drivers/acpi/evged.c

   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
  52 struct acpi_ged_event {
  53         struct list_head node;
  54         struct device *dev;
  55         unsigned int gsi;
  56         unsigned int irq;
  57         acpi_handle handle;
  58 };
  59
  60 static irqreturn_t acpi_ged_irq_handler(int irq, void *data)
  61 {
  62         struct acpi_ged_event *event = data;
  63         acpi_status acpi_ret;
  64
  65         acpi_ret = acpi_execute_simple_method(event->handle, NULL, event->gsi);
  66         if (ACPI_FAILURE(acpi_ret))
  67                 dev_err_once(event->dev, "IRQ method execution failed\n");
  68
  69         return IRQ_HANDLED;
  70 }
  71
  72 static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
  73                                               void *context)
  74 {
  75         struct acpi_ged_event *event;
  76         unsigned int irq;
  77         unsigned int gsi;
  78         unsigned int irqflags = IRQF_ONESHOT;
  79         struct device *dev = context;
  80         acpi_handle handle = ACPI_HANDLE(dev);
  81         acpi_handle evt_handle;
  82         struct resource r;
  83         struct acpi_resource_irq *p = &ares->data.irq;
  84         struct acpi_resource_extended_irq *pext = &ares->data.extended_irq;
  85
  86         if (ares->type == ACPI_RESOURCE_TYPE_END_TAG)
  87                 return AE_OK;
  88
  89         if (!acpi_dev_resource_interrupt(ares, 0, &r)) {
  90                 dev_err(dev, "unable to parse IRQ resource\n");
  91                 return AE_ERROR;
  92         }
  93         if (ares->type == ACPI_RESOURCE_TYPE_IRQ)
  94                 gsi = p->interrupts[0];
  95         else
  96                 gsi = pext->interrupts[0];
  97
  98         irq = r.start;
  99
 100         if (ACPI_FAILURE(acpi_get_handle(handle, "_EVT", &evt_handle))) {
 101                 dev_err(dev, "cannot locate _EVT method\n");
 102                 return AE_ERROR;
 103         }
 104
 105         dev_info(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);
 106
 107         event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL);
 108         if (!event)
 109                 return AE_ERROR;
 110
 111         event->gsi = gsi;
 112         event->dev = dev;
 113         event->irq = irq;
 114         event->handle = evt_handle;
 115
 116         if (r.flags & IORESOURCE_IRQ_SHAREABLE)
 117                 irqflags |= IRQF_SHARED;
 118
 119         if (devm_request_threaded_irq(dev, irq, NULL, acpi_ged_irq_handler,
 120                                       irqflags, "ACPI:Ged", event)) {
 121                 dev_err(dev, "failed to setup event handler for irq %u\n", irq);
 122                 return AE_ERROR;
 123         }
 124
 125         return AE_OK;
 126 }
 127
 128 static int ged_probe(struct platform_device *pdev)
 129 {
 130         acpi_status acpi_ret;
 131
 132         acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
 133                                        acpi_ged_request_interrupt, &pdev->dev);
 134         if (ACPI_FAILURE(acpi_ret)) {
 135                 dev_err(&pdev->dev, "unable to parse the _CRS record\n");
 136                 return -EINVAL;
 137         }
 138
 139         return 0;
 140 }
 141
 142 static const struct acpi_device_id ged_acpi_ids[] = {
 143         {"ACPI0013"},
 144         {},
 145 };
 146
 147 static struct platform_driver ged_driver = {
 148         .probe = ged_probe,
 149         .driver = {
 150                 .name = MODULE_NAME,
 151                 .acpi_match_table = ACPI_PTR(ged_acpi_ids),
 152         },
 153 };
 154 builtin_platform_driver(ged_driver);