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%02hhX", 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); 197