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_device {
  53         struct device *dev;
  54         struct list_head event_list;
  55 };
  56
  57 struct acpi_ged_event {
  58         struct list_head node;
  59         struct device *dev;
  60         unsigned int gsi;
  61         unsigned int irq;
  62         acpi_handle handle;
  63 };
  64
  65 static irqreturn_t acpi_ged_irq_handler(int irq, void *data)
  66 {
  67         struct acpi_ged_event *event = data;
  68         acpi_status acpi_ret;
  69
  70         acpi_ret = acpi_execute_simple_method(event->handle, NULL, event->gsi);
  71         if (ACPI_FAILURE(acpi_ret))
  72                 dev_err_once(event->dev, "IRQ method execution failed\n");
  73
  74         return IRQ_HANDLED;
  75 }
  76
  77 static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
  78                                               void *context)
  79 {
  80         struct acpi_ged_event *event;
  81         unsigned int irq;
  82         unsigned int gsi;
  83         unsigned int irqflags = IRQF_ONESHOT;
  84         struct acpi_ged_device *geddev = context;
  85         struct device *dev = geddev->dev;
  86         acpi_handle handle = ACPI_HANDLE(dev);
  87         acpi_handle evt_handle;
  88         struct resource r;
  89         struct acpi_resource_irq *p = &ares->data.irq;
  90         struct acpi_resource_extended_irq *pext = &ares->data.extended_irq;
  91
  92         if (ares->type == ACPI_RESOURCE_TYPE_END_TAG)
  93                 return AE_OK;
  94
  95         if (!acpi_dev_resource_interrupt(ares, 0, &r)) {
  96                 dev_err(dev, "unable to parse IRQ resource\n");
  97                 return AE_ERROR;
  98         }
  99         if (ares->type == ACPI_RESOURCE_TYPE_IRQ)
 100                 gsi = p->interrupts[0];
 101         else
 102                 gsi = pext->interrupts[0];
 103
 104         irq = r.start;
 105
 106         if (ACPI_FAILURE(acpi_get_handle(handle, "_EVT", &evt_handle))) {
 107                 dev_err(dev, "cannot locate _EVT method\n");
 108                 return AE_ERROR;
 109         }
 110
 111         event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL);
 112         if (!event)
 113                 return AE_ERROR;
 114
 115         event->gsi = gsi;
 116         event->dev = dev;
 117         event->irq = irq;
 118         event->handle = evt_handle;
 119
 120         if (r.flags & IORESOURCE_IRQ_SHAREABLE)
 121                 irqflags |= IRQF_SHARED;
 122
 123         if (request_threaded_irq(irq, NULL, acpi_ged_irq_handler,
 124                                  irqflags, "ACPI:Ged", event)) {
 125                 dev_err(dev, "failed to setup event handler for irq %u\n", irq);
 126                 return AE_ERROR;
 127         }
 128
 129         dev_dbg(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);
 130         list_add_tail(&event->node, &geddev->event_list);
 131         return AE_OK;
 132 }
 133
 134 static int ged_probe(struct platform_device *pdev)
 135 {
 136         struct acpi_ged_device *geddev;
 137         acpi_status acpi_ret;
 138
 139         geddev = devm_kzalloc(&pdev->dev, sizeof(*geddev), GFP_KERNEL);
 140         if (!geddev)
 141                 return -ENOMEM;
 142
 143         geddev->dev = &pdev->dev;
 144         INIT_LIST_HEAD(&geddev->event_list);
 145         acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
 146                                        acpi_ged_request_interrupt, geddev);
 147         if (ACPI_FAILURE(acpi_ret)) {
 148                 dev_err(&pdev->dev, "unable to parse the _CRS record\n");
 149                 return -EINVAL;
 150         }
 151         platform_set_drvdata(pdev, geddev);
 152
 153         return 0;
 154 }
 155
 156 static void ged_shutdown(struct platform_device *pdev)
 157 {
 158         struct acpi_ged_device *geddev = platform_get_drvdata(pdev);
 159         struct acpi_ged_event *event, *next;
 160
 161         list_for_each_entry_safe(event, next, &geddev->event_list, node) {
 162                 free_irq(event->irq, event);
 163                 list_del(&event->node);
 164                 dev_dbg(geddev->dev, "GED releasing GSI %u @ IRQ %u\n",
 165                          event->gsi, event->irq);
 166         }
 167 }
 168
 169 static int ged_remove(struct platform_device *pdev)
 170 {
 171         ged_shutdown(pdev);
 172         return 0;
 173 }
 174
 175 static const struct acpi_device_id ged_acpi_ids[] = {
 176         {"ACPI0013"},
 177         {},
 178 };
 179
 180 static struct platform_driver ged_driver = {
 181         .probe = ged_probe,
 182         .remove = ged_remove,
 183         .shutdown = ged_shutdown,
 184         .driver = {
 185                 .name = MODULE_NAME,
 186                 .acpi_match_table = ACPI_PTR(ged_acpi_ids),
 187         },
 188 };
 189 builtin_platform_driver(ged_driver);