diff options
Diffstat (limited to 'arch/s390/lib/delay.c')
| -rw-r--r-- | arch/s390/lib/delay.c | 130 |
1 files changed, 104 insertions, 26 deletions
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c index e96c35bddac..a9f3d0042d5 100644 --- a/arch/s390/lib/delay.c +++ b/arch/s390/lib/delay.c @@ -1,23 +1,19 @@ /* - * arch/s390/kernel/delay.c * Precise Delay Loops for S390 * - * S390 version - * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation - * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), - * - * Derived from "arch/i386/lib/delay.c" - * Copyright (C) 1993 Linus Torvalds - * Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> + * Copyright IBM Corp. 1999, 2008 + * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>, + * Heiko Carstens <heiko.carstens@de.ibm.com>, */ -#include <linux/config.h> #include <linux/sched.h> #include <linux/delay.h> - -#ifdef CONFIG_SMP -#include <asm/smp.h> -#endif +#include <linux/timex.h> +#include <linux/module.h> +#include <linux/irqflags.h> +#include <linux/interrupt.h> +#include <asm/vtimer.h> +#include <asm/div64.h> void __delay(unsigned long loops) { @@ -28,24 +24,106 @@ void __delay(unsigned long loops) * yield the megahertz number of the cpu. The important function * is udelay and that is done using the tod clock. -- martin. */ - __asm__ __volatile__( - "0: brct %0,0b" - : /* no outputs */ : "r" (loops/2) ); + asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1)); +} + +static void __udelay_disabled(unsigned long long usecs) +{ + unsigned long cr0, cr6, new; + u64 clock_saved, end; + + end = get_tod_clock() + (usecs << 12); + clock_saved = local_tick_disable(); + __ctl_store(cr0, 0, 0); + __ctl_store(cr6, 6, 6); + new = (cr0 & 0xffff00e0) | 0x00000800; + __ctl_load(new , 0, 0); + new = 0; + __ctl_load(new, 6, 6); + lockdep_off(); + do { + set_clock_comparator(end); + vtime_stop_cpu(); + } while (get_tod_clock_fast() < end); + lockdep_on(); + __ctl_load(cr0, 0, 0); + __ctl_load(cr6, 6, 6); + local_tick_enable(clock_saved); +} + +static void __udelay_enabled(unsigned long long usecs) +{ + u64 clock_saved, end; + + end = get_tod_clock_fast() + (usecs << 12); + do { + clock_saved = 0; + if (end < S390_lowcore.clock_comparator) { + clock_saved = local_tick_disable(); + set_clock_comparator(end); + } + vtime_stop_cpu(); + if (clock_saved) + local_tick_enable(clock_saved); + } while (get_tod_clock_fast() < end); } /* - * Waits for 'usecs' microseconds using the tod clock, giving up the time slice - * of the virtual PU inbetween to avoid congestion. + * Waits for 'usecs' microseconds using the TOD clock comparator. */ -void __udelay(unsigned long usecs) +void __udelay(unsigned long long usecs) { - uint64_t start_cc, end_cc; + unsigned long flags; - if (usecs == 0) - return; - asm volatile ("STCK %0" : "=m" (start_cc)); - do { + preempt_disable(); + local_irq_save(flags); + if (in_irq()) { + __udelay_disabled(usecs); + goto out; + } + if (in_softirq()) { + if (raw_irqs_disabled_flags(flags)) + __udelay_disabled(usecs); + else + __udelay_enabled(usecs); + goto out; + } + if (raw_irqs_disabled_flags(flags)) { + local_bh_disable(); + __udelay_disabled(usecs); + _local_bh_enable(); + goto out; + } + __udelay_enabled(usecs); +out: + local_irq_restore(flags); + preempt_enable(); +} +EXPORT_SYMBOL(__udelay); + +/* + * Simple udelay variant. To be used on startup and reboot + * when the interrupt handler isn't working. + */ +void udelay_simple(unsigned long long usecs) +{ + u64 end; + + end = get_tod_clock_fast() + (usecs << 12); + while (get_tod_clock_fast() < end) cpu_relax(); - asm volatile ("STCK %0" : "=m" (end_cc)); - } while (((end_cc - start_cc)/4096) < usecs); } + +void __ndelay(unsigned long long nsecs) +{ + u64 end; + + nsecs <<= 9; + do_div(nsecs, 125); + end = get_tod_clock_fast() + nsecs; + if (nsecs & ~0xfffUL) + __udelay(nsecs >> 12); + while (get_tod_clock_fast() < end) + barrier(); +} +EXPORT_SYMBOL(__ndelay); |