Here's the button driver and event queue logic

[fw/altos] / src / drivers / ao_event.c

diff --git a/src/drivers/ao_event.c b/src/drivers/ao_event.c
new file mode 100644 (file)
index 0000000..440ef2d
--- /dev/null
+++ b/src/drivers/ao_event.c
@@ -0,0 +1,77 @@
+/*
+ * Copyright © 2012 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_event.h>
+
+#define AO_EVENT_QUEUE 64
+
+#define ao_event_queue_next(n) (((n) + 1) & (AO_EVENT_QUEUE - 1))
+#define ao_event_queue_prev(n) (((n) - 1) & (AO_EVENT_QUEUE - 1))
+#define ao_event_queue_empty() (ao_event_queue_insert == ao_event_queue_remove)
+#define ao_event_queue_full()  (ao_event_queue_next(ao_event_queue_insert) == ao_event_queue_remove)
+
+/*
+ * Whether a sequence of events from the same device should be collapsed
+ */
+#define ao_event_can_collapse(type)    ((type) == AO_EVENT_QUADRATURE)
+
+struct ao_event ao_event_queue[AO_EVENT_QUEUE];
+uint8_t                ao_event_queue_insert;
+uint8_t                ao_event_queue_remove;
+
+
+uint8_t
+ao_event_get(struct ao_event *ev)
+{
+       ao_arch_critical(
+               while (ao_event_queue_empty())
+                       ao_sleep(&ao_event_queue);
+               *ev = ao_event_queue[ao_event_queue_remove];
+               ao_event_queue_remove = ao_event_queue_next(ao_event_queue_remove);
+               );
+}
+
+/* called with interrupts disabled */
+void
+ao_event_put_isr(uint8_t type, uint8_t unit, uint32_t value)
+{
+       if (!ao_event_queue_full()) {
+
+               if (ao_event_can_collapse(type) && !ao_event_queue_empty()) {
+                       uint8_t prev = ao_event_queue_prev(ao_event_queue_insert);
+
+                       if (ao_event_queue[prev].type == type &&
+                           ao_event_queue[prev].unit == unit)
+                               ao_event_queue_insert = prev;
+               }
+               ao_event_queue[ao_event_queue_insert] = (struct ao_event) {
+                       .type = type,
+                       .unit = unit,
+                       .tick = ao_tick_count,
+                       .value = value
+               };
+               ao_event_queue_insert = ao_event_queue_next(ao_event_queue_insert);
+               ao_wakeup(&ao_event_queue);
+       }
+}
+
+void
+ao_event_put(uint8_t type, uint8_t unit, uint32_t value)
+{
+       ao_arch_critical(ao_event_put_isr(type, unit, value););
+}