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         char ev_name[5];
  92         u8 trigger;
  93
  94         if (ares->type == ACPI_RESOURCE_TYPE_END_TAG)
  95                 return AE_OK;
  96
  97         if (!acpi_dev_resource_interrupt(ares, 0, &r)) {
  98                 dev_err(dev, "unable to parse IRQ resource\n");
  99                 return AE_ERROR;
 100         }
 101         if (ares->type == ACPI_RESOURCE_TYPE_IRQ) {
 102                 gsi = p->interrupts[0];
 103                 trigger = p->triggering;
 104         } else {
 105                 gsi = pext->interrupts[0];
 106                 trigger = pext->triggering;
 107         }
 108
 109         irq = r.start;
 110
 111         switch (gsi) {
 112         case 0 ... 255:
 113                 sprintf(ev_name, "_%c%02hhX",
 114                         trigger == ACPI_EDGE_SENSITIVE ? 'E' : 'L', gsi);
 115
 116                 if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
 117                         break;
 118                 /* fall through */
 119         default:
 120                 if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
 121                         break;
 122
 123                 dev_err(dev, "cannot locate _EVT method\n");
 124                 return AE_ERROR;
 125         }
 126
 127         event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL);
 128         if (!event)
 129                 return AE_ERROR;
 130
 131         event->gsi = gsi;
 132         event->dev = dev;
 133         event->irq = irq;
 134         event->handle = evt_handle;
 135
 136         if (r.flags & IORESOURCE_IRQ_SHAREABLE)
 137                 irqflags |= IRQF_SHARED;
 138
 139         if (request_threaded_irq(irq, NULL, acpi_ged_irq_handler,
 140                                  irqflags, "ACPI:Ged", event)) {
 141                 dev_err(dev, "failed to setup event handler for irq %u\n", irq);
 142                 return AE_ERROR;
 143         }
 144
 145         dev_dbg(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);
 146         list_add_tail(&event->node, &geddev->event_list);
 147         return AE_OK;
 148 }
 149
 150 static int ged_probe(struct platform_device *pdev)
 151 {
 152         struct acpi_ged_device *geddev;
 153         acpi_status acpi_ret;
 154
 155         geddev = devm_kzalloc(&pdev->dev, sizeof(*geddev), GFP_KERNEL);
 156         if (!geddev)
 157                 return -ENOMEM;
 158
 159         geddev->dev = &pdev->dev;
 160         INIT_LIST_HEAD(&geddev->event_list);
 161         acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
 162                                        acpi_ged_request_interrupt, geddev);
 163         if (ACPI_FAILURE(acpi_ret)) {
 164                 dev_err(&pdev->dev, "unable to parse the _CRS record\n");
 165                 return -EINVAL;
 166         }
 167         platform_set_drvdata(pdev, geddev);
 168
 169         return 0;
 170 }
 171
 172 static void ged_shutdown(struct platform_device *pdev)
 173 {
 174         struct acpi_ged_device *geddev = platform_get_drvdata(pdev);
 175         struct acpi_ged_event *event, *next;
 176
 177         list_for_each_entry_safe(event, next, &geddev->event_list, node) {
 178                 free_irq(event->irq, event);
 179                 list_del(&event->node);
 180                 dev_dbg(geddev->dev, "GED releasing GSI %u @ IRQ %u\n",
 181                          event->gsi, event->irq);
 182         }
 183 }
 184
 185 static int ged_remove(struct platform_device *pdev)
 186 {
 187         ged_shutdown(pdev);
 188         return 0;
 189 }
 190
 191 static const struct acpi_device_id ged_acpi_ids[] = {
 192         {"ACPI0013"},
 193         {},
 194 };
 195
 196 static struct platform_driver ged_driver = {
 197         .probe = ged_probe,
 198         .remove = ged_remove,
 199         .shutdown = ged_shutdown,
 200         .driver = {
 201                 .name = MODULE_NAME,
 202                 .acpi_match_table = ACPI_PTR(ged_acpi_ids),
 203         },
 204 };
 205 builtin_platform_driver(ged_driver);