Merge branch 'core/urgent' into core/locking

[deliverable/linux.git] / arch / xtensa / include / asm / delay.h

diff --git a/arch/xtensa/include/asm/delay.h b/arch/xtensa/include/asm/delay.h
index 3899610c1dfff71a53e0144969fd990e59e75f62..24304b39a5c7c902042273d60ca6dd033bd282f4 100644 (file)
--- a/arch/xtensa/include/asm/delay.h
+++ b/arch/xtensa/include/asm/delay.h
@@ -19,23 +19,57 @@ extern unsigned long loops_per_jiffy;
 
 static inline void __delay(unsigned long loops)
 {
-       /* 2 cycles per loop. */
-       __asm__ __volatile__ ("1: addi %0, %0, -2; bgeui %0, 2, 1b"
-                             : "=r" (loops) : "0" (loops));
+       if (__builtin_constant_p(loops) && loops < 2)
+               __asm__ __volatile__ ("nop");
+       else if (loops >= 2)
+               /* 2 cycles per loop. */
+               __asm__ __volatile__ ("1: addi %0, %0, -2; bgeui %0, 2, 1b"
+                               : "+r" (loops));
 }
 
-/* For SMP/NUMA systems, change boot_cpu_data to something like
- * local_cpu_data->... where local_cpu_data points to the current
- * cpu. */
+/* Undefined function to get compile-time error */
+void __bad_udelay(void);
+void __bad_ndelay(void);
 
-static __inline__ void udelay (unsigned long usecs)
+#define __MAX_UDELAY 30000
+#define __MAX_NDELAY 30000
+
+static inline void __udelay(unsigned long usecs)
 {
        unsigned long start = get_ccount();
-       unsigned long cycles = usecs * (loops_per_jiffy / (1000000UL / HZ));
+       unsigned long cycles = (usecs * (ccount_freq >> 15)) >> 5;
 
        /* Note: all variables are unsigned (can wrap around)! */
        while (((unsigned long)get_ccount()) - start < cycles)
-               ;
+               cpu_relax();
+}
+
+static inline void udelay(unsigned long usec)
+{
+       if (__builtin_constant_p(usec) && usec >= __MAX_UDELAY)
+               __bad_udelay();
+       else
+               __udelay(usec);
+}
+
+static inline void __ndelay(unsigned long nsec)
+{
+       /*
+        * Inner shift makes sure multiplication doesn't overflow
+        * for legitimate nsec values
+        */
+       unsigned long cycles = (nsec * (ccount_freq >> 15)) >> 15;
+       __delay(cycles);
+}
+
+#define ndelay(n) ndelay(n)
+
+static inline void ndelay(unsigned long nsec)
+{
+       if (__builtin_constant_p(nsec) && nsec >= __MAX_NDELAY)
+               __bad_ndelay();
+       else
+               __ndelay(nsec);
 }
 
 #endif