Re: [PATCH] binman: nxp_imx8mcst: Handle FCFB header during SPI NOR boot

Hi Marek,

On Mon, 20 Jul 2026 at 20:10, Marek Vasut <[email protected]> wrote:
>
> On 7/17/26 4:05 PM, Simon Glass wrote:
>
> Hello Simon,
>
> >> diff --git a/tools/binman/etype/nxp_imx8mcst.py b/tools/binman/etype/nxp_imx8mcst.py
> >> @@ -114,6 +115,13 @@ class Entry_nxp_imx8mcst(Entry_mkimage):
> >> +        elif signtype == MAGIC_NXP_IMX_FCFB: # SPL/imx8mimage with FCFB
> >> +            # Sign the payload including FCFB and imx8mimage headers
> >> +            # (extra 0x1000 and 0x40 bytes before the payload)
> >> +            signbase -= 0x1040
> >> +            signsize = struct.unpack('<I', data[4120:4124])[0] - signbase
> >
> > Please see below for test ideas.
> >
> > Also, 4120 is quite obscure as a decimal literal. Since this branch is
> > the IVT one shifted by 0x1000, perhaps the two could be merged, e.g.:
> >
> >      if signtype in (MAGIC_NXP_IMX_IVT, MAGIC_NXP_IMX_FCFB):
> >          off = 0x1000 if signtype == MAGIC_NXP_IMX_FCFB else 0
> >          signbase -= off + 0x40
> >          signsize = struct.unpack(
> >              '<I', data[off + 24:off + 28])[0] - signbase
> >          data = data[:signsize]
> >
> > That makes it clear the value being read is the csf pointer at IVT
> > offset 24, same as the existing case. What do you think?
>
> Yuck, no, I would very much prefer the current readable form than this
> conflated horribleness. The image assembly is convoluted enough as it is.
>
> >> diff --git a/tools/binman/etype/nxp_imx8mcst.py b/tools/binman/etype/nxp_imx8mcst.py
> >> @@ -114,6 +115,13 @@ class Entry_nxp_imx8mcst(Entry_mkimage):
> >> +        elif signtype == MAGIC_NXP_IMX_FCFB: # SPL/imx8mimage with FCFB
> >
> > Please can you also update the block comment above this code ("Parse
> > the input data and figure out what it is that is being signed") to
> > mention the FCFB case?
>
> Done in V2.
>
> > Here is my attempt at a test (it doesn't actually check the output though):
> If you would like to write a proper test, I can help with providing
> expected outputs.

Checking outputs is nice but (perhaps oddly!) not essential. Binman
just requires that tests exercise the code. So the test I sent
previously should be enough to get 'binman test -T' to pass.

Regards,
Simon