Re: [PATCH v4 2/5] nvmem: core: verify cell's raw_len

[Dmitry Baryshkov]

On Thu, Feb 20, 2025 at 02:18:06PM +0000, Mark Brown wrote:
> On Wed, Feb 19, 2025 at 05:14:43PM +0200, Dmitry Baryshkov wrote:
> > On Wed, 19 Feb 2025 at 16:51, Mark Brown <broonie@xxxxxxxxxx> wrote:
> > > On Thu, Jan 09, 2025 at 06:35:46AM +0200, Dmitry Baryshkov wrote:
> 
> > > > Check that the NVMEM cell's raw_len is a aligned to word_size. Otherwise
> > > > Otherwise drivers might face incomplete read while accessing the last
> > > > part of the NVMEM cell.
> 
> > > I'm seeing a bunch of failures on i.MX platforms in -next which bisect
> > > to this patch.  For example on the i.MX6q based UDOOq various things
> > > including the ethernet fail to come up due to the efuse not appearing:
> 
> > > [    1.735264] nvmem imx-ocotp0: cell mac-addr raw len 6 unaligned to nvmem word size 4
> > > [    1.735289] imx_ocotp 21bc000.efuse: probe with driver imx_ocotp failed with error -22
> 
> > This looks like an error on the i.MX platforms. The raw_len must be
> > aligned to word size. I think the easiest fix is to implement the
> > .fixup_dt_cell_info() callback like I did for the qfprom driver.
> 
> That sounds pluasible, but as things stand we've got a regression on
> these platforms - taking out ethernet breaks NFS boot apart from
> anything else.  I'd also be a bit concerned that there might be other
> users with issues, does this need an audit of users before trying to
> enforce this requirement?

A quick grep shows that there are enough drivers using word size greater
than 1. Would you mind checking if the following patch fixes an issue
for you? (Note, compile-tested only.)