Mount other SRAM Filesystem

[jennifer averett]

Joel Sherrill wrote:

> Sturniolo Jose wrote:
> >
> > Hi, I am trying to mount other memory block, SRAM, using the MOUNT function,
> > however I can't find how to indicate the SRAM address to use.
> >
> > My target is:
> > - Create a directory, called /SRAM
> > - Mount on it, other memory area, SRAM.
> >
> > Any ideas? Is possible?
>
> At the current time, the IMFS uses memory obtained via malloc().  There
> needs to be modifications to it for use with memory obtained via other
> means.
> For your case, it would be enough to define some mechanism where the
> IMFS
> had plug-in memory allocation routines.  Then it could get them via
> that.
>
> I think long term, the best thing would be to add a parameter to the
> mount()
> call which allowed for filesystem specific configuration information to
> be associated with this instantiation of the filesystem type.  This way,
> you could mount the IMFS using malloc/free or another memory allocation
> scheme for your SRAM.
>

I don't think adding a parameter is the answer.  The device parameter was
meant to be the connection between the filesystem and whatever device
(SRAM) in this case, was controlling the memory.  There is already a
parameter that allows filesystem specific configuraiton information to
passed in ( rtems_filesystem_mount_table_entry_t) has a void * entry
that is specific to the file system being mounted.  The IMFS is just
not using this entry.

Just my 2 cents

Jennifer

>
> Does that make sense?
>
> Long term, there needs to be a derivative of the IMFS which does NOT
> assume it can write directly into storage.  It should obtain blocks
> and assume that it only has a copy of them.  This would allow it to
> work with non-volatile storage such as flash where it can not treat
> it like RAM.
>
> > Regards.
> >
> > Jose Sturniolo
>
> --
> Joel Sherrill, Ph.D.             Director of Research & Development
> joel at OARcorp.com                 On-Line Applications Research
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