/*
- * arch/s390/kernel/delay.c
+ * arch/s390/lib/delay.c
* Precise Delay Loops for S390
*
* S390 version
#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)
{
* 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) + 1));
+ asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1));
}
/*
- * 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, end_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;
- asm volatile ("STCK %0" : "=m" (start_cc));
- do {
- cpu_relax();
- asm volatile ("STCK %0" : "=m" (end_cc));
- } while (((end_cc - 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);
}