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