1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Gasket common interrupt module. Defines functions for enabling
4  * eventfd-triggered interrupts between a Gasket device and a host process.
5  *
6  * Copyright (C) 2018 Google, Inc.
7  */
8 #ifndef __GASKET_INTERRUPT_H__
9 #define __GASKET_INTERRUPT_H__
10 
11 #include <linux/eventfd.h>
12 #include <linux/pci.h>
13 
14 #include "gasket_core.h"
15 
16 /* Note that this currently assumes that device interrupts are a dense set,
17  * numbered from 0 - (num_interrupts - 1). Should this have to change, these
18  * APIs will have to be updated.
19  */
20 
21 /* Opaque type used to hold interrupt subsystem data. */
22 struct gasket_interrupt_data;
23 
24 /*
25  * Initialize the interrupt module.
26  * @gasket_dev: The Gasket device structure for the device to be initted.
27  */
28 int gasket_interrupt_init(struct gasket_dev *gasket_dev);
29 
30 /*
31  * Clean up a device's interrupt structure.
32  * @gasket_dev: The Gasket information structure for this device.
33  *
34  * Cleans up the device's interrupts and deallocates data.
35  */
36 void gasket_interrupt_cleanup(struct gasket_dev *gasket_dev);
37 
38 /*
39  * Clean up and re-initialize the MSI-x subsystem.
40  * @gasket_dev: The Gasket information structure for this device.
41  *
42  * Performs a teardown of the MSI-x subsystem and re-initializes it. Does not
43  * free the underlying data structures. Returns 0 on success and an error code
44  * on error.
45  */
46 int gasket_interrupt_reinit(struct gasket_dev *gasket_dev);
47 
48 /*
49  * Reset the counts stored in the interrupt subsystem.
50  * @gasket_dev: The Gasket information structure for this device.
51  *
52  * Sets the counts of all interrupts in the subsystem to 0.
53  */
54 int gasket_interrupt_reset_counts(struct gasket_dev *gasket_dev);
55 
56 /*
57  * Associates an eventfd with a device interrupt.
58  * @data: Pointer to device interrupt data.
59  * @interrupt: The device interrupt to configure.
60  * @event_fd: The eventfd to associate with the interrupt.
61  *
62  * Prepares the host to receive notification of device interrupts by associating
63  * event_fd with interrupt. Upon receipt of a device interrupt, event_fd will be
64  * signaled, after successful configuration.
65  *
66  * Returns 0 on success, a negative error code otherwise.
67  */
68 int gasket_interrupt_set_eventfd(struct gasket_interrupt_data *interrupt_data,
69 				 int interrupt, int event_fd);
70 
71 /*
72  * Removes an interrupt-eventfd association.
73  * @data: Pointer to device interrupt data.
74  * @interrupt: The device interrupt to de-associate.
75  *
76  * Removes any eventfd associated with the specified interrupt, if any.
77  */
78 int gasket_interrupt_clear_eventfd(struct gasket_interrupt_data *interrupt_data,
79 				   int interrupt);
80 
81 /*
82  * The below functions exist for backwards compatibility.
83  * No new uses should be written.
84  */
85 /*
86  * Get the health of the interrupt subsystem.
87  * @gasket_dev: The Gasket device struct.
88  *
89  * Returns DEAD if not set up, LAMED if initialization failed, and ALIVE
90  * otherwise.
91  */
92 
93 int gasket_interrupt_system_status(struct gasket_dev *gasket_dev);
94 
95 #endif
96