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Diffstat (limited to 'include/asm-xtensa/delay.h')
| -rw-r--r-- | include/asm-xtensa/delay.h | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/include/asm-xtensa/delay.h b/include/asm-xtensa/delay.h new file mode 100644 index 00000000000..6359c55e77a --- /dev/null +++ b/include/asm-xtensa/delay.h @@ -0,0 +1,50 @@ +/* + * 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 <linux/config.h> +#include <asm/processor.h> +#include <asm/param.h> + +extern unsigned long loops_per_jiffy; + +extern __inline__ void __delay(unsigned long loops) +{ + /* 2 cycles per loop. */ + __asm__ __volatile__ ("1: addi %0, %0, -2; bgeui %0, 1, 1b" + : "=r" (loops) : "0" (loops)); +} + +static __inline__ u32 xtensa_get_ccount(void) +{ + u32 ccount; + asm volatile ("rsr %0, 234; # CCOUNT\n" : "=r" (ccount)); + return ccount; +} + +/* For SMP/NUMA systems, change boot_cpu_data to something like + * local_cpu_data->... where local_cpu_data points to the current + * cpu. */ + +static __inline__ void udelay (unsigned long usecs) +{ + unsigned long start = xtensa_get_ccount(); + unsigned long cycles = usecs * (loops_per_jiffy / (1000000UL / HZ)); + + /* Note: all variables are unsigned (can wrap around)! */ + while (((unsigned long)xtensa_get_ccount()) - start < cycles) + ; +} + +#endif + |