projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 | 1 | /* |
| d54853ef | 2 | * arch/s390/lib/delay.c |
| 1da177e4 LT |
3 | * Precise Delay Loops for S390 |
| 4 | * | |
| 5 | * S390 version | |
| 6 | * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation | |
| 7 | * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), | |
| 8 | * | |
| 9 | * Derived from "arch/i386/lib/delay.c" | |
| 10 | * Copyright (C) 1993 Linus Torvalds | |
| 11 | * Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> | |
| 12 | */ | |
| 13 | ||
| 1da177e4 LT |
14 | #include <linux/sched.h> |
| 15 | #include <linux/delay.h> | |
| d54853ef MS |
16 | #include <linux/timex.h> |
| 17 | #include <linux/irqflags.h> | |
| 1da177e4 LT |
18 | |
| 19 | void __delay(unsigned long loops) | |
| 20 | { | |
| 21 | /* | |
| 22 | * To end the bloody studid and useless discussion about the | |
| 23 | * BogoMips number I took the liberty to define the __delay | |
| 24 | * function in a way that that resulting BogoMips number will | |
| 25 | * yield the megahertz number of the cpu. The important function | |
| 26 | * is udelay and that is done using the tod clock. -- martin. | |
| 27 | */ | |
| 94c12cc7 | 28 | asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1)); |
| 1da177e4 LT |
29 | } |
| 30 | ||
| 31 | /* | |
| d54853ef | 32 | * Waits for 'usecs' microseconds using the TOD clock comparator. |
| 1da177e4 LT |
33 | */ |
| 34 | void __udelay(unsigned long usecs) | |
| 35 | { | |
| d54853ef MS |
36 | u64 end, time, jiffy_timer = 0; |
| 37 | unsigned long flags, cr0, mask, dummy; | |
| 38 | ||
| 39 | local_irq_save(flags); | |
| 40 | if (raw_irqs_disabled_flags(flags)) { | |
| 41 | jiffy_timer = S390_lowcore.jiffy_timer; | |
| 42 | S390_lowcore.jiffy_timer = -1ULL - (4096 << 12); | |
| 43 | __ctl_store(cr0, 0, 0); | |
| 44 | dummy = (cr0 & 0xffff00e0) | 0x00000800; | |
| 45 | __ctl_load(dummy , 0, 0); | |
| 46 | mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT; | |
| 47 | } else | |
| 48 | mask = psw_kernel_bits | PSW_MASK_WAIT | | |
| 49 | PSW_MASK_EXT | PSW_MASK_IO; | |
| 50 | ||
| 51 | end = get_clock() + ((u64) usecs << 12); | |
| 52 | do { | |
| 53 | time = end < S390_lowcore.jiffy_timer ? | |
| 54 | end : S390_lowcore.jiffy_timer; | |
| 55 | set_clock_comparator(time); | |
| 56 | trace_hardirqs_on(); | |
| 57 | __load_psw_mask(mask); | |
| 58 | local_irq_disable(); | |
| 59 | } while (get_clock() < end); | |
| 1da177e4 | 60 | |
| d54853ef MS |
61 | if (raw_irqs_disabled_flags(flags)) { |
| 62 | __ctl_load(cr0, 0, 0); | |
| 63 | S390_lowcore.jiffy_timer = jiffy_timer; | |
| 64 | } | |
| 65 | set_clock_comparator(S390_lowcore.jiffy_timer); | |
| 66 | local_irq_restore(flags); | |
| 1da177e4 | 67 | } |