1 /***************************************************************************//**
2 * \file cy_wdg.c
3 *
4 * \brief
5 * Provides a high level interface for interacting with the Cypress Watchdog Timer.
6 * This interface abstracts out the chip specific details. If any chip specific
7 * functionality is necessary, or performance is critical the low level functions
8 * can be used directly.
9 *
10 *
11 ********************************************************************************
12 * \copyright
13 * Copyright 2019-2020 Cypress Semiconductor Corporation
14 * SPDX-License-Identifier: Apache-2.0
15 *
16 * Licensed under the Apache License, Version 2.0 (the "License");
17 * you may not use this file except in compliance with the License.
18 * You may obtain a copy of the License at
19 *
20 * http://www.apache.org/licenses/LICENSE-2.0
21 *
22 * Unless required by applicable law or agreed to in writing, software
23 * distributed under the License is distributed on an "AS IS" BASIS,
24 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
25 * See the License for the specific language governing permissions and
26 * limitations under the License.
27 *******************************************************************************/
28
29 #include <stdbool.h>
30 #include "watchdog.h"
31 #include "cy_wdt.h"
32 #include "cy_utils.h"
33
34 #if defined(__cplusplus)
35 extern "C" {
36 #endif
37
38 #if defined(COMPONENT_PSOC6)
39 #define _cy_wdg_lock() Cy_WDT_Lock()
40 #define _cy_wdg_unlock() Cy_WDT_Unlock()
41 #else
42 #define _cy_wdg_lock()
43 #define _cy_wdg_unlock()
44 #endif
45
46 // ((2^16 * 2) + (2^16 - 1)) * .030518 ms
47 /** Maximum WDT timeout in milliseconds */
48 #define _cy_wdg_MAX_TIMEOUT_MS 6000
49
50 /** Maximum number of ignore bits */
51 #define _cy_wdg_MAX_IGNORE_BITS 12
52
53 typedef struct {
54 uint16_t min_period_ms; // Minimum period in milliseconds that can be represented with this many ignored bits
55 uint16_t round_threshold_ms; // Timeout threshold in milliseconds from which to round up to the minimum period
56 } _cy_wdg_ignore_bits_data_t;
57
58 // ILO Frequency = 32768 Hz
59 // ILO Period = 1 / 32768 Hz = .030518 ms
60 // WDT Reset Period (timeout_ms) = .030518 ms * (2 * 2^(16 - ignore_bits) + match)
61 // ignore_bits range: 0 - 12
62 // match range: 0 - (2^(16 - ignore_bits) - 1)
63 static const _cy_wdg_ignore_bits_data_t _cy_wdg_ignore_data[] = {
64 {4001, 3001}, // 0 bits: min period: 4001ms, max period: 6000ms, round up from 3001+ms
65 {2001, 1500}, // 1 bit: min period: 2001ms, max period: 3000ms, round up from 1500+ms
66 {1001, 750}, // 2 bits: min period: 1001ms, max period: 1499ms, round up from 750+ms
67 {501, 375}, // 3 bits: min period: 501ms, max period: 749ms, round up from 375+ms
68 {251, 188}, // 4 bits: min period: 251ms, max period: 374ms, round up from 188+ms
69 {126, 94}, // 5 bits: min period: 126ms, max period: 187ms, round up from 94+ms
70 {63, 47}, // 6 bits: min period: 63ms, max period: 93ms, round up from 47+ms
71 {32, 24}, // 7 bits: min period: 32ms, max period: 46ms, round up from 24+ms
72 {16, 12}, // 8 bits: min period: 16ms, max period: 23ms, round up from 12+ms
73 {8, 6}, // 9 bits: min period: 8ms, max period: 11ms, round up from 6+ms
74 {4, 3}, // 10 bits: min period: 4ms, max period: 5ms, round up from 3+ms
75 {2, 2}, // 11 bits: min period: 2ms, max period: 2ms
76 {1, 1} // 12 bits: min period: 1ms, max period: 1ms
77 };
78
79 static bool _cy_wdg_initialized = false;
80 static bool _cy_wdg_pdl_initialized = false;
81 static uint16_t _cy_wdg_initial_timeout_ms = 0;
82 static uint8_t _cy_wdg_initial_ignore_bits = 0;
83
_cy_wdg_timeout_to_ignore_bits(uint32_t * timeout_ms)84 static __INLINE uint32_t _cy_wdg_timeout_to_ignore_bits(uint32_t *timeout_ms) {
85 for (uint32_t i = 0; i <= _cy_wdg_MAX_IGNORE_BITS; i++)
86 {
87 if (*timeout_ms >= _cy_wdg_ignore_data[i].round_threshold_ms)
88 {
89 if (*timeout_ms < _cy_wdg_ignore_data[i].min_period_ms)
90 *timeout_ms = _cy_wdg_ignore_data[i].min_period_ms;
91 return i;
92 }
93 }
94 return _cy_wdg_MAX_IGNORE_BITS; // Should never reach this
95 }
96
_cy_wdg_timeout_to_match(uint16_t timeout_ms,uint16_t ignore_bits)97 static __INLINE uint16_t _cy_wdg_timeout_to_match(uint16_t timeout_ms, uint16_t ignore_bits)
98 {
99 // match = (timeout_ms / .030518 ms) - (2 * 2^(16 - ignore_bits))
100 return (uint16_t)(timeout_ms / .030518) - (1UL << (17 - ignore_bits)) + Cy_WDT_GetCount();
101 }
102
103 /* Start API implementing */
104
cy_wdg_init(uint32_t timeout_ms)105 cy_rslt_t cy_wdg_init(uint32_t timeout_ms)
106 {
107 if (timeout_ms == 0 || timeout_ms > _cy_wdg_MAX_TIMEOUT_MS)
108 {
109 return -1;
110 }
111
112 if (_cy_wdg_initialized)
113 {
114 return -1;
115 }
116
117 _cy_wdg_initialized = true;
118
119 if (!_cy_wdg_pdl_initialized)
120 {
121 Cy_WDT_Enable();
122 Cy_WDT_MaskInterrupt();
123 _cy_wdg_pdl_initialized = true;
124 }
125
126 cy_wdg_stop();
127
128 _cy_wdg_initial_timeout_ms = timeout_ms;
129 uint8_t ignore_bits = _cy_wdg_timeout_to_ignore_bits(&timeout_ms);
130 _cy_wdg_initial_ignore_bits = ignore_bits;
131
132 Cy_WDT_SetIgnoreBits(ignore_bits);
133
134 Cy_WDT_SetMatch(_cy_wdg_timeout_to_match(timeout_ms, ignore_bits));
135
136 cy_wdg_start();
137
138 return CY_RSLT_SUCCESS;
139 }
140
cy_wdg_free()141 void cy_wdg_free()
142 {
143 cy_wdg_stop();
144
145 _cy_wdg_initialized = false;
146 }
147
cy_wdg_kick()148 void cy_wdg_kick()
149 {
150 /* Clear to prevent reset from WDT */
151 Cy_WDT_ClearWatchdog();
152
153 _cy_wdg_unlock();
154 Cy_WDT_SetMatch(_cy_wdg_timeout_to_match(_cy_wdg_initial_timeout_ms, _cy_wdg_initial_ignore_bits));
155 _cy_wdg_lock();
156 }
157
cy_wdg_start()158 void cy_wdg_start()
159 {
160 _cy_wdg_unlock();
161 Cy_WDT_Enable();
162 _cy_wdg_lock();
163 }
164
cy_wdg_stop()165 void cy_wdg_stop()
166 {
167 _cy_wdg_unlock();
168 Cy_WDT_Disable();
169 }
170
cy_wdg_get_timeout_ms()171 uint32_t cy_wdg_get_timeout_ms()
172 {
173 return _cy_wdg_initial_timeout_ms;
174 }
175
cy_wdg_get_max_timeout_ms(void)176 uint32_t cy_wdg_get_max_timeout_ms(void)
177 {
178 return _cy_wdg_MAX_TIMEOUT_MS;
179 }
180
181 #if defined(__cplusplus)
182 }
183 #endif
184
