altos: Add power management APIs

This provides sequenced suspend/resume functionality, allowing modules
to register for power management at configuration time.

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

3 files changed, 143 insertions, 0 deletions

diff --git a/src/kernel/ao.h b/src/kernel/ao.h
index 59a469ae..a794ba71 100644
--- a/src/kernel/ao.h
+++ b/src/kernel/ao.h
@@ -124,6 +124,16 @@ ao_timer_init(void);
 void
 ao_clock_init(void);
 
+#if AO_POWER_MANAGEMENT
+/* Go to low power clock */
+void
+ao_clock_suspend(void);
+
+/* Restart full-speed clock */
+void
+ao_clock_resume(void);
+#endif
+
 /*
  * ao_mutex.c
  */
diff --git a/src/kernel/ao_power.c b/src/kernel/ao_power.c
new file mode 100644
index 00000000..bead5944
--- /dev/null
+++ b/src/kernel/ao_power.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright © 2016 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_power.h>
+
+static struct ao_power	*head, *tail;
+
+void
+ao_power_register(struct ao_power *power)
+{
+	if (power->registered)
+		return;
+	power->registered = TRUE;
+	if (tail) {
+		tail->next = power;
+		power->prev = tail;
+		tail = power;
+	} else {
+		head = tail = power;
+	}
+#ifdef AO_LED_POWER
+	ao_led_on(AO_LED_POWER);
+#endif
+}
+
+void
+ao_power_unregister(struct ao_power *power)
+{
+	if (!power->registered)
+		return;
+	power->registered = FALSE;
+	if (power->prev)
+		power->prev->next = power->next;
+	else
+		head = power->next;
+	if (power->next)
+		power->next->prev = power->prev;
+	else
+		tail = power->prev;
+}
+
+void
+ao_power_suspend(void)
+{
+	struct ao_power	*p;
+
+#ifdef AO_LED_POWER
+	ao_led_off(AO_LED_POWER);
+#endif
+	for (p = tail; p; p = p->prev)
+		p->suspend(p->arg);
+}
+
+void
+ao_power_resume(void)
+{
+	struct ao_power	*p;
+
+	for (p = head; p; p = p->next)
+		p->resume(p->arg);
+#ifdef AO_LED_POWER
+	ao_led_on(AO_LED_POWER);
+#endif
+}
+
diff --git a/src/kernel/ao_power.h b/src/kernel/ao_power.h
new file mode 100644
index 00000000..98a8c1c7
--- /dev/null
+++ b/src/kernel/ao_power.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright © 2016 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.
+ */
+
+#ifndef _AO_POWER_H_
+#define _AO_POWER_H_
+
+#if AO_POWER_MANAGEMENT
+
+struct ao_power {
+	struct ao_power	*prev, *next;
+
+	void (*suspend)(void *arg);
+	void (*resume)(void *arg);
+	void *arg;
+	uint8_t	registered;
+};
+
+void
+ao_power_register(struct ao_power *power);
+
+void
+ao_power_unregister(struct ao_power *power);
+
+void
+ao_power_suspend(void);
+
+void
+ao_power_resume(void);
+
+#else /* AO_POWER_MANAGEMENT */
+
+#define ao_power_register(power)
+#define ao_power_unregister(power)
+#define ao_power_suspend()
+#define ao_power_resume()
+
+#endif /* else AO_POWER_MANAGEMENT */
+
+#endif /* _AO_POWER_H_ */