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 
13 struct 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  */
45 struct 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  */
71 struct 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 
82 int irq_bypass_register_producer(struct irq_bypass_producer *);
83 void irq_bypass_unregister_producer(struct irq_bypass_producer *);
84 int irq_bypass_register_consumer(struct irq_bypass_consumer *);
85 void irq_bypass_unregister_consumer(struct irq_bypass_consumer *);
86 
87 #endif /* IRQBYPASS_H */
88