diff options
Diffstat (limited to 'arch/s390/lib/delay.c')
| -rw-r--r-- | arch/s390/lib/delay.c | 48 |
1 files changed, 34 insertions, 14 deletions
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c index 027c4742a001..02854449b74b 100644 --- a/arch/s390/lib/delay.c +++ b/arch/s390/lib/delay.c @@ -1,5 +1,5 @@ /* - * arch/s390/kernel/delay.c + * arch/s390/lib/delay.c * Precise Delay Loops for S390 * * S390 version @@ -13,10 +13,8 @@ #include <linux/sched.h> #include <linux/delay.h> - -#ifdef CONFIG_SMP -#include <asm/smp.h> -#endif +#include <linux/timex.h> +#include <linux/irqflags.h> void __delay(unsigned long loops) { @@ -31,17 +29,39 @@ void __delay(unsigned long loops) } /* - * 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) { - uint64_t start_cc; + u64 end, time, jiffy_timer = 0; + unsigned long flags, cr0, mask, dummy; + + local_irq_save(flags); + if (raw_irqs_disabled_flags(flags)) { + jiffy_timer = S390_lowcore.jiffy_timer; + S390_lowcore.jiffy_timer = -1ULL - (4096 << 12); + __ctl_store(cr0, 0, 0); + dummy = (cr0 & 0xffff00e0) | 0x00000800; + __ctl_load(dummy , 0, 0); + mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT; + } else + mask = psw_kernel_bits | PSW_MASK_WAIT | + PSW_MASK_EXT | PSW_MASK_IO; + + end = get_clock() + ((u64) usecs << 12); + do { + time = end < S390_lowcore.jiffy_timer ? + end : S390_lowcore.jiffy_timer; + set_clock_comparator(time); + trace_hardirqs_on(); + __load_psw_mask(mask); + local_irq_disable(); + } while (get_clock() < end); - if (usecs == 0) - return; - start_cc = get_clock(); - do { - cpu_relax(); - } while (((get_clock() - start_cc)/4096) < usecs); + if (raw_irqs_disabled_flags(flags)) { + __ctl_load(cr0, 0, 0); + S390_lowcore.jiffy_timer = jiffy_timer; + } + set_clock_comparator(S390_lowcore.jiffy_timer); + local_irq_restore(flags); } |