[S390] ETR support.

[linux-2.6-omap-h63xx.git] / arch / s390 / lib / delay.c

diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index 468f4ea33f99efdf1f83802ed4433146ac485b57..02854449b74ba64dea7230b606f72b63c3890218 100644 (file)
--- 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)
 {
@@ -27,24 +25,43 @@ 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);
 }