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authorJakob Odersky <jodersky@gmail.com>2014-03-17 16:50:15 +0100
committerJakob Odersky <jodersky@gmail.com>2014-03-17 16:53:46 +0100
commit2500120f64db83fc682f38a83f7f9e03ed8a5123 (patch)
tree4b9c2086c9d5dde0a89b4968db05e3b52aaa1e65
parent01c10b2eadbcd09b6ac34ab80cac1b65c302152e (diff)
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add spin-locks
-rw-r--r--kernel/task/include/task/lock.h11
-rw-r--r--kernel/task/sched.c10
-rw-r--r--kernel/time/mcu/atmega2560/clock.c2
-rw-r--r--main.c38
4 files changed, 34 insertions, 27 deletions
diff --git a/kernel/task/include/task/lock.h b/kernel/task/include/task/lock.h
index eaa661c..47246b2 100644
--- a/kernel/task/include/task/lock.h
+++ b/kernel/task/include/task/lock.h
@@ -1,20 +1,21 @@
#ifndef LOCK_H
#define LOCK_H
-#include "task/shed.h"
+#include "task/sched.h"
-typedef char spin_lock_t;
+typedef volatile char spin_lock_t;
#define SPIN_LOCK_UNLOCKED 0
+#define SPIN_LOCK_LOCKED 0
-static inline void spin_lock(struct spin_lock_t* lock) {
+static inline void spin_lock(spin_lock_t* lock) {
while(*lock != SPIN_LOCK_UNLOCKED) {yield();};
cli();
- *lock = 1;
+ *lock = SPIN_LOCK_LOCKED;
sei();
}
-static inline void spin_unlock(struct spin_lock_t* lock) {
+static inline void spin_unlock(spin_lock_t* lock) {
cli();
*lock = SPIN_LOCK_UNLOCKED;
sei();
diff --git a/kernel/task/sched.c b/kernel/task/sched.c
index 652d562..ceaf9bb 100644
--- a/kernel/task/sched.c
+++ b/kernel/task/sched.c
@@ -35,7 +35,17 @@ void sched_init() {
ret();
}
+
+#include <avr/io.h>
+void toggle_led() {
+ DDRB |= (1 << 7);
+ PORTB ^= (1 << 7);
+}
+
+
+
void schedule() {
+ toggle_led();
if(!list_empty(&ready)) {
current = list_entry(ready.next, struct tcb_t, queue);
list_move_tail(ready.next, &ready);
diff --git a/kernel/time/mcu/atmega2560/clock.c b/kernel/time/mcu/atmega2560/clock.c
index 6821456..95622dc 100644
--- a/kernel/time/mcu/atmega2560/clock.c
+++ b/kernel/time/mcu/atmega2560/clock.c
@@ -16,7 +16,7 @@ void clock_init(int ms, void (*tick)()) {
unsigned long int fcpu = (unsigned long int) F_CPU;
unsigned long int hz = 1000l / ((unsigned long int) ms);
- unsigned long int hz_counter = fcpu / (1024 * (hz)) - 1;
+ unsigned long int hz_counter = fcpu / (1024l * (hz)) - 1;
OCR3A = hz_counter;
on_tick = tick;
}
diff --git a/main.c b/main.c
index 79ca41b..526d75f 100644
--- a/main.c
+++ b/main.c
@@ -6,54 +6,50 @@
#include "task/sched.h"
#include "bug/panic.h"
#include "bug/debug.h"
+#include "task/lock.h"
+#include "time/clock.h"
#include "mcu/task/context.h"
#include "tshield/tshield.h"
#define WAIT_CYCLES(cycles) for (volatile unsigned long i = 0; i < cycles; ++i) {}
-struct list_head frozen = LIST_HEAD_INIT(frozen);
+spin_lock_t on_lock = SPIN_LOCK_UNLOCKED;
+volatile char on = 0;
-void freeze() __attribute__ ( ( naked ) );
-void freeze() {
- context_save();
- sleep_queue(&frozen);
- schedule();
- context_restore();
+void read(char id) {
+ while(1) {
+ spin_lock(&on_lock);
+ debug_led(0,on);
+ spin_unlock(&on_lock);
+ }
}
-void blink( char id) {
+void write( char id) {
while(1) {
- debug_led(id - 1,1);
- WAIT_CYCLES((long) 30000);
- debug_led(id - 1,0);
- WAIT_CYCLES((long) 30000);
+ spin_lock(&on_lock);
+ on = !on;
+ WAIT_CYCLES(30000);
+ spin_unlock(&on_lock);
}
}
-DECLARE_TASK(task1, DEFAULT_STACK_SIZE, blink, 1);
-DECLARE_TASK(task2, DEFAULT_STACK_SIZE, blink, 2);
-DECLARE_TASK(task3, DEFAULT_STACK_SIZE, blink, 3);
-DECLARE_TASK(task4, DEFAULT_STACK_SIZE, blink, 4);
+DECLARE_TASK(task1, DEFAULT_STACK_SIZE, read, 1);
+DECLARE_TASK(task2, DEFAULT_STACK_SIZE, write, 2);
int main(int argc, char *argv[]) {
cli();
tshield_init();
-
spawn(&task1);
spawn(&task2);
- spawn(&task3);
- spawn(&task4);
sei();
clock_init(10, schedule);
clock_start();
sched_init();
-
-
panic(); //should never reach here
while(1){}
}