From 292cb8380b478542555b5f370e8252eafa2f74ac Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Sat, 5 Jul 2014 00:04:06 -0700
Subject: altos: Rework packet receive for cc1120

Instead of blocking on PQT, just set up the receiver to start going
and when the first bit interrupt comes in, grab the SPI bus if
possible and configure it for reception. This improves sensitivity in
the radio by a significant amount while making the code conceptually a
bit nicer.

Signed-off-by: Keith Packard <keithp@keithp.com>
---
 src/kernel/ao.h       |  3 +++
 src/kernel/ao_mutex.c | 23 +++++++++++++++++++++++
 2 files changed, 26 insertions(+)

(limited to 'src/kernel')

diff --git a/src/kernel/ao.h b/src/kernel/ao.h
index c11aa028..a225bc4a 100644
--- a/src/kernel/ao.h
+++ b/src/kernel/ao.h
@@ -132,6 +132,9 @@ ao_clock_init(void);
  */
 
 #ifndef ao_mutex_get
+uint8_t
+ao_mutex_try(__xdata uint8_t *ao_mutex, uint8_t task_id) __reentrant;
+
 void
 ao_mutex_get(__xdata uint8_t *ao_mutex) __reentrant;
 
diff --git a/src/kernel/ao_mutex.c b/src/kernel/ao_mutex.c
index 952ff462..a36fe939 100644
--- a/src/kernel/ao_mutex.c
+++ b/src/kernel/ao_mutex.c
@@ -17,6 +17,29 @@
 
 #include "ao.h"
 
+#ifndef HAS_MUTEX_TRY
+#define HAS_MUTEX_TRY 1
+#endif
+
+#if HAS_MUTEX_TRY
+
+uint8_t
+ao_mutex_try(__xdata uint8_t *mutex, uint8_t task_id) __reentrant
+{
+	uint8_t	ret;
+	if (*mutex == task_id)
+		ao_panic(AO_PANIC_MUTEX);
+	ao_arch_critical(
+		if (*mutex)
+			ret = 0;
+		else {
+			*mutex = task_id;
+			ret = 1;
+		});
+	return ret;
+}
+#endif
+
 void
 ao_mutex_get(__xdata uint8_t *mutex) __reentrant
 {
-- 
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