altos: Add watchdog timer task

This new task frobs a pin periodically to inform the hardware that the
operating system is running.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/src/drivers/ao_watchdog.c b/src/drivers/ao_watchdog.c
new file mode 100644
index 00000000..096a5564
--- /dev/null
+++ b/src/drivers/ao_watchdog.c
@@ -0,0 +1,62 @@
+/*
+ * Copyright © 2013 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>
+
+static int	ao_watchdog_enabled = TRUE;
+
+static void
+ao_watchdog(void)
+{
+	for (;;) {
+		while (!ao_watchdog_enabled)
+			ao_sleep(&ao_watchdog_enabled);
+		while (ao_watchdog_enabled) {
+			ao_delay(AO_WATCHDOG_INTERVAL);
+			ao_gpio_set(AO_WATCHDOG_PORT, AO_WATCHDOG_BIT, AO_WATCHDOG_PIN, 1);
+			ao_delay(1);
+			ao_gpio_set(AO_WATCHDOG_PORT, AO_WATCHDOG_BIT, AO_WATCHDOG_PIN, 0);
+		}
+	}
+}
+
+static void
+ao_watchdog_set(void)
+{
+	ao_cmd_hex();
+	if (ao_cmd_status == ao_cmd_success) {
+		ao_watchdog_enabled = ao_cmd_lex_i != 0;
+		ao_wakeup(&ao_watchdog_enabled);
+	}
+}
+	
+
+static __code struct ao_cmds ao_watchdog_cmds[] = {
+	{ ao_watchdog_set,	"Q <0 off, 1 on>\0Enable or disable watchdog timer" },
+	{ 0,			NULL },
+};
+
+static struct ao_task watchdog_task;
+
+void
+ao_watchdog_init(void)
+{
+	ao_enable_output(AO_WATCHDOG_PORT, AO_WATCHDOG_BIT, AO_WATCHDOG, 0);
+	ao_cmd_register(&ao_watchdog_cmds[0]);
+	ao_add_task(&watchdog_task, ao_watchdog, "watchdog");
+}
+