galileo: Add support for Clock module

This patch adds support for Contiki's clock module. All functions from
core/sys/clock.h are implemented, except clock_set_seconds() and clock_
delay_usec(). The CLOCK_CONF_SECOND macro is set to 128. This value
seems to be good enough since several platforms used it. Finally, we
use the RTC driver to track the number of ticks from the system clock.

platform/galileo/Makefile.galileo

@@ -3,7 +3,7 @@ LIBGCC_PATH = /usr/lib/gcc/$(shell gcc -dumpmachine)/$(shell gcc -dumpversion)
 
 CONTIKI_TARGET_DIRS = .
 CONTIKI_TARGET_MAIN = ${addprefix $(OBJECTDIR)/,contiki-main.o}
-CONTIKI_SOURCEFILES += contiki-main.c newlib-syscalls.c loader.S
+CONTIKI_SOURCEFILES += contiki-main.c newlib-syscalls.c loader.S clock.c
 
 LINKERSCRIPT = $(CONTIKI)/platform/galileo/galileo.ld
 

platform/galileo/clock.c

@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2015, Intel Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "sys/clock.h"
+
+#include "contiki-conf.h"
+#include "drivers/rtc.h"
+
+#if CLOCK_CONF_SECOND == 2
+#define FREQ   RTC_2_HZ
+#elif CLOCK_CONF_SECOND == 4
+#define FREQ   RTC_4_HZ
+#elif CLOCK_CONF_SECOND == 8
+#define FREQ   RTC_8_HZ
+#elif CLOCK_CONF_SECOND == 16
+#define FREQ   RTC_16_HZ
+#elif CLOCK_CONF_SECOND == 32
+#define FREQ   RTC_32_HZ
+#elif CLOCK_CONF_SECOND == 64
+#define FREQ   RTC_64_HZ
+#elif CLOCK_CONF_SECOND == 128
+#define FREQ   RTC_128_HZ
+#elif CLOCK_CONF_SECOND == 256
+#define FREQ   RTC_256_HZ
+#elif CLOCK_CONF_SECOND == 512
+#define FREQ   RTC_512_HZ
+#elif CLOCK_CONF_SECOND == 1024
+#define FREQ   RTC_1024_HZ
+#elif CLOCK_CONF_SECOND == 2048
+#define FREQ   RTC_2048_HZ
+#elif CLOCK_CONF_SECOND == 4096
+#define FREQ   RTC_4096_HZ
+#elif CLOCK_CONF_SECOND == 8192
+#define FREQ   RTC_8192_HZ
+#else
+#define FREQ   -1
+#error "RTC is being used thus CLOCK_CONF_SECOND has to be a value defined by rtc_frequency_t."
+#endif
+
+static volatile clock_time_t tick_count = 0;
+
+static void
+update_ticks(void)
+{
+  tick_count++;
+}
+/*---------------------------------------------------------------------------*/
+void
+clock_init(void)
+{
+  rtc_init(FREQ, update_ticks);
+}
+/*---------------------------------------------------------------------------*/
+clock_time_t
+clock_time(void)
+{
+  return tick_count;
+}
+/*---------------------------------------------------------------------------*/
+unsigned long
+clock_seconds(void)
+{
+  return tick_count / CLOCK_CONF_SECOND;
+}
+/*---------------------------------------------------------------------------*/
+void
+clock_wait(clock_time_t t)
+{
+  clock_time_t initial = tick_count;
+
+  while(tick_count < t + initial);
+}
+/*---------------------------------------------------------------------------*/
+void
+clock_set_seconds(unsigned long sec)
+{
+  /* Stubbed function */
+}
+/*---------------------------------------------------------------------------*/
+void
+clock_delay_usec(uint16_t t)
+{
+  /* Stubbed function */
+}

platform/galileo/contiki-conf.h

@@ -33,13 +33,15 @@
 
 #include <inttypes.h>
 
+#define CLOCK_CONF_SECOND 128
+typedef unsigned long clock_time_t;
+
 /* We define the following macros and types otherwise Contiki does not
  * compile.
  */
 #define CCIF
 #define CLIF
 
-typedef unsigned long clock_time_t;
 typedef unsigned short uip_stats_t;
 
 #endif /* CONTIKI_CONF_H */

platform/galileo/contiki-main.c

@@ -36,6 +36,7 @@ int
 main(void)
 {
   cpu_init();
+  clock_init();
 
   ENABLE_IRQ();