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
  83         if (ares->type == ACPI_RESOURCE_TYPE_END_TAG)
  84                 return AE_OK;
  85
  86         if (!acpi_dev_resource_interrupt(ares, 0, &r)) {
  87                 dev_err(dev, "unable to parse IRQ resource\n");
  88                 return AE_ERROR;
  89         }
  90         if (ares->type == ACPI_RESOURCE_TYPE_IRQ)
  91                 gsi = p->interrupts[0];
  92         else
  93                 gsi = pext->interrupts[0];
  94
  95         irq = r.start;
  96
  97         if (ACPI_FAILURE(acpi_get_handle(handle, "_EVT", &evt_handle))) {
  98                 dev_err(dev, "cannot locate _EVT method\n");
  99                 return AE_ERROR;
 100         }
 101
 102         event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL);
 103         if (!event)
 104                 return AE_ERROR;
 105
 106         event->gsi = gsi;
 107         event->dev = dev;
 108         event->irq = irq;
 109         event->handle = evt_handle;
 110
 111         if (r.flags & IORESOURCE_IRQ_SHAREABLE)
 112                 irqflags |= IRQF_SHARED;
 113
 114         if (request_threaded_irq(irq, NULL, acpi_ged_irq_handler,
 115                                  irqflags, "ACPI:Ged", event)) {
 116                 dev_err(dev, "failed to setup event handler for irq %u\n", irq);
 117                 return AE_ERROR;
 118         }
 119
 120         dev_dbg(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);
 121         list_add_tail(&event->node, &geddev->event_list);
 122         return AE_OK;
 123 }
 124
 125 static int ged_probe(struct platform_device *pdev)
 126 {
 127         struct acpi_ged_device *geddev;
 128         acpi_status acpi_ret;
 129
 130         geddev = devm_kzalloc(&pdev->dev, sizeof(*geddev), GFP_KERNEL);
 131         if (!geddev)
 132                 return -ENOMEM;
 133
 134         geddev->dev = &pdev->dev;
 135         INIT_LIST_HEAD(&geddev->event_list);
 136         acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
 137                                        acpi_ged_request_interrupt, geddev);
 138         if (ACPI_FAILURE(acpi_ret)) {
 139                 dev_err(&pdev->dev, "unable to parse the _CRS record\n");
 140                 return -EINVAL;
 141         }
 142         platform_set_drvdata(pdev, geddev);
 143
 144         return 0;
 145 }
 146
 147 static void ged_shutdown(struct platform_device *pdev)
 148 {
 149         struct acpi_ged_device *geddev = platform_get_drvdata(pdev);
 150         struct acpi_ged_event *event, *next;
 151
 152         list_for_each_entry_safe(event, next, &geddev->event_list, node) {
 153                 free_irq(event->irq, event);
 154                 list_del(&event->node);
 155                 dev_dbg(geddev->dev, "GED releasing GSI %u @ IRQ %u\n",
 156                          event->gsi, event->irq);
 157         }
 158 }
 159
 160 static int ged_remove(struct platform_device *pdev)
 161 {
 162         ged_shutdown(pdev);
 163         return 0;
 164 }
 165
 166 static const struct acpi_device_id ged_acpi_ids[] = {
 167         {"ACPI0013"},
 168         {},
 169 };
 170
 171 static struct platform_driver ged_driver = {
 172         .probe = ged_probe,
 173         .remove = ged_remove,
 174         .shutdown = ged_shutdown,
 175         .driver = {
 176                 .name = MODULE_NAME,
 177                 .acpi_match_table = ACPI_PTR(ged_acpi_ids),
 178         },
 179 };
 180 builtin_platform_driver(ged_driver);