1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES
4 */
5
6#include <linux/auxiliary_bus.h>
7#include <linux/slab.h>
8
9#define AUXILIARY_MAX_IRQ_NAME 11
10
11struct auxiliary_irq_info {
12 struct device_attribute sysfs_attr;
13 char name[AUXILIARY_MAX_IRQ_NAME];
14};
15
16static struct attribute *auxiliary_irq_attrs[] = {
17 NULL
18};
19
20static const struct attribute_group auxiliary_irqs_group = {
21 .name = "irqs",
22 .attrs = auxiliary_irq_attrs,
23};
24
25static int auxiliary_irq_dir_prepare(struct auxiliary_device *auxdev)
26{
27 int ret = 0;
28
29 guard(mutex)(T: &auxdev->sysfs.lock);
30 if (auxdev->sysfs.irq_dir_exists)
31 return 0;
32
33 ret = devm_device_add_group(dev: &auxdev->dev, grp: &auxiliary_irqs_group);
34 if (ret)
35 return ret;
36
37 auxdev->sysfs.irq_dir_exists = true;
38 xa_init(xa: &auxdev->sysfs.irqs);
39 return 0;
40}
41
42/**
43 * auxiliary_device_sysfs_irq_add - add a sysfs entry for the given IRQ
44 * @auxdev: auxiliary bus device to add the sysfs entry.
45 * @irq: The associated interrupt number.
46 *
47 * This function should be called after auxiliary device have successfully
48 * received the irq.
49 * The driver is responsible to add a unique irq for the auxiliary device. The
50 * driver can invoke this function from multiple thread context safely for
51 * unique irqs of the auxiliary devices. The driver must not invoke this API
52 * multiple times if the irq is already added previously.
53 *
54 * Return: zero on success or an error code on failure.
55 */
56int auxiliary_device_sysfs_irq_add(struct auxiliary_device *auxdev, int irq)
57{
58 struct auxiliary_irq_info *info __free(kfree) = NULL;
59 struct device *dev = &auxdev->dev;
60 int ret;
61
62 ret = auxiliary_irq_dir_prepare(auxdev);
63 if (ret)
64 return ret;
65
66 info = kzalloc(sizeof(*info), GFP_KERNEL);
67 if (!info)
68 return -ENOMEM;
69
70 sysfs_attr_init(&info->sysfs_attr.attr);
71 snprintf(buf: info->name, AUXILIARY_MAX_IRQ_NAME, fmt: "%d", irq);
72
73 ret = xa_insert(xa: &auxdev->sysfs.irqs, index: irq, entry: info, GFP_KERNEL);
74 if (ret)
75 return ret;
76
77 info->sysfs_attr.attr.name = info->name;
78 ret = sysfs_add_file_to_group(kobj: &dev->kobj, attr: &info->sysfs_attr.attr,
79 group: auxiliary_irqs_group.name);
80 if (ret)
81 goto sysfs_add_err;
82
83 xa_store(&auxdev->sysfs.irqs, index: irq, no_free_ptr(info), GFP_KERNEL);
84 return 0;
85
86sysfs_add_err:
87 xa_erase(&auxdev->sysfs.irqs, index: irq);
88 return ret;
89}
90EXPORT_SYMBOL_GPL(auxiliary_device_sysfs_irq_add);
91
92/**
93 * auxiliary_device_sysfs_irq_remove - remove a sysfs entry for the given IRQ
94 * @auxdev: auxiliary bus device to add the sysfs entry.
95 * @irq: the IRQ to remove.
96 *
97 * This function should be called to remove an IRQ sysfs entry.
98 * The driver must invoke this API when IRQ is released by the device.
99 */
100void auxiliary_device_sysfs_irq_remove(struct auxiliary_device *auxdev, int irq)
101{
102 struct auxiliary_irq_info *info __free(kfree) = xa_load(&auxdev->sysfs.irqs, index: irq);
103 struct device *dev = &auxdev->dev;
104
105 if (!info) {
106 dev_err(&auxdev->dev, "IRQ %d doesn't exist\n", irq);
107 return;
108 }
109 sysfs_remove_file_from_group(kobj: &dev->kobj, attr: &info->sysfs_attr.attr,
110 group: auxiliary_irqs_group.name);
111 xa_erase(&auxdev->sysfs.irqs, index: irq);
112}
113EXPORT_SYMBOL_GPL(auxiliary_device_sysfs_irq_remove);
114