diff options
Diffstat (limited to 'src/drivers/ao_event.c')
| -rw-r--r-- | src/drivers/ao_event.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/src/drivers/ao_event.c b/src/drivers/ao_event.c new file mode 100644 index 00000000..440ef2de --- /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);); +} |