diff options
Diffstat (limited to 'arch/metag/lib/delay.c')
-rw-r--r-- | arch/metag/lib/delay.c | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/arch/metag/lib/delay.c b/arch/metag/lib/delay.c new file mode 100644 index 000000000000..0b308f48b37a --- /dev/null +++ b/arch/metag/lib/delay.c @@ -0,0 +1,56 @@ +/* + * Precise Delay Loops for Meta + * + * Copyright (C) 1993 Linus Torvalds + * Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> + * Copyright (C) 2007,2009 Imagination Technologies Ltd. + * + */ + +#include <linux/export.h> +#include <linux/sched.h> +#include <linux/delay.h> + +#include <asm/core_reg.h> +#include <asm/processor.h> + +/* + * TXTACTCYC is only 24 bits, so on chips with fast clocks it will wrap + * many times per-second. If it does wrap __delay will return prematurely, + * but this is only likely with large delay values. + * + * We also can't implement read_current_timer() with TXTACTCYC due to + * this wrapping behaviour. + */ +#define rdtimer(t) t = __core_reg_get(TXTACTCYC) + +void __delay(unsigned long loops) +{ + unsigned long bclock, now; + + rdtimer(bclock); + do { + asm("NOP"); + rdtimer(now); + } while ((now-bclock) < loops); +} +EXPORT_SYMBOL(__delay); + +inline void __const_udelay(unsigned long xloops) +{ + u64 loops = (u64)xloops * (u64)loops_per_jiffy * HZ; + __delay(loops >> 32); +} +EXPORT_SYMBOL(__const_udelay); + +void __udelay(unsigned long usecs) +{ + __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */ +} +EXPORT_SYMBOL(__udelay); + +void __ndelay(unsigned long nsecs) +{ + __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */ +} +EXPORT_SYMBOL(__ndelay); |