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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
058dfc76 MW |
2 | /* |
3 | * ACPI watchdog table parsing support. | |
4 | * | |
5 | * Copyright (C) 2016, Intel Corporation | |
6 | * Author: Mika Westerberg <mika.westerberg@linux.intel.com> | |
058dfc76 MW |
7 | */ |
8 | ||
9 | #define pr_fmt(fmt) "ACPI: watchdog: " fmt | |
10 | ||
11 | #include <linux/acpi.h> | |
12 | #include <linux/ioport.h> | |
13 | #include <linux/platform_device.h> | |
14 | ||
15 | #include "internal.h" | |
16 | ||
5a802a7a MW |
17 | #ifdef CONFIG_RTC_MC146818_LIB |
18 | #include <linux/mc146818rtc.h> | |
19 | ||
20 | /* | |
21 | * There are several systems where the WDAT table is accessing RTC SRAM to | |
22 | * store persistent information. This does not work well with the Linux RTC | |
23 | * driver so on those systems we skip WDAT driver and prefer iTCO_wdt | |
24 | * instead. | |
25 | * | |
26 | * See also https://bugzilla.kernel.org/show_bug.cgi?id=199033. | |
27 | */ | |
28 | static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat) | |
29 | { | |
30 | const struct acpi_wdat_entry *entries; | |
31 | int i; | |
32 | ||
33 | entries = (struct acpi_wdat_entry *)(wdat + 1); | |
34 | for (i = 0; i < wdat->entries; i++) { | |
35 | const struct acpi_generic_address *gas; | |
36 | ||
37 | gas = &entries[i].register_region; | |
38 | if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) { | |
39 | switch (gas->address) { | |
40 | case RTC_PORT(0): | |
41 | case RTC_PORT(1): | |
42 | case RTC_PORT(2): | |
43 | case RTC_PORT(3): | |
44 | return true; | |
45 | } | |
46 | } | |
47 | } | |
48 | ||
49 | return false; | |
50 | } | |
51 | #else | |
52 | static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat) | |
53 | { | |
54 | return false; | |
55 | } | |
56 | #endif | |
a0a37862 MW |
57 | |
58 | static const struct acpi_table_wdat *acpi_watchdog_get_wdat(void) | |
59 | { | |
60 | const struct acpi_table_wdat *wdat = NULL; | |
61 | acpi_status status; | |
62 | ||
63 | if (acpi_disabled) | |
64 | return NULL; | |
65 | ||
a0a37862 MW |
66 | status = acpi_get_table(ACPI_SIG_WDAT, 0, |
67 | (struct acpi_table_header **)&wdat); | |
68 | if (ACPI_FAILURE(status)) { | |
69 | /* It is fine if there is no WDAT */ | |
70 | return NULL; | |
71 | } | |
72 | ||
5a802a7a MW |
73 | if (acpi_watchdog_uses_rtc(wdat)) { |
74 | pr_info("Skipping WDAT on this system because it uses RTC SRAM\n"); | |
75 | return NULL; | |
76 | } | |
77 | ||
a0a37862 MW |
78 | return wdat; |
79 | } | |
80 | ||
058dfc76 MW |
81 | /** |
82 | * Returns true if this system should prefer ACPI based watchdog instead of | |
83 | * the native one (which are typically the same hardware). | |
84 | */ | |
85 | bool acpi_has_watchdog(void) | |
86 | { | |
a0a37862 | 87 | return !!acpi_watchdog_get_wdat(); |
058dfc76 MW |
88 | } |
89 | EXPORT_SYMBOL_GPL(acpi_has_watchdog); | |
90 | ||
91 | void __init acpi_watchdog_init(void) | |
92 | { | |
93 | const struct acpi_wdat_entry *entries; | |
94 | const struct acpi_table_wdat *wdat; | |
95 | struct list_head resource_list; | |
96 | struct resource_entry *rentry; | |
97 | struct platform_device *pdev; | |
98 | struct resource *resources; | |
99 | size_t nresources = 0; | |
058dfc76 MW |
100 | int i; |
101 | ||
a0a37862 MW |
102 | wdat = acpi_watchdog_get_wdat(); |
103 | if (!wdat) { | |
058dfc76 MW |
104 | /* It is fine if there is no WDAT */ |
105 | return; | |
106 | } | |
107 | ||
108 | /* Watchdog disabled by BIOS */ | |
109 | if (!(wdat->flags & ACPI_WDAT_ENABLED)) | |
110 | return; | |
111 | ||
112 | /* Skip legacy PCI WDT devices */ | |
113 | if (wdat->pci_segment != 0xff || wdat->pci_bus != 0xff || | |
114 | wdat->pci_device != 0xff || wdat->pci_function != 0xff) | |
115 | return; | |
116 | ||
117 | INIT_LIST_HEAD(&resource_list); | |
118 | ||
119 | entries = (struct acpi_wdat_entry *)(wdat + 1); | |
120 | for (i = 0; i < wdat->entries; i++) { | |
121 | const struct acpi_generic_address *gas; | |
122 | struct resource_entry *rentry; | |
6ce14f64 | 123 | struct resource res = {}; |
058dfc76 MW |
124 | bool found; |
125 | ||
126 | gas = &entries[i].register_region; | |
127 | ||
128 | res.start = gas->address; | |
129 | if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { | |
130 | res.flags = IORESOURCE_MEM; | |
b1abf6fc | 131 | res.end = res.start + ALIGN(gas->access_width, 4) - 1; |
058dfc76 MW |
132 | } else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) { |
133 | res.flags = IORESOURCE_IO; | |
b1abf6fc | 134 | res.end = res.start + gas->access_width - 1; |
058dfc76 MW |
135 | } else { |
136 | pr_warn("Unsupported address space: %u\n", | |
137 | gas->space_id); | |
138 | goto fail_free_resource_list; | |
139 | } | |
140 | ||
141 | found = false; | |
142 | resource_list_for_each_entry(rentry, &resource_list) { | |
31e86cb9 RK |
143 | if (rentry->res->flags == res.flags && |
144 | resource_overlaps(rentry->res, &res)) { | |
145 | if (res.start < rentry->res->start) | |
146 | rentry->res->start = res.start; | |
147 | if (res.end > rentry->res->end) | |
148 | rentry->res->end = res.end; | |
058dfc76 MW |
149 | found = true; |
150 | break; | |
151 | } | |
152 | } | |
153 | ||
154 | if (!found) { | |
155 | rentry = resource_list_create_entry(NULL, 0); | |
156 | if (!rentry) | |
157 | goto fail_free_resource_list; | |
158 | ||
159 | *rentry->res = res; | |
160 | resource_list_add_tail(rentry, &resource_list); | |
161 | nresources++; | |
162 | } | |
163 | } | |
164 | ||
165 | resources = kcalloc(nresources, sizeof(*resources), GFP_KERNEL); | |
166 | if (!resources) | |
167 | goto fail_free_resource_list; | |
168 | ||
169 | i = 0; | |
170 | resource_list_for_each_entry(rentry, &resource_list) | |
171 | resources[i++] = *rentry->res; | |
172 | ||
173 | pdev = platform_device_register_simple("wdat_wdt", PLATFORM_DEVID_NONE, | |
174 | resources, nresources); | |
175 | if (IS_ERR(pdev)) | |
c6e2c1e1 | 176 | pr_err("Device creation failed: %ld\n", PTR_ERR(pdev)); |
058dfc76 MW |
177 | |
178 | kfree(resources); | |
179 | ||
180 | fail_free_resource_list: | |
181 | resource_list_free(&resource_list); | |
182 | } |