diff options
Diffstat (limited to 'arch/xtensa/include/asm/delay.h')
-rw-r--r-- | arch/xtensa/include/asm/delay.h | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/arch/xtensa/include/asm/delay.h b/arch/xtensa/include/asm/delay.h new file mode 100644 index 000000000..24304b39a --- /dev/null +++ b/arch/xtensa/include/asm/delay.h @@ -0,0 +1,75 @@ +/* + * include/asm-xtensa/delay.h + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2001 - 2005 Tensilica Inc. + * + */ + +#ifndef _XTENSA_DELAY_H +#define _XTENSA_DELAY_H + +#include <asm/timex.h> +#include <asm/param.h> + +extern unsigned long loops_per_jiffy; + +static inline void __delay(unsigned long 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)); +} + +/* Undefined function to get compile-time error */ +void __bad_udelay(void); +void __bad_ndelay(void); + +#define __MAX_UDELAY 30000 +#define __MAX_NDELAY 30000 + +static inline void __udelay(unsigned long usecs) +{ + unsigned long start = get_ccount(); + 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 |