1 /*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <plat/pwr.h>
18 #include <plat/wdt.h>
19 #include <plat/cmsis.h>
20
21 struct StmWwdg {
22 volatile uint16_t CR;
23 uint8_t unused0[2];
24 volatile uint16_t CFR;
25 uint8_t unused1[2];
26 volatile uint16_t SR;
27 uint8_t unused2[2];
28 };
29
30 #define WWDG ((struct StmWwdg*)WWDG_BASE)
31
32 /* WWDG bit definitions */
33 #define WWDG_CR_ENABLE 0x80
34
35 #define WWDG_TCNT_HIGH 0x40
36 #define WWDG_TCNT_MASK 0x3F
37
38 #define WWDG_CFR_DIV2 0x0080
39 #define WWDG_CFR_DIV4 0x0100
40 #define WWDG_CFR_DIV8 0x0180
41 #define WWDG_CFR_EWI 0x0200
42
43 /* WWDG parameters */
44 #define WWDG_WINDOW_SIZE 0x3F // 0 < x <= 0x3F
45
46 void WWDG_IRQHandler(void);
WWDG_IRQHandler(void)47 void __attribute__((naked)) WWDG_IRQHandler(void)
48 {
49 asm volatile(
50 "mov r0, #2 \n"
51 "b cpuCommonFaultCode \n"
52 );
53 }
54
wdtEnableClk()55 void wdtEnableClk()
56 {
57 pwrUnitClock(PERIPH_BUS_APB1, PERIPH_APB1_WWDG, true);
58 }
59
wdtEnableIrq()60 void wdtEnableIrq()
61 {
62 NVIC_EnableIRQ(WWDG_IRQn);
63 }
64
wdtDisableClk()65 void wdtDisableClk()
66 {
67 pwrUnitClock(PERIPH_BUS_APB1, PERIPH_APB1_WWDG, false);
68 }
69
wdtDisableIrq()70 void wdtDisableIrq()
71 {
72 NVIC_DisableIRQ(WWDG_IRQn);
73 }
74
wdtInit()75 void wdtInit()
76 {
77 wdtEnableClk();
78 WWDG->CFR = WWDG_CFR_EWI | WWDG_CFR_DIV8 | WWDG_TCNT_HIGH | (WWDG_WINDOW_SIZE & WWDG_TCNT_MASK);
79 WWDG->CR = WWDG_CR_ENABLE | WWDG_TCNT_HIGH | (WWDG_WINDOW_SIZE & WWDG_TCNT_MASK);
80 // with 16Mhz APB1 clock, this is 256*DIV = 2,048 uS per WWDG tick with DIV=8, max 131,072 uS WWDG window
81 wdtEnableIrq();
82 }
83
wdtPing()84 void wdtPing()
85 {
86 WWDG->CR = (WWDG->CR & ~WWDG_TCNT_MASK) | WWDG_TCNT_HIGH | (WWDG_WINDOW_SIZE & WWDG_TCNT_MASK);
87 }
88