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authorDaniel Vetter <daniel.vetter@ffwll.ch>2013-12-09 09:17:02 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2013-12-09 09:19:14 +0100
commitf7698ba75fa283435f5077b9dfb4319d28b9de9a (patch)
tree4bc16a615a35baaf2b482de81cd256a69067ff72 /arch/parisc/lib/delay.c
parent798183c54799fbe1e5a5bfabb3a8c0505ffd2149 (diff)
parent374b105797c3d4f29c685f3be535c35f5689b30e (diff)
Merge tag 'v3.13-rc3' into drm-intel-next-queued
Linux 3.13-rc3 I need a backmerge for two reasons: - For merging the ppgtt patches from Ben I need to pull in the bdw support. - We now have duplicated calls to intel_uncore_forcewake_reset in the setup code to due 2 different patches merged into -next and 3.13. The conflict is silen so I need the merge to be able to apply Deepak's fixup patch. Conflicts: drivers/gpu/drm/i915/intel_display.c Trivial conflict, it doesn't even show up in the merge diff. Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'arch/parisc/lib/delay.c')
-rw-r--r--arch/parisc/lib/delay.c73
1 files changed, 73 insertions, 0 deletions
diff --git a/arch/parisc/lib/delay.c b/arch/parisc/lib/delay.c
new file mode 100644
index 00000000000..ec9255f27a8
--- /dev/null
+++ b/arch/parisc/lib/delay.c
@@ -0,0 +1,73 @@
+/*
+ * Precise Delay Loops for parisc
+ *
+ * based on code by:
+ * Copyright (C) 1993 Linus Torvalds
+ * Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
+ * Copyright (C) 2008 Jiri Hladky <hladky _dot_ jiri _at_ gmail _dot_ com>
+ *
+ * parisc implementation:
+ * Copyright (C) 2013 Helge Deller <deller@gmx.de>
+ */
+
+
+#include <linux/module.h>
+#include <linux/preempt.h>
+#include <linux/init.h>
+
+#include <asm/processor.h>
+#include <asm/delay.h>
+
+#include <asm/special_insns.h> /* for mfctl() */
+#include <asm/processor.h> /* for boot_cpu_data */
+
+/* CR16 based delay: */
+static void __cr16_delay(unsigned long __loops)
+{
+ /*
+ * Note: Due to unsigned math, cr16 rollovers shouldn't be
+ * a problem here. However, on 32 bit, we need to make sure
+ * we don't pass in too big a value. The current default
+ * value of MAX_UDELAY_MS should help prevent this.
+ */
+ u32 bclock, now, loops = __loops;
+ int cpu;
+
+ preempt_disable();
+ cpu = smp_processor_id();
+ bclock = mfctl(16);
+ for (;;) {
+ now = mfctl(16);
+ if ((now - bclock) >= loops)
+ break;
+
+ /* Allow RT tasks to run */
+ preempt_enable();
+ asm volatile(" nop\n");
+ barrier();
+ preempt_disable();
+
+ /*
+ * It is possible that we moved to another CPU, and
+ * since CR16's are per-cpu we need to calculate
+ * that. The delay must guarantee that we wait "at
+ * least" the amount of time. Being moved to another
+ * CPU could make the wait longer but we just need to
+ * make sure we waited long enough. Rebalance the
+ * counter for this CPU.
+ */
+ if (unlikely(cpu != smp_processor_id())) {
+ loops -= (now - bclock);
+ cpu = smp_processor_id();
+ bclock = mfctl(16);
+ }
+ }
+ preempt_enable();
+}
+
+
+void __udelay(unsigned long usecs)
+{
+ __cr16_delay(usecs * ((unsigned long)boot_cpu_data.cpu_hz / 1000000UL));
+}
+EXPORT_SYMBOL(__udelay);