diff mbox

[U-Boot,PATCHv2] Add support for LZ4 decompression algorithm

Message ID 1443850347-5437-1-git-send-email-jwerner@chromium.org
State Superseded
Headers show

Commit Message

Julius Werner Oct. 3, 2015, 5:32 a.m. UTC
This patch adds support for LZ4-compressed FIT image contents. This
algorithm has a slightly worse compression ration than LZO while being
nearly twice as fast to decompress. When loading images from a fast
storage medium this usually results in a boot time win.

Compile-tested only since I don't have a U-Boot development system set
up right now. The code was imported unchanged from coreboot where it's
proven to work, though. I'm mostly interested in getting this recognized
by mkImage for use in a downstream project.

Signed-off-by: Julius Werner <jwerner@chromium.org>
---
 common/bootm.c     |   9 ++
 common/image.c     |   1 +
 include/common.h   |   3 +
 include/image.h    |   1 +
 lib/Kconfig        |  18 ++++
 lib/Makefile       |   1 +
 lib/lz4.c          | 243 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/lz4_wrapper.c  | 137 ++++++++++++++++++++++++++++++
 test/Kconfig       |   1 +
 test/compression.c |  57 +++++++++++++
 10 files changed, 471 insertions(+)
 create mode 100644 lib/lz4.c
 create mode 100644 lib/lz4_wrapper.c

Comments

Simon Glass Oct. 3, 2015, 4:36 p.m. UTC | #1
Hi Julius,

On 3 October 2015 at 06:32, Julius Werner <jwerner@chromium.org> wrote:
> This patch adds support for LZ4-compressed FIT image contents. This
> algorithm has a slightly worse compression ration than LZO while being
> nearly twice as fast to decompress. When loading images from a fast
> storage medium this usually results in a boot time win.
>
> Compile-tested only since I don't have a U-Boot development system set
> up right now. The code was imported unchanged from coreboot where it's
> proven to work, though. I'm mostly interested in getting this recognized
> by mkImage for use in a downstream project.
>
> Signed-off-by: Julius Werner <jwerner@chromium.org>
> ---
>  common/bootm.c     |   9 ++
>  common/image.c     |   1 +
>  include/common.h   |   3 +
>  include/image.h    |   1 +
>  lib/Kconfig        |  18 ++++
>  lib/Makefile       |   1 +
>  lib/lz4.c          | 243 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  lib/lz4_wrapper.c  | 137 ++++++++++++++++++++++++++++++
>  test/Kconfig       |   1 +
>  test/compression.c |  57 +++++++++++++
>  10 files changed, 471 insertions(+)
>  create mode 100644 lib/lz4.c
>  create mode 100644 lib/lz4_wrapper.c

Actually you should enable the option in configs/sandbox_defconfig,
not lib/Kconfig. See the condition used by compression.c:

obj-$(CONFIG_SANDBOX) += compression.o

Also, for me the test fails:

./b/sandbox/u-boot -c "ut_compression"
...
 testing lz4 ...
orig_size:350
compressed_size:276
uncompressed_size:350
compress does not overrun
Failed: ret != 0
 lz4: FAILED
ut_compression FAILED

Regards,
Simon
Julius Werner Oct. 5, 2015, 6:09 p.m. UTC | #2
> You can build U-Boot with NO_SDL=1

Ah, thanks... that was the important magic flag I needed!

> Actually you should enable the option in configs/sandbox_defconfig,
> not lib/Kconfig. See the condition used by compression.c:
>
> obj-$(CONFIG_SANDBOX) += compression.o

Okay, makes sense. I looked at the wrong line in the Makefile.

> Also, for me the test fails:
>
> ./b/sandbox/u-boot -c "ut_compression"
> ...
>  testing lz4 ...
> orig_size:350
> compressed_size:276
> uncompressed_size:350
> compress does not overrun
> Failed: ret != 0
>  lz4: FAILED
> ut_compression FAILED

Huh... that's odd. When I run this now, I get:

 testing lz4 ...
        orig_size:350
        compressed_size:276
        uncompressed_size:350
        compress does not overrun
        uncompress does not overrun
 lz4: ok

And if I change a byte in the compressed test data, it fails on
memcmp() as expected. Are you sure you have no local changes or
anything (I based the patch off 1f8836396)? I don't see how this could
give different results...
Simon Glass Oct. 6, 2015, 1:47 p.m. UTC | #3
Hi Julius,

On 5 October 2015 at 19:09, Julius Werner <jwerner@chromium.org> wrote:
>
> > You can build U-Boot with NO_SDL=1
>
> Ah, thanks... that was the important magic flag I needed!
>
> > Actually you should enable the option in configs/sandbox_defconfig,
> > not lib/Kconfig. See the condition used by compression.c:
> >
> > obj-$(CONFIG_SANDBOX) += compression.o
>
> Okay, makes sense. I looked at the wrong line in the Makefile.
>
> > Also, for me the test fails:
> >
> > ./b/sandbox/u-boot -c "ut_compression"
> > ...
> >  testing lz4 ...
> > orig_size:350
> > compressed_size:276
> > uncompressed_size:350
> > compress does not overrun
> > Failed: ret != 0
> >  lz4: FAILED
> > ut_compression FAILED
>
> Huh... that's odd. When I run this now, I get:
>
>  testing lz4 ...
>         orig_size:350
>         compressed_size:276
>         uncompressed_size:350
>         compress does not overrun
>         uncompress does not overrun
>  lz4: ok
>
> And if I change a byte in the compressed test data, it fails on
> memcmp() as expected. Are you sure you have no local changes or
> anything (I based the patch off 1f8836396)? I don't see how this could
> give different results...

 git reset --hard HEAD~
HEAD is now at 1f88363 Prepare v2015.10-rc4
(try-julius=1f8836: asc.1 b/ et sandbox/) ~/u> !pw
pwclient git-am 525863
Applying patch #525863 using 'git am'
Description: [U-Boot,PATCHv2] Add support for LZ4 decompression algorithm
Applying: Add support for LZ4 decompression algorithm
.git/rebase-apply/patch:91: trailing whitespace.

warning: 1 line adds whitespace errors.
(try-julius=b3cf2a: asc.1 b/ et sandbox/) ~/u> 1cro
1cro: command not found
127 (try-julius=b3cf2a: asc.1 b/ et sandbox/) ~/u> !cro
crosfw -b sandbox -w

../lib/lz4_wrapper.c: In function ‘ulz4fn’:
../lib/lz4_wrapper.c:72:6: warning: ‘ret’ may be used uninitialized in
this function [-Wmaybe-uninitialized]
  int ret;
      ^

./b/sandbox/u-boot -c "ut_compression"


U-Boot 2015.10-rc4-00001-gb3cf2a9 (Oct 06 2015 - 14:42:07 +0100)

DRAM:  128 MiB
Using default environment

In:    serial
Out:   lcd
Err:   lcd
Net:   No ethernet found.
 testing gzip ...
orig_size:350
compressed_size:206
uncompressed_size:350
Deflate need more space to compress left 350 bytes
compress does not overrun
Error: inflate() returned -5
uncompress does not overrun
 gzip: ok
 testing bzip2 ...
orig_size:350
compressed_size:240
uncompressed_size:350
compress does not overrun
uncompress does not overrun
 bzip2: ok
 testing lzma ...
orig_size:350
compressed_size:229
uncompressed_size:350
compress does not overrun
uncompress does not overrun
 lzma: ok
 testing lzo ...
orig_size:350
compressed_size:334
uncompressed_size:350
compress does not overrun
uncompress does not overrun
 lzo: ok
 testing lz4 ...
orig_size:350
compressed_size:276
uncompressed_size:350
compress does not overrun
Failed: ret != 0
 lz4: FAILED
ut_compression FAILED

I pushed it to u-boot-x86 branch 'julius-working' for you to check.

Regards,
Simon
Julius Werner Oct. 7, 2015, 3:01 a.m. UTC | #4
Well then... a few hours and a significant reduction in sanity later,
I found that I'm shadowing the new 'ret' variable from changing the
API around because I forgot to remove the declaration part from the
'ret' that already existed in the else block. It would be nice if
U-Boot compiled with -Wshadow...

This made the (outer) return variable uninitialized in the compression
error case, which on my native x86_64 happened to produce a non-zero
value... but with an i686 cross-compiler I could reproduce the error
you saw. Fixed in the next version and moved the config to
sandbox_defconfig as you suggested.
Simon Glass Oct. 8, 2015, 6:18 p.m. UTC | #5
Hi Julius,

On 7 October 2015 at 04:01, Julius Werner <jwerner@chromium.org> wrote:
> Well then... a few hours and a significant reduction in sanity later,
> I found that I'm shadowing the new 'ret' variable from changing the
> API around because I forgot to remove the declaration part from the
> 'ret' that already existed in the else block. It would be nice if
> U-Boot compiled with -Wshadow...

I saw an 'unused variable' warning which I mentioned in my email. It
may have been another symptom. You could send a patch to change the
flags if you like.

>
> This made the (outer) return variable uninitialized in the compression
> error case, which on my native x86_64 happened to produce a non-zero
> value... but with an i686 cross-compiler I could reproduce the error
> you saw. Fixed in the next version and moved the config to
> sandbox_defconfig as you suggested.

Seems to work now, so we are good.

Regards,
Simon
diff mbox

Patch

diff --git a/common/bootm.c b/common/bootm.c
index 667c934..5f99ec8 100644
--- a/common/bootm.c
+++ b/common/bootm.c
@@ -389,6 +389,15 @@  int bootm_decomp_image(int comp, ulong load, ulong image_start, int type,
 		break;
 	}
 #endif /* CONFIG_LZO */
+#ifdef CONFIG_LZ4
+	case IH_COMP_LZ4: {
+		size_t size = unc_len;
+
+		ret = ulz4fn(image_buf, image_len, load_buf, &size);
+		image_len = size;
+		break;
+	}
+#endif /* CONFIG_LZ4 */
 	default:
 		printf("Unimplemented compression type %d\n", comp);
 		return BOOTM_ERR_UNIMPLEMENTED;
diff --git a/common/image.c b/common/image.c
index 1325e07..c33749d 100644
--- a/common/image.c
+++ b/common/image.c
@@ -167,6 +167,7 @@  static const table_entry_t uimage_comp[] = {
 	{	IH_COMP_GZIP,	"gzip",		"gzip compressed",	},
 	{	IH_COMP_LZMA,	"lzma",		"lzma compressed",	},
 	{	IH_COMP_LZO,	"lzo",		"lzo compressed",	},
+	{	IH_COMP_LZ4,	"lz4",		"lz4 compressed",	},
 	{	-1,		"",		"",			},
 };
 
diff --git a/include/common.h b/include/common.h
index 68b24d0..ecb1f06 100644
--- a/include/common.h
+++ b/include/common.h
@@ -826,6 +826,9 @@  int gzwrite(unsigned char *src, int len,
 	    u64 startoffs,
 	    u64 szexpected);
 
+/* lib/lz4_wrapper.c */
+int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn);
+
 /* lib/qsort.c */
 void qsort(void *base, size_t nmemb, size_t size,
 	   int(*compar)(const void *, const void *));
diff --git a/include/image.h b/include/image.h
index 8a864ae..08ae24a 100644
--- a/include/image.h
+++ b/include/image.h
@@ -259,6 +259,7 @@  struct lmb;
 #define IH_COMP_BZIP2		2	/* bzip2 Compression Used	*/
 #define IH_COMP_LZMA		3	/* lzma  Compression Used	*/
 #define IH_COMP_LZO		4	/* lzo   Compression Used	*/
+#define IH_COMP_LZ4		5	/* lz4   Compression Used	*/
 
 #define IH_MAGIC	0x27051956	/* Image Magic Number		*/
 #define IH_NMLEN		32	/* Image Name Length		*/
diff --git a/lib/Kconfig b/lib/Kconfig
index 0673072..a8f8460 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -100,6 +100,24 @@  config SHA_PROG_HW_ACCEL
 	  is performed in hardware.
 endmenu
 
+menu "Compression Support"
+
+config LZ4
+	bool "Enable LZ4 decompression support"
+	help
+	  If this option is set, support for LZ4 compressed images
+	  is included. The LZ4 algorithm can run in-place as long as the
+	  compressed image is loaded to the end of the output buffer, and
+	  trades lower compression ratios for much faster decompression.
+	  
+	  NOTE: This implements the release version of the LZ4 frame
+	  format as generated by default by the 'lz4' command line tool.
+	  This is not the same as the outdated, less efficient legacy
+	  frame format currently (2015) implemented in the Linux kernel
+	  (generated by 'lz4 -l'). The two formats are incompatible.
+
+endmenu
+
 config ERRNO_STR
 	bool "Enable function for getting errno-related string message"
 	help
diff --git a/lib/Makefile b/lib/Makefile
index 96f832e..3eecefa 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -34,6 +34,7 @@  obj-$(CONFIG_GZIP_COMPRESSED) += gzip.o
 obj-y += initcall.o
 obj-$(CONFIG_LMB) += lmb.o
 obj-y += ldiv.o
+obj-$(CONFIG_LZ4) += lz4_wrapper.o
 obj-$(CONFIG_MD5) += md5.o
 obj-y += net_utils.o
 obj-$(CONFIG_PHYSMEM) += physmem.o
diff --git a/lib/lz4.c b/lib/lz4.c
new file mode 100644
index 0000000..f518341
--- /dev/null
+++ b/lib/lz4.c
@@ -0,0 +1,243 @@ 
+/*
+   LZ4 - Fast LZ compression algorithm
+   Copyright (C) 2011-2015, Yann Collet.
+
+   SPDX-License-Identifier: BSD-2-Clause
+
+   You can contact the author at :
+   - LZ4 source repository : https://github.com/Cyan4973/lz4
+   - LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c
+*/
+
+
+/**************************************
+*  Reading and writing into memory
+**************************************/
+
+/* customized version of memcpy, which may overwrite up to 7 bytes beyond dstEnd */
+static void LZ4_wildCopy(void* dstPtr, const void* srcPtr, void* dstEnd)
+{
+    BYTE* d = (BYTE*)dstPtr;
+    const BYTE* s = (const BYTE*)srcPtr;
+    BYTE* e = (BYTE*)dstEnd;
+    do { LZ4_copy8(d,s); d+=8; s+=8; } while (d<e);
+}
+
+
+/**************************************
+*  Common Constants
+**************************************/
+#define MINMATCH 4
+
+#define COPYLENGTH 8
+#define LASTLITERALS 5
+#define MFLIMIT (COPYLENGTH+MINMATCH)
+static const int LZ4_minLength = (MFLIMIT+1);
+
+#define KB *(1 <<10)
+#define MB *(1 <<20)
+#define GB *(1U<<30)
+
+#define MAXD_LOG 16
+#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
+
+#define ML_BITS  4
+#define ML_MASK  ((1U<<ML_BITS)-1)
+#define RUN_BITS (8-ML_BITS)
+#define RUN_MASK ((1U<<RUN_BITS)-1)
+
+
+/**************************************
+*  Local Structures and types
+**************************************/
+typedef enum { noDict = 0, withPrefix64k, usingExtDict } dict_directive;
+typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive;
+typedef enum { full = 0, partial = 1 } earlyEnd_directive;
+
+
+
+/*******************************
+*  Decompression functions
+*******************************/
+/*
+ * This generic decompression function cover all use cases.
+ * It shall be instantiated several times, using different sets of directives
+ * Note that it is essential this generic function is really inlined,
+ * in order to remove useless branches during compilation optimization.
+ */
+FORCE_INLINE int LZ4_decompress_generic(
+                 const char* const source,
+                 char* const dest,
+                 int inputSize,
+                 int outputSize,         /* If endOnInput==endOnInputSize, this value is the max size of Output Buffer. */
+
+                 int endOnInput,         /* endOnOutputSize, endOnInputSize */
+                 int partialDecoding,    /* full, partial */
+                 int targetOutputSize,   /* only used if partialDecoding==partial */
+                 int dict,               /* noDict, withPrefix64k, usingExtDict */
+                 const BYTE* const lowPrefix,  /* == dest if dict == noDict */
+                 const BYTE* const dictStart,  /* only if dict==usingExtDict */
+                 const size_t dictSize         /* note : = 0 if noDict */
+                 )
+{
+    /* Local Variables */
+    const BYTE* ip = (const BYTE*) source;
+    const BYTE* const iend = ip + inputSize;
+
+    BYTE* op = (BYTE*) dest;
+    BYTE* const oend = op + outputSize;
+    BYTE* cpy;
+    BYTE* oexit = op + targetOutputSize;
+    const BYTE* const lowLimit = lowPrefix - dictSize;
+
+    const BYTE* const dictEnd = (const BYTE*)dictStart + dictSize;
+    const size_t dec32table[] = {4, 1, 2, 1, 4, 4, 4, 4};
+    const size_t dec64table[] = {0, 0, 0, (size_t)-1, 0, 1, 2, 3};
+
+    const int safeDecode = (endOnInput==endOnInputSize);
+    const int checkOffset = ((safeDecode) && (dictSize < (int)(64 KB)));
+
+
+    /* Special cases */
+    if ((partialDecoding) && (oexit> oend-MFLIMIT)) oexit = oend-MFLIMIT;                         /* targetOutputSize too high => decode everything */
+    if ((endOnInput) && (unlikely(outputSize==0))) return ((inputSize==1) && (*ip==0)) ? 0 : -1;  /* Empty output buffer */
+    if ((!endOnInput) && (unlikely(outputSize==0))) return (*ip==0?1:-1);
+
+
+    /* Main Loop */
+    while (1)
+    {
+        unsigned token;
+        size_t length;
+        const BYTE* match;
+
+        /* get literal length */
+        token = *ip++;
+        if ((length=(token>>ML_BITS)) == RUN_MASK)
+        {
+            unsigned s;
+            do
+            {
+                s = *ip++;
+                length += s;
+            }
+            while (likely((endOnInput)?ip<iend-RUN_MASK:1) && (s==255));
+            if ((safeDecode) && unlikely((size_t)(op+length)<(size_t)(op))) goto _output_error;   /* overflow detection */
+            if ((safeDecode) && unlikely((size_t)(ip+length)<(size_t)(ip))) goto _output_error;   /* overflow detection */
+        }
+
+        /* copy literals */
+        cpy = op+length;
+        if (((endOnInput) && ((cpy>(partialDecoding?oexit:oend-MFLIMIT)) || (ip+length>iend-(2+1+LASTLITERALS))) )
+            || ((!endOnInput) && (cpy>oend-COPYLENGTH)))
+        {
+            if (partialDecoding)
+            {
+                if (cpy > oend) goto _output_error;                           /* Error : write attempt beyond end of output buffer */
+                if ((endOnInput) && (ip+length > iend)) goto _output_error;   /* Error : read attempt beyond end of input buffer */
+            }
+            else
+            {
+                if ((!endOnInput) && (cpy != oend)) goto _output_error;       /* Error : block decoding must stop exactly there */
+                if ((endOnInput) && ((ip+length != iend) || (cpy > oend))) goto _output_error;   /* Error : input must be consumed */
+            }
+            memcpy(op, ip, length);
+            ip += length;
+            op += length;
+            break;     /* Necessarily EOF, due to parsing restrictions */
+        }
+        LZ4_wildCopy(op, ip, cpy);
+        ip += length; op = cpy;
+
+        /* get offset */
+        match = cpy - LZ4_readLE16(ip); ip+=2;
+        if ((checkOffset) && (unlikely(match < lowLimit))) goto _output_error;   /* Error : offset outside destination buffer */
+
+        /* get matchlength */
+        length = token & ML_MASK;
+        if (length == ML_MASK)
+        {
+            unsigned s;
+            do
+            {
+                if ((endOnInput) && (ip > iend-LASTLITERALS)) goto _output_error;
+                s = *ip++;
+                length += s;
+            } while (s==255);
+            if ((safeDecode) && unlikely((size_t)(op+length)<(size_t)op)) goto _output_error;   /* overflow detection */
+        }
+        length += MINMATCH;
+
+        /* check external dictionary */
+        if ((dict==usingExtDict) && (match < lowPrefix))
+        {
+            if (unlikely(op+length > oend-LASTLITERALS)) goto _output_error;   /* doesn't respect parsing restriction */
+
+            if (length <= (size_t)(lowPrefix-match))
+            {
+                /* match can be copied as a single segment from external dictionary */
+                match = dictEnd - (lowPrefix-match);
+                memmove(op, match, length); op += length;
+            }
+            else
+            {
+                /* match encompass external dictionary and current segment */
+                size_t copySize = (size_t)(lowPrefix-match);
+                memcpy(op, dictEnd - copySize, copySize);
+                op += copySize;
+                copySize = length - copySize;
+                if (copySize > (size_t)(op-lowPrefix))   /* overlap within current segment */
+                {
+                    BYTE* const endOfMatch = op + copySize;
+                    const BYTE* copyFrom = lowPrefix;
+                    while (op < endOfMatch) *op++ = *copyFrom++;
+                }
+                else
+                {
+                    memcpy(op, lowPrefix, copySize);
+                    op += copySize;
+                }
+            }
+            continue;
+        }
+
+        /* copy repeated sequence */
+        cpy = op + length;
+        if (unlikely((op-match)<8))
+        {
+            const size_t dec64 = dec64table[op-match];
+            op[0] = match[0];
+            op[1] = match[1];
+            op[2] = match[2];
+            op[3] = match[3];
+            match += dec32table[op-match];
+            LZ4_copy4(op+4, match);
+            op += 8; match -= dec64;
+        } else { LZ4_copy8(op, match); op+=8; match+=8; }
+
+        if (unlikely(cpy>oend-12))
+        {
+            if (cpy > oend-LASTLITERALS) goto _output_error;    /* Error : last LASTLITERALS bytes must be literals */
+            if (op < oend-8)
+            {
+                LZ4_wildCopy(op, match, oend-8);
+                match += (oend-8) - op;
+                op = oend-8;
+            }
+            while (op<cpy) *op++ = *match++;
+        }
+        else
+            LZ4_wildCopy(op, match, cpy);
+        op=cpy;   /* correction */
+    }
+
+    /* end of decoding */
+    if (endOnInput)
+       return (int) (((char*)op)-dest);     /* Nb of output bytes decoded */
+    else
+       return (int) (((const char*)ip)-source);   /* Nb of input bytes read */
+
+    /* Overflow error detected */
+_output_error:
+    return (int) (-(((const char*)ip)-source))-1;
+}
diff --git a/lib/lz4_wrapper.c b/lib/lz4_wrapper.c
new file mode 100644
index 0000000..28fea76
--- /dev/null
+++ b/lib/lz4_wrapper.c
@@ -0,0 +1,137 @@ 
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * SPDX-License-Identifier: GPL 2.0+ BSD-3-Clause
+ */
+
+#include <common.h>
+#include <compiler.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+static u16 LZ4_readLE16(const void *src) { return le16_to_cpu(*(u16 *)src); }
+static void LZ4_copy4(void *dst, const void *src) { *(u32 *)dst = *(u32 *)src; }
+static void LZ4_copy8(void *dst, const void *src) { *(u64 *)dst = *(u64 *)src; }
+
+typedef  uint8_t BYTE;
+typedef uint16_t U16;
+typedef uint32_t U32;
+typedef  int32_t S32;
+typedef uint64_t U64;
+
+#define FORCE_INLINE static inline __attribute__((always_inline))
+
+/* Unaltered (except removing unrelated code) from github.com/Cyan4973/lz4. */
+#include "lz4.c"	/* #include for inlining, do not link! */
+
+#define LZ4F_MAGIC 0x184D2204
+
+struct lz4_frame_header {
+	u32 magic;
+	union {
+		u8 flags;
+		struct {
+			u8 reserved0:2;
+			u8 has_content_checksum:1;
+			u8 has_content_size:1;
+			u8 has_block_checksum:1;
+			u8 independent_blocks:1;
+			u8 version:2;
+		};
+	};
+	union {
+		u8 block_descriptor;
+		struct {
+			u8 reserved1:4;
+			u8 max_block_size:3;
+			u8 reserved2:1;
+		};
+	};
+	/* + u64 content_size iff has_content_size is set */
+	/* + u8 header_checksum */
+} __packed;
+
+struct lz4_block_header {
+	union {
+		u32 raw;
+		struct {
+			u32 size:31;
+			u32 not_compressed:1;
+		};
+	};
+	/* + size bytes of data */
+	/* + u32 block_checksum iff has_block_checksum is set */
+} __packed;
+
+int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn)
+{
+	const void *end = dst + *dstn;
+	const void *in = src;
+	void *out = dst;
+	int has_block_checksum;
+	int ret;
+	*dstn = 0;
+
+	{ /* With in-place decompression the header may become invalid later. */
+		const struct lz4_frame_header *h = in;
+
+		if (srcn < sizeof(*h) + sizeof(u64) + sizeof(u8))
+			return -EINVAL;	/* input overrun */
+
+		/* We assume there's always only a single, standard frame. */
+		if (le32_to_cpu(h->magic) != LZ4F_MAGIC || h->version != 1)
+			return -EPROTONOSUPPORT;	/* unknown format */
+		if (h->reserved0 || h->reserved1 || h->reserved2)
+			return -EINVAL;	/* reserved must be zero */
+		if (!h->independent_blocks)
+			return -EPROTONOSUPPORT; /* we can't support this yet */
+		has_block_checksum = h->has_block_checksum;
+
+		in += sizeof(*h);
+		if (h->has_content_size)
+			in += sizeof(u64);
+		in += sizeof(u8);
+	}
+
+	while (1) {
+		struct lz4_block_header b = { .raw = le32_to_cpu(*(u32 *)in) };
+		in += sizeof(struct lz4_block_header);
+
+		if (in - src + b.size > srcn) {
+			ret = -EINVAL;		/* input overrun */
+			break;
+		}
+
+		if (!b.size) {
+			ret = 0;	/* decompression successful */
+			break;
+		}
+
+		if (b.not_compressed) {
+			size_t size = min((ptrdiff_t)b.size, end - out);
+			memcpy(out, in, size);
+			out += size;
+			if (size < b.size) {
+				ret = -ENOBUFS;	/* output overrun */
+				break;
+			}
+		} else {
+			/* constant folding essential, do not touch params! */
+			int ret = LZ4_decompress_generic(in, out, b.size,
+					end - out, endOnInputSize,
+					full, 0, noDict, out, NULL, 0);
+			if (ret < 0) {
+				ret = -EPROTO;	/* decompression error */
+				break;
+			}
+			out += ret;
+		}
+
+		in += b.size;
+		if (has_block_checksum)
+			in += sizeof(u32);
+	}
+
+	*dstn = out - dst;
+	return ret;
+}
diff --git a/test/Kconfig b/test/Kconfig
index d71c332..c888de6 100644
--- a/test/Kconfig
+++ b/test/Kconfig
@@ -1,5 +1,6 @@ 
 menuconfig UNIT_TEST
 	bool "Unit tests"
+	select LZ4
 	help
 	  Select this to compile in unit tests for various parts of
 	  U-Boot. Test suites will be subcommands of the "ut" command.
diff --git a/test/compression.c b/test/compression.c
index 7ef3a8c..be4e04e 100644
--- a/test/compression.c
+++ b/test/compression.c
@@ -95,6 +95,28 @@  static const char lzo_compressed[] =
 	"\x73\x61\x67\x65\x73\x2e\x0a\x11\x00\x00\x00\x00\x00\x00";
 static const unsigned long lzo_compressed_size = 334;
 
+/* lz4 -z /tmp/plain.txt > /tmp/plain.lz4 */
+static const char lz4_compressed[] =
+	"\x04\x22\x4d\x18\x64\x70\xb9\x01\x01\x00\x00\xff\x19\x49\x20\x61"
+	"\x6d\x20\x61\x20\x68\x69\x67\x68\x6c\x79\x20\x63\x6f\x6d\x70\x72"
+	"\x65\x73\x73\x61\x62\x6c\x65\x20\x62\x69\x74\x20\x6f\x66\x20\x74"
+	"\x65\x78\x74\x2e\x0a\x28\x00\x3d\xf1\x25\x54\x68\x65\x72\x65\x20"
+	"\x61\x72\x65\x20\x6d\x61\x6e\x79\x20\x6c\x69\x6b\x65\x20\x6d\x65"
+	"\x2c\x20\x62\x75\x74\x20\x74\x68\x69\x73\x20\x6f\x6e\x65\x20\x69"
+	"\x73\x20\x6d\x69\x6e\x65\x2e\x0a\x49\x66\x20\x49\x20\x77\x32\x00"
+	"\xd1\x6e\x79\x20\x73\x68\x6f\x72\x74\x65\x72\x2c\x20\x74\x45\x00"
+	"\xf4\x0b\x77\x6f\x75\x6c\x64\x6e\x27\x74\x20\x62\x65\x20\x6d\x75"
+	"\x63\x68\x20\x73\x65\x6e\x73\x65\x20\x69\x6e\x0a\xcf\x00\x50\x69"
+	"\x6e\x67\x20\x6d\x12\x00\x00\x32\x00\xf0\x11\x20\x66\x69\x72\x73"
+	"\x74\x20\x70\x6c\x61\x63\x65\x2e\x20\x41\x74\x20\x6c\x65\x61\x73"
+	"\x74\x20\x77\x69\x74\x68\x20\x6c\x7a\x6f\x2c\x63\x00\xf5\x14\x77"
+	"\x61\x79\x2c\x0a\x77\x68\x69\x63\x68\x20\x61\x70\x70\x65\x61\x72"
+	"\x73\x20\x74\x6f\x20\x62\x65\x68\x61\x76\x65\x20\x70\x6f\x6f\x72"
+	"\x6c\x79\x4e\x00\x30\x61\x63\x65\x27\x01\x01\x95\x00\x01\x2d\x01"
+	"\xb0\x0a\x6d\x65\x73\x73\x61\x67\x65\x73\x2e\x0a\x00\x00\x00\x00"
+	"\x9d\x12\x8c\x9d";
+static const unsigned long lz4_compressed_size = 276;
+
 
 #define TEST_BUFFER_SIZE	512
 
@@ -227,6 +249,39 @@  static int uncompress_using_lzo(void *in, unsigned long in_size,
 	return (ret != LZO_E_OK);
 }
 
+static int compress_using_lz4(void *in, unsigned long in_size,
+			      void *out, unsigned long out_max,
+			      unsigned long *out_size)
+{
+	/* There is no lz4 compression in u-boot, so fake it. */
+	assert(in_size == strlen(plain));
+	assert(memcmp(plain, in, in_size) == 0);
+
+	if (lz4_compressed_size > out_max)
+		return -1;
+
+	memcpy(out, lz4_compressed, lz4_compressed_size);
+	if (out_size)
+		*out_size = lz4_compressed_size;
+
+	return 0;
+}
+
+static int uncompress_using_lz4(void *in, unsigned long in_size,
+				void *out, unsigned long out_max,
+				unsigned long *out_size)
+{
+	int ret;
+	size_t input_size = in_size;
+	size_t output_size = out_max;
+
+	ret = ulz4fn(in, input_size, out, &output_size);
+	if (out_size)
+		*out_size = output_size;
+
+	return (ret != 0);
+}
+
 #define errcheck(statement) if (!(statement)) { \
 	fprintf(stderr, "\tFailed: %s\n", #statement); \
 	ret = 1; \
@@ -325,6 +380,7 @@  static int do_ut_compression(cmd_tbl_t *cmdtp, int flag, int argc,
 	err += run_test("bzip2", compress_using_bzip2, uncompress_using_bzip2);
 	err += run_test("lzma", compress_using_lzma, uncompress_using_lzma);
 	err += run_test("lzo", compress_using_lzo, uncompress_using_lzo);
+	err += run_test("lz4", compress_using_lz4, uncompress_using_lz4);
 
 	printf("ut_compression %s\n", err == 0 ? "ok" : "FAILED");
 
@@ -401,6 +457,7 @@  static int do_ut_image_decomp(cmd_tbl_t *cmdtp, int flag, int argc,
 	err |= run_bootm_test(IH_COMP_BZIP2, compress_using_bzip2);
 	err |= run_bootm_test(IH_COMP_LZMA, compress_using_lzma);
 	err |= run_bootm_test(IH_COMP_LZO, compress_using_lzo);
+	err |= run_bootm_test(IH_COMP_LZ4, compress_using_lz4);
 	err |= run_bootm_test(IH_COMP_NONE, compress_using_none);
 
 	printf("ut_image_decomp %s\n", err == 0 ? "ok" : "FAILED");