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);
}
|
