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-rw-r--r--src/kernel/ao_task.c548
1 files changed, 548 insertions, 0 deletions
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();
+}
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