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// SPDX-License-Identifier: GPL-2.0-only
/*
* Generic Event Device for ACPI.
*
* Copyright (c) 2016, The Linux Foundation. All rights reserved.
*
* Generic Event Device allows platforms to handle interrupts in ACPI
* ASL statements. It follows very similar to _EVT method approach
* from GPIO events. All interrupts are listed in _CRS and the handler
* is written in _EVT method. Here is an example.
*
* Device (GED0)
* {
*
* Name (_HID, "ACPI0013")
* Name (_UID, 0)
* Method (_CRS, 0x0, Serialized)
* {
* Name (RBUF, ResourceTemplate ()
* {
* Interrupt(ResourceConsumer, Edge, ActiveHigh, Shared, , , )
* {123}
* }
* })
*
* Method (_EVT, 1) {
* if (Lequal(123, Arg0))
* {
* }
* }
* }
*/
#include <linux/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/platform_device.h>
#include <linux/acpi.h>
#define MODULE_NAME "acpi-ged"
struct acpi_ged_device {
struct device *dev;
struct list_head event_list;
};
struct acpi_ged_event {
struct list_head node;
struct device *dev;
unsigned int gsi;
unsigned int irq;
acpi_handle handle;
};
static irqreturn_t acpi_ged_irq_handler(int irq, void *data)
{
struct acpi_ged_event *event = data;
acpi_status acpi_ret;
acpi_ret = acpi_execute_simple_method(event->handle, NULL, event->gsi);
if (ACPI_FAILURE(acpi_ret))
dev_err_once(event->dev, "IRQ method execution failed\n");
return IRQ_HANDLED;
}
static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
void *context)
{
struct acpi_ged_event *event;
unsigned int irq;
unsigned int gsi;
unsigned int irqflags = IRQF_ONESHOT;
struct acpi_ged_device *geddev = context;
struct device *dev = geddev->dev;
acpi_handle handle = ACPI_HANDLE(dev);
acpi_handle evt_handle;
struct resource r;
struct acpi_resource_irq *p = &ares->data.irq;
struct acpi_resource_extended_irq *pext = &ares->data.extended_irq;
char ev_name[5];
u8 trigger;
if (ares->type == ACPI_RESOURCE_TYPE_END_TAG)
return AE_OK;
if (!acpi_dev_resource_interrupt(ares, 0, &r)) {
dev_err(dev, "unable to parse IRQ resource\n");
return AE_ERROR;
}
if (ares->type == ACPI_RESOURCE_TYPE_IRQ) {
gsi = p->interrupts[0];
trigger = p->triggering;
} else {
gsi = pext->interrupts[0];
trigger = pext->triggering;
}
irq = r.start;
switch (gsi) {
case 0 ... 255:
sprintf(ev_name, "_%c%02X",
trigger == ACPI_EDGE_SENSITIVE ? 'E' : 'L', gsi);
if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
break;
fallthrough;
default:
if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
break;
dev_err(dev, "cannot locate _EVT method\n");
return AE_ERROR;
}
event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL);
if (!event)
return AE_ERROR;
event->gsi = gsi;
event->dev = dev;
event->irq = irq;
event->handle = evt_handle;
if (r.flags & IORESOURCE_IRQ_SHAREABLE)
irqflags |= IRQF_SHARED;
if (request_threaded_irq(irq, NULL, acpi_ged_irq_handler,
irqflags, "ACPI:Ged", event)) {
dev_err(dev, "failed to setup event handler for irq %u\n", irq);
return AE_ERROR;
}
dev_dbg(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);
list_add_tail(&event->node, &geddev->event_list);
return AE_OK;
}
static int ged_probe(struct platform_device *pdev)
{
struct acpi_ged_device *geddev;
acpi_status acpi_ret;
geddev = devm_kzalloc(&pdev->dev, sizeof(*geddev), GFP_KERNEL);
if (!geddev)
return -ENOMEM;
geddev->dev = &pdev->dev;
INIT_LIST_HEAD(&geddev->event_list);
acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
acpi_ged_request_interrupt, geddev);
if (ACPI_FAILURE(acpi_ret)) {
dev_err(&pdev->dev, "unable to parse the _CRS record\n");
return -EINVAL;
}
platform_set_drvdata(pdev, geddev);
return 0;
}
static void ged_shutdown(struct platform_device *pdev)
{
struct acpi_ged_device *geddev = platform_get_drvdata(pdev);
struct acpi_ged_event *event, *next;
list_for_each_entry_safe(event, next, &geddev->event_list, node) {
free_irq(event->irq, event);
list_del(&event->node);
dev_dbg(geddev->dev, "GED releasing GSI %u @ IRQ %u\n",
event->gsi, event->irq);
}
}
static void ged_remove(struct platform_device *pdev)
{
ged_shutdown(pdev);
}
static const struct acpi_device_id ged_acpi_ids[] = {
{"ACPI0013"},
{},
};
static struct platform_driver ged_driver = {
.probe = ged_probe,
.remove = ged_remove,
.shutdown = ged_shutdown,
.driver = {
.name = MODULE_NAME,
.acpi_match_table = ACPI_PTR(ged_acpi_ids),
},
};
builtin_platform_driver(ged_driver);
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