evged.c 4.6 KB

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  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. #include <linux/err.h>
  34. #include <linux/init.h>
  35. #include <linux/interrupt.h>
  36. #include <linux/list.h>
  37. #include <linux/platform_device.h>
  38. #include <linux/acpi.h>
  39. #define MODULE_NAME "acpi-ged"
  40. struct acpi_ged_device {
  41. struct device *dev;
  42. struct list_head event_list;
  43. };
  44. struct acpi_ged_event {
  45. struct list_head node;
  46. struct device *dev;
  47. unsigned int gsi;
  48. unsigned int irq;
  49. acpi_handle handle;
  50. };
  51. static irqreturn_t acpi_ged_irq_handler(int irq, void *data)
  52. {
  53. struct acpi_ged_event *event = data;
  54. acpi_status acpi_ret;
  55. acpi_ret = acpi_execute_simple_method(event->handle, NULL, event->gsi);
  56. if (ACPI_FAILURE(acpi_ret))
  57. dev_err_once(event->dev, "IRQ method execution failed\n");
  58. return IRQ_HANDLED;
  59. }
  60. static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
  61. void *context)
  62. {
  63. struct acpi_ged_event *event;
  64. unsigned int irq;
  65. unsigned int gsi;
  66. unsigned int irqflags = IRQF_ONESHOT;
  67. struct acpi_ged_device *geddev = context;
  68. struct device *dev = geddev->dev;
  69. acpi_handle handle = ACPI_HANDLE(dev);
  70. acpi_handle evt_handle;
  71. struct resource r;
  72. struct acpi_resource_irq *p = &ares->data.irq;
  73. struct acpi_resource_extended_irq *pext = &ares->data.extended_irq;
  74. char ev_name[5];
  75. u8 trigger;
  76. if (ares->type == ACPI_RESOURCE_TYPE_END_TAG)
  77. return AE_OK;
  78. if (!acpi_dev_resource_interrupt(ares, 0, &r)) {
  79. dev_err(dev, "unable to parse IRQ resource\n");
  80. return AE_ERROR;
  81. }
  82. if (ares->type == ACPI_RESOURCE_TYPE_IRQ) {
  83. gsi = p->interrupts[0];
  84. trigger = p->triggering;
  85. } else {
  86. gsi = pext->interrupts[0];
  87. trigger = pext->triggering;
  88. }
  89. irq = r.start;
  90. switch (gsi) {
  91. case 0 ... 255:
  92. sprintf(ev_name, "_%c%02X",
  93. trigger == ACPI_EDGE_SENSITIVE ? 'E' : 'L', gsi);
  94. if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
  95. break;
  96. fallthrough;
  97. default:
  98. if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
  99. break;
  100. dev_err(dev, "cannot locate _EVT method\n");
  101. return AE_ERROR;
  102. }
  103. event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL);
  104. if (!event)
  105. return AE_ERROR;
  106. event->gsi = gsi;
  107. event->dev = dev;
  108. event->irq = irq;
  109. event->handle = evt_handle;
  110. if (r.flags & IORESOURCE_IRQ_SHAREABLE)
  111. irqflags |= IRQF_SHARED;
  112. if (request_threaded_irq(irq, NULL, acpi_ged_irq_handler,
  113. irqflags, "ACPI:Ged", event)) {
  114. dev_err(dev, "failed to setup event handler for irq %u\n", irq);
  115. return AE_ERROR;
  116. }
  117. dev_dbg(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);
  118. list_add_tail(&event->node, &geddev->event_list);
  119. return AE_OK;
  120. }
  121. static int ged_probe(struct platform_device *pdev)
  122. {
  123. struct acpi_ged_device *geddev;
  124. acpi_status acpi_ret;
  125. geddev = devm_kzalloc(&pdev->dev, sizeof(*geddev), GFP_KERNEL);
  126. if (!geddev)
  127. return -ENOMEM;
  128. geddev->dev = &pdev->dev;
  129. INIT_LIST_HEAD(&geddev->event_list);
  130. acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
  131. acpi_ged_request_interrupt, geddev);
  132. if (ACPI_FAILURE(acpi_ret)) {
  133. dev_err(&pdev->dev, "unable to parse the _CRS record\n");
  134. return -EINVAL;
  135. }
  136. platform_set_drvdata(pdev, geddev);
  137. return 0;
  138. }
  139. static void ged_shutdown(struct platform_device *pdev)
  140. {
  141. struct acpi_ged_device *geddev = platform_get_drvdata(pdev);
  142. struct acpi_ged_event *event, *next;
  143. list_for_each_entry_safe(event, next, &geddev->event_list, node) {
  144. free_irq(event->irq, event);
  145. list_del(&event->node);
  146. dev_dbg(geddev->dev, "GED releasing GSI %u @ IRQ %u\n",
  147. event->gsi, event->irq);
  148. }
  149. }
  150. static int ged_remove(struct platform_device *pdev)
  151. {
  152. ged_shutdown(pdev);
  153. return 0;
  154. }
  155. static const struct acpi_device_id ged_acpi_ids[] = {
  156. {"ACPI0013"},
  157. {},
  158. };
  159. static struct platform_driver ged_driver = {
  160. .probe = ged_probe,
  161. .remove = ged_remove,
  162. .shutdown = ged_shutdown,
  163. .driver = {
  164. .name = MODULE_NAME,
  165. .acpi_match_table = ACPI_PTR(ged_acpi_ids),
  166. },
  167. };
  168. builtin_platform_driver(ged_driver);