altos: Add bit-bang i2c driver
[fw/altos] / src / kernel / ao_task.c
index 1ecdd7dd1261246dc18eeb1483262274c2a76cb9..dd278bde064740f3ed0ac1a6ef11d90ccb85ab7c 100644 (file)
@@ -3,7 +3,8 @@
  *
  * 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.
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
 #if HAS_STACK_GUARD
 #include <ao_mpu.h>
 #endif
+#include <picotls.h>
 
 #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
+struct ao_task * ao_tasks[AO_NUM_TASKS];
+uint8_t ao_num_tasks;
+struct ao_task *ao_cur_task;
 
 #ifdef ao_arch_task_globals
 ao_arch_task_globals
@@ -54,17 +50,24 @@ static inline void ao_check_stack(void) {
 #define ao_check_stack()
 #endif
 
-#if HAS_TASK_QUEUE
+#if DEBUG
+#define ao_task_irq_check()    ao_arch_irq_check()
+#else
+#define ao_task_irq_check()
+#endif
 
+#ifndef SLEEP_HASH_SIZE
 #define SLEEP_HASH_SIZE        17
+#endif
 
 static struct ao_list  run_queue;
 static struct ao_list  alarm_queue;
-static struct ao_list  sleep_queue[SLEEP_HASH_SIZE];
+static struct ao_list  ao_sleep_queue[SLEEP_HASH_SIZE];
 
 static void
-ao_task_to_run_queue(struct ao_task *task)
+_ao_task_to_run_queue(struct ao_task *task)
 {
+       ao_task_irq_check();
        ao_list_del(&task->queue);
        ao_list_append(&task->queue, &run_queue);
 }
@@ -72,12 +75,13 @@ ao_task_to_run_queue(struct ao_task *task)
 static struct ao_list *
 ao_task_sleep_queue(void *wchan)
 {
-       return &sleep_queue[(uintptr_t) wchan % SLEEP_HASH_SIZE];
+       return &ao_sleep_queue[(uintptr_t) wchan % SLEEP_HASH_SIZE];
 }
 
 static void
-ao_task_to_sleep_queue(struct ao_task *task, void *wchan)
+_ao_task_to_sleep_queue(struct ao_task *task, void *wchan)
 {
+       ao_task_irq_check();
        ao_list_del(&task->queue);
        ao_list_append(&task->queue, ao_task_sleep_queue(wchan));
 }
@@ -116,12 +120,13 @@ ao_task_validate_alarm_queue(void)
 #define ao_task_validate_alarm_queue()
 #endif
 
-uint16_t       ao_task_alarm_tick;
+AO_TICK_TYPE   ao_task_alarm_tick;
 
 static void
-ao_task_to_alarm_queue(struct ao_task *task)
+_ao_task_to_alarm_queue(struct ao_task *task)
 {
        struct ao_task  *alarm;
+       ao_task_irq_check();
        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);
@@ -136,8 +141,9 @@ ao_task_to_alarm_queue(struct ao_task *task)
 }
 
 static void
-ao_task_from_alarm_queue(struct ao_task *task)
+_ao_task_from_alarm_queue(struct ao_task *task)
 {
+       ao_task_irq_check();
        ao_list_del(&task->alarm_queue);
        if (ao_list_is_empty(&alarm_queue))
                ao_task_alarm_tick = 0;
@@ -156,22 +162,24 @@ ao_task_init_queue(struct ao_task *task)
 static void
 ao_task_exit_queue(struct ao_task *task)
 {
+       ao_task_irq_check();
        ao_list_del(&task->queue);
        ao_list_del(&task->alarm_queue);
 }
 
 void
-ao_task_check_alarm(uint16_t tick)
+ao_task_alarm(AO_TICK_TYPE 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);
-       }
+       ao_arch_critical(
+               ao_list_for_each_entry_safe(alarm, next, &alarm_queue, struct ao_task, alarm_queue) {
+                       if ((AO_TICK_SIGNED) (tick - alarm->alarm) < 0)
+                               break;
+                       alarm->alarm = 0;
+                       _ao_task_from_alarm_queue(alarm);
+                       _ao_task_to_run_queue(alarm);
+               });
 }
 
 void
@@ -182,7 +190,7 @@ ao_task_init(void)
        ao_list_init(&alarm_queue);
        ao_task_alarm_tick = 0;
        for (i = 0; i < SLEEP_HASH_SIZE; i++)
-               ao_list_init(&sleep_queue[i]);
+               ao_list_init(&ao_sleep_queue[i]);
 }
 
 #if DEBUG
@@ -274,10 +282,23 @@ ao_task_validate(void)
 }
 #endif /* DEBUG */
 
-#endif /* HAS_TASK_QUEUE */
+static inline void *
+ao_stack_top(struct ao_task *task)
+{
+       uint8_t *top = &task->stack8[AO_STACK_SIZE];
+
+       /* Subtract off the TLS space, but keep the resulting
+        * stack 8-byte aligned
+        */
+#if USE_TLS
+       return top - ((_tls_size() + 7) & ~3);
+#else
+       return top;
+#endif
+}
 
 void
-ao_add_task(__xdata struct ao_task * task, void (*start)(void), __code char *name) __reentrant
+ao_add_task(struct ao_task * task, void (*task_func)(void), const char *name) 
 {
        uint8_t task_id;
        uint8_t t;
@@ -297,51 +318,40 @@ ao_add_task(__xdata struct ao_task * task, void (*start)(void), __code char *nam
         * 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);
+       uint32_t *sp = ao_stack_top(task);
+#if USE_TLS
+       _init_tls(sp);
 #endif
+       ao_arch_init_stack(task, sp, task_func);
+       ao_task_init_queue(task);
+       ao_arch_critical(
+               _ao_task_to_run_queue(task);
                ao_tasks[ao_num_tasks] = task;
                ao_num_tasks++;
                );
 }
 
-__data uint8_t ao_task_minimize_latency;
+uint8_t        ao_task_minimize_latency;
 
-/* Task switching function. This must not use any stack variables */
+/* Task switching function. */
 void
-ao_yield(void) ao_arch_naked_define
+ao_yield(void)
 {
-       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 (ao_cur_task)
        {
 #if HAS_SAMPLE_PROFILE
-               uint16_t        tick = ao_sample_profile_timer_value();
-               uint16_t        run = tick - ao_cur_task->start;
+               AO_TICK_TYPE    tick = ao_sample_profile_timer_value();
+               AO_TICK_TYPE    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_regs();
                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();
+       ao_arch_block_interrupts();
 
 #if AO_CHECK_STACK
        in_yield = 1;
@@ -349,46 +359,23 @@ ao_yield(void) ao_arch_naked_define
        /* 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;
+       if (ao_cur_task && ao_cur_task->wchan == NULL)
+               _ao_task_to_run_queue(ao_cur_task);
        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();
+               if (ao_task_minimize_latency) {
+                       ao_arch_release_interrupts();
+                       ao_arch_block_interrupts();
+               } else
+                       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
@@ -397,22 +384,20 @@ ao_yield(void) ao_arch_naked_define
 #endif
 #if AO_CHECK_STACK
        in_yield = 0;
+#endif
+#if USE_TLS
+       _set_tls(ao_stack_top(ao_cur_task));
 #endif
        ao_arch_restore_stack();
 }
 
 uint8_t
-ao_sleep(__xdata void *wchan)
+ao_sleep(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_arch_critical(
+               ao_cur_task->wchan = wchan;
+               _ao_task_to_sleep_queue(ao_cur_task, wchan);
+               );
        ao_yield();
        if (ao_cur_task->wchan) {
                ao_cur_task->wchan = NULL;
@@ -423,9 +408,9 @@ ao_sleep(__xdata void *wchan)
 }
 
 void
-ao_wakeup(__xdata void *wchan) __reentrant
+ao_wakeup(void *wchan) 
 {
-#if HAS_TASK_QUEUE
+       ao_validate_cur_stack();
        struct ao_task  *sleep, *next;
        struct ao_list  *sleep_queue;
        uint32_t        flags;
@@ -437,69 +422,44 @@ ao_wakeup(__xdata void *wchan) __reentrant
        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_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();
 }
 
-static 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
-}
-
-static 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
-}
-
 uint8_t
-ao_sleep_for(__xdata void *wchan, uint16_t timeout)
+ao_sleep_for(void *wchan, AO_TICK_TYPE timeout)
 {
        uint8_t ret;
-       if (timeout)
-               ao_alarm(timeout);
+       if (timeout) {
+               ao_arch_critical(
+                       /* 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
+                        */
+                       if (!(ao_cur_task->alarm = ao_time() + timeout + 1))
+                               ao_cur_task->alarm = 1;
+                       _ao_task_to_alarm_queue(ao_cur_task);
+                       );
+       }
        ret = ao_sleep(wchan);
-       if (timeout)
-               ao_clear_alarm();
+       if (timeout) {
+               ao_arch_critical(
+                       ao_cur_task->alarm = 0;
+                       _ao_task_from_alarm_queue(ao_cur_task);
+                       );
+       }
        return ret;
 }
 
-static __xdata uint8_t ao_forever;
+static uint8_t ao_forever;
 
 void
-ao_delay(uint16_t ticks)
+ao_delay(AO_TICK_TYPE ticks)
 {
+       if (!ticks)
+               ticks = 1;
        ao_sleep_for(&ao_forever, ticks);
 }
 
@@ -508,21 +468,17 @@ 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
+       /* Remove task from list */
+       ao_num_tasks--;
        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 */
+       __builtin_unreachable();
 }
 
 #if HAS_TASK_INFO
@@ -530,15 +486,18 @@ void
 ao_task_info(void)
 {
        uint8_t         i;
-       __xdata struct ao_task *task;
+       struct ao_task *task;
+       AO_TICK_TYPE    now = ao_time();
 
        for (i = 0; i < ao_num_tasks; i++) {
                task = ao_tasks[i];
-               printf("%12s: wchan %04x\n",
-                      task->name,
-                      (int) task->wchan);
+               printf("%2d: wchan %08x alarm %5d %s\n",
+                      task->task_id,
+                      (int) task->wchan,
+                      task->alarm ? (int16_t) (task->alarm - now) : 9999,
+                      task->name);
        }
-#if HAS_TASK_QUEUE && DEBUG
+#if DEBUG
        ao_task_validate();
 #endif
 }
@@ -547,12 +506,10 @@ ao_task_info(void)
 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();
+       __builtin_unreachable();
 }