Question on flash node on device tree source

Question on flash node on device tree source

[Angelo]

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Hi all.

I need some info about device tree blob.
I'm testing a powerpc board (very similar to mpc512xev) with the following feature:
 - 256MB flash (only 1 bank)

Changes some lines of device tree source about flash

localbus@80000020 {
        compatible = "fsl,mpc5121ads-localbus";
        #address-cells = <2>;
        #size-cells = <1>;
        reg = <0000020 40>;

        ranges = <0 0 fc000000 04000000
              2 0 82000000 00008000>;

        flash@0,0 {
            device_type = "rom";
            compatible = "direct-mapped";
            probe-type = "CFI";
            reg = <0 0 4000000>;
            #address-cells = <1>;
            #size-cells = <1>;
            bank-width = <4>;
            device-width = <2>;
            partitions = <00000000 00040000        // first sector is protected
                      00040000 03c00000        // 60 Mb for filesystem
                      03c40000 00280000        // 2.5 Mb for kernel
                      03ec0000 00040000        // one sector for device tree
                      03f00000 00100000>;    // one Mb for u-boot
            partition-names = "protected", "filesystem", "kernel", "device-tree", "u-boot";
        };
.....
with these changes:
.....
        flash@0,0 {
            device_type = "rom";
            compatible = "direct-mapped";
            probe-type = "CFI";
            reg = <0 0 1000000>;
            #address-cells = <1>;
            #size-cells = <1>;
            bank-width = <1>;
            device-width = <1>;
            partitions = <300000 200000        //uimage
                        400000 3200000>;    // fs
            partition-names = "uimage", "fs";
        };
.....

The problem is that on bootstrap stage, kernel truncate the flash memory to 16MB, so i cannot access to the whole flash. kernel messages:

mtd: partition "fs" extends  beyond the end of device "60000000.flash" size truncated to 0xc00000.

I'd like to know if i have to specify into the dtb file the size of flash mem. What about nand flash controller and its functionality? 
If you have more info about this, please write to me.

Thanks in advance,
@s




      

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Re: Question on flash node on device tree source

[David Gibson]

On Tue, Sep 08, 2009 at 12:18:33PM +0000, Angelo wrote:
> Hi all.
> 
> I need some info about device tree blob.
> I'm testing a powerpc board (very similar to mpc512xev) with the following feature:
>  - 256MB flash (only 1 bank)
> 
> Changes some lines of device tree source about flash
> 
> localbus@80000020 {
>         compatible = "fsl,mpc5121ads-localbus";
>         #address-cells = <2>;
>         #size-cells = <1>;
>         reg = <0000020 40>;
> 
>         ranges = <0 0 fc000000 04000000
>               2 0 82000000 00008000>;

First thing to note is that you're still using dts-v0 syntax.  You
really want to change over to dts-v1 syntax.  Which probably means
you've based your tree on an old version of the mpc512eev dts.  All
the in-kernel dts files have already been converted and current
versions of dtc don't support the old syntax.

>         flash@0,0 {
>             device_type = "rom";
>             compatible = "direct-mapped";

Second thing to note is that you're using the old, broken flash
binding.  You should use the new binding described in
Documentation/powerpc/dts-bindings/mtd-physmap.txt.

>             probe-type = "CFI";
>             reg = <0 0 4000000>;
>             #address-cells = <1>;
>             #size-cells = <1>;
>             bank-width = <4>;
>             device-width = <2>;
>             partitions = <00000000 00040000        // first sector is protected
>                       00040000 03c00000        // 60 Mb for filesystem
>                       03c40000 00280000        // 2.5 Mb for kernel
>                       03ec0000 00040000        // one sector for device tree
>                       03f00000 00100000>;    // one Mb for u-boot
>             partition-names = "protected", "filesystem", "kernel", "device-tree", "u-boot";
>         };
> .....
> with these changes:
> .....
>         flash@0,0 {
>             device_type = "rom";
>             compatible = "direct-mapped";
>             probe-type = "CFI";
>             reg = <0 0 1000000>;

And the third thing to note is that 0x1000000 == 16MB.

>             #address-cells = <1>;
>             #size-cells = <1>;
>             bank-width = <1>;
>             device-width = <1>;
>             partitions = <300000 200000        //uimage
>                         400000 3200000>;    // fs
>             partition-names = "uimage", "fs";
>         };
> .....
> 
> The problem is that on bootstrap stage, kernel truncate the flash
> memory to 16MB, so i cannot access to the whole flash. kernel
> messages:

That would be because you told the kernel your flash was 16MB in the
'reg' property.  Looks like you missed out a zero.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson