| 1 | |
| 2 | |
| 3 | * Precise Delay Loops for S390
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| 4 | *
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| 5 | * Copyright IBM Corp. 1999, 2008
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| 6 | * Author(s): Martin Schwidefsky <[email protected]>,
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| 7 |
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| 8 |
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| 9 | #include <linux/processor.h>
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| 10 | #include <linux/export.h>
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| 11 | #include <linux/delay.h>
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| 12 | #include <asm/div64.h>
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| 13 | #include <asm/timex.h>
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| 14 |
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| 15 | void __delay(unsigned long loops)
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| 16 | {
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| 17 | |
| 18 | * Loop 'loops' times. Callers must not assume a specific
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| 19 | * amount of time passes before this function returns.
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| 20 |
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| 21 | asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1));
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| 22 | }
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| 23 | EXPORT_SYMBOL(__delay);
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| 24 |
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| 25 | static void delay_loop(unsigned long delta)
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| 26 | {
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| 27 | unsigned long end;
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| 28 |
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| 29 | end = get_tod_clock_monotonic() + delta;
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| 30 | while (!tod_after(get_tod_clock_monotonic(), end))
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| 31 | cpu_relax();
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| 32 | }
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| 33 |
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| 34 | void __udelay(unsigned long usecs)
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| 35 | {
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| 36 | delay_loop(usecs << 12);
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| 37 | }
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| 38 | EXPORT_SYMBOL(__udelay);
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| 39 |
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| 40 | void __ndelay(unsigned long nsecs)
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| 41 | {
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| 42 | nsecs <<= 9;
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| 43 | do_div(nsecs, 125);
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| 44 | delay_loop(nsecs);
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| 45 | }
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| 46 | EXPORT_SYMBOL(__ndelay);
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