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Diffstat (limited to 'include/asm-powerpc/delay.h')
| -rw-r--r-- | include/asm-powerpc/delay.h | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/include/asm-powerpc/delay.h b/include/asm-powerpc/delay.h new file mode 100644 index 000000000000..1492aa9ab716 --- /dev/null +++ b/include/asm-powerpc/delay.h @@ -0,0 +1,55 @@ +#ifndef _ASM_POWERPC_DELAY_H +#define _ASM_POWERPC_DELAY_H + +/* + * Copyright 1996, Paul Mackerras. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * PPC64 Support added by Dave Engebretsen, Todd Inglett, Mike Corrigan, + * Anton Blanchard. + */ + +extern unsigned long tb_ticks_per_usec; + +#ifdef CONFIG_PPC64 +/* define these here to prevent circular dependencies */ +/* these instructions control the thread priority on multi-threaded cpus */ +#define __HMT_low() asm volatile("or 1,1,1") +#define __HMT_medium() asm volatile("or 2,2,2") +#else +#define __HMT_low() +#define __HMT_medium() +#endif + +#define __barrier() asm volatile("" ::: "memory") + +static inline unsigned long __get_tb(void) +{ + unsigned long rval; + + asm volatile("mftb %0" : "=r" (rval)); + return rval; +} + +static inline void __delay(unsigned long loops) +{ + unsigned long start = __get_tb(); + + while((__get_tb() - start) < loops) + __HMT_low(); + __HMT_medium(); + __barrier(); +} + +static inline void udelay(unsigned long usecs) +{ + unsigned long loops = tb_ticks_per_usec * usecs; + + __delay(loops); +} + +#endif /* _ASM_POWERPC_DELAY_H */ |