cbfs: Support reading compression information

CBFS now supports compressed filed. Add support for reading this
information so that the correct decompression can be applied. The
decompression itself is not implemented in CBFS.

Signed-off-by: Simon Glass <sjg@chromium.org>

include/cbfs.h

@@ -75,6 +75,15 @@ struct cbfs_fileheader {
 	char filename[];
 } __packed;
 
+/**
+ * These are standard values for the known compression alogrithms that coreboot
+ * knows about for stages and payloads.  Of course, other CBFS users can use
+ * whatever values they want, as long as they understand them.
+ */
+#define CBFS_COMPRESS_NONE  0
+#define CBFS_COMPRESS_LZMA  1
+#define CBFS_COMPRESS_LZ4   2
+
 /*
  * Depending on how the header was initialized, it may be backed with 0x00 or
  * 0xff, so support both
@@ -119,6 +128,8 @@ struct cbfs_cachenode {
 	u32 data_length;
 	u32 name_length;
 	u32 attr_offset;
+	u32 comp_algo;
+	u32 decomp_size;
 };
 
 /**