28 lines
657 B
C
28 lines
657 B
C
/*
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* Precise Delay Loops for ETRAX FS
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*
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* Copyright (C) 2006 Axis Communications AB.
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*
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*/
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#include <hwregs/reg_map.h>
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#include <hwregs/reg_rdwr.h>
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#include <hwregs/timer_defs.h>
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#include <linux/types.h>
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#include <linux/delay.h>
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#include <linux/module.h>
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/*
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* On ETRAX FS, we can check the free-running read-only 100MHz timer
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* getting 32-bit 10ns precision, theoretically good for 42.94967295
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* seconds. Unsigned arithmetic and careful expression handles
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* wrapping.
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*/
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void cris_delay10ns(u32 n10ns)
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{
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u32 t0 = REG_RD(timer, regi_timer0, r_time);
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while (REG_RD(timer, regi_timer0, r_time) - t0 < n10ns)
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;
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}
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EXPORT_SYMBOL(cris_delay10ns);
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