1 files changed, 76 insertions, 0 deletions
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 <linux/processor.h>
+#include <asm/time.h>
+
+/*
+ * 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 */