Re: [PATCH v2 02/10] binman: Make compressed data header optional

Hi Simon,

Am 13.08.2022 um 16:59 schrieb Simon Glass:

Hi Stefan,

On Mon, 8 Aug 2022 at 04:51, Stefan Herbrechtsmeier stefan.herbrechtsmeier-oss@weidmueller.com wrote:

...

From: Stefan Herbrechtsmeier stefan.herbrechtsmeier@weidmueller.com

Move the compressed data header handling into the dtb blob entry class and make it optional. The header is uncommon, not supported by U-Boot and incompatible with external compressed artifacts.

If needed the header could be enabled with the following attribute beside the compress attribute: prepend = "length";

The header was introduced as part of commit eb0f4a4cb402 ("binman: Support replacing data in a cbfs") to allow device tree entries to be larger that the compressed contents. Regarding the commit "this is necessary to cope with a compressed device tree being updated in such a way that it shrinks after the entry size is already set (an obscure case)". This case need to be fixed without influence any compressed data by itself.

Signed-off-by: Stefan Herbrechtsmeier stefan.herbrechtsmeier@weidmueller.com

---

Changes in v2:

• Reworked to make the feature optional.

  tools/binman/cbfs_util.py | 8 ++--- tools/binman/comp_util.py | 11 ++---- tools/binman/entries.rst | 4 +++ tools/binman/entry.py | 2 +- tools/binman/etype/blob_dtb.py | 21 ++++++++++++ tools/binman/ftest.py | 34 ++++++++++++++++--- .../test/235_compress_prepend_length_dtb.dts | 17 ++++++++++ 7 files changed, 78 insertions(+), 19 deletions(-) create mode 100644 tools/binman/test/235_compress_prepend_length_dtb.dts

I've been through this and I think it is a good change. We can use your technique (property in the blob_dtb etype) to deal with any future problems that come up.

But I would like to split this patch into three:

1. Add your blob_dtb property and the test
2. Change all uses of compress()/decompress() to call with add with_header=False
3. Drop the with_header arg from comp_util.py

Okay, I will split the commit.

A few more tweaks below.

...

diff --git a/tools/binman/cbfs_util.py b/tools/binman/cbfs_util.py index 9cad03886f..a1836f4ad3 100644 --- a/tools/binman/cbfs_util.py +++ b/tools/binman/cbfs_util.py @@ -241,9 +241,9 @@ class CbfsFile(object): """Handle decompressing data if necessary""" indata = self.data if self.compress == COMPRESS_LZ4:

•        data = comp_util.decompress(indata, 'lz4', with_header=False)
  

•        data = comp_util.decompress(indata, 'lz4')
      elif self.compress == COMPRESS_LZMA:
  

•        data = comp_util.decompress(indata, 'lzma', with_header=False)
  

•        data = comp_util.decompress(indata, 'lzma')
      else:
          data = indata
      self.memlen = len(data)
  

@@ -362,9 +362,9 @@ class CbfsFile(object): elif self.ftype == TYPE_RAW: orig_data = data if self.compress == COMPRESS_LZ4:

•            data = comp_util.compress(orig_data, 'lz4', with_header=False)
  

•            data = comp_util.compress(orig_data, 'lz4')
          elif self.compress == COMPRESS_LZMA:
  

•            data = comp_util.compress(orig_data, 'lzma', with_header=False)
  

•            data = comp_util.compress(orig_data, 'lzma')
          self.memlen = len(orig_data)
          self.data_len = len(data)
          attr = struct.pack(ATTR_COMPRESSION_FORMAT,
  

diff --git a/tools/binman/comp_util.py b/tools/binman/comp_util.py index dc76adab35..269bbf7975 100644 --- a/tools/binman/comp_util.py +++ b/tools/binman/comp_util.py @@ -3,7 +3,6 @@ # """Utilities to compress and decompress data"""

-import struct import tempfile

from binman import bintool @@ -16,7 +15,7 @@ LZMA_ALONE = bintool.Bintool.create('lzma_alone') HAVE_LZMA_ALONE = LZMA_ALONE.is_present()

-def compress(indata, algo, with_header=True): +def compress(indata, algo): """Compress some data using a given algorithm

  Note that for lzma this uses an old version of the algorithm, not that

@@ -41,12 +40,9 @@ def compress(indata, algo, with_header=True): data = LZMA_ALONE.compress(indata) else: raise ValueError("Unknown algorithm '%s'" % algo)

• if with_header:

•    hdr = struct.pack('<I', len(data))
  

•    data = hdr + data
  return data
  
  

-def decompress(indata, algo, with_header=True): +def decompress(indata, algo): """Decompress some data using a given algorithm

  Note that for lzma this uses an old version of the algorithm, not that

@@ -64,9 +60,6 @@ def decompress(indata, algo, with_header=True): """ if algo == 'none': return indata

• if with_header:

•    data_len = struct.unpack('<I', indata[:4])[0]
  

•    indata = indata[4:4 + data_len]
  if algo == 'lz4':
      data = LZ4.decompress(indata)
  elif algo == 'lzma':
  

diff --git a/tools/binman/entries.rst b/tools/binman/entries.rst index ae4305c99e..8e722426d3 100644 --- a/tools/binman/entries.rst +++ b/tools/binman/entries.rst @@ -208,6 +208,10 @@ This is a blob containing a device tree. The contents of the blob are obtained from the list of available device-tree files, managed by the 'state' module.

+Additional Properties / Entry arguments:

• • prepend: Header type to use:

•    none: No header
  

•    length: 32-bit length header
  
  
  

  Entry: blob-ext: Externally built binary blob

diff --git a/tools/binman/entry.py b/tools/binman/entry.py index a07a588864..8cbfd43af9 100644 --- a/tools/binman/entry.py +++ b/tools/binman/entry.py @@ -1069,7 +1069,7 @@ features to produce new behaviours. indata: Data to compress

      Returns:

•        Compressed data (first word is the compressed size)
  

•        Compressed data
      """
      self.uncomp_data = indata
      if self.compress != 'none':
  

diff --git a/tools/binman/etype/blob_dtb.py b/tools/binman/etype/blob_dtb.py index 4159e3032a..652b8abd8f 100644 --- a/tools/binman/etype/blob_dtb.py +++ b/tools/binman/etype/blob_dtb.py @@ -7,6 +7,8 @@

from binman.entry import Entry from binman.etype.blob import Entry_blob +from dtoc import fdt_util +import struct

# This is imported if needed state = None @@ -17,6 +19,9 @@ class Entry_blob_dtb(Entry_blob): This is a blob containing a device tree. The contents of the blob are obtained from the list of available device-tree files, managed by the 'state' module.

• Additional attributes:

•    prepend: Header used (e.g. 'length'), 'none' if none
  """
  def __init__(self, section, etype, node):
      # Put this here to allow entry-docs and help to work without libfdt
  

@@ -25,6 +30,12 @@ class Entry_blob_dtb(Entry_blob):

      super().__init__(section, etype, node)

•    self.prepend = 'none'
  

None ?

I copy this from the compress attribute. You only need one check to support a missing value or a 'none' value. But I don't need this check and can use None.

...

• def ReadNode(self):

•    super().ReadNode()
  

•    self.prepend = fdt_util.GetString(self._node, 'prepend', 'none')
  

Can you drop the 'none' so that it uses None instead?

Is 'none' a valid entry? Do we need to distinguish between 'none' and an invalid value?

Aso we should check for a valid value here - e.g. it must be 'length' and not something else, otherwise self.Raise()

Okay. I will remove the 'none' and only support 'length'.

Regards Stefan