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// See LICENSE for license details.
#include <stdio.h>
#include <stdlib.h>
#include "platform.h"
#include <string.h>
#include "plic_driver.h"
#include "encoding.h"
#include <unistd.h>
#include "stdatomic.h"
#define RTC_FREQUENCY 32768
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;
/*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);
}
/*Entry Point for Machine Timer Interrupt Handler*/
void handle_m_time_interrupt(){
clear_csr(mie, MIP_MTIP);
// Reset the timer for 3s in the future.
// This also clears the existing timer interrupt.
volatile uint64_t * mtime = (uint64_t*) (CLINT_BASE_ADDR + CLINT_MTIME);
volatile uint64_t * mtimecmp = (uint64_t*) (CLINT_BASE_ADDR + CLINT_MTIMECMP);
uint64_t now = *mtime;
uint64_t then = now + 1.5 * RTC_FREQUENCY;
*mtimecmp = then;
// read the current value of the LEDS and invert them.
uint32_t leds = GPIO_REG(GPIO_OUTPUT_VAL);
GPIO_REG(GPIO_OUTPUT_VAL) ^= ((0x1 << RED_LED_OFFSET) |
(0x1 << GREEN_LED_OFFSET) |
(0x1 << BLUE_LED_OFFSET));
// Re-enable the timer interrupt.
set_csr(mie, MIP_MTIP);
}
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\
SiFive E-Series Software Development Kit 'demo_gpio' program.\n\
Every 1.5 second, the Timer Interrupt will invert the LEDs.\n\
(Arty Dev Kit Only): Press Buttons 0, 1, 2 to Set the LEDs.\n\
Pin 19 (HiFive1) or A5 (Arty Dev Kit) is being bit-banged\n\
for GPIO speed demonstration.\n\
\n\
";
void print_instructions() {
write (STDOUT_FILENO, instructions_msg, strlen(instructions_msg));
}
#ifdef HAS_BOARD_BUTTONS
void button_0_handler(void) {
// Red LED on
GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1 << RED_LED_OFFSET);
// Clear the GPIO Pending interrupt by writing 1.
GPIO_REG(GPIO_RISE_IP) = (0x1 << BUTTON_0_OFFSET);
};
void button_1_handler(void) {
// Green LED On
GPIO_REG(GPIO_OUTPUT_VAL) |= (1 << GREEN_LED_OFFSET);
// Clear the GPIO Pending interrupt by writing 1.
GPIO_REG(GPIO_RISE_IP) = (0x1 << BUTTON_1_OFFSET);
};
void button_2_handler(void) {
// Blue LED On
GPIO_REG(GPIO_OUTPUT_VAL) |= (1 << BLUE_LED_OFFSET);
GPIO_REG(GPIO_RISE_IP) = (0x1 << BUTTON_2_OFFSET);
};
#endif
void reset_demo (){
// Disable the machine & timer interrupts until setup is done.
clear_csr(mie, MIP_MEIP);
clear_csr(mie, MIP_MTIP);
for (int ii = 0; ii < PLIC_NUM_INTERRUPTS; ii ++){
g_ext_interrupt_handlers[ii] = no_interrupt_handler;
}
#ifdef HAS_BOARD_BUTTONS
g_ext_interrupt_handlers[INT_DEVICE_BUTTON_0] = button_0_handler;
g_ext_interrupt_handlers[INT_DEVICE_BUTTON_1] = button_1_handler;
g_ext_interrupt_handlers[INT_DEVICE_BUTTON_2] = button_2_handler;
#endif
print_instructions();
#ifdef HAS_BOARD_BUTTONS
// Have to enable the interrupt both at the GPIO level,
// and at the PLIC level.
PLIC_enable_interrupt (&g_plic, INT_DEVICE_BUTTON_0);
PLIC_enable_interrupt (&g_plic, INT_DEVICE_BUTTON_1);
PLIC_enable_interrupt (&g_plic, INT_DEVICE_BUTTON_2);
// Priority must be set > 0 to trigger the interrupt.
PLIC_set_priority(&g_plic, INT_DEVICE_BUTTON_0, 1);
PLIC_set_priority(&g_plic, INT_DEVICE_BUTTON_1, 1);
PLIC_set_priority(&g_plic, INT_DEVICE_BUTTON_2, 1);
GPIO_REG(GPIO_RISE_IE) |= (1 << BUTTON_0_OFFSET);
GPIO_REG(GPIO_RISE_IE) |= (1 << BUTTON_1_OFFSET);
GPIO_REG(GPIO_RISE_IE) |= (1 << BUTTON_2_OFFSET);
#endif
// Set the machine timer to go off in 3 seconds.
// The
volatile uint64_t * mtime = (uint64_t*) (CLINT_BASE_ADDR + CLINT_MTIME);
volatile uint64_t * mtimecmp = (uint64_t*) (CLINT_BASE_ADDR + CLINT_MTIMECMP);
uint64_t now = *mtime;
uint64_t then = now + 1.5*RTC_FREQUENCY;
*mtimecmp = then;
// Enable the Machine-External bit in MIE
set_csr(mie, MIP_MEIP);
// Enable the Machine-Timer bit in MIE
set_csr(mie, MIP_MTIP);
// Enable interrupts in general.
set_csr(mstatus, MSTATUS_MIE);
}
int main(int argc, char **argv)
{
// Set up the GPIOs such that the LED GPIO
// can be used as both Inputs and Outputs.
#ifdef HAS_BOARD_BUTTONS
GPIO_REG(GPIO_OUTPUT_EN) &= ~((0x1 << BUTTON_0_OFFSET) | (0x1 << BUTTON_1_OFFSET) | (0x1 << BUTTON_2_OFFSET));
GPIO_REG(GPIO_PULLUP_EN) &= ~((0x1 << BUTTON_0_OFFSET) | (0x1 << BUTTON_1_OFFSET) | (0x1 << BUTTON_2_OFFSET));
GPIO_REG(GPIO_INPUT_EN) |= ((0x1 << BUTTON_0_OFFSET) | (0x1 << BUTTON_1_OFFSET) | (0x1 << BUTTON_2_OFFSET));
#endif
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 << BLUE_LED_OFFSET) ;
GPIO_REG(GPIO_OUTPUT_VAL) &= ~((0x1<< RED_LED_OFFSET) | (0x1<< GREEN_LED_OFFSET)) ;
// For Bit-banging with Atomics demo.
GPIO_REG(GPIO_OUTPUT_EN) |= (0x1 << PIN_19_OFFSET);
/**************************************************************************
* Set up the PLIC
*
*************************************************************************/
PLIC_init(&g_plic,
PLIC_BASE_ADDR,
PLIC_NUM_INTERRUPTS,
PLIC_NUM_PRIORITIES);
reset_demo();
/**************************************************************************
* Demonstrate fast GPIO bit-banging.
* One can bang it faster than this if you know
* the entire OUTPUT_VAL that you want to write, but
* Atomics give a quick way to control a single bit.
*************************************************************************/
uint32_t mask = (1 << PIN_19_OFFSET);
uint32_t other_mask = (1 << PIN_19_OFFSET);
while (1){
atomic_fetch_xor(&GPIO_REG(GPIO_OUTPUT_VAL), mask);
}
return 0;
}
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