diff options
Diffstat (limited to 'arch/s390/lib/delay.c')
| -rw-r--r-- | arch/s390/lib/delay.c | 101 |
1 files changed, 67 insertions, 34 deletions
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c index fc6ab6094df..6ccb9fab055 100644 --- a/arch/s390/lib/delay.c +++ b/arch/s390/lib/delay.c @@ -1,14 +1,9 @@ /* - * arch/s390/lib/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/sched.h> @@ -29,30 +24,31 @@ void __delay(unsigned long loops) asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1)); } -/* - * Waits for 'usecs' microseconds using the TOD clock comparator. - */ -void __udelay(unsigned long usecs) +static void __udelay_disabled(unsigned long usecs) { - u64 end, time, old_cc = 0; - unsigned long flags, cr0, mask, dummy; - int irq_context; + unsigned long mask, cr0, cr0_saved; + u64 clock_saved; - irq_context = in_interrupt(); - if (!irq_context) - local_bh_disable(); - local_irq_save(flags); - if (raw_irqs_disabled_flags(flags)) { - old_cc = local_tick_disable(); - S390_lowcore.clock_comparator = -1ULL; - __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; + clock_saved = local_tick_disable(); + set_clock_comparator(get_clock() + ((u64) usecs << 12)); + __ctl_store(cr0_saved, 0, 0); + cr0 = (cr0_saved & 0xffff00e0) | 0x00000800; + __ctl_load(cr0 , 0, 0); + mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT; + trace_hardirqs_on(); + __load_psw_mask(mask); + local_irq_disable(); + __ctl_load(cr0_saved, 0, 0); + local_tick_enable(clock_saved); + set_clock_comparator(S390_lowcore.clock_comparator); +} + +static void __udelay_enabled(unsigned long usecs) +{ + unsigned long mask; + u64 end, time; + mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT | PSW_MASK_IO; end = get_clock() + ((u64) usecs << 12); do { time = end < S390_lowcore.clock_comparator ? @@ -62,13 +58,50 @@ void __udelay(unsigned long usecs) __load_psw_mask(mask); local_irq_disable(); } while (get_clock() < end); + set_clock_comparator(S390_lowcore.clock_comparator); +} - if (raw_irqs_disabled_flags(flags)) { - __ctl_load(cr0, 0, 0); - local_tick_enable(old_cc); +/* + * Waits for 'usecs' microseconds using the TOD clock comparator. + */ +void __udelay(unsigned long usecs) +{ + unsigned long flags; + + preempt_disable(); + local_irq_save(flags); + if (in_irq()) { + __udelay_disabled(usecs); + goto out; } - if (!irq_context) + 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(); - set_clock_comparator(S390_lowcore.clock_comparator); + goto out; + } + __udelay_enabled(usecs); +out: local_irq_restore(flags); + preempt_enable(); +} + +/* + * Simple udelay variant. To be used on startup and reboot + * when the interrupt handler isn't working. + */ +void udelay_simple(unsigned long usecs) +{ + u64 end; + + end = get_clock() + ((u64) usecs << 12); + while (get_clock() < end) + cpu_relax(); } |