1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Generic Event Device for ACPI.
4 *
5 * Copyright (c) 2016, The Linux Foundation. All rights reserved.
6 *
7 * Generic Event Device allows platforms to handle interrupts in ACPI
8 * ASL statements. It follows very similar to _EVT method approach
9 * from GPIO events. All interrupts are listed in _CRS and the handler
10 * is written in _EVT method. Here is an example.
11 *
12 * Device (GED0)
13 * {
14 *
15 * Name (_HID, "ACPI0013")
16 * Name (_UID, 0)
17 * Method (_CRS, 0x0, Serialized)
18 * {
19 * Name (RBUF, ResourceTemplate ()
20 * {
21 * Interrupt(ResourceConsumer, Edge, ActiveHigh, Shared, , , )
22 * {123}
23 * }
24 * })
25 *
26 * Method (_EVT, 1) {
27 * if (Lequal(123, Arg0))
28 * {
29 * }
30 * }
31 * }
32 */
33
34#include <linux/err.h>
35#include <linux/init.h>
36#include <linux/interrupt.h>
37#include <linux/list.h>
38#include <linux/platform_device.h>
39#include <linux/acpi.h>
40
41#define MODULE_NAME "acpi-ged"
42
43struct acpi_ged_device {
44 struct device *dev;
45 struct list_head event_list;
46};
47
48struct acpi_ged_event {
49 struct list_head node;
50 struct device *dev;
51 unsigned int gsi;
52 unsigned int irq;
53 acpi_handle handle;
54};
55
56static irqreturn_t acpi_ged_irq_handler(int irq, void *data)
57{
58 struct acpi_ged_event *event = data;
59 acpi_status acpi_ret;
60
61 acpi_ret = acpi_execute_simple_method(handle: event->handle, NULL, arg: event->gsi);
62 if (ACPI_FAILURE(acpi_ret))
63 dev_err_once(event->dev, "IRQ method execution failed\n");
64
65 return IRQ_HANDLED;
66}
67
68static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
69 void *context)
70{
71 struct acpi_ged_event *event;
72 unsigned int irq;
73 unsigned int gsi;
74 unsigned int irqflags = IRQF_ONESHOT;
75 struct acpi_ged_device *geddev = context;
76 struct device *dev = geddev->dev;
77 acpi_handle handle = ACPI_HANDLE(dev);
78 acpi_handle evt_handle;
79 struct resource r;
80 struct acpi_resource_irq *p = &ares->data.irq;
81 struct acpi_resource_extended_irq *pext = &ares->data.extended_irq;
82 char ev_name[5];
83 u8 trigger;
84
85 if (ares->type == ACPI_RESOURCE_TYPE_END_TAG)
86 return AE_OK;
87
88 if (!acpi_dev_resource_interrupt(ares, index: 0, res: &r)) {
89 dev_err(dev, "unable to parse IRQ resource\n");
90 return AE_ERROR;
91 }
92 if (ares->type == ACPI_RESOURCE_TYPE_IRQ) {
93 gsi = p->interrupts[0];
94 trigger = p->triggering;
95 } else {
96 gsi = pext->interrupts[0];
97 trigger = pext->triggering;
98 }
99
100 irq = r.start;
101
102 switch (gsi) {
103 case 0 ... 255:
104 sprintf(buf: ev_name, fmt: "_%c%02X",
105 trigger == ACPI_EDGE_SENSITIVE ? 'E' : 'L', gsi);
106
107 if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
108 break;
109 fallthrough;
110 default:
111 if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
112 break;
113
114 dev_err(dev, "cannot locate _EVT method\n");
115 return AE_ERROR;
116 }
117
118 event = devm_kzalloc(dev, size: sizeof(*event), GFP_KERNEL);
119 if (!event)
120 return AE_ERROR;
121
122 event->gsi = gsi;
123 event->dev = dev;
124 event->irq = irq;
125 event->handle = evt_handle;
126
127 if (r.flags & IORESOURCE_IRQ_SHAREABLE)
128 irqflags |= IRQF_SHARED;
129
130 if (request_threaded_irq(irq, NULL, thread_fn: acpi_ged_irq_handler,
131 flags: irqflags, name: "ACPI:Ged", dev: event)) {
132 dev_err(dev, "failed to setup event handler for irq %u\n", irq);
133 return AE_ERROR;
134 }
135
136 dev_dbg(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);
137 list_add_tail(new: &event->node, head: &geddev->event_list);
138 return AE_OK;
139}
140
141static int ged_probe(struct platform_device *pdev)
142{
143 struct acpi_ged_device *geddev;
144 acpi_status acpi_ret;
145
146 geddev = devm_kzalloc(dev: &pdev->dev, size: sizeof(*geddev), GFP_KERNEL);
147 if (!geddev)
148 return -ENOMEM;
149
150 geddev->dev = &pdev->dev;
151 INIT_LIST_HEAD(list: &geddev->event_list);
152 acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), name: "_CRS",
153 user_function: acpi_ged_request_interrupt, context: geddev);
154 if (ACPI_FAILURE(acpi_ret)) {
155 dev_err(&pdev->dev, "unable to parse the _CRS record\n");
156 return -EINVAL;
157 }
158 platform_set_drvdata(pdev, data: geddev);
159
160 return 0;
161}
162
163static void ged_shutdown(struct platform_device *pdev)
164{
165 struct acpi_ged_device *geddev = platform_get_drvdata(pdev);
166 struct acpi_ged_event *event, *next;
167
168 list_for_each_entry_safe(event, next, &geddev->event_list, node) {
169 free_irq(event->irq, event);
170 list_del(entry: &event->node);
171 dev_dbg(geddev->dev, "GED releasing GSI %u @ IRQ %u\n",
172 event->gsi, event->irq);
173 }
174}
175
176static void ged_remove(struct platform_device *pdev)
177{
178 ged_shutdown(pdev);
179}
180
181static const struct acpi_device_id ged_acpi_ids[] = {
182 {"ACPI0013"},
183 {},
184};
185
186static struct platform_driver ged_driver = {
187 .probe = ged_probe,
188 .remove = ged_remove,
189 .shutdown = ged_shutdown,
190 .driver = {
191 .name = MODULE_NAME,
192 .acpi_match_table = ACPI_PTR(ged_acpi_ids),
193 },
194};
195builtin_platform_driver(ged_driver);
196