Re: doc2000 nftl[abcd] devices

[Brendan J Simon <brendan.simon@ctam.com.au>]

>
>
>> Looking at them more closely, I see that I was mistaken -- we _don't_ 
>> continue the scan after finding the first NFTL on the device. 
>> Patching NFTL_mount() and find_boot_record() to take a 'start' 
>> argument for where to start scanning is simple enough -- you just 
>> need to fix NFTL_setup() to loop till NFTL_mount() stops working.
>>
> I expect it's not as easy as you suggest (at least for me as all this 
> MTD, NFTL stuff is doing my head in).
> In NFTL_mount, it uses the number of blocks supplied to it as 
> nftl->nb_blocks.  This is set in NFTP_setup() just before NFTL_mount 
> is called.  I think this is currently set to the entire mtd device 
> (ie. the DOC).  I'll put some more printks to find out exactly what it 
> is doing :)
> I guess the alternative to is to scan from some start address till the 
> next media headers are found, then the size is known and it can be 
> passed backed to NFTL_setup (directly or indirectly).
>
> Does this sound right ?
>
> What about holes in the DOC.  ie.  What if I have nftl_formatted 
> between 0x00000000-0x01FFFFFF & 0x04000000-0x7FFFFFFF.  This has a 
> hole between 0x02000000-0x03FFFFFF.  Does NFTL_mount cater for this ?  
> Should it ? If so, does this mean that the Media Header needs to be 
> searched to find the start of the partition and then the next Media 
> Header to find the end of the partition.  This seems wrong because the 
> first partition would be recognised as 4MB instead of 2MB.  There must 
> be some info in the media headers that give the size of the 
> partition.  Any clues ? I'll do some more research in the mean time. 


Does it make sense to put an nb_block_start in the NFTLRecord structure 
or would it better to pass this information to the NFTL_mount() and 
find_boot_records() functions.

When reading information from nftlb, nftlbc, etc, how does the device 
driver know where the first block of the device is ?
Does it need to know or does it use some of the other variables such as 
EUN, VUN, etc.

Thanks,
Brendan Simon.