Re: [PATCH v1] mtd: parsers: ofpart: Fix parsing when size-cells is 0

Miquel Raynal
2022-12-02T17:06:14Z

Hi Francesco,

francesco@dolcini.it wrote on Fri, 2 Dec 2022 17:45:37 +0100:

> On Fri, Dec 02, 2022 at 05:17:59PM +0100, Marek Vasut wrote:
> > On 12/2/22 16:49, Miquel Raynal wrote:
> > > , not the NAND controller node. I hope this
> > > is correctly supported in U-Boot though. So if there is a NAND chip
> > > subnode, I suppose U-Boot would try to create the partitions that are
> > > inside, or even in the sub "partitions" container.
> >
> > My understanding is that U-Boot checks the nand-controller node size-cells,
> > not the nand-chip{} or partitions{} subnode size-cells .
> Not 100% correct.
>
> - U-Boot before v2022.04 updates the nand-controller{} node, no matter what.
> - U-Boot starting from v2022.04 looks for `partitions{}` into the
> nand-controller{} node, and creates the partition into it if found.
> If not found it behaves the same way as the previous versions.
> See commit 36fee2f7621e ("common: fdt_support: add support for "partitions" subnode to fdt_fixup_mtdparts()")
>
> I'd like to stress once more the fact that we cannot expect old U-Boot
> to be updated in the field, and they will keep generating the partitions
> as child of the nand-controller node whatever we do with the dts file.
>
> I think that this should be treated the same way as any other fixup we
> might have for broken firmware, especially considering that this used to
> "work" (yes, I can agree that it horrible, but I cannot change the past)
> without even a warning since the imx7 support was first introduced in
> the linux kernel years ago.
>
> > Francesco, can you please share the DT, including the U-Boot generated
> > partitions, which is passed to Linux on Colibri MX7 ? I think that should
> > make all confusion go away.
>
> The device tree part is easy, just
> arch/arm/boot/dts/imx7d-colibri-eval-v3.dts.
>
> and the nand-controller node is coming from
>
> #include "imx7d.dtsi"
>
> plus
>
> &gpmi {
> fsl,use-minimum-ecc;
> nand-ecc-mode = "hw";
> nand-on-flash-bbt;
> pinctrl-names = "default";
> pinctrl-0 = <&pinctrl_gpmi_nand>;
> };
>
> The partitions nodes are generated 100% by U-Boot, nothing is present in
> the dts source files.

I hope if you provide a NAND chip child node, the partitions are created
at the right location, otherwise this is so, so wrong...

>
> With this DTS file as input, whatever U-Boot version is used I have the
> following generated:
>
> root@colibri-imx7-02844233:/# ls /proc/device-tree/soc/nand-controller@33002000/
> #address-cells dma-names nand-on-flash-bbt pinctrl-0
> #size-cells dmas partition@0 pinctrl-names
> assigned-clock-parents fsl,use-minimum-ecc partition@200000 reg
> assigned-clocks interrupt-names partition@380000 reg-names
> clock-names interrupts partition@400000 status
> clocks name partition@80000
> compatible nand-ecc-mode phandle
>
> root@colibri-imx7-02844233:/# ls /proc/device-tree/soc/nand-controller@33002000/partition@*
> /proc/device-tree/soc/nand-controller@33002000/partition@0:
> label name reg
>
> /proc/device-tree/soc/nand-controller@33002000/partition@200000:
> label name read_only reg
>
> /proc/device-tree/soc/nand-controller@33002000/partition@380000:
> label name reg
>
> /proc/device-tree/soc/nand-controller@33002000/partition@400000:
> label name reg
>
> /proc/device-tree/soc/nand-controller@33002000/partition@80000:
> label name read_only reg
>
>

Thanks,
Miquèl