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49 lines
1.2 KiB
49 lines
1.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Precise Delay Loops for S390 |
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* |
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* Copyright IBM Corp. 1999, 2008 |
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* Author(s): Martin Schwidefsky <[email protected]>, |
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* Heiko Carstens <[email protected]>, |
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*/ |
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#include <linux/processor.h> |
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#include <linux/delay.h> |
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#include <asm/div64.h> |
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#include <asm/timex.h> |
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void __delay(unsigned long loops) |
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{ |
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/* |
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* To end the bloody studid and useless discussion about the |
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* BogoMips number I took the liberty to define the __delay |
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* function in a way that that resulting BogoMips number will |
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* yield the megahertz number of the cpu. The important function |
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* is udelay and that is done using the tod clock. -- martin. |
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*/ |
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asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1)); |
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} |
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EXPORT_SYMBOL(__delay); |
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static void delay_loop(unsigned long delta) |
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{ |
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unsigned long end; |
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end = get_tod_clock_monotonic() + delta; |
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while (!tod_after(get_tod_clock_monotonic(), end)) |
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cpu_relax(); |
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} |
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void __udelay(unsigned long usecs) |
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{ |
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delay_loop(usecs << 12); |
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} |
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EXPORT_SYMBOL(__udelay); |
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void __ndelay(unsigned long nsecs) |
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{ |
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nsecs <<= 9; |
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do_div(nsecs, 125); |
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delay_loop(nsecs); |
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} |
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EXPORT_SYMBOL(__ndelay);
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