if CONFIG_SCHED_TICKLESS is defined, then the global variable g_system_timer does not exist

arch/sim/src/up_internal.h

@@ -150,60 +150,66 @@ extern volatile int g_eventloop;
 
 /* up_setjmp.S ************************************************************/
 
-extern int  up_setjmp(int *jb);
+int  up_setjmp(int *jb);
-extern void up_longjmp(int *jb, int val) noreturn_function;
+void up_longjmp(int *jb, int val) noreturn_function;
+
+/* up_tickless.c **********************************************************/
+
+#ifdef CONFIG_SCHED_TICKLESS
+void up_timer_update(void);
+#endif
 
 /* up_devconsole.c ********************************************************/
 
-extern void up_devconsole(void);
+void up_devconsole(void);
-extern void up_registerblockdevice(void);
+void up_registerblockdevice(void);
 
 /* up_deviceimage.c *******************************************************/
 
-extern char *up_deviceimage(void);
+char *up_deviceimage(void);
 
 /* up_stdio.c *************************************************************/
 
-extern size_t up_hostread(void *buffer, size_t len);
+size_t up_hostread(void *buffer, size_t len);
-extern size_t up_hostwrite(const void *buffer, size_t len);
+size_t up_hostwrite(const void *buffer, size_t len);
 
 /* up_netdev.c ************************************************************/
 
 #ifdef CONFIG_NET
-extern unsigned long up_getwalltime( void );
+unsigned long up_getwalltime( void );
 #endif
 
 /* up_x11framebuffer.c ******************************************************/
 
 #ifdef CONFIG_SIM_X11FB
-extern int up_x11initialize(unsigned short width, unsigned short height,
+int up_x11initialize(unsigned short width, unsigned short height,
-                            void **fbmem, unsigned int *fblen, unsigned char *bpp,
+                     void **fbmem, unsigned int *fblen, unsigned char *bpp,
-                            unsigned short *stride);
+                     unsigned short *stride);
 #ifdef CONFIG_FB_CMAP
-extern int up_x11cmap(unsigned short first, unsigned short len,
+int up_x11cmap(unsigned short first, unsigned short len,
-                      unsigned char *red, unsigned char *green,
+               unsigned char *red, unsigned char *green,
-                      unsigned char *blue, unsigned char  *transp);
+               unsigned char *blue, unsigned char  *transp);
 #endif
 #endif
 
 /* up_eventloop.c ***********************************************************/
 
 #if defined(CONFIG_SIM_X11FB) && defined(CONFIG_SIM_TOUCHSCREEN)
-extern void up_x11events(void);
+void up_x11events(void);
 #endif
 
 /* up_eventloop.c ***********************************************************/
 
 #if defined(CONFIG_SIM_X11FB) && defined(CONFIG_SIM_TOUCHSCREEN)
-extern int up_buttonevent(int x, int y, int buttons);
+int up_buttonevent(int x, int y, int buttons);
 #endif
 
 /* up_tapdev.c ************************************************************/
 
 #if defined(CONFIG_NET) && !defined(__CYGWIN__)
-extern void tapdev_init(void);
+void tapdev_init(void);
-extern unsigned int tapdev_read(unsigned char *buf, unsigned int buflen);
+unsigned int tapdev_read(unsigned char *buf, unsigned int buflen);
-extern void tapdev_send(unsigned char *buf, unsigned int buflen);
+void tapdev_send(unsigned char *buf, unsigned int buflen);
 
 #define netdev_init()           tapdev_init()
 #define netdev_read(buf,buflen) tapdev_read(buf,buflen)
@@ -213,9 +219,9 @@ extern void tapdev_send(unsigned char *buf, unsigned int buflen);
 /* up_wpcap.c *************************************************************/
 
 #if defined(CONFIG_NET) && defined(__CYGWIN__)
-extern void wpcap_init(void);
+void wpcap_init(void);
-extern unsigned int wpcap_read(unsigned char *buf, unsigned int buflen);
+unsigned int wpcap_read(unsigned char *buf, unsigned int buflen);
-extern void wpcap_send(unsigned char *buf, unsigned int buflen);
+void wpcap_send(unsigned char *buf, unsigned int buflen);
 
 #define netdev_init()           wpcap_init()
 #define netdev_read(buf,buflen) wpcap_read(buf,buflen)
@@ -225,9 +231,9 @@ extern void wpcap_send(unsigned char *buf, unsigned int buflen);
 /* up_netdriver.c *********************************************************/
 
 #ifdef CONFIG_NET
-extern int netdriver_init(void);
+int netdriver_init(void);
-extern int netdriver_setmacaddr(unsigned char *macaddr);
+int netdriver_setmacaddr(unsigned char *macaddr);
-extern void netdriver_loop(void);
+void netdriver_loop(void);
 #endif
 
 #endif /* __ASSEMBLY__ */

include/nuttx/clock.h

@@ -53,12 +53,15 @@
 /* Efficient, direct access to OS global timer variables will be supported
  * if the execution environment has direct access to kernel global data.
  * The code in this execution context can access the kernel global data
- * directly if:  (1) this is an un-protected, non-kernel build, or (2)
+ * directly if:  (1) we are not running tick-less (in which case there is
- * this code is being built for execution within the kernel.
+ * no global timer data), (2) this is an un-protected, non-kernel build, or
+ * (2) this is a protectd build, but this code is being built for execution
+ * within the kernel space.
  */
 
 #undef __HAVE_KERNEL_GLOBALS
-#if !defined(CONFIG_NUTTX_KERNEL) || defined(__KERNEL__)
+#if !defined(CONFIG_SCHED_TICKLESS) && \
+    (!defined(CONFIG_NUTTX_KERNEL) || defined(__KERNEL__))
 #  define __HAVE_KERNEL_GLOBALS 1
 #else
 #  define __HAVE_KERNEL_GLOBALS 0
@@ -85,12 +88,13 @@
 #define USEC_PER_MSEC               1000
 #define NSEC_PER_USEC               1000
 
-/* The interrupt interval of the system timer is given by MSEC_PER_TICK.
+/* If CONFIG_SCHED_TICKLESS is not defined, then the interrupt interval of
- * This is the expected number of milliseconds between calls from the
+ * the system timer is given by MSEC_PER_TICK.  This is the expected number
- * processor-specific logic to sched_process_timer().  The default value
+ * of milliseconds between calls from the processor-specific logic to
- * of MSEC_PER_TICK is 10 milliseconds (100KHz).  However, this default
+ * sched_process_timer().  The default value of MSEC_PER_TICK is 10
- * setting can be overridden by defining the interval in milliseconds as
+ * milliseconds (100KHz).  However, this default setting can be overridden
- * CONFIG_MSEC_PER_TICK in the board configuration file.
+ * by defining the interval in milliseconds as CONFIG_MSEC_PER_TICK in the
+ * board configuration file.
  *
  * The following calculations are only accurate when (1) there is no
  * truncation involved and (2) the underlying system timer is an even

sched/clock_initialize.c

@@ -80,11 +80,17 @@
  * Public Variables
  ****************************************************************************/
 
+#ifndef CONFIG_SCHED_TICKLESS
 #ifdef CONFIG_SYSTEM_TIME64
 volatile uint64_t g_system_timer;
-uint64_t          g_tickbias;
 #else
 volatile uint32_t g_system_timer;
+#endif
+#endif
+
+#ifdef CONFIG_SYSTEM_TIME64
+uint64_t          g_tickbias;
+#else
 uint32_t          g_tickbias;
 #endif
 
@@ -182,7 +188,9 @@ static void clock_inittime(void)
   /* (Re-)initialize the time value to match the RTC */
 
   clock_basetime(&g_basetime);
+#ifndef CONFIG_SCHED_TICKLESS
   g_system_timer = 0;
+#endif
   g_tickbias     = 0;
 }
 
@@ -262,9 +270,11 @@ void clock_synchronize(void)
  *
  ****************************************************************************/
 
+#ifndef CONFIG_SCHED_TICKLESS
 void clock_timer(void)
 {
   /* Increment the per-tick system counter */
 
   g_system_timer++;
 }
+#endif