From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- arch/powerpc/include/asm/delay.h | 76 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 arch/powerpc/include/asm/delay.h (limited to 'arch/powerpc/include/asm/delay.h') diff --git a/arch/powerpc/include/asm/delay.h b/arch/powerpc/include/asm/delay.h new file mode 100644 index 0000000000..51bb8c1476 --- /dev/null +++ b/arch/powerpc/include/asm/delay.h @@ -0,0 +1,76 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _ASM_POWERPC_DELAY_H +#define _ASM_POWERPC_DELAY_H +#ifdef __KERNEL__ + +#include +#include + +/* + * Copyright 1996, Paul Mackerras. + * Copyright (C) 2009 Freescale Semiconductor, Inc. All rights reserved. + * + * PPC64 Support added by Dave Engebretsen, Todd Inglett, Mike Corrigan, + * Anton Blanchard. + */ + +extern void __delay(unsigned long loops); +extern void udelay(unsigned long usecs); + +/* + * On shared processor machines the generic implementation of mdelay can + * result in large errors. While each iteration of the loop inside mdelay + * is supposed to take 1ms, the hypervisor could sleep our partition for + * longer (eg 10ms). With the right timing these errors can add up. + * + * Since there is no 32bit overflow issue on 64bit kernels, just call + * udelay directly. + */ +#ifdef CONFIG_PPC64 +#define mdelay(n) udelay((n) * 1000) +#endif + +/** + * spin_event_timeout - spin until a condition gets true or a timeout elapses + * @condition: a C expression to evalate + * @timeout: timeout, in microseconds + * @delay: the number of microseconds to delay between each evaluation of + * @condition + * + * The process spins until the condition evaluates to true (non-zero) or the + * timeout elapses. The return value of this macro is the value of + * @condition when the loop terminates. This allows you to determine the cause + * of the loop terminates. If the return value is zero, then you know a + * timeout has occurred. + * + * This primary purpose of this macro is to poll on a hardware register + * until a status bit changes. The timeout ensures that the loop still + * terminates even if the bit never changes. The delay is for devices that + * need a delay in between successive reads. + * + * gcc will optimize out the if-statement if @delay is a constant. + */ +#define spin_event_timeout(condition, timeout, delay) \ +({ \ + typeof(condition) __ret; \ + unsigned long __loops = tb_ticks_per_usec * timeout; \ + unsigned long __start = mftb(); \ + \ + if (delay) { \ + while (!(__ret = (condition)) && \ + (tb_ticks_since(__start) <= __loops)) \ + udelay(delay); \ + } else { \ + spin_begin(); \ + while (!(__ret = (condition)) && \ + (tb_ticks_since(__start) <= __loops)) \ + spin_cpu_relax(); \ + spin_end(); \ + } \ + if (!__ret) \ + __ret = (condition); \ + __ret; \ +}) + +#endif /* __KERNEL__ */ +#endif /* _ASM_POWERPC_DELAY_H */ -- cgit v1.2.3