drivers/acpi/evged.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Generic Event Device for ACPI.
   4  *
   5  * Copyright (c) 2016, The Linux Foundation. All rights reserved.
   6  *
   7  * Generic Event Device allows platforms to handle interrupts in ACPI
   8  * ASL statements. It follows very similar to  _EVT method approach
   9  * from GPIO events. All interrupts are listed in _CRS and the handler
  10  * is written in _EVT method. Here is an example.
  11  *
  12  * Device (GED0)
  13  * {
  14  *
  15  *     Name (_HID, "ACPI0013")
  16  *     Name (_UID, 0)
  17  *     Method (_CRS, 0x0, Serialized)
  18  *     {
  19  *              Name (RBUF, ResourceTemplate ()
  20  *              {
  21  *              Interrupt(ResourceConsumer, Edge, ActiveHigh, Shared, , , )
  22  *              {123}
  23  *              }
  24  *     })
  25  *
  26  *     Method (_EVT, 1) {
  27  *             if (Lequal(123, Arg0))
  28  *             {
  29  *             }
  30  *     }
  31  * }
  32  */
  33
  34 #include <linux/err.h>
  35 #include <linux/init.h>
  36 #include <linux/interrupt.h>
  37 #include <linux/list.h>
  38 #include <linux/platform_device.h>
  39 #include <linux/acpi.h>
  40
  41 #define MODULE_NAME     "acpi-ged"
  42
  43 struct acpi_ged_device {
  44         struct device *dev;
  45         struct list_head event_list;
  46 };
  47
  48 struct acpi_ged_event {
  49         struct list_head node;
  50         struct device *dev;
  51         unsigned int gsi;
  52         unsigned int irq;
  53         acpi_handle handle;
  54 };
  55
  56 static irqreturn_t acpi_ged_irq_handler(int irq, void *data)
  57 {
  58         struct acpi_ged_event *event = data;
  59         acpi_status acpi_ret;
  60
  61         acpi_ret = acpi_execute_simple_method(event->handle, NULL, event->gsi);
  62         if (ACPI_FAILURE(acpi_ret))
  63                 dev_err_once(event->dev, "IRQ method execution failed\n");
  64
  65         return IRQ_HANDLED;
  66 }
  67
  68 static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
  69                                               void *context)
  70 {
  71         struct acpi_ged_event *event;
  72         unsigned int irq;
  73         unsigned int gsi;
  74         unsigned int irqflags = IRQF_ONESHOT;
  75         struct acpi_ged_device *geddev = context;
  76         struct device *dev = geddev->dev;
  77         acpi_handle handle = ACPI_HANDLE(dev);
  78         acpi_handle evt_handle;
  79         struct resource r;
  80         struct acpi_resource_irq *p = &ares->data.irq;
  81         struct acpi_resource_extended_irq *pext = &ares->data.extended_irq;
  82         char ev_name[5];
  83         u8 trigger;
  84
  85         if (ares->type == ACPI_RESOURCE_TYPE_END_TAG)
  86                 return AE_OK;
  87
  88         if (!acpi_dev_resource_interrupt(ares, 0, &r)) {
  89                 dev_err(dev, "unable to parse IRQ resource\n");
  90                 return AE_ERROR;
  91         }
  92         if (ares->type == ACPI_RESOURCE_TYPE_IRQ) {
  93                 gsi = p->interrupts[0];
  94                 trigger = p->triggering;
  95         } else {
  96                 gsi = pext->interrupts[0];
  97                 trigger = pext->triggering;
  98         }
  99
 100         irq = r.start;
 101
 102         switch (gsi) {
 103         case 0 ... 255:
 104                 sprintf(ev_name, "_%c%02X",
 105                         trigger == ACPI_EDGE_SENSITIVE ? 'E' : 'L', gsi);
 106
 107                 if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
 108                         break;
 109                 fallthrough;
 110         default:
 111                 if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
 112                         break;
 113
 114                 dev_err(dev, "cannot locate _EVT method\n");
 115                 return AE_ERROR;
 116         }
 117
 118         event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL);
 119         if (!event)
 120                 return AE_ERROR;
 121
 122         event->gsi = gsi;
 123         event->dev = dev;
 124         event->irq = irq;
 125         event->handle = evt_handle;
 126
 127         if (r.flags & IORESOURCE_IRQ_SHAREABLE)
 128                 irqflags |= IRQF_SHARED;
 129
 130         if (request_threaded_irq(irq, NULL, acpi_ged_irq_handler,
 131                                  irqflags, "ACPI:Ged", event)) {
 132                 dev_err(dev, "failed to setup event handler for irq %u\n", irq);
 133                 return AE_ERROR;
 134         }
 135
 136         dev_dbg(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);
 137         list_add_tail(&event->node, &geddev->event_list);
 138         return AE_OK;
 139 }
 140
 141 static int ged_probe(struct platform_device *pdev)
 142 {
 143         struct acpi_ged_device *geddev;
 144         acpi_status acpi_ret;
 145
 146         geddev = devm_kzalloc(&pdev->dev, sizeof(*geddev), GFP_KERNEL);
 147         if (!geddev)
 148                 return -ENOMEM;
 149
 150         geddev->dev = &pdev->dev;
 151         INIT_LIST_HEAD(&geddev->event_list);
 152         acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
 153                                        acpi_ged_request_interrupt, geddev);
 154         if (ACPI_FAILURE(acpi_ret)) {
 155                 dev_err(&pdev->dev, "unable to parse the _CRS record\n");
 156                 return -EINVAL;
 157         }
 158         platform_set_drvdata(pdev, geddev);
 159
 160         return 0;
 161 }
 162
 163 static void ged_shutdown(struct platform_device *pdev)
 164 {
 165         struct acpi_ged_device *geddev = platform_get_drvdata(pdev);
 166         struct acpi_ged_event *event, *next;
 167
 168         list_for_each_entry_safe(event, next, &geddev->event_list, node) {
 169                 free_irq(event->irq, event);
 170                 list_del(&event->node);
 171                 dev_dbg(geddev->dev, "GED releasing GSI %u @ IRQ %u\n",
 172                          event->gsi, event->irq);
 173         }
 174 }
 175
 176 static int ged_remove(struct platform_device *pdev)
 177 {
 178         ged_shutdown(pdev);
 179         return 0;
 180 }
 181
 182 static const struct acpi_device_id ged_acpi_ids[] = {
 183         {"ACPI0013"},
 184         {},
 185 };
 186
 187 static struct platform_driver ged_driver = {
 188         .probe = ged_probe,
 189         .remove = ged_remove,
 190         .shutdown = ged_shutdown,
 191         .driver = {
 192                 .name = MODULE_NAME,
 193                 .acpi_match_table = ACPI_PTR(ged_acpi_ids),
 194         },
 195 };
 196 builtin_platform_driver(ged_driver);