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Diffstat (limited to 'arch/xtensa/include/asm/delay.h')
-rw-r--r--arch/xtensa/include/asm/delay.h52
1 files changed, 43 insertions, 9 deletions
diff --git a/arch/xtensa/include/asm/delay.h b/arch/xtensa/include/asm/delay.h
index 3899610c1dff..24304b39a5c7 100644
--- 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