From b3de052e0135c6e54c5c04becedd2a3666d42b26 Mon Sep 17 00:00:00 2001
From: George Oikonomou <g.oikonomou@bristol.ac.uk>
Date: Mon, 2 Apr 2012 17:05:08 +0100
Subject: [PATCH] Ported the stack-friendly clock ISR code over from cc243x to
 cc253x

---
 cpu/cc253x/dev/clock.c           |  9 +++++++++
 platform/cc2530dk/contiki-conf.h |  8 ++++++++
 platform/cc2530dk/contiki-main.c | 14 ++++++++++++++
 3 files changed, 31 insertions(+)

diff --git a/cpu/cc253x/dev/clock.c b/cpu/cc253x/dev/clock.c
index 937151dcf..c67b3a93b 100644
--- a/cpu/cc253x/dev/clock.c
+++ b/cpu/cc253x/dev/clock.c
@@ -47,6 +47,11 @@
 /* One clock tick is 7.8 ms */
 #define TICK_VAL (32768/128)  /* 256 */
 /*---------------------------------------------------------------------------*/
+#if CLOCK_CONF_STACK_FRIENDLY
+volatile __bit sleep_flag;
+#else
+#endif
+/*---------------------------------------------------------------------------*/
 /* Do NOT remove the absolute address and do NOT remove the initialiser here */
 __xdata __at(0x0000) static unsigned long timer_value = 0;
 
@@ -158,10 +163,14 @@ clock_isr(void) __interrupt(ST_VECTOR)
     ++seconds;
   }
   
+#if CLOCK_CONF_STACK_FRIENDLY
+  sleep_flag = 1;
+#else
   if(etimer_pending()
       && (etimer_next_expiration_time() - count - 1) > MAX_TICKS) {
     etimer_request_poll();
   }
+#endif
   
   STIF = 0; /* IRCON.STIF */
   ENERGEST_OFF(ENERGEST_TYPE_IRQ);
diff --git a/platform/cc2530dk/contiki-conf.h b/platform/cc2530dk/contiki-conf.h
index 647cb39b3..27d7317d5 100644
--- a/platform/cc2530dk/contiki-conf.h
+++ b/platform/cc2530dk/contiki-conf.h
@@ -10,6 +10,14 @@
 #include "project-conf.h"
 #endif /* PROJECT_CONF_H */
 
+/*
+ * Define this as 1 to poll the etimer process from within main instead of from
+ * the clock ISR. This reduces the ISR's stack usage and may prevent crashes.
+ */
+#ifndef CLOCK_CONF_STACK_FRIENDLY
+#define CLOCK_CONF_STACK_FRIENDLY 1
+#endif
+
 /* Energest Module */
 #ifndef ENERGEST_CONF_ON
 #define ENERGEST_CONF_ON      0
diff --git a/platform/cc2530dk/contiki-main.c b/platform/cc2530dk/contiki-main.c
index bbf469dff..63d42eaab 100644
--- a/platform/cc2530dk/contiki-main.c
+++ b/platform/cc2530dk/contiki-main.c
@@ -45,6 +45,10 @@ PROCESS_NAME(viztool_process);
 #define PUTCHAR(...) do {} while(0)
 #endif
 /*---------------------------------------------------------------------------*/
+#if CLOCK_CONF_STACK_FRIENDLY
+extern volatile __bit sleep_flag;
+#endif
+/*---------------------------------------------------------------------------*/
 extern rimeaddr_t rimeaddr_node_addr;
 static __data int r;
 static __data int len;
@@ -252,6 +256,16 @@ main(void)
     do {
       /* Reset watchdog and handle polls and events */
       watchdog_periodic();
+
+#if CLOCK_CONF_STACK_FRIENDLY
+      if(sleep_flag) {
+        if(etimer_pending() &&
+            (etimer_next_expiration_time() - clock_time() - 1) > MAX_TICKS) {
+          etimer_request_poll();
+        }
+        sleep_flag = 0;
+      }
+#endif
       r = process_run();
     } while(r > 0);
     len = NETSTACK_RADIO.pending_packet();