1/* SPDX-License-Identifier: GPL-2.0-only */
 2/*
 3 * IRQ offload/bypass manager
 4 *
 5 * Copyright (C) 2015 Red Hat, Inc.
 6 * Copyright (c) 2015 Linaro Ltd.
 7 */
 8#ifndef IRQBYPASS_H
 9#define IRQBYPASS_H
10
11#include <linux/list.h>
12
13struct irq_bypass_consumer;
14
15/*
16 * Theory of operation
17 *
18 * The IRQ bypass manager is a simple set of lists and callbacks that allows
19 * IRQ producers (ex. physical interrupt sources) to be matched to IRQ
20 * consumers (ex. virtualization hardware that allows IRQ bypass or offload)
21 * via a shared token (ex. eventfd_ctx).  Producers and consumers register
22 * independently.  When a token match is found, the optional @stop callback
23 * will be called for each participant.  The pair will then be connected via
24 * the @add_* callbacks, and finally the optional @start callback will allow
25 * any final coordination.  When either participant is unregistered, the
26 * process is repeated using the @del_* callbacks in place of the @add_*
27 * callbacks.  Match tokens must be unique per producer/consumer, 1:N pairings
28 * are not supported.
29 */
30
31/**
32 * struct irq_bypass_producer - IRQ bypass producer definition
33 * @node: IRQ bypass manager private list management
34 * @token: opaque token to match between producer and consumer (non-NULL)
35 * @irq: Linux IRQ number for the producer device
36 * @add_consumer: Connect the IRQ producer to an IRQ consumer (optional)
37 * @del_consumer: Disconnect the IRQ producer from an IRQ consumer (optional)
38 * @stop: Perform any quiesce operations necessary prior to add/del (optional)
39 * @start: Perform any startup operations necessary after add/del (optional)
40 *
41 * The IRQ bypass producer structure represents an interrupt source for
42 * participation in possible host bypass, for instance an interrupt vector
43 * for a physical device assigned to a VM.
44 */
45struct irq_bypass_producer {
46	struct list_head node;
47	void *token;
48	int irq;
49	int (*add_consumer)(struct irq_bypass_producer *,
50			    struct irq_bypass_consumer *);
51	void (*del_consumer)(struct irq_bypass_producer *,
52			     struct irq_bypass_consumer *);
53	void (*stop)(struct irq_bypass_producer *);
54	void (*start)(struct irq_bypass_producer *);
55};
56
57/**
58 * struct irq_bypass_consumer - IRQ bypass consumer definition
59 * @node: IRQ bypass manager private list management
60 * @token: opaque token to match between producer and consumer (non-NULL)
61 * @add_producer: Connect the IRQ consumer to an IRQ producer
62 * @del_producer: Disconnect the IRQ consumer from an IRQ producer
63 * @stop: Perform any quiesce operations necessary prior to add/del (optional)
64 * @start: Perform any startup operations necessary after add/del (optional)
65 *
66 * The IRQ bypass consumer structure represents an interrupt sink for
67 * participation in possible host bypass, for instance a hypervisor may
68 * support offloads to allow bypassing the host entirely or offload
69 * portions of the interrupt handling to the VM.
70 */
71struct irq_bypass_consumer {
72	struct list_head node;
73	void *token;
74	int (*add_producer)(struct irq_bypass_consumer *,
75			    struct irq_bypass_producer *);
76	void (*del_producer)(struct irq_bypass_consumer *,
77			     struct irq_bypass_producer *);
78	void (*stop)(struct irq_bypass_consumer *);
79	void (*start)(struct irq_bypass_consumer *);
80};
81
82int irq_bypass_register_producer(struct irq_bypass_producer *);
83void irq_bypass_unregister_producer(struct irq_bypass_producer *);
84int irq_bypass_register_consumer(struct irq_bypass_consumer *);
85void irq_bypass_unregister_consumer(struct irq_bypass_consumer *);
86
87#endif /* IRQBYPASS_H */