1 files changed, 59 insertions, 0 deletions
diff --git a/lib/sbi/sbi_scratch.c b/lib/sbi/sbi_scratch.c
new file mode 100644
index 0000000..0a615a2
--- /dev/null
+++ b/lib/sbi/sbi_scratch.c
@@ -0,0 +1,59 @@
+ /*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *   Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <sbi/riscv_locks.h>
+#include <sbi/sbi_scratch.h>
+
+static spinlock_t extra_lock = SPIN_LOCK_INITIALIZER;
+static unsigned long extra_offset = SBI_SCRATCH_EXTRA_SPACE_OFFSET;
+
+unsigned long sbi_scratch_alloc_offset(unsigned long size, const char *owner)
+{
+	unsigned long ret = 0;
+
+	/*
+	 * We have a simple brain-dead allocator which never expects
+	 * anything to be free-ed hence it keeps incrementing the
+	 * next allocation offset until it runs-out of space.
+	 *
+	 * In future, we will have more sophisticated allocator which
+	 * will allow us to re-claim free-ed space.
+	 */
+
+	if (!size)
+		return 0;
+
+	while (size & (__SIZEOF_POINTER__ - 1))
+		size++;
+
+	spin_lock(&extra_lock);
+
+	if (SBI_SCRATCH_SIZE < (extra_offset + size))
+		goto done;
+
+	ret = extra_offset;
+	extra_offset += size;
+
+done:
+	spin_unlock(&extra_lock);
+
+	return ret;
+}
+
+void sbi_scratch_free_offset(unsigned long offset)
+{
+	if ((offset < SBI_SCRATCH_EXTRA_SPACE_OFFSET) ||
+	    (SBI_SCRATCH_SIZE <= offset))
+		return;
+
+	/*
+	 * We don't actually free-up because it's a simple
+	 * brain-dead allocator.
+	 */
+}