1 /*
2 * Copyright (c) 2020, Google LLC. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7 #include <common/debug.h>
8 #include <lib/mmio.h>
9 #include <mt8173_def.h>
10 #include <plat_sip_calls.h>
11 #include <lib/psci/psci.h>
12 #include <smccc_helpers.h>
13 #include <wdt.h>
14
15 #define WDT_BASE (RGU_BASE + 0)
16 #define WDT_MODE (WDT_BASE + 0x00)
17 #define WDT_LENGTH (WDT_BASE + 0x04)
18 #define WDT_RESTART (WDT_BASE + 0x08)
19 #define WDT_SWRST (WDT_BASE + 0x14)
20
21 #define WDT_MODE_DUAL_MODE 0x40
22 #define WDT_MODE_IRQ 0x8
23 #define WDT_MODE_KEY 0x22000000
24 #define WDT_MODE_EXTEN 0x4
25 #define WDT_MODE_EN 0x1
26 #define WDT_LENGTH_KEY 0x8
27 #define WDT_RESTART_KEY 0x1971
28 #define WDT_SWRST_KEY 0x1209
29
30
31 #define WDT_MIN_TIMEOUT 1
32 #define WDT_MAX_TIMEOUT 31
33
34 enum smcwd_call {
35 SMCWD_INFO = 0,
36 SMCWD_SET_TIMEOUT = 1,
37 SMCWD_ENABLE = 2,
38 SMCWD_PET = 3,
39 };
40
41 static int wdt_enabled_before_suspend;
42
43 /*
44 * We expect the WDT registers to be correctly initialized by BL2 firmware
45 * (which may be board specific), so we do not reinitialize them here.
46 */
47
wdt_trigger_reset(void)48 void wdt_trigger_reset(void)
49 {
50 mmio_write_32(WDT_SWRST, WDT_SWRST_KEY);
51 }
52
wdt_pet(void)53 void wdt_pet(void)
54 {
55 mmio_write_32(WDT_RESTART, WDT_RESTART_KEY);
56 }
57
wdt_set_timeout(uint32_t timeout)58 int wdt_set_timeout(uint32_t timeout)
59 {
60 /* One tick here equals 512 32KHz ticks. 512 / 32000 * 125 / 2 = 1 */
61 uint32_t ticks = timeout * 125 / 2;
62
63 if (timeout < WDT_MIN_TIMEOUT || timeout > WDT_MAX_TIMEOUT)
64 return PSCI_E_INVALID_PARAMS;
65
66 mmio_write_32(WDT_LENGTH, ticks << 5 | WDT_LENGTH_KEY);
67
68 return PSCI_E_SUCCESS;
69 }
70
wdt_set_enable(int enable)71 void wdt_set_enable(int enable)
72 {
73 if (enable)
74 wdt_pet();
75 mmio_clrsetbits_32(WDT_MODE, WDT_MODE_EN,
76 WDT_MODE_KEY | (enable ? WDT_MODE_EN : 0));
77 }
78
wdt_suspend(void)79 void wdt_suspend(void)
80 {
81 wdt_enabled_before_suspend = mmio_read_32(WDT_MODE) & WDT_MODE_EN;
82 if (wdt_enabled_before_suspend)
83 wdt_set_enable(0);
84 }
85
wdt_resume(void)86 void wdt_resume(void)
87 {
88 if (wdt_enabled_before_suspend)
89 wdt_set_enable(1);
90 }
91
wdt_smc_handler(uint32_t x1,uint32_t x2,void * handle)92 uint64_t wdt_smc_handler(uint32_t x1,
93 uint32_t x2,
94 void *handle)
95 {
96 int ret;
97
98 switch (x1) {
99 case SMCWD_INFO:
100 SMC_RET3(handle, PSCI_E_SUCCESS,
101 WDT_MIN_TIMEOUT, WDT_MAX_TIMEOUT);
102 case SMCWD_SET_TIMEOUT:
103 ret = wdt_set_timeout(x2);
104 SMC_RET1(handle, ret);
105 case SMCWD_ENABLE:
106 wdt_set_enable(x2 > 0);
107 SMC_RET1(handle, PSCI_E_SUCCESS);
108 case SMCWD_PET:
109 wdt_pet();
110 SMC_RET1(handle, PSCI_E_SUCCESS);
111 default:
112 ERROR("Unimplemented SMCWD call (%d)\n", x1);
113 SMC_RET1(handle, PSCI_E_NOT_SUPPORTED);
114 }
115 }
116