Re: [PATCH v2] mtd: nand: support BENAND (Built-in ECC NAND)

[Matthieu CASTET <matthieu.castet@parrot.com>]

Gupta, Pekon a écrit :
> Hi,
> 
>> This enables support for BENAND, which is an SLC NAND flash solution
>> with embedded error correction code (ECC), currently supports only
>> 128bytes OOB type.
>>
>> In the read sequence, "status read command" is executed to check the
>> ECC status after read data. If bitflips occur, these are
>> automatically corrected by BENAND and the status indicates the result.
>>
>> The write sequence is the same as raw write and the ECC data are
>> automatically written to OOB by BENAND.
> 
> Just inquisitive, can anyone please share any throughput comparison between 'BENAND' & 'normal NAND' devices having same capacity and working on same clock-freq ?
> 
> (a) Usually on-chip memory controllers work on faster clock frequencies, as compared to the NAND devices connected to them externally on board.
> Thus I assume, ECC computation & correction can be done at faster rate.
> 
> (b) However, on other hand BENAND(s) have luxury of accessing the Flash storage array locally, thus eliminating I/O delays | un-optimized IO signal timing from the access-path.
> 
> So, if you can share the details throughput comparison between the two types of NAND devices, under various conditions it would be helpful.
> 
You always have to transfer the data from/to the nand devices to/from the host.

- Either the ecc internal controller is fast and the throughput are the same
than 'normal nand' (assuming the ecc controller on the host is fast),
- either it is slow and the throughput is limited by the internal ecc controller
(throughput is slower than 'normal nand')


Matthieu