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// See LICENSE for license details.
#include <stdio.h>
#include <stdlib.h>
#include "platform.h"
#include <string.h>
#include "plic/plic_driver.h"
#include "encoding.h"
#include <unistd.h>
#include "stdatomic.h"
void reset_demo (void);
// Structures for registering different interrupt handlers
// for different parts of the application.
typedef void (*function_ptr_t) (void);
void no_interrupt_handler (void) {};
function_ptr_t g_ext_interrupt_handlers[PLIC_NUM_INTERRUPTS];
// Instance data for the PLIC.
plic_instance_t g_plic;
/**
* use mtime to wait for a specified number of ticks.
* async determins if this is a busy wait, or if
* an irq is scheduled
*/
void mtime_wait( uint64_t ticks, uint32_t async)
{
volatile uint64_t * mtime = (uint64_t*) (CLINT_CTRL_ADDR + CLINT_MTIME);
uint64_t now = *mtime;
//if async, schedule irq
if(async) {
volatile uint64_t * mtimecmp = (uint64_t*) (CLINT_CTRL_ADDR + CLINT_MTIMECMP);
uint64_t then = now + ticks;
*mtimecmp = then;
set_csr(mie, MIP_MTIP);
} else {
//else busy wait
uint64_t then = now + ticks;
while(*mtime<then) {}
}
}
/*Entry Point for PLIC Interrupt Handler*/
void handle_m_ext_interrupt(){
plic_source int_num = PLIC_claim_interrupt(&g_plic);
if ((int_num >=1 ) && (int_num < PLIC_NUM_INTERRUPTS)) {
g_ext_interrupt_handlers[int_num]();
}
else {
exit(1 + (uintptr_t) int_num);
}
PLIC_complete_interrupt(&g_plic, int_num);
}
//global countdown timer
static uint32_t countdown = 10;
/*Entry Point for Machine Timer Interrupt Handler*/
void handle_m_time_interrupt(){
//cleare the timer irq
clear_csr(mie, MIP_MTIP);
//schedule next timer irq for 1 second
mtime_wait(1*RTC_FREQ, 1);
//flash a led
GPIO_REG(GPIO_OUTPUT_VAL) ^= (0x1 << BLUE_LED_OFFSET);
//print the count
printf("watchdog reset in %d\n", countdown--);
}
const char * instructions_msg = " \
\n\
SIFIVE, INC.\n\
\n\
5555555555555555555555555\n\
5555 5555\n\
5555 5555\n\
5555 5555\n\
5555 5555555555555555555555\n\
5555 555555555555555555555555\n\
5555 5555\n\
5555 5555\n\
5555 5555\n\
5555555555555555555555555555 55555\n\
55555 555555555 55555\n\
55555 55555 55555\n\
55555 5 55555\n\
55555 55555\n\
55555 55555\n\
55555 55555\n\
55555 55555\n\
55555 55555\n\
555555555\n\
55555\n\
5\n\
\n\
This application demonstrates the functionality of\n\
the watchdog timer present in the HiFive1 AON peripheral.\n\
\n\
The Watchdog timer will expire in 10 seconds resulting in\n\
a software reset.\n\
\n\
Press a key to prevent a reset\n\
";
void print_instructions() {
write (STDOUT_FILENO, instructions_msg, strlen(instructions_msg));
}
/**
* Flash the red led for a second, then set up
* blue for blinking during mtime irq
*/
void led_init() {
// Set up the GPIOs such that the LED GPIO
// can be used as both Inputs and Outputs.
GPIO_REG(GPIO_INPUT_EN) &= ~((0x1<< RED_LED_OFFSET) | (0x1<< GREEN_LED_OFFSET) | (0x1 << BLUE_LED_OFFSET)) ;
GPIO_REG(GPIO_OUTPUT_EN) |= ((0x1<< RED_LED_OFFSET)| (0x1<< GREEN_LED_OFFSET)| (0x1<< BLUE_LED_OFFSET));
GPIO_REG(GPIO_OUTPUT_VAL) |= ((0x1<< RED_LED_OFFSET) | (0x1<< GREEN_LED_OFFSET) | (0x1<< BLUE_LED_OFFSET));
//flash red led to indicate reset
GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << RED_LED_OFFSET) ;
mtime_wait(1*RTC_FREQ,0);
GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1 << RED_LED_OFFSET) ;
}
/**
* initialize the watchdog to reset in
* 5 seconds
**/
void watchdog_init() {
//reset in 10 seconds
AON_REG(AON_WDOGKEY) = AON_WDOGKEY_VALUE;
AON_REG(AON_WDOGCMP) = 11;
//wdogconfig: : wdogrsten | enablealways | reset to 0 | max scale
AON_REG(AON_WDOGKEY) = AON_WDOGKEY_VALUE;
AON_REG(AON_WDOGCFG) |= (AON_WDOGCFG_RSTEN | AON_WDOGCFG_ENALWAYS |\
AON_WDOGCFG_ZEROCMP | AON_WDOGCFG_SCALE) ;
}
void reset_demo () {
// Disable the machine & timer interrupts until setup is done.
clear_csr(mie, MIP_MEIP);
clear_csr(mie, MIP_MTIP);
//enable uart input
UART0_REG(UART_REG_RXCTRL) = UART_RXEN;
/**************************************************************************
* Set up the PLIC
*************************************************************************/
PLIC_init(&g_plic,
PLIC_CTRL_ADDR,
PLIC_NUM_INTERRUPTS,
PLIC_NUM_PRIORITIES);
for (int ii = 0; ii < PLIC_NUM_INTERRUPTS; ii ++){
g_ext_interrupt_handlers[ii] = no_interrupt_handler;
}
led_init();
print_instructions();
watchdog_init();
// Enable the Machine-External bit in MIE
set_csr(mie, MIP_MEIP);
// Enable interrupts in general.
set_csr(mstatus, MSTATUS_MIE);
}
int main(int argc, char **argv)
{
reset_demo();
//schedule a 1 second timer
mtime_wait(1*RTC_FREQ,1);
while (1){
char c;
if(((int32_t) UART0_REG(UART_REG_RXFIFO)) > 0){
//flash green led to indicate Kick
GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << GREEN_LED_OFFSET) ;
printf("Feeding Watchdog.\nHiFive1 will reset in 10 seconds.\n");
countdown = 10;
AON_REG(AON_WDOGKEY) = AON_WDOGKEY_VALUE;
AON_REG(AON_WDOGFEED) = AON_WDOGFEED_VALUE;
//busy wait a bit so the user sees the led blink
mtime_wait(5000, 0);
//turn off led
GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1 << GREEN_LED_OFFSET) ;
}
}
return 0;
}
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