diff options
| -rw-r--r-- | arch/parisc/include/asm/delay.h | 41 | ||||
| -rw-r--r-- | arch/parisc/lib/Makefile | 2 | ||||
| -rw-r--r-- | arch/parisc/lib/delay.c | 73 |
3 files changed, 84 insertions, 32 deletions
diff --git a/arch/parisc/include/asm/delay.h b/arch/parisc/include/asm/delay.h index 912ee7e6a579..08e58e679e3e 100644 --- a/arch/parisc/include/asm/delay.h +++ b/arch/parisc/include/asm/delay.h @@ -1,15 +1,5 @@ -#ifndef _PARISC_DELAY_H -#define _PARISC_DELAY_H - -#include <asm/special_insns.h> /* for mfctl() */ -#include <asm/processor.h> /* for boot_cpu_data */ - - -/* - * Copyright (C) 1993 Linus Torvalds - * - * Delay routines - */ +#ifndef _ASM_PARISC_DELAY_H +#define _ASM_PARISC_DELAY_H static __inline__ void __delay(unsigned long loops) { asm volatile( @@ -19,25 +9,14 @@ static __inline__ void __delay(unsigned long loops) { : "=r" (loops) : "0" (loops)); } -static __inline__ void __cr16_delay(unsigned long clocks) { - unsigned long start; - - /* - * Note: Due to unsigned math, cr16 rollovers shouldn't be - * a problem here. However, on 32 bit, we need to make sure - * we don't pass in too big a value. The current default - * value of MAX_UDELAY_MS should help prevent this. - */ +extern void __udelay(unsigned long usecs); +extern void __udelay_bad(unsigned long usecs); - start = mfctl(16); - while ((mfctl(16) - start) < clocks) - ; +static inline void udelay(unsigned long usecs) +{ + if (__builtin_constant_p(usecs) && (usecs) > 20000) + __udelay_bad(usecs); + __udelay(usecs); } -static __inline__ void __udelay(unsigned long usecs) { - __cr16_delay(usecs * ((unsigned long)boot_cpu_data.cpu_hz / 1000000UL)); -} - -#define udelay(n) __udelay(n) - -#endif /* defined(_PARISC_DELAY_H) */ +#endif /* _ASM_PARISC_DELAY_H */ diff --git a/arch/parisc/lib/Makefile b/arch/parisc/lib/Makefile index 5651536ac733..8fa92b8d839a 100644 --- a/arch/parisc/lib/Makefile +++ b/arch/parisc/lib/Makefile @@ -3,6 +3,6 @@ # lib-y := lusercopy.o bitops.o checksum.o io.o memset.o fixup.o memcpy.o \ - ucmpdi2.o + ucmpdi2.o delay.o obj-y := iomap.o diff --git a/arch/parisc/lib/delay.c b/arch/parisc/lib/delay.c new file mode 100644 index 000000000000..ec9255f27a81 --- /dev/null +++ b/arch/parisc/lib/delay.c @@ -0,0 +1,73 @@ +/* + * Precise Delay Loops for parisc + * + * based on code by: + * Copyright (C) 1993 Linus Torvalds + * Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> + * Copyright (C) 2008 Jiri Hladky <hladky _dot_ jiri _at_ gmail _dot_ com> + * + * parisc implementation: + * Copyright (C) 2013 Helge Deller <deller@gmx.de> + */ + + +#include <linux/module.h> +#include <linux/preempt.h> +#include <linux/init.h> + +#include <asm/processor.h> +#include <asm/delay.h> + +#include <asm/special_insns.h> /* for mfctl() */ +#include <asm/processor.h> /* for boot_cpu_data */ + +/* CR16 based delay: */ +static void __cr16_delay(unsigned long __loops) +{ + /* + * Note: Due to unsigned math, cr16 rollovers shouldn't be + * a problem here. However, on 32 bit, we need to make sure + * we don't pass in too big a value. The current default + * value of MAX_UDELAY_MS should help prevent this. + */ + u32 bclock, now, loops = __loops; + int cpu; + + preempt_disable(); + cpu = smp_processor_id(); + bclock = mfctl(16); + for (;;) { + now = mfctl(16); + if ((now - bclock) >= loops) + break; + + /* Allow RT tasks to run */ + preempt_enable(); + asm volatile(" nop\n"); + barrier(); + preempt_disable(); + + /* + * It is possible that we moved to another CPU, and + * since CR16's are per-cpu we need to calculate + * that. The delay must guarantee that we wait "at + * least" the amount of time. Being moved to another + * CPU could make the wait longer but we just need to + * make sure we waited long enough. Rebalance the + * counter for this CPU. + */ + if (unlikely(cpu != smp_processor_id())) { + loops -= (now - bclock); + cpu = smp_processor_id(); + bclock = mfctl(16); + } + } + preempt_enable(); +} + + +void __udelay(unsigned long usecs) +{ + __cr16_delay(usecs * ((unsigned long)boot_cpu_data.cpu_hz / 1000000UL)); +} +EXPORT_SYMBOL(__udelay); |