1/*
2 * Generic Event Device for ACPI.
3 *
4 * Copyright (c) 2016, The Linux Foundation. All rights reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 and
8 * only version 2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * Generic Event Device allows platforms to handle interrupts in ACPI
16 * ASL statements. It follows very similar to _EVT method approach
17 * from GPIO events. All interrupts are listed in _CRS and the handler
18 * is written in _EVT method. Here is an example.
19 *
20 * Device (GED0)
21 * {
22 *
23 * Name (_HID, "ACPI0013")
24 * Name (_UID, 0)
25 * Method (_CRS, 0x0, Serialized)
26 * {
27 * Name (RBUF, ResourceTemplate ()
28 * {
29 * Interrupt(ResourceConsumer, Edge, ActiveHigh, Shared, , , )
30 * {123}
31 * }
32 * })
33 *
34 * Method (_EVT, 1) {
35 * if (Lequal(123, Arg0))
36 * {
37 * }
38 * }
39 * }
40 *
41 */
42
43#include <linux/err.h>
44#include <linux/init.h>
45#include <linux/interrupt.h>
46#include <linux/list.h>
47#include <linux/platform_device.h>
48#include <linux/acpi.h>
49
50#define MODULE_NAME "acpi-ged"
51
52struct acpi_ged_device {
53 struct device *dev;
54 struct list_head event_list;
55};
56
57struct acpi_ged_event {
58 struct list_head node;
59 struct device *dev;
60 unsigned int gsi;
61 unsigned int irq;
62 acpi_handle handle;
63};
64
65static irqreturn_t acpi_ged_irq_handler(int irq, void *data)
66{
67 struct acpi_ged_event *event = data;
68 acpi_status acpi_ret;
69
70 acpi_ret = acpi_execute_simple_method(event->handle, NULL, event->gsi);
71 if (ACPI_FAILURE(acpi_ret))
72 dev_err_once(event->dev, "IRQ method execution failed\n");
73
74 return IRQ_HANDLED;
75}
76
77static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
78 void *context)
79{
80 struct acpi_ged_event *event;
81 unsigned int irq;
82 unsigned int gsi;
83 unsigned int irqflags = IRQF_ONESHOT;
84 struct acpi_ged_device *geddev = context;
85 struct device *dev = geddev->dev;
86 acpi_handle handle = ACPI_HANDLE(dev);
87 acpi_handle evt_handle;
88 struct resource r;
89 struct acpi_resource_irq *p = &ares->data.irq;
90 struct acpi_resource_extended_irq *pext = &ares->data.extended_irq;
91
92 if (ares->type == ACPI_RESOURCE_TYPE_END_TAG)
93 return AE_OK;
94
95 if (!acpi_dev_resource_interrupt(ares, 0, &r)) {
96 dev_err(dev, "unable to parse IRQ resource\n");
97 return AE_ERROR;
98 }
99 if (ares->type == ACPI_RESOURCE_TYPE_IRQ)
100 gsi = p->interrupts[0];
101 else
102 gsi = pext->interrupts[0];
103
104 irq = r.start;
105
106 if (ACPI_FAILURE(acpi_get_handle(handle, "_EVT", &evt_handle))) {
107 dev_err(dev, "cannot locate _EVT method\n");
108 return AE_ERROR;
109 }
110
111 event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL);
112 if (!event)
113 return AE_ERROR;
114
115 event->gsi = gsi;
116 event->dev = dev;
117 event->irq = irq;
118 event->handle = evt_handle;
119
120 if (r.flags & IORESOURCE_IRQ_SHAREABLE)
121 irqflags |= IRQF_SHARED;
122
123 if (request_threaded_irq(irq, NULL, acpi_ged_irq_handler,
124 irqflags, "ACPI:Ged", event)) {
125 dev_err(dev, "failed to setup event handler for irq %u\n", irq);
126 return AE_ERROR;
127 }
128
129 dev_dbg(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);
130 list_add_tail(&event->node, &geddev->event_list);
131 return AE_OK;
132}
133
134static int ged_probe(struct platform_device *pdev)
135{
136 struct acpi_ged_device *geddev;
137 acpi_status acpi_ret;
138
139 geddev = devm_kzalloc(&pdev->dev, sizeof(*geddev), GFP_KERNEL);
140 if (!geddev)
141 return -ENOMEM;
142
143 geddev->dev = &pdev->dev;
144 INIT_LIST_HEAD(&geddev->event_list);
145 acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
146 acpi_ged_request_interrupt, geddev);
147 if (ACPI_FAILURE(acpi_ret)) {
148 dev_err(&pdev->dev, "unable to parse the _CRS record\n");
149 return -EINVAL;
150 }
151 platform_set_drvdata(pdev, geddev);
152
153 return 0;
154}
155
156static void ged_shutdown(struct platform_device *pdev)
157{
158 struct acpi_ged_device *geddev = platform_get_drvdata(pdev);
159 struct acpi_ged_event *event, *next;
160
161 list_for_each_entry_safe(event, next, &geddev->event_list, node) {
162 free_irq(event->irq, event);
163 list_del(&event->node);
164 dev_dbg(geddev->dev, "GED releasing GSI %u @ IRQ %u\n",
165 event->gsi, event->irq);
166 }
167}
168
169static int ged_remove(struct platform_device *pdev)
170{
171 ged_shutdown(pdev);
172 return 0;
173}
174
175static const struct acpi_device_id ged_acpi_ids[] = {
176 {"ACPI0013"},
177 {},
178};
179
180static struct platform_driver ged_driver = {
181 .probe = ged_probe,
182 .remove = ged_remove,
183 .shutdown = ged_shutdown,
184 .driver = {
185 .name = MODULE_NAME,
186 .acpi_match_table = ACPI_PTR(ged_acpi_ids),
187 },
188};
189builtin_platform_driver(ged_driver);
190