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(event->handle, NULL, 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, 0, &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(ev_name, "_%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, 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, acpi_ged_irq_handler,
131				 irqflags, "ACPI:Ged", 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(&event->node, &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(&pdev->dev, sizeof(*geddev), GFP_KERNEL);
147	if (!geddev)
148		return -ENOMEM;
149
150	geddev->dev = &pdev->dev;
151	INIT_LIST_HEAD(&geddev->event_list);
152	acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
153				       acpi_ged_request_interrupt, 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, 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(&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_new = 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