pico-sdk/src/rp2_common/hardware_watchdog/watchdog.c

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2021-01-20 16:44:27 +00:00
/*
* Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <stdio.h>
#include "hardware/watchdog.h"
#include "hardware/structs/watchdog.h"
#include "hardware/structs/psm.h"
/// \tag::watchdog_start_tick[]
void watchdog_start_tick(uint cycles) {
// Important: This function also provides a tick reference to the timer
watchdog_hw->tick = cycles | WATCHDOG_TICK_ENABLE_BITS;
}
/// \end::watchdog_start_tick[]
// Value to load when updating the watchdog
// tag::watchdog_update[]
static uint32_t load_value;
void watchdog_update(void) {
watchdog_hw->load = load_value;
}
// end::watchdog_update[]
uint32_t watchdog_get_count(void) {
return (watchdog_hw->ctrl & WATCHDOG_CTRL_TIME_BITS) / 2 ;
}
// tag::watchdog_enable[]
// Helper function used by both watchdog_enable and watchdog_reboot
void _watchdog_enable(uint32_t delay_ms, bool pause_on_debug) {
hw_clear_bits(&watchdog_hw->ctrl, WATCHDOG_CTRL_ENABLE_BITS);
// Reset everything apart from ROSC and XOSC
hw_set_bits(&psm_hw->wdsel, PSM_WDSEL_BITS & ~(PSM_WDSEL_ROSC_BITS | PSM_WDSEL_XOSC_BITS));
uint32_t dbg_bits = WATCHDOG_CTRL_PAUSE_DBG0_BITS |
WATCHDOG_CTRL_PAUSE_DBG1_BITS |
WATCHDOG_CTRL_PAUSE_JTAG_BITS;
if (pause_on_debug) {
hw_set_bits(&watchdog_hw->ctrl, dbg_bits);
} else {
hw_clear_bits(&watchdog_hw->ctrl, dbg_bits);
}
if (!delay_ms) delay_ms = 50;
// Note, we have x2 here as the watchdog HW currently decrements twice per tick
load_value = delay_ms * 1000 * 2;
if (load_value > 0xffffffu)
load_value = 0xffffffu;
watchdog_update();
hw_set_bits(&watchdog_hw->ctrl, WATCHDOG_CTRL_ENABLE_BITS);
}
// end::watchdog_enable[]
void watchdog_enable(uint32_t delay_ms, bool pause_on_debug) {
// This watchdog enable doesn't reboot so clear scratch register
// with magic word to jump into code
watchdog_hw->scratch[4] = 0;
_watchdog_enable(delay_ms, pause_on_debug);
}
void watchdog_reboot(uint32_t pc, uint32_t sp, uint32_t delay_ms) {
check_hw_layout(watchdog_hw_t, scratch[7], WATCHDOG_SCRATCH7_OFFSET);
// Clear enable before setting up scratch registers
hw_clear_bits(&watchdog_hw->ctrl, WATCHDOG_CTRL_ENABLE_BITS);
if (pc) {
pc |= 1u; // thumb mode
watchdog_hw->scratch[4] = 0xb007c0d3;
watchdog_hw->scratch[5] = pc ^ -0xb007c0d3;
watchdog_hw->scratch[6] = sp;
watchdog_hw->scratch[7] = pc;
// printf("rebooting %08x/%08x in %dms...\n", (uint) pc, (uint) sp, (uint) delay_ms);
} else {
watchdog_hw->scratch[4] = 0;
// printf("rebooting (regular)) in %dms...\n", (uint) delay_ms);
}
// Don't pause watchdog for debug
_watchdog_enable(delay_ms, 0);
}
bool watchdog_caused_reboot(void) {
// If any reason bits are set this is true
return watchdog_hw->reason;
}