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Commit 58f60c22 authored by Max Filippov's avatar Max Filippov
Browse files

xtensa: clean up udelay 



Replace division with shift, use ccount_freq instead of loops_per_jiffy.
Introduce __MAX_UDELAY and (undefined) __bad_udelay, break build for too
big udelay constants.
Remove irrelevant comment, clean up code style.

Signed-off-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent a6f3eefa

arch/xtensa/include/asm/delay.h

+15 −6
Original line number Diff line number Diff line
@@ -27,18 +27,27 @@ static inline void __delay(unsigned long loops) 
				: "+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);



static __inline__ void udelay (unsigned long usecs)

#define __MAX_UDELAY 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);

}



#endif