1 files changed, 101 insertions, 0 deletions

diff --git a/usr/Kconfig b/usr/Kconfig
index 86cecb59dd07..588c588791e2 100644
--- a/usr/Kconfig
+++ b/usr/Kconfig
@@ -44,3 +44,104 @@ config INITRAMFS_ROOT_GID
           owned by group root in the initial ramdisk image.
 
           If you are not sure, leave it set to "0".
+
+config RD_GZIP
+        bool "Support initial ramdisks compressed using gzip" if EMBEDDED
+        default y
+        depends on BLK_DEV_INITRD
+        select DECOMPRESS_GZIP
+        help
+          Support loading of a gzip encoded initial ramdisk or cpio buffer.
+          If unsure, say Y.
+
+config RD_BZIP2
+        bool "Support initial ramdisks compressed using bzip2" if EMBEDDED
+        default !EMBEDDED
+        depends on BLK_DEV_INITRD
+        select DECOMPRESS_BZIP2
+        help
+          Support loading of a bzip2 encoded initial ramdisk or cpio buffer
+          If unsure, say N.
+
+config RD_LZMA
+        bool "Support initial ramdisks compressed using LZMA" if EMBEDDED
+        default !EMBEDDED
+        depends on BLK_DEV_INITRD
+        select DECOMPRESS_LZMA
+        help
+          Support loading of a LZMA encoded initial ramdisk or cpio buffer
+          If unsure, say N.
+
+if INITRAMFS_SOURCE!=""
+
+choice
+        prompt "Built-in initramfs compression mode"
+        help
+          This option decides by which algorithm the builtin initramfs
+          will be compressed.  Several compression algorithms are
+          available, which differ in efficiency, compression and
+          decompression speed.  Compression speed is only relevant
+          when building a kernel.  Decompression speed is relevant at
+          each boot.
+
+          If you have any problems with bzip2 or LZMA compressed
+          initramfs, mail me (Alain Knaff) <alain@knaff.lu>.
+
+          High compression options are mostly useful for users who are
+          low on RAM, since it reduces the memory consumption during
+          boot.
+
+          If in doubt, select 'gzip'
+
+config INITRAMFS_COMPRESSION_NONE
+        bool "None"
+        help
+          Do not compress the built-in initramfs at all. This may
+          sound wasteful in space, but, you should be aware that the
+          built-in initramfs will be compressed at a later stage
+          anyways along with the rest of the kernel, on those
+          architectures that support this.
+          However, not compressing the initramfs may lead to slightly
+          higher memory consumption during a short time at boot, while
+          both the cpio image and the unpacked filesystem image will
+          be present in memory simultaneously
+
+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.
+
+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
+          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.
+
+config INITRAMFS_COMPRESSION_LZMA
+        bool "LZMA"
+        depends on RD_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%
+          smaller with LZMA in comparison to gzip.
+
+endchoice
+
+endif
+
+if INITRAMFS_SOURCE=""
+# The builtin initramfs is so small so we don't want to bug the user...
+
+config INITRAMFS_COMPRESSION_NONE
+        bool
+        default y
+
+endif