On Tuesday 24 March 2009, Grant Likely wrote:
> > OK, in the example above such a spanning partition is not so likely. But
> > think about my original example, the Intel P30 with two different cfi
> > compatible chips on one die. Here a partition spanning over both devices
> > is very likely.
>
> I agree. Same thing when two or more flash chips are put on a board
> in consecutive addresses. I've worked on plenty of these arrangements
> myself.
Yes, multiple identical devices are no problem at all. This is handled
correctly with the current code and device tree syntax.
> This case really does sound like a driver bug and that the existing
> cfi-flash binding is sufficient to describe the hardware. IIUC, when
> all the flash chips are of the same type the physmap_of driver should
> be smart enough to detect each of the flash chips within the reg
> range.
*When* all are identical then this works, yes. But in the Intel P30 case the 2
chips are not identical. And from my understanding this is not a problem/bug
in the physmap_of driver.
> If I'm wrong and it cannot do this, then it would be a simple matter
> of adding an additional tuple to reg for each discrete chip. A
> simple, backwards compatible extension which doesn't require a new
> binding.
So you are thinking of something like this?
fl...@f0000000,0 {
#address-cells = <1>;
#size-cells = <1>;
compatible = "cfi-flash";
reg = <0 0x00000000 0x02000000
0 0x02000000 0x02000000>;
bank-width = <2>;
device-width = <2>;
partit...@0 {
label = "test-part1";
reg = <0 0x04000000>;
};
};
That's also fine with me. Changes to physmap_of would be minimal this way.
Do we have a consensus that this should be the way to implement concat support
in physmap_of?
Thanks.
Best regards,
Stefan
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