Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6

[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 fc6ab6094df811c4511b37ceb7d9783170d98e5a..6ccb9fab055a5b08abb129bbd8752d11f1a0dd8c 100644 (file)
--- 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();
 }