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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /arch/arm64/lib/delay.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/arm64/lib/delay.c')
-rw-r--r--arch/arm64/lib/delay.c69
1 files changed, 69 insertions, 0 deletions
diff --git a/arch/arm64/lib/delay.c b/arch/arm64/lib/delay.c
new file mode 100644
index 0000000000..5b7890139b
--- /dev/null
+++ b/arch/arm64/lib/delay.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Delay loops based on the OpenRISC implementation.
+ *
+ * Copyright (C) 2012 ARM Limited
+ *
+ * Author: Will Deacon <will.deacon@arm.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/timex.h>
+
+#include <clocksource/arm_arch_timer.h>
+
+#define USECS_TO_CYCLES(time_usecs) \
+ xloops_to_cycles((time_usecs) * 0x10C7UL)
+
+static inline unsigned long xloops_to_cycles(unsigned long xloops)
+{
+ return (xloops * loops_per_jiffy * HZ) >> 32;
+}
+
+void __delay(unsigned long cycles)
+{
+ cycles_t start = get_cycles();
+
+ if (cpus_have_const_cap(ARM64_HAS_WFXT)) {
+ u64 end = start + cycles;
+
+ /*
+ * Start with WFIT. If an interrupt makes us resume
+ * early, use a WFET loop to complete the delay.
+ */
+ wfit(end);
+ while ((get_cycles() - start) < cycles)
+ wfet(end);
+ } else if (arch_timer_evtstrm_available()) {
+ const cycles_t timer_evt_period =
+ USECS_TO_CYCLES(ARCH_TIMER_EVT_STREAM_PERIOD_US);
+
+ while ((get_cycles() - start + timer_evt_period) < cycles)
+ wfe();
+ }
+
+ while ((get_cycles() - start) < cycles)
+ cpu_relax();
+}
+EXPORT_SYMBOL(__delay);
+
+inline void __const_udelay(unsigned long xloops)
+{
+ __delay(xloops_to_cycles(xloops));
+}
+EXPORT_SYMBOL(__const_udelay);
+
+void __udelay(unsigned long usecs)
+{
+ __const_udelay(usecs * 0x10C7UL); /* 2**32 / 1000000 (rounded up) */
+}
+EXPORT_SYMBOL(__udelay);
+
+void __ndelay(unsigned long nsecs)
+{
+ __const_udelay(nsecs * 0x5UL); /* 2**32 / 1000000000 (rounded up) */
+}
+EXPORT_SYMBOL(__ndelay);