1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * EFI watchdog
4 *
5 * Copyright (c) 2017 Heinrich Schuchardt
6 */
7
8 #include <common.h>
9 #include <efi_loader.h>
10
11 /* Conversion factor from seconds to multiples of 100ns */
12 #define EFI_SECONDS_TO_100NS 10000000ULL
13
14 static struct efi_event *watchdog_timer_event;
15
16 /*
17 * Reset the system when the watchdog event is notified.
18 *
19 * @event: the watchdog event
20 * @context: not used
21 */
efi_watchdog_timer_notify(struct efi_event * event,void * context)22 static void EFIAPI efi_watchdog_timer_notify(struct efi_event *event,
23 void *context)
24 {
25 EFI_ENTRY("%p, %p", event, context);
26
27 printf("\nEFI: Watchdog timeout\n");
28 EFI_CALL_VOID(efi_runtime_services.reset_system(EFI_RESET_COLD,
29 EFI_SUCCESS, 0, NULL));
30
31 EFI_EXIT(EFI_UNSUPPORTED);
32 }
33
34 /*
35 * Reset the watchdog timer.
36 *
37 * This function is used by the SetWatchdogTimer service.
38 *
39 * @timeout: seconds before reset by watchdog
40 * @return: status code
41 */
efi_set_watchdog(unsigned long timeout)42 efi_status_t efi_set_watchdog(unsigned long timeout)
43 {
44 efi_status_t r;
45
46 if (timeout)
47 /* Reset watchdog */
48 r = efi_set_timer(watchdog_timer_event, EFI_TIMER_RELATIVE,
49 EFI_SECONDS_TO_100NS * timeout);
50 else
51 /* Deactivate watchdog */
52 r = efi_set_timer(watchdog_timer_event, EFI_TIMER_STOP, 0);
53 return r;
54 }
55
56 /*
57 * Initialize the EFI watchdog.
58 *
59 * This function is called by efi_init_obj_list()
60 */
efi_watchdog_register(void)61 efi_status_t efi_watchdog_register(void)
62 {
63 efi_status_t r;
64
65 /*
66 * Create a timer event.
67 */
68 r = efi_create_event(EVT_TIMER | EVT_NOTIFY_SIGNAL, TPL_CALLBACK,
69 efi_watchdog_timer_notify, NULL, NULL,
70 &watchdog_timer_event);
71 if (r != EFI_SUCCESS) {
72 printf("ERROR: Failed to register watchdog event\n");
73 return r;
74 }
75 /*
76 * The UEFI standard requires that the watchdog timer is set to five
77 * minutes when invoking an EFI boot option.
78 *
79 * Unified Extensible Firmware Interface (UEFI), version 2.7 Errata A
80 * 7.5. Miscellaneous Boot Services - EFI_BOOT_SERVICES.SetWatchdogTimer
81 */
82 r = efi_set_watchdog(300);
83 if (r != EFI_SUCCESS) {
84 printf("ERROR: Failed to set watchdog timer\n");
85 return r;
86 }
87 return EFI_SUCCESS;
88 }
89