xtensa: add support for the xtensa processor architecture [2/2]

The Xtensa processor architecture is a configurable, extensible,
and synthesizable 32-bit RISC processor core provided by Tensilica, inc.

This is the second part of the basic architecture port, adding the
'arch/xtensa' directory and a readme file.

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/xtensa/include/asm/bootparam.h b/arch/xtensa/include/asm/bootparam.h
new file mode 100644
index 0000000..a2a9013
--- /dev/null
+++ b/arch/xtensa/include/asm/bootparam.h
@@ -0,0 +1,54 @@
+/*
+ * Definition of the Linux/Xtensa boot parameter structure
+ *
+ * Copyright (C) 2001 - 2009  Tensilica Inc.
+ *
+ * (Concept borrowed from the 68K port)
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _XTENSA_BOOTPARAM_H
+#define _XTENSA_BOOTPARAM_H
+
+#define BP_VERSION 0x0001
+
+#define BP_TAG_COMMAND_LINE	0x1001	/* command line (0-terminated string)*/
+#define BP_TAG_INITRD		0x1002	/* ramdisk addr and size (bp_meminfo) */
+#define BP_TAG_MEMORY		0x1003	/* memory addr and size (bp_meminfo) */
+#define BP_TAG_SERIAL_BAUDRATE	0x1004	/* baud rate of current console */
+#define BP_TAG_SERIAL_PORT	0x1005	/* serial device of current console */
+#define BP_TAG_FDT		0x1006	/* flat device tree */
+
+#define BP_TAG_FIRST		0x7B0B  /* first tag with a version number */
+#define BP_TAG_LAST		0x7E0B	/* last tag */
+
+#ifndef __ASSEMBLY__
+
+/* All records are aligned to 4 bytes */
+
+struct bp_tag {
+	unsigned short id;	/* tag id */
+	unsigned short size;	/* size of this record excluding the structure*/
+	unsigned long data[0];	/* data */
+};
+
+#define bp_tag_next(tag)						\
+	((struct bp_tag *)((unsigned long)((tag) + 1) + (tag)->size))
+
+struct meminfo {
+	unsigned long type;
+	unsigned long start;
+	unsigned long end;
+};
+
+#define MEMORY_TYPE_CONVENTIONAL     0x1000
+#define MEMORY_TYPE_NONE             0x2000
+
+struct sysmem_info {
+	int nr_banks;
+	struct meminfo bank[0];
+};
+
+#endif
+#endif