From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/sparc/lib/bitext.c | 127 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 arch/sparc/lib/bitext.c

(limited to 'arch/sparc/lib/bitext.c')

diff --git a/arch/sparc/lib/bitext.c b/arch/sparc/lib/bitext.c
new file mode 100644
index 000000000..8ec4e9c02
--- /dev/null
+++ b/arch/sparc/lib/bitext.c
@@ -0,0 +1,127 @@
+/*
+ * bitext.c: kernel little helper (of bit shuffling variety).
+ *
+ * Copyright (C) 2002 Pete Zaitcev <zaitcev@yahoo.com>
+ *
+ * The algorithm to search a zero bit string is geared towards its application.
+ * We expect a couple of fixed sizes of requests, so a rotating counter, reset
+ * by align size, should provide fast enough search while maintaining low
+ * fragmentation.
+ */
+
+#include <linux/string.h>
+#include <linux/bitmap.h>
+
+#include <asm/bitext.h>
+
+/**
+ * bit_map_string_get - find and set a bit string in bit map.
+ * @t: the bit map.
+ * @len: requested string length
+ * @align: requested alignment
+ *
+ * Returns offset in the map or -1 if out of space.
+ *
+ * Not safe to call from an interrupt (uses spin_lock).
+ */
+int bit_map_string_get(struct bit_map *t, int len, int align)
+{
+	int offset, count;	/* siamese twins */
+	int off_new;
+	int align1;
+	int i, color;
+
+	if (t->num_colors) {
+		/* align is overloaded to be the page color */
+		color = align;
+		align = t->num_colors;
+	} else {
+		color = 0;
+		if (align == 0)
+			align = 1;
+	}
+	align1 = align - 1;
+	if ((align & align1) != 0)
+		BUG();
+	if (align < 0 || align >= t->size)
+		BUG();
+	if (len <= 0 || len > t->size)
+		BUG();
+	color &= align1;
+
+	spin_lock(&t->lock);
+	if (len < t->last_size)
+		offset = t->first_free;
+	else
+		offset = t->last_off & ~align1;
+	count = 0;
+	for (;;) {
+		off_new = find_next_zero_bit(t->map, t->size, offset);
+		off_new = ((off_new + align1) & ~align1) + color;
+		count += off_new - offset;
+		offset = off_new;
+		if (offset >= t->size)
+			offset = 0;
+		if (count + len > t->size) {
+			spin_unlock(&t->lock);
+/* P3 */ printk(KERN_ERR
+  "bitmap out: size %d used %d off %d len %d align %d count %d\n",
+  t->size, t->used, offset, len, align, count);
+			return -1;
+		}
+
+		if (offset + len > t->size) {
+			count += t->size - offset;
+			offset = 0;
+			continue;
+		}
+
+		i = 0;
+		while (test_bit(offset + i, t->map) == 0) {
+			i++;
+			if (i == len) {
+				bitmap_set(t->map, offset, len);
+				if (offset == t->first_free)
+					t->first_free = find_next_zero_bit
+							(t->map, t->size,
+							 t->first_free + len);
+				if ((t->last_off = offset + len) >= t->size)
+					t->last_off = 0;
+				t->used += len;
+				t->last_size = len;
+				spin_unlock(&t->lock);
+				return offset;
+			}
+		}
+		count += i + 1;
+		if ((offset += i + 1) >= t->size)
+			offset = 0;
+	}
+}
+
+void bit_map_clear(struct bit_map *t, int offset, int len)
+{
+	int i;
+
+	if (t->used < len)
+		BUG();		/* Much too late to do any good, but alas... */
+	spin_lock(&t->lock);
+	for (i = 0; i < len; i++) {
+		if (test_bit(offset + i, t->map) == 0)
+			BUG();
+		__clear_bit(offset + i, t->map);
+	}
+	if (offset < t->first_free)
+		t->first_free = offset;
+	t->used -= len;
+	spin_unlock(&t->lock);
+}
+
+void bit_map_init(struct bit_map *t, unsigned long *map, int size)
+{
+	bitmap_zero(map, size);
+	memset(t, 0, sizeof *t);
+	spin_lock_init(&t->lock);
+	t->map = map;
+	t->size = size;
+}
-- 
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