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authorMegan Wachs <megan@sifive.com>2017-05-04 05:50:00 -0700
committerGitHub <noreply@github.com>2017-05-04 05:49:59 -0700
commit5b2498467020616de013fd557b6a1e685544ee18 (patch)
treebb197ca9ef8f9265a79485f3a13e4e921a0ff93b /software/global_interrupts
parent3a01ac1b7c0e72c04679f0cd6552c4ff0b308863 (diff)
parent4d5cbec9118cbedf2d4ae5b54acaa22862245a4c (diff)
Merge pull request #54 from sifive/tag_v20170504
Update SDK For E31/E51 Coreplex IP Evaluation
Diffstat (limited to 'software/global_interrupts')
-rw-r--r--software/global_interrupts/Makefile9
-rw-r--r--software/global_interrupts/global_interrupts.c250
2 files changed, 259 insertions, 0 deletions
diff --git a/software/global_interrupts/Makefile b/software/global_interrupts/Makefile
new file mode 100644
index 0000000..6a09f97
--- /dev/null
+++ b/software/global_interrupts/Makefile
@@ -0,0 +1,9 @@
+TARGET = global_interrupts
+CFLAGS += -O2 -fno-builtin-printf -DUSE_LOCAL_ISR
+
+BSP_BASE = ../../bsp
+
+C_SRCS += global_interrupts.c
+C_SRCS += $(BSP_BASE)/drivers/plic/plic_driver.c
+
+include $(BSP_BASE)/env/common.mk
diff --git a/software/global_interrupts/global_interrupts.c b/software/global_interrupts/global_interrupts.c
new file mode 100644
index 0000000..4d3a554
--- /dev/null
+++ b/software/global_interrupts/global_interrupts.c
@@ -0,0 +1,250 @@
+// 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>
+
+#ifndef _SIFIVE_COREPLEXIP_ARTY_H
+#error 'global_interrupts' demo only supported for Coreplex IP Eval Kits
+#endif
+
+// Global Instance data for the PLIC
+// for use by the PLIC Driver.
+plic_instance_t g_plic;
+
+// Flag for state
+int g_switch1Wins;
+
+// Debounce counter (PWM can't go slow enough)
+int g_debounce;
+
+void debounce();
+
+// Structures for registering different interrupt handlers
+// for different parts of the application.
+typedef void (*interrupt_function_ptr_t) (void);
+
+// See bsp/env/<BOARD>/init.c for how this
+// interrupt vector is used.
+interrupt_function_ptr_t localISR[32];
+
+interrupt_function_ptr_t g_ext_interrupt_handlers[PLIC_NUM_INTERRUPTS];
+
+void set_timer() {
+
+ volatile uint64_t * mtime = (uint64_t*) (CLINT_CTRL_ADDR + CLINT_MTIME);
+ volatile uint64_t * mtimecmp = (uint64_t*) (CLINT_CTRL_ADDR + CLINT_MTIMECMP);
+ uint64_t now = *mtime;
+ uint64_t then = now + 10*RTC_FREQ;
+ *mtimecmp = then;
+
+}
+
+/*Entry Point for Machine Timer Interrupt Handler*/
+void mti_isr(){
+
+ if (g_switch1Wins) {
+ printf("#### Giving Switch 1 Priority for 10 seconds ####\n");
+ // All other things being equal, lower IDs have
+ // higher priority. We have already set
+ // Switch 1 to priority 2
+ // in the setup, so by giving these equal priority Switch 1 will win.
+ PLIC_set_priority(&g_plic, INT_EXT_DEVICE_SW_2, 2);
+ } else {
+ printf("**** Giving Switch 2 Priority for 10 seconds ****\n");
+ // By setting Switch 2 a higher integer priority, it will win over switch 1.
+ PLIC_set_priority(&g_plic, INT_EXT_DEVICE_SW_2, 3);
+ }
+ g_switch1Wins ^= 0x1;
+
+ set_timer();
+
+}
+
+/*Entry Point for PLIC Interrupt Handler*/
+void mei_isr(){
+ 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);
+}
+
+const char * instructions_msg = " \
+\n\
+ SIFIVE, INC.\n\
+E31/E51 Coreplex IP Eval Kit 'global_interrupts' demo.\n\
+\n\
+Switches 1 and 2 are enabled as External Global Interrupts \n\
+(they don't go through the PLIC). You an observe priorities.\n\
+Priorities invert every few seconds, which is driven by the \n\
+PWM0 global interrupt. \n\
+\n";
+
+void print_instructions() {
+
+ write (STDOUT_FILENO, instructions_msg, strlen(instructions_msg));
+
+}
+
+void invalid_global_isr() {
+ printf("Unexpected global interrupt!\n");
+}
+
+void invalid_local_isr() {
+ printf ("Unexpected local interrupt!\n");
+}
+
+void switch_1_handler() {
+
+ printf("Switch 1 is on! Even if Switch 2 is on, Switch 1 must have higher priority right now.\n");
+
+ // Set Green LED
+ GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1 << GREEN_LED_OFFSET) ;
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~((0x1<< RED_LED_OFFSET));
+
+ debounce();
+
+}
+
+void switch_2_handler() {
+ printf("Switch 2 is on! Even if Switch 1 is on, Switch 2 must have higher priority right now.\n");
+
+ // Set RED LED
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1 << GREEN_LED_OFFSET) ;
+ GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1<< RED_LED_OFFSET);
+
+ debounce();
+}
+
+// We use PWM 0 as a
+// timer interrupt for debouncing.
+
+void pwm_0_handler() {
+
+
+ if (g_debounce == 0) {
+ printf(" Done debouncing.\n");
+
+ //Lower the threshold s.t. the switches can hit.
+ PLIC_set_threshold(&g_plic, 1);
+
+ // Clear the PWM interrupt
+ PWM0_REG(PWM_CFG) = 0;
+
+ } else {
+ // Keep waiting
+ g_debounce --;
+ // This clears out the interrupt and re-arms the timer.
+ PWM0_REG(PWM_CFG) = ((PWM_CFG_ONESHOT) | (PWM_CFG_ZEROCMP)| 0x7 | (PWM_CFG_STICKY));
+
+ }
+
+}
+
+void debounce(int local_interrupt_num) {
+
+ printf(" Starting a debounce.\n");
+
+ g_debounce = 600;
+
+ // This clears out the interrupt and re-arms the timer.
+ PWM0_REG(PWM_CFG) = ((PWM_CFG_ONESHOT) | (PWM_CFG_ZEROCMP)| 0x7 | (PWM_CFG_STICKY));
+
+ // Set the threshold high enough that the
+ // switches won't cause the interrupt to fire,
+ // only the PWM or timer interrupts.
+ PLIC_set_threshold(&g_plic, 4);
+
+}
+
+int main(int argc, char **argv)
+{
+
+ for (int gisr = 0; gisr < PLIC_NUM_INTERRUPTS; gisr++){
+ g_ext_interrupt_handlers[PLIC_NUM_INTERRUPTS] = invalid_global_isr;
+ }
+ g_ext_interrupt_handlers[PWM0_INT_BASE + 0] = pwm_0_handler;
+ g_ext_interrupt_handlers[INT_EXT_DEVICE_SW_1] = switch_1_handler;
+ g_ext_interrupt_handlers[INT_EXT_DEVICE_SW_2] = switch_2_handler;
+
+ for (int lisr = 0; lisr < 32; lisr++){
+ localISR[lisr] = invalid_local_isr;
+ }
+
+ localISR[IRQ_M_TIMER] = mti_isr;
+ localISR[IRQ_M_EXT] = mei_isr;
+
+ print_instructions();
+
+ // Set up RGB LEDs for a visual.
+
+ GPIO_REG(GPIO_OUTPUT_EN) |= ((0x1<< RED_LED_OFFSET)| (0x1<< GREEN_LED_OFFSET));
+ GPIO_REG(GPIO_OUTPUT_VAL) |= (0x1 << GREEN_LED_OFFSET) ;
+ GPIO_REG(GPIO_OUTPUT_VAL) &= ~(0x1<< RED_LED_OFFSET);
+
+ /**************************************************************************
+ * Set up the PLIC
+ *
+ *************************************************************************/
+ PLIC_init(&g_plic,
+ PLIC_CTRL_ADDR,
+ PLIC_NUM_INTERRUPTS,
+ PLIC_NUM_PRIORITIES);
+
+ /**************************************************************************
+ * Give Switch 1 and Switch 2 Equal priority of 2.
+ *
+ *************************************************************************/
+
+ PLIC_enable_interrupt (&g_plic, PWM0_INT_BASE + 0);
+ PLIC_enable_interrupt (&g_plic, INT_EXT_DEVICE_SW_1);
+ PLIC_enable_interrupt (&g_plic, INT_EXT_DEVICE_SW_2);
+
+ // PWM always beats the switches, because we use it
+ // as a debouncer, and we lower the threshold
+ // to do so.
+
+ PWM0_REG(PWM_CFG) = 0;
+
+ // Make sure people aren't blinded by LEDs connected here.
+ PWM0_REG(PWM_CMP0) = 0xFE;
+ PWM0_REG(PWM_CMP1) = 0xFF;
+ PWM0_REG(PWM_CMP2) = 0xFF;
+ PWM0_REG(PWM_CMP3) = 0xFF;
+ PLIC_set_priority(&g_plic, PWM0_INT_BASE + 0 , 5);
+
+ // Start the switches out at the same priority. Switch1
+ // would win.
+ PLIC_set_priority(&g_plic, INT_EXT_DEVICE_SW_1, 2);
+ PLIC_set_priority(&g_plic, INT_EXT_DEVICE_SW_2, 2);
+
+ // Set up machine timer interrupt. Every few seconds it
+ // will invert the switch priorities.
+ set_timer();
+
+ // Enable timer interrupts.
+ set_csr(mie, MIP_MTIP);
+
+ // Enable Global (PLIC) interrupts.
+ set_csr(mie, MIP_MEIP);
+
+ g_switch1Wins = 1;
+
+ // Enable all interrupts
+ set_csr(mstatus, MSTATUS_MIE);
+
+ while(1){
+ asm volatile ("wfi");
+ }
+
+ return 0;
+
+}