. */
+	void *handler_arg;
+
+	/** Callback for done notification. */
+	intel_adsp_ipc_done_t done_notify;
+
+	/** Argument for done notification callback. */
+	void *done_arg;
+#endif /* CONFIG_INTEL_ADSP_IPC_OLD_INTERFACE */
+
+#ifdef CONFIG_PM_DEVICE
+	/** Pointer to resume handler. */
+	intel_adsp_ipc_resume_handler_t resume_fn;
+
+	/** Argument for resume handler. */
+	void *resume_fn_args;
+
+	/** Pointer to suspend handler. */
+	intel_adsp_ipc_suspend_handler_t suspend_fn;
+
+	/** Argument for suspend handler. */
+	void *suspend_fn_args;
+#endif /* CONFIG_PM_DEVICE */
+};
+
+/**
+ * Endpoint private data struct.
+ */
+struct intel_adsp_ipc_ept_priv_data {
+	/** Callback return value (enum intel_adsp_cb_ret). */
+	int cb_ret;
+
+	/** Pointer to additional private data. */
+	void *priv;
+};
+
+#ifdef CONFIG_PM_DEVICE
+
+/**
+ * @brief Registers resume callback handler used to resume Device from suspended state.
+ *
+ * @param dev IPC device.
+ * @param fn Callback function.
+ * @param arg Value to pass as the "arg" parameter to the function.
+ */
+void intel_adsp_ipc_set_resume_handler(const struct device *dev, intel_adsp_ipc_resume_handler_t fn,
+				       void *arg);
+
+/**
+ * @brief Registers suspend callback handler used to suspend active Device.
+ *
+ * @param dev IPC device.
+ * @param fn Callback function.
+ * @param arg Value to pass as the "arg" parameter to the function.
+ */
+void intel_adsp_ipc_set_suspend_handler(const struct device *dev,
+					intel_adsp_ipc_suspend_handler_t fn, void *arg);
+
+#endif /* CONFIG_PM_DEVICE */
+
+#endif /* ZEPHYR_INCLUDE_IPC_BACKEND_INTEL_ADSP_IPC_H */

soc/intel/intel_adsp/Kconfig

@@ -11,6 +11,7 @@ config SOC_FAMILY_INTEL_ADSP
 	select ARCH_HAS_USERSPACE if XTENSA_MMU
 	imply XTENSA_MMU_DOUBLE_MAP
 	select CPU_CACHE_INCOHERENT
+	select IPC_SERVICE if DT_HAS_INTEL_ADSP_HOST_IPC_ENABLED
 
 if SOC_FAMILY_INTEL_ADSP
 
@@ -32,14 +33,20 @@ config INTEL_ADSP_SIM_NO_SECONDARY_CORE_FLOW
 
 endif # INTEL_ADSP_SIM
 
-DT_COMPAT_INTEL_ADSP_HOST_IPC := intel,adsp-host-ipc
-
 config INTEL_ADSP_IPC
 	bool "Driver for the host IPC interrupt delivery"
-	default $(dt_compat_enabled,$(DT_COMPAT_INTEL_ADSP_HOST_IPC)) if !SOF
+	select DEPRECATED
+	help
+	  Deprecated config for IPC. Will be removed in the future.
+
+config INTEL_ADSP_IPC_OLD_INTERFACE
+	bool "Expose old interface for the IPC"
+	depends on IPC_SERVICE_BACKEND_INTEL_ADSP_HOST_IPC
+	default y
+	select INTEL_ADSP_IPC
 	help
-	  Driver for the host IPC interrupt delivery mechanism.
-	  Currently SOF has its own driver for this hardware.
+	  Expose the old IPC interface (intel_adsp_ipc_* functions) to
+	  maintain backward compatibility.
 
 config MEMORY_WIN_0_SIZE
 	int "Size of memory window 0"

soc/intel/intel_adsp/common/CMakeLists.txt

@@ -9,7 +9,7 @@ zephyr_library_named(intel_adsp_common)
 zephyr_include_directories(include)
 zephyr_library_include_directories(${ZEPHYR_BASE}/drivers)
 
-zephyr_library_sources_ifdef(CONFIG_INTEL_ADSP_IPC ipc.c)
+zephyr_library_sources_ifdef(CONFIG_INTEL_ADSP_IPC_OLD_INTERFACE ipc.c)
 
 zephyr_library_sources_ifdef(CONFIG_GDBSTUB
     gdbstub_backend_sram.c