Re: mtd concat OF question

On Mon, Jan 24, 2011 at 03:37:49PM +0300, Stanislav O. Bezzubtsev wrote:

Hello all.

1) Is there an ability to specify in .dts an mtd_concat partition that
consists of several parts of a same flash drive?
For example, let there be 2MB flash drive and for some hardware limitations
u-boot can be stored only at 1MB offset. So, can I specify an mtd device to
own [0 -- 1MB] and [1.5MB -- 2MB]? As far as I can see (from
the drivers/mtd/ofpart.c) there is no support for such a feature.

I don't think so, no.

2) If the answer on the previous question is "no". What shall be the most
natural way to enhance the dts format? As for me it seems to be reasonable
to allow partition regs description to consists more then of 2 values (N
pairs). Example is below:

nor-flash@0,0 {
    compatible = "amd,s29gl01gp", "cfi-flash";
    bank-width = <2>;
    reg = <0x0 0x200000>;
    #address-cells = <1>;
    #size-cells = <1>;

BTW, you're missing a 'ranges' property here (It appears that the
documentation is missing it too, which definitely needs to be fixed).

    partition@100000 {
        label = "uboot";
        reg = <0x100000 0x80000>;
        read-only;
    };

    partition@0 {
        label = "user";
        reg = <0x000000 0x100000
                  0x180000 0x80000>;

Yes, I think this sounds reasonable, but the devil is in the
implementation.  Write a patch adding support for this binding, and
amend the documentation, and we'll see what it looks like.

g.