| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Precise Delay Loops for Meta |
| * |
| * Copyright (C) 1993 Linus Torvalds |
| * Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> |
| * Copyright (C) 2007,2009 Imagination Technologies Ltd. |
| * |
| */ |
| |
| #include <linux/export.h> |
| #include <linux/sched.h> |
| #include <linux/delay.h> |
| |
| #include <asm/core_reg.h> |
| #include <asm/processor.h> |
| |
| /* |
| * TXTACTCYC is only 24 bits, so on chips with fast clocks it will wrap |
| * many times per-second. If it does wrap __delay will return prematurely, |
| * but this is only likely with large delay values. |
| * |
| * We also can't implement read_current_timer() with TXTACTCYC due to |
| * this wrapping behaviour. |
| */ |
| #define rdtimer(t) t = __core_reg_get(TXTACTCYC) |
| |
| void __delay(unsigned long loops) |
| { |
| unsigned long bclock, now; |
| |
| rdtimer(bclock); |
| do { |
| asm("NOP"); |
| rdtimer(now); |
| } while ((now-bclock) < loops); |
| } |
| EXPORT_SYMBOL(__delay); |
| |
| inline void __const_udelay(unsigned long xloops) |
| { |
| u64 loops = (u64)xloops * (u64)loops_per_jiffy * HZ; |
| __delay(loops >> 32); |
| } |
| EXPORT_SYMBOL(__const_udelay); |
| |
| void __udelay(unsigned long usecs) |
| { |
| __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */ |
| } |
| EXPORT_SYMBOL(__udelay); |
| |
| void __ndelay(unsigned long nsecs) |
| { |
| __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */ |
| } |
| EXPORT_SYMBOL(__ndelay); |