ACPI: implement Generic Event Device

acpi-y				+= int340x_thermal.o

acpi-y				+= power.o

acpi-y				+= event.o

acpi-$(CONFIG_ACPI_REDUCED_HARDWARE_ONLY) += evged.o

acpi-y				+= sysfs.o

acpi-y				+= property.o

acpi-$(CONFIG_X86)		+= acpi_cmos_rtc.o

/*

 * Generic Event Device for ACPI.

 *

 * Copyright (c) 2016, The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * 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_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 device *dev = context;

	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;

	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];

	else

		gsi = pext->interrupts[0];

	irq = r.start;

	if (ACPI_FAILURE(acpi_get_handle(handle, "_EVT", &evt_handle))) {

		dev_err(dev, "cannot locate _EVT method\n");

		return AE_ERROR;

	}

	dev_info(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);

	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 (devm_request_threaded_irq(dev, 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;

	}

	return AE_OK;

}

static int ged_probe(struct platform_device *pdev)

{

	acpi_status acpi_ret;

	acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",

				       acpi_ged_request_interrupt, &pdev->dev);

	if (ACPI_FAILURE(acpi_ret)) {

		dev_err(&pdev->dev, "unable to parse the _CRS record\n");

		return -EINVAL;

	}

	return 0;

}

static const struct acpi_device_id ged_acpi_ids[] = {

	{"ACPI0013"},

	{},

};

static struct platform_driver ged_driver = {

	.probe = ged_probe,

	.driver = {

		.name = MODULE_NAME,

		.acpi_match_table = ACPI_PTR(ged_acpi_ids),

	},

};

module_platform_driver(ged_driver);

MODULE_LICENSE("GPL v2");