x1000: disable CPU idle stats by default

There's no point including this in normal builds: the stats are not
used for anything, they are not really of interest to anyone except
developers, and add a small overhead to the kernel tick.

Change-Id: I1b4f67cc62d11d634a8cec279dca513dd10eea96

firmware/target/mips/ingenic_x1000/debug-x1000.c

@@ -130,6 +130,7 @@ static bool dbg_audio(void)
     return false;
 }
 
+#ifdef X1000_CPUIDLE_STATS
 static bool dbg_cpuidle(void)
 {
     do {
@@ -143,6 +144,7 @@ static bool dbg_cpuidle(void)
 
     return false;
 }
+#endif
 
 #ifdef FIIO_M3K
 extern bool dbg_fiiom3k_touchpad(void);
@@ -156,7 +158,9 @@ static const struct {
 } menuitems[] = {
     {"Clocks", &dbg_clocks},
     {"GPIOs", &dbg_gpios},
+#ifdef X1000_CPUIDLE_STATS
     {"CPU idle", &dbg_cpuidle},
+#endif
     {"Audio", &dbg_audio},
 #ifdef FIIO_M3K
     {"Touchpad", &dbg_fiiom3k_touchpad},

firmware/target/mips/ingenic_x1000/kernel-x1000.c

@@ -57,6 +57,7 @@ void tick_start(unsigned interval_in_ms)
 
 void OST(void)
 {
+#ifdef X1000_CPUIDLE_STATS
     /* CPU idle time accounting */
     uint32_t now = __ost_read32();
     uint32_t div = now - __cpu_idle_reftick;
@@ -67,6 +68,7 @@ void OST(void)
         __cpu_idle_ticks = 0;
         __cpu_idle_reftick = now;
     }
+#endif
 
     /* Call regular kernel tick */
     jz_write(OST_1FLG, 0);

firmware/target/mips/ingenic_x1000/system-target.h

@@ -37,6 +37,11 @@
 # define MIPS_CACHEFUNC_ATTR
 #endif
 
+#ifdef DEBUG
+/* Define this to get CPU idle stats, visible in the debug menu. */
+# define X1000_CPUIDLE_STATS
+#endif
+
 #include "mmu-mips.h"
 #include "mipsregs.h"
 #include "mipsr2-endian.h"
@@ -66,16 +71,20 @@ static inline int set_irq_level(int lev)
     return oldreg;
 }
 
+#ifdef X1000_CPUIDLE_STATS
 /* CPU idle stats, updated each kernel tick in kernel-x1000.c */
 extern int __cpu_idle_avg;
 extern int __cpu_idle_cur;
 extern uint32_t __cpu_idle_ticks;
 extern uint32_t __cpu_idle_reftick;
+#endif
 
 static inline uint32_t __ost_read32(void);
 static inline void core_sleep(void)
 {
+#ifdef X1000_CPUIDLE_STATS
     uint32_t t1 = __ost_read32();
+#endif
 
     __asm__ __volatile__(
         ".set push\n\t"
@@ -90,8 +99,10 @@ static inline void core_sleep(void)
         ".set pop\n\t"
         ::: "t0", "t1", "t2");
 
+#ifdef X1000_CPUIDLE_STATS
     uint32_t t2 = __ost_read32();
     __cpu_idle_ticks += t2 - t1;
+#endif
 
     enable_irq();
 }

firmware/target/mips/ingenic_x1000/system-x1000.c

@@ -35,10 +35,12 @@
 #include "x1000/msc.h"
 #include "x1000/aic.h"
 
+#ifdef X1000_CPUIDLE_STATS
 int __cpu_idle_avg = 0;
 int __cpu_idle_cur = 0;
 uint32_t __cpu_idle_ticks = 0;
 uint32_t __cpu_idle_reftick = 0;
+#endif
 
 /* Prepare the CPU to process interrupts, but don't enable them yet */
 static void system_init_irq(void)