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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 | // SPDX-License-Identifier: GPL-2.0-only /* * ACPI watchdog table parsing support. * * Copyright (C) 2016, Intel Corporation * Author: Mika Westerberg <mika.westerberg@linux.intel.com> */ #define pr_fmt(fmt) "ACPI: watchdog: " fmt #include <linux/acpi.h> #include <linux/ioport.h> #include <linux/platform_device.h> #include "internal.h" #ifdef CONFIG_RTC_MC146818_LIB #include <linux/mc146818rtc.h> /* * There are several systems where the WDAT table is accessing RTC SRAM to * store persistent information. This does not work well with the Linux RTC * driver so on those systems we skip WDAT driver and prefer iTCO_wdt * instead. * * See also https://bugzilla.kernel.org/show_bug.cgi?id=199033. */ static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat) { const struct acpi_wdat_entry *entries; int i; entries = (struct acpi_wdat_entry *)(wdat + 1); for (i = 0; i < wdat->entries; i++) { const struct acpi_generic_address *gas; gas = &entries[i].register_region; if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) { switch (gas->address) { case RTC_PORT(0): case RTC_PORT(1): case RTC_PORT(2): case RTC_PORT(3): return true; } } } return false; } #else static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat) { return false; } #endif static const struct acpi_table_wdat *acpi_watchdog_get_wdat(void) { const struct acpi_table_wdat *wdat = NULL; acpi_status status; if (acpi_disabled) return NULL; status = acpi_get_table(ACPI_SIG_WDAT, 0, (struct acpi_table_header **)&wdat); if (ACPI_FAILURE(status)) { /* It is fine if there is no WDAT */ return NULL; } if (acpi_watchdog_uses_rtc(wdat)) { pr_info("Skipping WDAT on this system because it uses RTC SRAM\n"); return NULL; } return wdat; } /** * Returns true if this system should prefer ACPI based watchdog instead of * the native one (which are typically the same hardware). */ bool acpi_has_watchdog(void) { return !!acpi_watchdog_get_wdat(); } EXPORT_SYMBOL_GPL(acpi_has_watchdog); void __init acpi_watchdog_init(void) { const struct acpi_wdat_entry *entries; const struct acpi_table_wdat *wdat; struct list_head resource_list; struct resource_entry *rentry; struct platform_device *pdev; struct resource *resources; size_t nresources = 0; int i; wdat = acpi_watchdog_get_wdat(); if (!wdat) { /* It is fine if there is no WDAT */ return; } /* Watchdog disabled by BIOS */ if (!(wdat->flags & ACPI_WDAT_ENABLED)) return; /* Skip legacy PCI WDT devices */ if (wdat->pci_segment != 0xff || wdat->pci_bus != 0xff || wdat->pci_device != 0xff || wdat->pci_function != 0xff) return; INIT_LIST_HEAD(&resource_list); entries = (struct acpi_wdat_entry *)(wdat + 1); for (i = 0; i < wdat->entries; i++) { const struct acpi_generic_address *gas; struct resource_entry *rentry; struct resource res = {}; bool found; gas = &entries[i].register_region; res.start = gas->address; if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { res.flags = IORESOURCE_MEM; res.end = res.start + ALIGN(gas->access_width, 4) - 1; } else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) { res.flags = IORESOURCE_IO; res.end = res.start + gas->access_width - 1; } else { pr_warn("Unsupported address space: %u\n", gas->space_id); goto fail_free_resource_list; } found = false; resource_list_for_each_entry(rentry, &resource_list) { if (rentry->res->flags == res.flags && resource_overlaps(rentry->res, &res)) { if (res.start < rentry->res->start) rentry->res->start = res.start; if (res.end > rentry->res->end) rentry->res->end = res.end; found = true; break; } } if (!found) { rentry = resource_list_create_entry(NULL, 0); if (!rentry) goto fail_free_resource_list; *rentry->res = res; resource_list_add_tail(rentry, &resource_list); nresources++; } } resources = kcalloc(nresources, sizeof(*resources), GFP_KERNEL); if (!resources) goto fail_free_resource_list; i = 0; resource_list_for_each_entry(rentry, &resource_list) resources[i++] = *rentry->res; pdev = platform_device_register_simple("wdat_wdt", PLATFORM_DEVID_NONE, resources, nresources); if (IS_ERR(pdev)) pr_err("Device creation failed: %ld\n", PTR_ERR(pdev)); kfree(resources); fail_free_resource_list: resource_list_free(&resource_list); } |