X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=blobdiff_plain;f=src%2Fkernel%2Fao_task.c;fp=src%2Fkernel%2Fao_task.c;h=bafb49439d4441022be1b9159947f30a9f8d7bff;hp=0000000000000000000000000000000000000000;hb=24167015705ae831692b95735968b04a876f935e;hpb=bb9fdef607728cc326a82aa632e59724f272e53b

diff --git a/src/kernel/ao_task.c b/src/kernel/ao_task.c
new file mode 100644
index 00000000..bafb4943
--- /dev/null
+++ b/src/kernel/ao_task.c
@@ -0,0 +1,548 @@
+/*
+ * Copyright © 2009 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include <ao.h>
+#include <ao_task.h>
+#if HAS_SAMPLE_PROFILE
+#include <ao_sample_profile.h>
+#endif
+#if HAS_STACK_GUARD
+#include <ao_mpu.h>
+#endif
+
+#define DEBUG	0
+
+#define AO_NO_TASK_INDEX	0xff
+
+__xdata struct ao_task * __xdata ao_tasks[AO_NUM_TASKS];
+__data uint8_t ao_num_tasks;
+__xdata struct ao_task *__data ao_cur_task;
+
+#if !HAS_TASK_QUEUE
+static __data uint8_t ao_cur_task_index;
+#endif
+
+#ifdef ao_arch_task_globals
+ao_arch_task_globals
+#endif
+
+#define AO_CHECK_STACK	0
+
+#if AO_CHECK_STACK
+static uint8_t	in_yield;
+
+static inline void ao_check_stack(void) {
+	uint8_t	q;
+	if (!in_yield && ao_cur_task && &q < &ao_cur_task->stack[0])
+		ao_panic(AO_PANIC_STACK);
+}
+#else
+#define ao_check_stack()
+#endif
+
+#if HAS_TASK_QUEUE
+
+#define SLEEP_HASH_SIZE	17
+
+static struct ao_list	run_queue;
+static struct ao_list	alarm_queue;
+static struct ao_list	sleep_queue[SLEEP_HASH_SIZE];
+
+static void
+ao_task_to_run_queue(struct ao_task *task)
+{
+	ao_list_del(&task->queue);
+	ao_list_append(&task->queue, &run_queue);
+}
+
+static struct ao_list *
+ao_task_sleep_queue(void *wchan)
+{
+	return &sleep_queue[(uintptr_t) wchan % SLEEP_HASH_SIZE];
+}
+
+static void
+ao_task_to_sleep_queue(struct ao_task *task, void *wchan)
+{
+	ao_list_del(&task->queue);
+	ao_list_append(&task->queue, ao_task_sleep_queue(wchan));
+}
+
+#if DEBUG
+static void
+ao_task_validate_alarm_queue(void)
+{
+	struct ao_task	*alarm, *prev = NULL;
+	int		i;
+
+	if (ao_list_is_empty(&alarm_queue))
+		return;
+	ao_list_for_each_entry(alarm, &alarm_queue, struct ao_task, alarm_queue) {
+		if (prev) {
+			if ((int16_t) (alarm->alarm - prev->alarm) < 0) {
+				ao_panic(1);
+			}
+		}
+		prev = alarm;
+	}
+	for (i = 0; i < ao_num_tasks; i++) {
+		alarm = ao_tasks[i];
+		if (alarm->alarm) {
+			if (ao_list_is_empty(&alarm->alarm_queue))
+				ao_panic(2);
+		} else {
+			if (!ao_list_is_empty(&alarm->alarm_queue))
+				ao_panic(3);
+		}
+	}
+	if (ao_task_alarm_tick != ao_list_first_entry(&alarm_queue, struct ao_task, alarm_queue)->alarm)
+		ao_panic(4);
+}
+#else
+#define ao_task_validate_alarm_queue()
+#endif
+
+uint16_t	ao_task_alarm_tick;
+
+static void
+ao_task_to_alarm_queue(struct ao_task *task)
+{
+	struct ao_task	*alarm;
+	ao_list_for_each_entry(alarm, &alarm_queue, struct ao_task, alarm_queue) {
+		if ((int16_t) (alarm->alarm - task->alarm) >= 0) {
+			ao_list_insert(&task->alarm_queue, alarm->alarm_queue.prev);
+			ao_task_alarm_tick = ao_list_first_entry(&alarm_queue, struct ao_task, alarm_queue)->alarm;
+			ao_task_validate_alarm_queue();
+			return;
+		}
+	}
+	ao_list_append(&task->alarm_queue, &alarm_queue);
+	ao_task_alarm_tick = ao_list_first_entry(&alarm_queue, struct ao_task, alarm_queue)->alarm;
+	ao_task_validate_alarm_queue();
+}
+
+static void
+ao_task_from_alarm_queue(struct ao_task *task)
+{
+	ao_list_del(&task->alarm_queue);
+	if (ao_list_is_empty(&alarm_queue))
+		ao_task_alarm_tick = 0;
+	else
+		ao_task_alarm_tick = ao_list_first_entry(&alarm_queue, struct ao_task, alarm_queue)->alarm;
+	ao_task_validate_alarm_queue();
+}
+
+static void
+ao_task_init_queue(struct ao_task *task)
+{
+	ao_list_init(&task->queue);
+	ao_list_init(&task->alarm_queue);
+}
+
+static void
+ao_task_exit_queue(struct ao_task *task)
+{
+	ao_list_del(&task->queue);
+	ao_list_del(&task->alarm_queue);
+}
+
+void
+ao_task_check_alarm(uint16_t tick)
+{
+	struct ao_task	*alarm, *next;
+
+	ao_list_for_each_entry_safe(alarm, next, &alarm_queue, struct ao_task, alarm_queue) {
+		if ((int16_t) (tick - alarm->alarm) < 0)
+			break;
+		alarm->alarm = 0;
+		ao_task_from_alarm_queue(alarm);
+		ao_task_to_run_queue(alarm);
+	}
+}
+
+void
+ao_task_init(void)
+{
+	uint8_t	i;
+	ao_list_init(&run_queue);
+	ao_list_init(&alarm_queue);
+	ao_task_alarm_tick = 0;
+	for (i = 0; i < SLEEP_HASH_SIZE; i++)
+		ao_list_init(&sleep_queue[i]);
+}
+
+#if DEBUG
+static uint8_t
+ao_task_validate_queue(struct ao_task *task)
+{
+	uint32_t flags;
+	struct ao_task *m;
+	uint8_t ret = 0;
+	struct ao_list *queue;
+
+	flags = ao_arch_irqsave();
+	if (task->wchan) {
+		queue = ao_task_sleep_queue(task->wchan);
+		ret |= 2;
+	} else {
+		queue = &run_queue;
+		ret |= 4;
+	}
+	ao_list_for_each_entry(m, queue, struct ao_task, queue) {
+		if (m == task) {
+			ret |= 1;
+			break;
+		}
+	}
+	ao_arch_irqrestore(flags);
+	return ret;
+}
+
+static uint8_t
+ao_task_validate_alarm(struct ao_task *task)
+{
+	uint32_t	flags;
+	struct ao_task	*m;
+	uint8_t		ret = 0;
+
+	flags = ao_arch_irqsave();
+	if (task->alarm == 0)
+		return 0xff;
+	ao_list_for_each_entry(m, &alarm_queue, struct ao_task, alarm_queue) {
+		if (m == task)
+			ret |= 1;
+		else {
+			if (!(ret&1)) {
+				if ((int16_t) (m->alarm - task->alarm) > 0)
+					ret |= 2;
+			} else {
+				if ((int16_t) (task->alarm - m->alarm) > 0)
+					ret |= 4;
+			}
+		}
+	}
+	ao_arch_irqrestore(flags);
+	return ret;
+}
+
+
+static void
+ao_task_validate(void)
+{
+	uint8_t		i;
+	struct ao_task	*task;
+	uint8_t		ret;
+
+	for (i = 0; i < ao_num_tasks; i++) {
+		task = ao_tasks[i];
+		ret = ao_task_validate_queue(task);
+		if (!(ret & 1)) {
+			if (ret & 2)
+				printf ("sleeping task not on sleep queue %s %08x\n",
+					task->name, task->wchan);
+			else
+				printf ("running task not on run queue %s\n",
+					task->name);
+		}
+		ret = ao_task_validate_alarm(task);
+		if (ret != 0xff) {
+			if (!(ret & 1))
+				printf ("alarm task not on alarm queue %s %d\n",
+					task->name, task->alarm);
+			if (ret & 2)
+				printf ("alarm queue has sooner entries after %s %d\n",
+					task->name, task->alarm);
+			if (ret & 4)
+				printf ("alarm queue has later entries before %s %d\n",
+					task->name, task->alarm);
+		}
+	}
+}
+#endif /* DEBUG */
+
+#endif /* HAS_TASK_QUEUE */
+
+void
+ao_add_task(__xdata struct ao_task * task, void (*start)(void), __code char *name) __reentrant
+{
+	uint8_t task_id;
+	uint8_t t;
+	if (ao_num_tasks == AO_NUM_TASKS)
+		ao_panic(AO_PANIC_NO_TASK);
+	for (task_id = 1; task_id != 0; task_id++) {
+		for (t = 0; t < ao_num_tasks; t++)
+			if (ao_tasks[t]->task_id == task_id)
+				break;
+		if (t == ao_num_tasks)
+			break;
+	}
+	task->task_id = task_id;
+	task->name = name;
+	task->wchan = NULL;
+	/*
+	 * Construct a stack frame so that it will 'return'
+	 * to the start of the task
+	 */
+	ao_arch_init_stack(task, start);
+	ao_arch_critical(
+#if HAS_TASK_QUEUE
+		ao_task_init_queue(task);
+		ao_task_to_run_queue(task);
+#endif
+		ao_tasks[ao_num_tasks] = task;
+		ao_num_tasks++;
+		);
+}
+
+__data uint8_t	ao_task_minimize_latency;
+
+/* Task switching function. This must not use any stack variables */
+void
+ao_yield(void) ao_arch_naked_define
+{
+	ao_arch_save_regs();
+
+#if HAS_TASK_QUEUE
+	if (ao_cur_task == NULL)
+		ao_cur_task = ao_tasks[ao_num_tasks-1];
+#else
+	if (ao_cur_task_index == AO_NO_TASK_INDEX)
+		ao_cur_task_index = ao_num_tasks-1;
+#endif
+	else
+	{
+#if HAS_SAMPLE_PROFILE
+		uint16_t	tick = ao_sample_profile_timer_value();
+		uint16_t	run = tick - ao_cur_task->start;
+		if (run > ao_cur_task->max_run)
+			ao_cur_task->max_run = run;
+		++ao_cur_task->yields;
+#endif
+		ao_arch_save_stack();
+	}
+
+	ao_arch_isr_stack();
+#if !HAS_TASK_QUEUE
+	if (ao_task_minimize_latency)
+		ao_arch_release_interrupts();
+	else
+#endif
+		ao_arch_block_interrupts();
+
+#if AO_CHECK_STACK
+	in_yield = 1;
+#endif
+	/* Find a task to run. If there isn't any runnable task,
+	 * this loop will run forever, which is just fine
+	 */
+#if HAS_TASK_QUEUE
+	/* If the current task is running, move it to the
+	 * end of the queue to allow other tasks a chance
+	 */
+	if (ao_cur_task->wchan == NULL)
+		ao_task_to_run_queue(ao_cur_task);
+	ao_cur_task = NULL;
+	for (;;) {
+		ao_arch_memory_barrier();
+		if (!ao_list_is_empty(&run_queue))
+			break;
+		/* Wait for interrupts when there's nothing ready */
+		ao_arch_wait_interrupt();
+	}
+	ao_cur_task = ao_list_first_entry(&run_queue, struct ao_task, queue);
+#else
+	{
+		__pdata uint8_t	ao_last_task_index = ao_cur_task_index;
+		for (;;) {
+			++ao_cur_task_index;
+			if (ao_cur_task_index == ao_num_tasks)
+				ao_cur_task_index = 0;
+
+			ao_cur_task = ao_tasks[ao_cur_task_index];
+
+			/* Check for ready task */
+			if (ao_cur_task->wchan == NULL)
+				break;
+
+			/* Check if the alarm is set for a time which has passed */
+			if (ao_cur_task->alarm &&
+			    (int16_t) (ao_time() - ao_cur_task->alarm) >= 0)
+				break;
+
+			/* Wait for interrupts when there's nothing ready */
+			if (ao_cur_task_index == ao_last_task_index && !ao_task_minimize_latency)
+				ao_arch_wait_interrupt();
+		}
+	}
+#endif
+#if HAS_SAMPLE_PROFILE
+	ao_cur_task->start = ao_sample_profile_timer_value();
+#endif
+#if HAS_STACK_GUARD
+	ao_mpu_stack_guard(ao_cur_task->stack);
+#endif
+#if AO_CHECK_STACK
+	in_yield = 0;
+#endif
+	ao_arch_restore_stack();
+}
+
+uint8_t
+ao_sleep(__xdata void *wchan)
+{
+#if HAS_TASK_QUEUE
+	uint32_t flags;
+	flags = ao_arch_irqsave();
+#endif
+	ao_cur_task->wchan = wchan;
+#if HAS_TASK_QUEUE
+	ao_task_to_sleep_queue(ao_cur_task, wchan);
+	ao_arch_irqrestore(flags);
+#endif
+	ao_yield();
+	if (ao_cur_task->wchan) {
+		ao_cur_task->wchan = NULL;
+		ao_cur_task->alarm = 0;
+		return 1;
+	}
+	return 0;
+}
+
+void
+ao_wakeup(__xdata void *wchan) __reentrant
+{
+#if HAS_TASK_QUEUE
+	struct ao_task	*sleep, *next;
+	struct ao_list	*sleep_queue;
+	uint32_t	flags;
+
+	if (ao_num_tasks == 0)
+		return;
+	sleep_queue = ao_task_sleep_queue(wchan);
+	flags = ao_arch_irqsave();
+	ao_list_for_each_entry_safe(sleep, next, sleep_queue, struct ao_task, queue) {
+		if (sleep->wchan == wchan) {
+			sleep->wchan = NULL;
+			ao_task_to_run_queue(sleep);
+		}
+	}
+	ao_arch_irqrestore(flags);
+#else
+	uint8_t	i;
+	for (i = 0; i < ao_num_tasks; i++)
+		if (ao_tasks[i]->wchan == wchan)
+			ao_tasks[i]->wchan = NULL;
+#endif
+	ao_check_stack();
+}
+
+void
+ao_alarm(uint16_t delay)
+{
+#if HAS_TASK_QUEUE
+	uint32_t flags;
+	/* Make sure we sleep *at least* delay ticks, which means adding
+	 * one to account for the fact that we may be close to the next tick
+	 */
+	flags = ao_arch_irqsave();
+#endif
+	if (!(ao_cur_task->alarm = ao_time() + delay + 1))
+		ao_cur_task->alarm = 1;
+#if HAS_TASK_QUEUE
+	ao_task_to_alarm_queue(ao_cur_task);
+	ao_arch_irqrestore(flags);
+#endif
+}
+
+void
+ao_clear_alarm(void)
+{
+#if HAS_TASK_QUEUE
+	uint32_t flags;
+
+	flags = ao_arch_irqsave();
+#endif
+	ao_cur_task->alarm = 0;
+#if HAS_TASK_QUEUE
+	ao_task_from_alarm_queue(ao_cur_task);
+	ao_arch_irqrestore(flags);
+#endif
+}
+
+static __xdata uint8_t ao_forever;
+
+void
+ao_delay(uint16_t ticks)
+{
+	ao_alarm(ticks);
+	ao_sleep(&ao_forever);
+	ao_clear_alarm();
+}
+
+void
+ao_exit(void)
+{
+	uint8_t	i;
+	ao_arch_block_interrupts();
+	ao_num_tasks--;
+#if HAS_TASK_QUEUE
+	for (i = 0; i < ao_num_tasks; i++)
+		if (ao_tasks[i] == ao_cur_task)
+			break;
+	ao_task_exit_queue(ao_cur_task);
+#else
+	i = ao_cur_task_index;
+	ao_cur_task_index = AO_NO_TASK_INDEX;
+#endif
+	for (; i < ao_num_tasks; i++)
+		ao_tasks[i] = ao_tasks[i+1];
+	ao_cur_task = NULL;
+	ao_yield();
+	/* we'll never get back here */
+}
+
+#if HAS_TASK_INFO
+void
+ao_task_info(void)
+{
+	uint8_t		i;
+	__xdata struct ao_task *task;
+
+	for (i = 0; i < ao_num_tasks; i++) {
+		task = ao_tasks[i];
+		printf("%12s: wchan %04x\n",
+		       task->name,
+		       (int) task->wchan);
+	}
+#if HAS_TASK_QUEUE && DEBUG
+	ao_task_validate();
+#endif
+}
+#endif
+
+void
+ao_start_scheduler(void)
+{
+#if !HAS_TASK_QUEUE
+	ao_cur_task_index = AO_NO_TASK_INDEX;
+#endif
+	ao_cur_task = NULL;
+#if HAS_ARCH_START_SCHEDULER
+	ao_arch_start_scheduler();
+#endif
+	ao_yield();
+}