Blackfin: initial XIP support

Signed-off-by: Barry Song <barry.song@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index c0d6d96..f46db59 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -26,9 +26,9 @@
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_TRACER
 	select HAVE_IDE
-	select HAVE_KERNEL_GZIP
-	select HAVE_KERNEL_BZIP2
-	select HAVE_KERNEL_LZMA
+	select HAVE_KERNEL_GZIP if RAMKERNEL
+	select HAVE_KERNEL_BZIP2 if RAMKERNEL
+	select HAVE_KERNEL_LZMA if RAMKERNEL
 	select HAVE_OPROFILE
 	select ARCH_WANT_OPTIONAL_GPIOLIB
 
@@ -407,10 +407,18 @@
 config ROM_BASE
 	hex "Kernel ROM Base"
 	depends on ROMKERNEL
-	default "0x20040000"
+	default "0x20040040"
 	range 0x20000000 0x20400000 if !(BF54x || BF561)
 	range 0x20000000 0x30000000 if (BF54x || BF561)
 	help
+	  Make sure your ROM base does not include any file-header
+	  information that is prepended to the kernel.
+
+	  For example, the bootable U-Boot format (created with
+	  mkimage) has a 64 byte header (0x40).  So while the image
+	  you write to flash might start at say 0x20080000, you have
+	  to add 0x40 to get the kernel's ROM base as it will come
+	  after the header.
 
 comment "Clock/PLL Setup"