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_event { 53 struct list_head node; 54 struct device *dev; 55 unsigned int gsi; 56 unsigned int irq; 57 acpi_handle handle; 58 }; 59 60 static irqreturn_t acpi_ged_irq_handler(int irq, void *data) 61 { 62 struct acpi_ged_event *event = data; 63 acpi_status acpi_ret; 64 65 acpi_ret = acpi_execute_simple_method(event->handle, NULL, event->gsi); 66 if (ACPI_FAILURE(acpi_ret)) 67 dev_err_once(event->dev, "IRQ method execution failed\n"); 68 69 return IRQ_HANDLED; 70 } 71 72 static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares, 73 void *context) 74 { 75 struct acpi_ged_event *event; 76 unsigned int irq; 77 unsigned int gsi; 78 unsigned int irqflags = IRQF_ONESHOT; 79 struct device *dev = context; 80 acpi_handle handle = ACPI_HANDLE(dev); 81 acpi_handle evt_handle; 82 struct resource r; 83 struct acpi_resource_irq *p = &ares->data.irq; 84 struct acpi_resource_extended_irq *pext = &ares->data.extended_irq; 85 86 if (ares->type == ACPI_RESOURCE_TYPE_END_TAG) 87 return AE_OK; 88 89 if (!acpi_dev_resource_interrupt(ares, 0, &r)) { 90 dev_err(dev, "unable to parse IRQ resource\n"); 91 return AE_ERROR; 92 } 93 if (ares->type == ACPI_RESOURCE_TYPE_IRQ) 94 gsi = p->interrupts[0]; 95 else 96 gsi = pext->interrupts[0]; 97 98 irq = r.start; 99 100 if (ACPI_FAILURE(acpi_get_handle(handle, "_EVT", &evt_handle))) { 101 dev_err(dev, "cannot locate _EVT method\n"); 102 return AE_ERROR; 103 } 104 105 dev_info(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq); 106 107 event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL); 108 if (!event) 109 return AE_ERROR; 110 111 event->gsi = gsi; 112 event->dev = dev; 113 event->irq = irq; 114 event->handle = evt_handle; 115 116 if (r.flags & IORESOURCE_IRQ_SHAREABLE) 117 irqflags |= IRQF_SHARED; 118 119 if (devm_request_threaded_irq(dev, irq, NULL, acpi_ged_irq_handler, 120 irqflags, "ACPI:Ged", event)) { 121 dev_err(dev, "failed to setup event handler for irq %u\n", irq); 122 return AE_ERROR; 123 } 124 125 return AE_OK; 126 } 127 128 static int ged_probe(struct platform_device *pdev) 129 { 130 acpi_status acpi_ret; 131 132 acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS", 133 acpi_ged_request_interrupt, &pdev->dev); 134 if (ACPI_FAILURE(acpi_ret)) { 135 dev_err(&pdev->dev, "unable to parse the _CRS record\n"); 136 return -EINVAL; 137 } 138 139 return 0; 140 } 141 142 static const struct acpi_device_id ged_acpi_ids[] = { 143 {"ACPI0013"}, 144 {}, 145 }; 146 147 static struct platform_driver ged_driver = { 148 .probe = ged_probe, 149 .driver = { 150 .name = MODULE_NAME, 151 .acpi_match_table = ACPI_PTR(ged_acpi_ids), 152 }, 153 }; 154 builtin_platform_driver(ged_driver); 155