[ECOS] RE : RE : [ECOS] Multiple partitions on a FLASH device.

Vincent Catros Vincent.Catros@elios-informatique.fr
Tue Nov 25 10:56:00 GMT 2003


Andrew,

Sorry for my late answer but, as a newbye with eCos, I preferred to
"dive" a little bit more into source code before saying something
obviously wrong.

> -----Message d'origine-----
> De : Andrew Lunn [mailto:andrew@lunn.ch]
> Envoyé : mercredi 19 novembre 2003 11:57
> À : Vincent Catros
> Cc : 'Andrew Lunn'; ecos-discuss@sources.redhat.com
> Objet : Re: RE : [ECOS] Multiple partitions on a FLASH device.
> 
> > OK, this will work on a "Linux Synthetic Target" because that way we
> > create a totaly separated FLASH device.
> 
> How are they seperate. I don't understand what you mean.

OK, my sentence was not clear.
I was thinking that you asked me to create 2 "Synthetic FLASH Device"
emulated by 2 different files. That was the meening of "totaly separated
FLASH devices".

I think that using 1 "Synthetic FLASH device" with 2 partitions will
work.
But this is a particular case.

With "Synthetic FLASH Driver", the "FLASH" device is emulated by a file.
Mutual access to different regions of a file (different FLASH
partitions) using different file handles are safe.

For "real FLASH device" driver I think it's different.

> > I think this is not possible without modifying the FLASH driver.
> 
> What do you think is wrong with the FLASH driver. Why cannot it do
> this?

Some FLASH registers are accessed for read/write/erase operations.
Mutual accesses to tis registers don't seem to be safe. 
I did'nt seen any critical ressource access protection.

So, mutual read/write/erase operations issued from 2 different JFFS2
file-system will probably go wrong at FLASH device level.

Regards

Vincent


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