Mika Westerberg | 058dfc7 | 2016-09-20 15:30:51 +0300 | [diff] [blame] | 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 | |
Mika Westerberg | 230c832 | 2018-05-22 14:16:50 +0300 | [diff] [blame] | 20 | #ifdef CONFIG_RTC_MC146818_LIB |
| 21 | #include <linux/mc146818rtc.h> |
| 22 | |
| 23 | /* |
| 24 | * There are several systems where the WDAT table is accessing RTC SRAM to |
| 25 | * store persistent information. This does not work well with the Linux RTC |
| 26 | * driver so on those systems we skip WDAT driver and prefer iTCO_wdt |
| 27 | * instead. |
| 28 | * |
| 29 | * See also https://bugzilla.kernel.org/show_bug.cgi?id=199033. |
| 30 | */ |
| 31 | static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat) |
| 32 | { |
| 33 | const struct acpi_wdat_entry *entries; |
| 34 | int i; |
| 35 | |
| 36 | entries = (struct acpi_wdat_entry *)(wdat + 1); |
| 37 | for (i = 0; i < wdat->entries; i++) { |
| 38 | const struct acpi_generic_address *gas; |
| 39 | |
| 40 | gas = &entries[i].register_region; |
| 41 | if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) { |
| 42 | switch (gas->address) { |
| 43 | case RTC_PORT(0): |
| 44 | case RTC_PORT(1): |
| 45 | case RTC_PORT(2): |
| 46 | case RTC_PORT(3): |
| 47 | return true; |
| 48 | } |
| 49 | } |
| 50 | } |
| 51 | |
| 52 | return false; |
| 53 | } |
| 54 | #else |
| 55 | static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat) |
| 56 | { |
| 57 | return false; |
| 58 | } |
| 59 | #endif |
Mika Westerberg | ad226b6 | 2018-04-23 14:16:03 +0300 | [diff] [blame] | 60 | |
Jean Delvare | f2a1853 | 2020-02-06 16:58:45 +0100 | [diff] [blame] | 61 | static bool acpi_no_watchdog; |
| 62 | |
Mika Westerberg | ad226b6 | 2018-04-23 14:16:03 +0300 | [diff] [blame] | 63 | static const struct acpi_table_wdat *acpi_watchdog_get_wdat(void) |
| 64 | { |
| 65 | const struct acpi_table_wdat *wdat = NULL; |
| 66 | acpi_status status; |
| 67 | |
Jean Delvare | f2a1853 | 2020-02-06 16:58:45 +0100 | [diff] [blame] | 68 | if (acpi_disabled || acpi_no_watchdog) |
Mika Westerberg | ad226b6 | 2018-04-23 14:16:03 +0300 | [diff] [blame] | 69 | return NULL; |
| 70 | |
Mika Westerberg | ad226b6 | 2018-04-23 14:16:03 +0300 | [diff] [blame] | 71 | status = acpi_get_table(ACPI_SIG_WDAT, 0, |
| 72 | (struct acpi_table_header **)&wdat); |
| 73 | if (ACPI_FAILURE(status)) { |
| 74 | /* It is fine if there is no WDAT */ |
| 75 | return NULL; |
| 76 | } |
| 77 | |
Mika Westerberg | 230c832 | 2018-05-22 14:16:50 +0300 | [diff] [blame] | 78 | if (acpi_watchdog_uses_rtc(wdat)) { |
| 79 | pr_info("Skipping WDAT on this system because it uses RTC SRAM\n"); |
| 80 | return NULL; |
| 81 | } |
| 82 | |
Mika Westerberg | ad226b6 | 2018-04-23 14:16:03 +0300 | [diff] [blame] | 83 | return wdat; |
| 84 | } |
| 85 | |
Mika Westerberg | 058dfc7 | 2016-09-20 15:30:51 +0300 | [diff] [blame] | 86 | /** |
| 87 | * Returns true if this system should prefer ACPI based watchdog instead of |
| 88 | * the native one (which are typically the same hardware). |
| 89 | */ |
| 90 | bool acpi_has_watchdog(void) |
| 91 | { |
Mika Westerberg | ad226b6 | 2018-04-23 14:16:03 +0300 | [diff] [blame] | 92 | return !!acpi_watchdog_get_wdat(); |
Mika Westerberg | 058dfc7 | 2016-09-20 15:30:51 +0300 | [diff] [blame] | 93 | } |
| 94 | EXPORT_SYMBOL_GPL(acpi_has_watchdog); |
| 95 | |
Jean Delvare | f2a1853 | 2020-02-06 16:58:45 +0100 | [diff] [blame] | 96 | /* ACPI watchdog can be disabled on boot command line */ |
| 97 | static int __init disable_acpi_watchdog(char *str) |
| 98 | { |
| 99 | acpi_no_watchdog = true; |
| 100 | return 1; |
| 101 | } |
| 102 | __setup("acpi_no_watchdog", disable_acpi_watchdog); |
| 103 | |
Mika Westerberg | 058dfc7 | 2016-09-20 15:30:51 +0300 | [diff] [blame] | 104 | void __init acpi_watchdog_init(void) |
| 105 | { |
| 106 | const struct acpi_wdat_entry *entries; |
| 107 | const struct acpi_table_wdat *wdat; |
| 108 | struct list_head resource_list; |
| 109 | struct resource_entry *rentry; |
| 110 | struct platform_device *pdev; |
| 111 | struct resource *resources; |
| 112 | size_t nresources = 0; |
Mika Westerberg | 058dfc7 | 2016-09-20 15:30:51 +0300 | [diff] [blame] | 113 | int i; |
| 114 | |
Mika Westerberg | ad226b6 | 2018-04-23 14:16:03 +0300 | [diff] [blame] | 115 | wdat = acpi_watchdog_get_wdat(); |
| 116 | if (!wdat) { |
Mika Westerberg | 058dfc7 | 2016-09-20 15:30:51 +0300 | [diff] [blame] | 117 | /* It is fine if there is no WDAT */ |
| 118 | return; |
| 119 | } |
| 120 | |
| 121 | /* Watchdog disabled by BIOS */ |
| 122 | if (!(wdat->flags & ACPI_WDAT_ENABLED)) |
| 123 | return; |
| 124 | |
| 125 | /* Skip legacy PCI WDT devices */ |
| 126 | if (wdat->pci_segment != 0xff || wdat->pci_bus != 0xff || |
| 127 | wdat->pci_device != 0xff || wdat->pci_function != 0xff) |
| 128 | return; |
| 129 | |
| 130 | INIT_LIST_HEAD(&resource_list); |
| 131 | |
| 132 | entries = (struct acpi_wdat_entry *)(wdat + 1); |
| 133 | for (i = 0; i < wdat->entries; i++) { |
| 134 | const struct acpi_generic_address *gas; |
| 135 | struct resource_entry *rentry; |
| 136 | struct resource res; |
| 137 | bool found; |
| 138 | |
| 139 | gas = &entries[i].register_region; |
| 140 | |
| 141 | res.start = gas->address; |
Mika Westerberg | e5d99f3 | 2020-02-12 17:59:40 +0300 | [diff] [blame] | 142 | res.end = res.start + ACPI_ACCESS_BYTE_WIDTH(gas->access_width) - 1; |
Mika Westerberg | 058dfc7 | 2016-09-20 15:30:51 +0300 | [diff] [blame] | 143 | if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { |
| 144 | res.flags = IORESOURCE_MEM; |
Mika Westerberg | 058dfc7 | 2016-09-20 15:30:51 +0300 | [diff] [blame] | 145 | } else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) { |
| 146 | res.flags = IORESOURCE_IO; |
Mika Westerberg | 058dfc7 | 2016-09-20 15:30:51 +0300 | [diff] [blame] | 147 | } else { |
| 148 | pr_warn("Unsupported address space: %u\n", |
| 149 | gas->space_id); |
| 150 | goto fail_free_resource_list; |
| 151 | } |
| 152 | |
| 153 | found = false; |
| 154 | resource_list_for_each_entry(rentry, &resource_list) { |
| 155 | if (resource_contains(rentry->res, &res)) { |
| 156 | found = true; |
| 157 | break; |
| 158 | } |
| 159 | } |
| 160 | |
| 161 | if (!found) { |
| 162 | rentry = resource_list_create_entry(NULL, 0); |
| 163 | if (!rentry) |
| 164 | goto fail_free_resource_list; |
| 165 | |
| 166 | *rentry->res = res; |
| 167 | resource_list_add_tail(rentry, &resource_list); |
| 168 | nresources++; |
| 169 | } |
| 170 | } |
| 171 | |
| 172 | resources = kcalloc(nresources, sizeof(*resources), GFP_KERNEL); |
| 173 | if (!resources) |
| 174 | goto fail_free_resource_list; |
| 175 | |
| 176 | i = 0; |
| 177 | resource_list_for_each_entry(rentry, &resource_list) |
| 178 | resources[i++] = *rentry->res; |
| 179 | |
| 180 | pdev = platform_device_register_simple("wdat_wdt", PLATFORM_DEVID_NONE, |
| 181 | resources, nresources); |
| 182 | if (IS_ERR(pdev)) |
| 183 | pr_err("Failed to create platform device\n"); |
| 184 | |
| 185 | kfree(resources); |
| 186 | |
| 187 | fail_free_resource_list: |
| 188 | resource_list_free(&resource_list); |
| 189 | } |