drivers/acpi/evged.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Generic Event Device for ACPI.
0004  *
0005  * Copyright (c) 2016, The Linux Foundation. All rights reserved.
0006  *
0007  * Generic Event Device allows platforms to handle interrupts in ACPI
0008  * ASL statements. It follows very similar to  _EVT method approach
0009  * from GPIO events. All interrupts are listed in _CRS and the handler
0010  * is written in _EVT method. Here is an example.
0011  *
0012  * Device (GED0)
0013  * {
0014  *
0015  *     Name (_HID, "ACPI0013")
0016  *     Name (_UID, 0)
0017  *     Method (_CRS, 0x0, Serialized)
0018  *     {
0019  *      Name (RBUF, ResourceTemplate ()
0020  *      {
0021  *      Interrupt(ResourceConsumer, Edge, ActiveHigh, Shared, , , )
0022  *      {123}
0023  *      }
0024  *     })
0025  *
0026  *     Method (_EVT, 1) {
0027  *             if (Lequal(123, Arg0))
0028  *             {
0029  *             }
0030  *     }
0031  * }
0032  */
0033
0034 #include <linux/err.h>
0035 #include <linux/init.h>
0036 #include <linux/interrupt.h>
0037 #include <linux/list.h>
0038 #include <linux/platform_device.h>
0039 #include <linux/acpi.h>
0040
0041 #define MODULE_NAME "acpi-ged"
0042
0043 struct acpi_ged_device {
0044     struct device *dev;
0045     struct list_head event_list;
0046 };
0047
0048 struct acpi_ged_event {
0049     struct list_head node;
0050     struct device *dev;
0051     unsigned int gsi;
0052     unsigned int irq;
0053     acpi_handle handle;
0054 };
0055
0056 static irqreturn_t acpi_ged_irq_handler(int irq, void *data)
0057 {
0058     struct acpi_ged_event *event = data;
0059     acpi_status acpi_ret;
0060
0061     acpi_ret = acpi_execute_simple_method(event->handle, NULL, event->gsi);
0062     if (ACPI_FAILURE(acpi_ret))
0063         dev_err_once(event->dev, "IRQ method execution failed\n");
0064
0065     return IRQ_HANDLED;
0066 }
0067
0068 static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
0069                           void *context)
0070 {
0071     struct acpi_ged_event *event;
0072     unsigned int irq;
0073     unsigned int gsi;
0074     unsigned int irqflags = IRQF_ONESHOT;
0075     struct acpi_ged_device *geddev = context;
0076     struct device *dev = geddev->dev;
0077     acpi_handle handle = ACPI_HANDLE(dev);
0078     acpi_handle evt_handle;
0079     struct resource r;
0080     struct acpi_resource_irq *p = &ares->data.irq;
0081     struct acpi_resource_extended_irq *pext = &ares->data.extended_irq;
0082     char ev_name[5];
0083     u8 trigger;
0084
0085     if (ares->type == ACPI_RESOURCE_TYPE_END_TAG)
0086         return AE_OK;
0087
0088     if (!acpi_dev_resource_interrupt(ares, 0, &r)) {
0089         dev_err(dev, "unable to parse IRQ resource\n");
0090         return AE_ERROR;
0091     }
0092     if (ares->type == ACPI_RESOURCE_TYPE_IRQ) {
0093         gsi = p->interrupts[0];
0094         trigger = p->triggering;
0095     } else {
0096         gsi = pext->interrupts[0];
0097         trigger = pext->triggering;
0098     }
0099
0100     irq = r.start;
0101
0102     switch (gsi) {
0103     case 0 ... 255:
0104         sprintf(ev_name, "_%c%02X",
0105             trigger == ACPI_EDGE_SENSITIVE ? 'E' : 'L', gsi);
0106
0107         if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
0108             break;
0109         fallthrough;
0110     default:
0111         if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
0112             break;
0113
0114         dev_err(dev, "cannot locate _EVT method\n");
0115         return AE_ERROR;
0116     }
0117
0118     event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL);
0119     if (!event)
0120         return AE_ERROR;
0121
0122     event->gsi = gsi;
0123     event->dev = dev;
0124     event->irq = irq;
0125     event->handle = evt_handle;
0126
0127     if (r.flags & IORESOURCE_IRQ_SHAREABLE)
0128         irqflags |= IRQF_SHARED;
0129
0130     if (request_threaded_irq(irq, NULL, acpi_ged_irq_handler,
0131                  irqflags, "ACPI:Ged", event)) {
0132         dev_err(dev, "failed to setup event handler for irq %u\n", irq);
0133         return AE_ERROR;
0134     }
0135
0136     dev_dbg(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);
0137     list_add_tail(&event->node, &geddev->event_list);
0138     return AE_OK;
0139 }
0140
0141 static int ged_probe(struct platform_device *pdev)
0142 {
0143     struct acpi_ged_device *geddev;
0144     acpi_status acpi_ret;
0145
0146     geddev = devm_kzalloc(&pdev->dev, sizeof(*geddev), GFP_KERNEL);
0147     if (!geddev)
0148         return -ENOMEM;
0149
0150     geddev->dev = &pdev->dev;
0151     INIT_LIST_HEAD(&geddev->event_list);
0152     acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
0153                        acpi_ged_request_interrupt, geddev);
0154     if (ACPI_FAILURE(acpi_ret)) {
0155         dev_err(&pdev->dev, "unable to parse the _CRS record\n");
0156         return -EINVAL;
0157     }
0158     platform_set_drvdata(pdev, geddev);
0159
0160     return 0;
0161 }
0162
0163 static void ged_shutdown(struct platform_device *pdev)
0164 {
0165     struct acpi_ged_device *geddev = platform_get_drvdata(pdev);
0166     struct acpi_ged_event *event, *next;
0167
0168     list_for_each_entry_safe(event, next, &geddev->event_list, node) {
0169         free_irq(event->irq, event);
0170         list_del(&event->node);
0171         dev_dbg(geddev->dev, "GED releasing GSI %u @ IRQ %u\n",
0172              event->gsi, event->irq);
0173     }
0174 }
0175
0176 static int ged_remove(struct platform_device *pdev)
0177 {
0178     ged_shutdown(pdev);
0179     return 0;
0180 }
0181
0182 static const struct acpi_device_id ged_acpi_ids[] = {
0183     {"ACPI0013"},
0184     {},
0185 };
0186
0187 static struct platform_driver ged_driver = {
0188     .probe = ged_probe,
0189     .remove = ged_remove,
0190     .shutdown = ged_shutdown,
0191     .driver = {
0192         .name = MODULE_NAME,
0193         .acpi_match_table = ACPI_PTR(ged_acpi_ids),
0194     },
0195 };
0196 builtin_platform_driver(ged_driver);