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 int ged_remove(struct platform_device *pdev)
177{
178	ged_shutdown(pdev);
179	return 0;
180}
181
182static const struct acpi_device_id ged_acpi_ids[] = {
183	{"ACPI0013"},
184	{},
185};
186
187static struct platform_driver ged_driver = {
188	.probe = ged_probe,
189	.remove = ged_remove,
190	.shutdown = ged_shutdown,
191	.driver = {
192		.name = MODULE_NAME,
193		.acpi_match_table = ACPI_PTR(ged_acpi_ids),
194	},
195};
196builtin_platform_driver(ged_driver);