Add LZO compression support for initramfs and old-style initrd

Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Tested-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Russell King <rmk@arm.linux.org.uk>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 21 insertions, 5 deletions

diff --git a/usr/Kconfig b/usr/Kconfig
index 1c3039f28909..e2721f5a3504 100644
--- a/usr/Kconfig
+++ b/usr/Kconfig
@@ -72,6 +72,15 @@ config RD_LZMA
           Support loading of a LZMA encoded initial ramdisk or cpio buffer
           If unsure, say N.
 
+config RD_LZO
+        bool "Support initial ramdisks compressed using LZO" if EMBEDDED
+        default !EMBEDDED
+        depends on BLK_DEV_INITRD
+        select DECOMPRESS_LZO
+        help
+          Support loading of a LZO encoded initial ramdisk or cpio buffer
+          If unsure, say N.
+
 choice
         prompt "Built-in initramfs compression mode" if INITRAMFS_SOURCE!=""
         help
@@ -108,16 +117,15 @@ config INITRAMFS_COMPRESSION_GZIP
         bool "Gzip"
         depends on RD_GZIP
         help
-          The old and tried gzip compression. Its compression ratio is
-          the poorest among the 3 choices; however its speed (both
-          compression and decompression) is the fastest.
+          The old and tried gzip compression. It provides a good balance
+          between compression ratio and decompression speed.
 
 config INITRAMFS_COMPRESSION_BZIP2
         bool "Bzip2"
         depends on RD_BZIP2
         help
           Its compression ratio and speed is intermediate.
-          Decompression speed is slowest among the three.  The initramfs
+          Decompression speed is slowest among the four.  The initramfs
           size is about 10% smaller with bzip2, in comparison to gzip.
           Bzip2 uses a large amount of memory. For modern kernels you
           will need at least 8MB RAM or more for booting.
@@ -128,7 +136,15 @@ config INITRAMFS_COMPRESSION_LZMA
         help
           The most recent compression algorithm.
           Its ratio is best, decompression speed is between the other
-          two. Compression is slowest.  The initramfs size is about 33%
+          three. Compression is slowest. The initramfs size is about 33%
           smaller with LZMA in comparison to gzip.
 
+config INITRAMFS_COMPRESSION_LZO
+        bool "LZO"
+        depends on RD_LZO
+        help
+          Its compression ratio is the poorest among the four. The kernel
+          size is about about 10% bigger than gzip; however its speed
+          (both compression and decompression) is the fastest.
+
 endchoice