[U-Boot] [PATCH 1/2 v2] cramfs: make cramfs usable on non NOR flash

[Wolfgang Denk]

Dear Heiko Schocher,

In message <4B613D24.7060604 at denx.de> you wrote:
> 
> The cramfs image is located in RAM (where it first was copied from
> whenever), and then files are read from it with the "cramfsload"
> command ...

OK.

> >> +#if !defined(CONFIG_SYS_NO_FLASH)
> >>  	part.offset = addr - flash_info[id.num].start[0];
> >> +#else
> >> +	part.offset = addr;
> >> +#endif
...
> No, we can have it in ROM or in RAM.

OK.

> > What about systems that have both NOR _and_ NAND?
> 
> Are there such systems, with cramfs support? Actual cramfs support
> in mainline is only for NOR devices ...

Yes, but I understand that you want to also support cramfs when not
stored in NOR.

With your code I can read files from a cramfs image stored in RAM
(when there is nor NOR flash), _or_ I can read it from NOR flash.
Right?

But what about reading from files a cramfs image stored in RAM  on  a
system  that  _has_  NOR flash? And being able to read files a cramfs
image stored in NOR as well? It seems your code cannot do this.


I understand that the suggested patch is an improvement over the
existing state (it adds the capability to read cramfs in RAM on
NOR-les systems), but I think this restriction ("on NOR-less
systems") should be lifted as well.

In other words: I think, the decision whether to use

	part.offset = addr - flash_info[id.num].start[0];
or
	part.offset = addr;

should be made at run time (based on the location of the image - in
NOR versus in RAM - have a look at how this is done in the "cp"
command), not at compile time.

Best regards,

Wolfgang Denk

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