1 /* 2 * ACPI watchdog table parsing support. 3 * 4 * Copyright (C) 2016, Intel Corporation 5 * Author: Mika Westerberg <mika.westerberg@linux.intel.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 12 #define pr_fmt(fmt) "ACPI: watchdog: " fmt 13 14 #include <linux/acpi.h> 15 #include <linux/ioport.h> 16 #include <linux/platform_device.h> 17 18 #include "internal.h" 19 20 /** 21 * Returns true if this system should prefer ACPI based watchdog instead of 22 * the native one (which are typically the same hardware). 23 */ 24 bool acpi_has_watchdog(void) 25 { 26 struct acpi_table_header hdr; 27 28 if (acpi_disabled) 29 return false; 30 31 return ACPI_SUCCESS(acpi_get_table_header(ACPI_SIG_WDAT, 0, &hdr)); 32 } 33 EXPORT_SYMBOL_GPL(acpi_has_watchdog); 34 35 void __init acpi_watchdog_init(void) 36 { 37 const struct acpi_wdat_entry *entries; 38 const struct acpi_table_wdat *wdat; 39 struct list_head resource_list; 40 struct resource_entry *rentry; 41 struct platform_device *pdev; 42 struct resource *resources; 43 size_t nresources = 0; 44 acpi_status status; 45 int i; 46 47 status = acpi_get_table(ACPI_SIG_WDAT, 0, 48 (struct acpi_table_header **)&wdat); 49 if (ACPI_FAILURE(status)) { 50 /* It is fine if there is no WDAT */ 51 return; 52 } 53 54 /* Watchdog disabled by BIOS */ 55 if (!(wdat->flags & ACPI_WDAT_ENABLED)) 56 return; 57 58 /* Skip legacy PCI WDT devices */ 59 if (wdat->pci_segment != 0xff || wdat->pci_bus != 0xff || 60 wdat->pci_device != 0xff || wdat->pci_function != 0xff) 61 return; 62 63 INIT_LIST_HEAD(&resource_list); 64 65 entries = (struct acpi_wdat_entry *)(wdat + 1); 66 for (i = 0; i < wdat->entries; i++) { 67 const struct acpi_generic_address *gas; 68 struct resource_entry *rentry; 69 struct resource res; 70 bool found; 71 72 gas = &entries[i].register_region; 73 74 res.start = gas->address; 75 if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { 76 res.flags = IORESOURCE_MEM; 77 res.end = res.start + ALIGN(gas->access_width, 4); 78 } else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) { 79 res.flags = IORESOURCE_IO; 80 res.end = res.start + gas->access_width; 81 } else { 82 pr_warn("Unsupported address space: %u\n", 83 gas->space_id); 84 goto fail_free_resource_list; 85 } 86 87 found = false; 88 resource_list_for_each_entry(rentry, &resource_list) { 89 if (resource_contains(rentry->res, &res)) { 90 found = true; 91 break; 92 } 93 } 94 95 if (!found) { 96 rentry = resource_list_create_entry(NULL, 0); 97 if (!rentry) 98 goto fail_free_resource_list; 99 100 *rentry->res = res; 101 resource_list_add_tail(rentry, &resource_list); 102 nresources++; 103 } 104 } 105 106 resources = kcalloc(nresources, sizeof(*resources), GFP_KERNEL); 107 if (!resources) 108 goto fail_free_resource_list; 109 110 i = 0; 111 resource_list_for_each_entry(rentry, &resource_list) 112 resources[i++] = *rentry->res; 113 114 pdev = platform_device_register_simple("wdat_wdt", PLATFORM_DEVID_NONE, 115 resources, nresources); 116 if (IS_ERR(pdev)) 117 pr_err("Failed to create platform device\n"); 118 119 kfree(resources); 120 121 fail_free_resource_list: 122 resource_list_free(&resource_list); 123 } 124