Re: [PATCH v1 2/3] colibri-imx7: specify MTD partitions on command line

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Francesco,

francesco@dolcini.it wrote on Mon, 16 Jan 2023 14:58:28 +0100:

> On Sun, Jan 15, 2023 at 03:33:25PM +0100, Marek Vasut wrote:
> > On 1/13/23 19:45, Francesco Dolcini wrote:  
> > > From: Francesco Dolcini <francesco.dolcini@toradex.com>
> > > 
> > > Disable fdt_fixup_mtdparts(), instead pass MTD partition on the command
> > > line. This is the preferred method to be used when partitions are not
> > > statically defined into the DTS according the Linux MTD subsystem
> > > maintainer.  
> > 
> > Do we really want to do this ?
> > I thought passing the mtdparts via DT is the preferred way ?  
> 
> Yes, to me it seems like the most robust approach to minimize chances
> of regressions and boot issues.
> 
> With the current dts schema, that expects the partitions to not be
> direct children of the nand controller node, but expecting having a
> nand-chip, and partitions as a child of the nand-chip this is the most
> likely approach to just works.
> 
> For example if I add a partition node to my DTS, older U-Boot will just
> ignore it and add the partitions as children of the nand controller.
> In this case the current parser will just fails leading to another
> flavor of boot failure on our board.
> 
> In reality I cannot really tell which u-boot/kernel combination is going
> to be used on our SOMs.
> 
> Said that, what would be the disadvantages of having the partitions on
> the command line? Miquel?

It only works with the simplest parser, but that's anyway the one
implied when tweaking the DT from U-Boot to add the partitions.

If that works, then it looks the simplest approach indeed.

Thanks,
Miquèl