12874c5fdSThomas Gleixner /* SPDX-License-Identifier: GPL-2.0-or-later */ 2b8b572e1SStephen Rothwell #ifndef _ASM_POWERPC_DELAY_H 3b8b572e1SStephen Rothwell #define _ASM_POWERPC_DELAY_H 4b8b572e1SStephen Rothwell #ifdef __KERNEL__ 5b8b572e1SStephen Rothwell 64e287e65SNicholas Piggin #include <linux/processor.h> 79317726dSTimur Tabi #include <asm/time.h> 89317726dSTimur Tabi 9b8b572e1SStephen Rothwell /* 10b8b572e1SStephen Rothwell * Copyright 1996, Paul Mackerras. 119317726dSTimur Tabi * Copyright (C) 2009 Freescale Semiconductor, Inc. All rights reserved. 12b8b572e1SStephen Rothwell * 13b8b572e1SStephen Rothwell * PPC64 Support added by Dave Engebretsen, Todd Inglett, Mike Corrigan, 14b8b572e1SStephen Rothwell * Anton Blanchard. 15b8b572e1SStephen Rothwell */ 16b8b572e1SStephen Rothwell 17b8b572e1SStephen Rothwell extern void __delay(unsigned long loops); 18b8b572e1SStephen Rothwell extern void udelay(unsigned long usecs); 19b8b572e1SStephen Rothwell 20b8b572e1SStephen Rothwell /* 21b8b572e1SStephen Rothwell * On shared processor machines the generic implementation of mdelay can 22b8b572e1SStephen Rothwell * result in large errors. While each iteration of the loop inside mdelay 23b8b572e1SStephen Rothwell * is supposed to take 1ms, the hypervisor could sleep our partition for 24b8b572e1SStephen Rothwell * longer (eg 10ms). With the right timing these errors can add up. 25b8b572e1SStephen Rothwell * 26b8b572e1SStephen Rothwell * Since there is no 32bit overflow issue on 64bit kernels, just call 27b8b572e1SStephen Rothwell * udelay directly. 28b8b572e1SStephen Rothwell */ 29b8b572e1SStephen Rothwell #ifdef CONFIG_PPC64 30b8b572e1SStephen Rothwell #define mdelay(n) udelay((n) * 1000) 31b8b572e1SStephen Rothwell #endif 32b8b572e1SStephen Rothwell 339317726dSTimur Tabi /** 349317726dSTimur Tabi * spin_event_timeout - spin until a condition gets true or a timeout elapses 359317726dSTimur Tabi * @condition: a C expression to evalate 369317726dSTimur Tabi * @timeout: timeout, in microseconds 379317726dSTimur Tabi * @delay: the number of microseconds to delay between each evaluation of 389317726dSTimur Tabi * @condition 399317726dSTimur Tabi * 409317726dSTimur Tabi * The process spins until the condition evaluates to true (non-zero) or the 419317726dSTimur Tabi * timeout elapses. The return value of this macro is the value of 429317726dSTimur Tabi * @condition when the loop terminates. This allows you to determine the cause 439317726dSTimur Tabi * of the loop terminates. If the return value is zero, then you know a 449317726dSTimur Tabi * timeout has occurred. 459317726dSTimur Tabi * 469317726dSTimur Tabi * This primary purpose of this macro is to poll on a hardware register 479317726dSTimur Tabi * until a status bit changes. The timeout ensures that the loop still 489317726dSTimur Tabi * terminates even if the bit never changes. The delay is for devices that 499317726dSTimur Tabi * need a delay in between successive reads. 509317726dSTimur Tabi * 519317726dSTimur Tabi * gcc will optimize out the if-statement if @delay is a constant. 529317726dSTimur Tabi */ 539317726dSTimur Tabi #define spin_event_timeout(condition, timeout, delay) \ 549317726dSTimur Tabi ({ \ 559317726dSTimur Tabi typeof(condition) __ret; \ 569317726dSTimur Tabi unsigned long __loops = tb_ticks_per_usec * timeout; \ 57942e8911SChristophe Leroy unsigned long __start = mftb(); \ 584e287e65SNicholas Piggin \ 594e287e65SNicholas Piggin if (delay) { \ 604e287e65SNicholas Piggin while (!(__ret = (condition)) && \ 614e287e65SNicholas Piggin (tb_ticks_since(__start) <= __loops)) \ 629317726dSTimur Tabi udelay(delay); \ 634e287e65SNicholas Piggin } else { \ 644e287e65SNicholas Piggin spin_begin(); \ 654e287e65SNicholas Piggin while (!(__ret = (condition)) && \ 664e287e65SNicholas Piggin (tb_ticks_since(__start) <= __loops)) \ 674e287e65SNicholas Piggin spin_cpu_relax(); \ 684e287e65SNicholas Piggin spin_end(); \ 694e287e65SNicholas Piggin } \ 70ad9064d5SGrant Likely if (!__ret) \ 71ad9064d5SGrant Likely __ret = (condition); \ 729317726dSTimur Tabi __ret; \ 739317726dSTimur Tabi }) 749317726dSTimur Tabi 75b8b572e1SStephen Rothwell #endif /* __KERNEL__ */ 76b8b572e1SStephen Rothwell #endif /* _ASM_POWERPC_DELAY_H */ 77