[uboot] create uboot from github:

repo: https://github.com/u-boot/u-boot
	commit: d80bb749fab53da72c4a0e09b8c2d2aaa3103c91

Change-Id: Ie6434426e1ec15bc08bb1832798e371f3fd5fb29

u-boot-2021.10/include/circbuf.h

@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * (C) Copyright 2003
+ * Gerry Hamel, geh@ti.com, Texas Instruments
+ */
+
+#ifndef __CIRCBUF_H__
+#define __CIRCBUF_H__
+
+typedef struct circbuf {
+	unsigned int size;	/* current number of bytes held */
+	unsigned int totalsize; /* number of bytes allocated */
+
+	char *top;		/* pointer to current buffer start */
+	char *tail;		/* pointer to space for next element */
+
+	char *data;		/* all data */
+	char *end;		/* end of data buffer */
+} circbuf_t;
+
+int buf_init (circbuf_t * buf, unsigned int size);
+int buf_free (circbuf_t * buf);
+int buf_pop (circbuf_t * buf, char *dest, unsigned int len);
+int buf_push (circbuf_t * buf, const char *src, unsigned int len);
+
+#endif