From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- arch/s390/lib/delay.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 arch/s390/lib/delay.c (limited to 'arch/s390/lib/delay.c') diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c new file mode 100644 index 000000000000..e96c35bddac7 --- /dev/null +++ b/arch/s390/lib/delay.c @@ -0,0 +1,51 @@ +/* + * arch/s390/kernel/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 + */ + +#include +#include +#include + +#ifdef CONFIG_SMP +#include +#endif + +void __delay(unsigned long loops) +{ + /* + * To end the bloody studid and useless discussion about the + * BogoMips number I took the liberty to define the __delay + * function in a way that that resulting BogoMips number will + * 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) ); +} + +/* + * Waits for 'usecs' microseconds using the tod clock, giving up the time slice + * of the virtual PU inbetween to avoid congestion. + */ +void __udelay(unsigned long usecs) +{ + uint64_t start_cc, end_cc; + + 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); +} -- cgit v1.2.3