Boot failure regression on 6.0.10 stable kernel on iMX7

[Francesco Dolcini]

+ u-boot list

On Thu, Dec 01, 2022 at 12:25:34PM +0100, Marek Vasut wrote:
> On 12/1/22 12:03, Francesco Dolcini wrote:
> > On Wed, Nov 30, 2022 at 11:59:04PM +0100, Marek Vasut wrote:
> > > On 11/30/22 21:51, Francesco Dolcini wrote:
> > > > On Wed, Nov 30, 2022 at 03:41:13PM +0100, Marek Vasut wrote:
> > > > > On 11/30/22 14:52, Francesco Dolcini wrote:
> > > > > > [    0.000000] Booting Linux on physical CPU 0x0
> > > > > > [    0.000000] Linux version 6.0.10 (francesco at francesco-nb) (arm-linux-gnueabihf-gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.
> > > > > > 4.0, GNU ld (GNU Binutils for Ubuntu) 2.34) #36 SMP Wed Nov 30 14:07:15 CET 2022
> > > > > > ...
> > > > > > [    4.407499] gpmi-nand: error parsing ofpart partition /soc/nand-controller at 33002000/partition at 0 (/soc/nand-controller
> > > > > > @33002000)
> > > > > > [    4.438401] gpmi-nand 33002000.nand-controller: driver registered.
> > > > > > ...
> > > > > > [    5.933906] VFS: Cannot open root device "ubi0:rootfs" or unknown-block(0,0): error -19
> > > > > > [    5.946504] Please append a correct "root=" boot option; here are the available partitions:
> > > > > > ...
> > > > > > 
> > > > > > Any idea? I'm not familiar with the gpmi-nand driver and I would just revert it, but
> > > > > > maybe you have a better idea.
> > > > > 
> > > > ...
> > > > OF partition are created by U-Boot from
> > > >     mtdparts=mtdparts=gpmi-nand:512k(mx7-bcb),1536k(u-boot1)ro,1536k(u-boot2)ro,512k(u-boot-env),-(ubi)
> > > > env variables calling fdt_fixup_mtdparts from colibri_imx7.c
> > > > 
> > > > This is generated by U-Boot, I would need to dump what he did generate
> > > > from the standard fdt_fixup_mtdparts(). I will try to do it tomorrow
> > > > unless what I wrote here is already enough to understand what's going
> > > > on.
> > > 
> > > Oh drat ... I see. It's the u-boot fdt_node_set_part_info() which checks the
> > > current NAND controller #size-cells and uses that when generating MTD
> > > partitions 'reg' properties. Since #size-cells is now zero, the reg
> > > properties would be malformed.
> > 
> > I think the issue is slightly different, the u-boot code checks it and
> > if not set it defaults to #size-cells = <1>. Said that u-boot
> > never set #size-cells anywhere.
> 
> Which it really should, can you send a patch there too ?

I guess that it is slightly more complicated.

U-Boot directly updates the nand-controller root node with the
partitions, unless there is already a partitions child node present. In
the first case (legacy OF partition definition) setting the #size-cells
does not seems that correct, while in the second case I agree it should
really do it. I'll see what I can come-up with.

> > diff --git a/drivers/mtd/parsers/ofpart_core.c b/drivers/mtd/parsers/ofpart_core.c
> > index 192190c42fc8..fffd60acd926 100644
> > --- a/drivers/mtd/parsers/ofpart_core.c
> > +++ b/drivers/mtd/parsers/ofpart_core.c
> > @@ -122,6 +122,8 @@ static int parse_fixed_partitions(struct mtd_info *master,
> > 
> >                  a_cells = of_n_addr_cells(pp);
> >                  s_cells = of_n_size_cells(pp);
> > +               if (s_cells == 0)
> > +                       s_cells = 1; // for backward compatibility
> >                  if (len / 4 != a_cells + s_cells) {
> >                          pr_debug("%s: ofpart partition %pOF (%pOF) error parsing reg property.\n",
> >                                   master->name, pp,
> 
> You might want to print a warning too, so users would fix their DTs, since
> once there is MTD partition > 4 GiB, this would break. Otherwise I like this
> option.

I tested it and it's working as expected, I'll send a proper patch soon.

Francesco