/* SPDX-License-Identifier: GPL-2.0 */
/*
 * GXP telemetry support
 *
 * Copyright (C) 2021 Google LLC
 */
#ifndef __GXP_TELEMETRY_H__
#define __GXP_TELEMETRY_H__

#include <linux/eventfd.h>
#include <linux/refcount.h>
#include <linux/types.h>

#include "gxp.h"
#include "gxp-internal.h"

struct gxp_telemetry_work {
	struct work_struct work;
	struct gxp_dev *gxp;
	uint core;
};

struct gxp_telemetry_manager {
	struct buffer_data {
		u32 host_status;
		void *buffers[GXP_NUM_CORES];
		dma_addr_t buffer_daddrs[GXP_NUM_CORES];
		u32 size;
		refcount_t ref_count;
	} *logging_buff_data, *tracing_buff_data;
	/* Protects logging_buff_data and tracing_buff_data */
	struct mutex lock;
	struct gxp_telemetry_work notification_works[GXP_NUM_CORES];
	wait_queue_head_t waitq;
	struct eventfd_ctx *logging_efd;
	struct eventfd_ctx *tracing_efd;
};

/**
 * gxp_telemetry_init() - Initialize telemetry support
 * @gxp: The GXP device to initialize telemetry support for
 *
 * Return:
 * * 0       - Success
 * * -ENOMEM - Insufficient memory is available to initialize support
 */
int gxp_telemetry_init(struct gxp_dev *gxp);

/**
 * gxp_telemetry_mmap_buffers() - Allocate a telemetry buffer for each core and
 *                                map them to their core and the user-space vma
 * @gxp: The GXP device to create the buffers for
 * @type: EIther `GXP_TELEMETRY_TYPE_LOGGING` or `GXP_TELEMETRY_TYPE_TRACING`
 * @vma: The vma from user-space which all cores' buffers will be mapped into
 *
 * Return:
 * * 0       - Success
 * * -ENODEV - Telemetry support has not been initialized. Must explicitly
 *             check this, since this function is called based on user-input.
 * * -EBUSY  - The requested telemetry @type is already in use
 * * -EINVAL - Either the vma size is not aligned or @type is not valid
 * * -ENOMEM - Insufficient memory is available to allocate and map the buffers
 */
int gxp_telemetry_mmap_buffers(struct gxp_dev *gxp, u8 type,
			       struct vm_area_struct *vma);

/**
 * gxp_telemetry_enable() - Enable logging or tracing for all DSP cores
 * @gxp: The GXP device to enable either logging or tracing for
 * @type: Either `GXP_TELEMETRY_TYPE_LOGGING` or `GXP_TELEMETRY_TYPE_TRACING`
 *
 * Return:
 * * 0       - Success
 * * -EINVAL - The @type provided is not valid
 * * -ENXIO  - Buffers for @type have not been created/mapped yet
 */
int gxp_telemetry_enable(struct gxp_dev *gxp, u8 type);

/**
 * gxp_telemetry_disable() - Disable logging or tracing for all DSP cores
 * @gxp: The GXP device to disable either logging or tracing for
 * @type: Either `GXP_TELEMETRY_TYPE_LOGGING` or `GXP_TELEMETRY_TYPE_TRACING`
 *
 * Return:
 * * 0       - Success
 * * -EINVAL - The @type provided is not valid
 * * -ENXIO  - Buffers for @type have not been created/mapped yet
 */
int gxp_telemetry_disable(struct gxp_dev *gxp, u8 type);

/**
 * gxp_telemetry_register_eventfd() - Register an eventfd to be signaled when
 *                                    telemetry notifications arrive while the
 *                                    specified @type of telemetry is enabled
 * @gxp: The GXP device to register the eventfd for
 * @type: Either `GXP_TELEMETRY_TYPE_LOGGING` or `GXP_TELEMETRY_TYPE_TRACING`
 * @fd: A file descriptor for an eventfd from user-space
 *
 * If another eventfd has already been registered for the given @type, the old
 * eventfd will be unregistered and replaced.
 *
 * Return:
 * * 0       - Success
 * * -EBADF  - @fd is not a valid file descriptor (via `eventfd_ctx_fdget()`)
 * * -EINVAL - Invalid @type or @fd is not an eventfd
 */
int gxp_telemetry_register_eventfd(struct gxp_dev *gxp, u8 type, int fd);

/**
 * gxp_telemetry_unregister_eventfd() - Unregister and release a reference to
 *                                      a previously registered eventfd
 * @gxp: The GXP device to unregister the eventfd for
 * @type: Either `GXP_TELEMETRY_TYPE_LOGGING` or `GXP_TELEMETRY_TYPE_TRACING`
 *
 * Return:
 * * 0       - Success
 * * -EINVAL - The @type provided is not valid
 */
int gxp_telemetry_unregister_eventfd(struct gxp_dev *gxp, u8 type);

/**
 * gxp_telemetry_get_notification_handler() - Get the notification handler work
 *                                            for the specified core
 * @gxp: The GXP device to obtain the handler for
 * @core: The physical core number to obtain the handler
 *
 * Return: A pointer to the work_struct for the @core's notification handler if
 *         successful. NULL if telemetry has not been initialized or @core is
 *         invalid.
 */
struct work_struct *gxp_telemetry_get_notification_handler(struct gxp_dev *gxp,
							   uint core);

#endif /* __GXP_TELEMETRY_H__ */