blob: 13caebd679f5b07503941f1023cf468901aeec36 [file] [log] [blame]
Mika Westerberg058dfc72016-09-20 15:30:51 +03001/*
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 */
24bool 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}
33EXPORT_SYMBOL_GPL(acpi_has_watchdog);
34
35void __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
121fail_free_resource_list:
122 resource_list_free(&resource_list);
123}