X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=drivers%2Fnet%2Fbnxt%2Ftf_core%2Fbitalloc.c;h=af1397071bc3bff8c20dc916cbeda70021cee982;hb=7100b0e5511e58269498900aea30bc03e15ba2fd;hp=fb4df9a1995878c70860fa04411369e3fe184857;hpb=a0dcaea290be0d48b748d0bfa5726250adbf86d8;p=dpdk.git

diff --git a/drivers/net/bnxt/tf_core/bitalloc.c b/drivers/net/bnxt/tf_core/bitalloc.c
index fb4df9a199..af1397071b 100644
--- a/drivers/net/bnxt/tf_core/bitalloc.c
+++ b/drivers/net/bnxt/tf_core/bitalloc.c
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: BSD-3-Clause
- * Copyright(c) 2019-2020 Broadcom
+ * Copyright(c) 2019-2021 Broadcom
  * All rights reserved.
  */
 
@@ -7,6 +7,40 @@
 
 #define BITALLOC_MAX_LEVELS 6
 
+
+/* Finds the last bit set plus 1, equivalent to gcc __builtin_fls */
+static int
+ba_fls(bitalloc_word_t v)
+{
+	int c = 32;
+
+	if (!v)
+		return 0;
+
+	if (!(v & 0xFFFF0000u)) {
+		v <<= 16;
+		c -= 16;
+	}
+	if (!(v & 0xFF000000u)) {
+		v <<= 8;
+		c -= 8;
+	}
+	if (!(v & 0xF0000000u)) {
+		v <<= 4;
+		c -= 4;
+	}
+	if (!(v & 0xC0000000u)) {
+		v <<= 2;
+		c -= 2;
+	}
+	if (!(v & 0x80000000u)) {
+		v <<= 1;
+		c -= 1;
+	}
+
+	return c;
+}
+
 /* Finds the first bit set plus 1, equivalent to gcc __builtin_ffs */
 static int
 ba_ffs(bitalloc_word_t v)
@@ -120,6 +154,79 @@ ba_alloc(struct bitalloc *pool)
 	return ba_alloc_helper(pool, 0, 1, 32, 0, &clear);
 }
 
+/**
+ * Help function to alloc entry from highest available index
+ *
+ * Searching the pool from highest index for the empty entry.
+ *
+ * [in] pool
+ *   Pointer to the resource pool
+ *
+ * [in] offset
+ *   Offset of the storage in the pool
+ *
+ * [in] words
+ *   Number of words in this level
+ *
+ * [in] size
+ *   Number of entries in this level
+ *
+ * [in] index
+ *   Index of words that has the entry
+ *
+ * [in] clear
+ *   Indicate if a bit needs to be clear due to the entry is allocated
+ *
+ * Returns:
+ *     0 - Success
+ *    -1 - Failure
+ */
+static int
+ba_alloc_reverse_helper(struct bitalloc *pool,
+			int offset,
+			int words,
+			unsigned int size,
+			int index,
+			int *clear)
+{
+	bitalloc_word_t *storage = &pool->storage[offset];
+	int loc = ba_fls(storage[index]);
+	int r;
+
+	if (loc == 0)
+		return -1;
+
+	loc--;
+
+	if (pool->size > size) {
+		r = ba_alloc_reverse_helper(pool,
+					    offset + words + 1,
+					    storage[words],
+					    size * 32,
+					    index * 32 + loc,
+					    clear);
+	} else {
+		r = index * 32 + loc;
+		*clear = 1;
+		pool->free_count--;
+	}
+
+	if (*clear) {
+		storage[index] &= ~(1 << loc);
+		*clear = (storage[index] == 0);
+	}
+
+	return r;
+}
+
+int
+ba_alloc_reverse(struct bitalloc *pool)
+{
+	int clear = 0;
+
+	return ba_alloc_reverse_helper(pool, 0, 1, 32, 0, &clear);
+}
+
 static int
 ba_alloc_index_helper(struct bitalloc *pool,
 		      int              offset,