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
11 struct auxiliary_irq_info {
12 struct device_attribute sysfs_attr;
13 char name[AUXILIARY_MAX_IRQ_NAME];
14 };
15
16 static struct attribute *auxiliary_irq_attrs[] = {
17 NULL
18 };
19
20 static const struct attribute_group auxiliary_irqs_group = {
21 .name = "irqs",
22 .attrs = auxiliary_irq_attrs,
23 };
24
auxiliary_irq_dir_prepare(struct auxiliary_device * auxdev)25 static int auxiliary_irq_dir_prepare(struct auxiliary_device *auxdev)
26 {
27 int ret = 0;
28
29 guard(mutex)(&auxdev->sysfs.lock);
30 if (auxdev->sysfs.irq_dir_exists)
31 return 0;
32
33 ret = devm_device_add_group(&auxdev->dev, &auxiliary_irqs_group);
34 if (ret)
35 return ret;
36
37 auxdev->sysfs.irq_dir_exists = true;
38 xa_init(&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 */
auxiliary_device_sysfs_irq_add(struct auxiliary_device * auxdev,int irq)56 int 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(info->name, AUXILIARY_MAX_IRQ_NAME, "%d", irq);
72
73 ret = xa_insert(&auxdev->sysfs.irqs, irq, 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(&dev->kobj, &info->sysfs_attr.attr,
79 auxiliary_irqs_group.name);
80 if (ret)
81 goto sysfs_add_err;
82
83 xa_store(&auxdev->sysfs.irqs, irq, no_free_ptr(info), GFP_KERNEL);
84 return 0;
85
86 sysfs_add_err:
87 xa_erase(&auxdev->sysfs.irqs, irq);
88 return ret;
89 }
90 EXPORT_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 */
auxiliary_device_sysfs_irq_remove(struct auxiliary_device * auxdev,int irq)100 void 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, 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(&dev->kobj, &info->sysfs_attr.attr,
110 auxiliary_irqs_group.name);
111 xa_erase(&auxdev->sysfs.irqs, irq);
112 }
113 EXPORT_SYMBOL_GPL(auxiliary_device_sysfs_irq_remove);
114