Messages in this thread | | | Date | Thu, 7 Jan 2016 13:53:00 +0800 | Subject | Re: [PATCH v2 00/12] mtd: nand_bbt: introduce independent nand BBT | From | Peter Pan <> |
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Hi Boris,
On Wed, Jan 6, 2016 at 10:29 PM, Boris Brezillon <boris.brezillon@free-electrons.com> wrote: > On Wed, 30 Dec 2015 09:31:06 +0100 > Boris Brezillon <boris.brezillon@free-electrons.com> wrote: > >> Hi Peter, >> >> On Wed, 30 Dec 2015 15:18:39 +0800 >> 潘栋 <peterpansjtu@gmail.com> wrote: >> >> > Hi Boris and Ezequiel, >> > >> > 2015-12-29 23:11 GMT+08:00 Boris Brezillon <boris.brezillon@free-electrons.com>: >> > > On Tue, 29 Dec 2015 12:07:50 -0300 >> > > Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> wrote: >> > > >> > >> On 29 December 2015 at 06:35, Boris Brezillon >> > >> <boris.brezillon@free-electrons.com> wrote: >> > >> > Hi, >> > >> > >> > >> > On Mon, 28 Dec 2015 17:42:50 -0300 >> > >> > Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> wrote: >> > >> > >> > >> >> This is looking a lot better, thanks for the good work! >> > >> >> >> > >> >> On 15 December 2015 at 02:59, Peter Pan <peterpansjtu@gmail.com> wrote: >> > >> >> > Currently nand_bbt.c is tied with struct nand_chip, and it makes other >> > >> >> > NAND family chips hard to use nand_bbt.c. Maybe it's the reason why >> > >> >> > onenand has own bbt(onenand_bbt.c). >> > >> >> > >> > >> >> > Separate struct nand_chip from BBT code can make current BBT shareable. >> > >> >> > We create struct nand_bbt to take place of nand_chip in nand_bbt.c. >> > >> >> > Struct nand_bbt contains all the information BBT needed from outside and >> > >> >> > it should be embedded into NAND family chip struct (such as struct nand_chip). >> > >> >> > NAND family driver should allocate, initialize and free struct nand_bbt. >> > >> >> > >> > >> >> > Below is mtd folder structure we want: >> > >> >> > mtd >> > >> >> > ├── Kconfig >> > >> >> > ├── Makefile >> > >> >> > ├── ... >> > >> >> > ├── nand_bbt.c >> > >> >> >> > >> >> Hm.. I'm not sure about having nand_bbt.c in drivers/mtd. >> > >> >> What's wrong with drivers/mtd/nand ? >> > >> > >> > >> > I haven't reviewed the series yet, but I agree. If the BBT code is only >> > >> > meant to be used on NAND based devices, it should probably stay in >> > >> > drivers/mtd/nand. >> > >> > >> > >> >> >> > >> >> In fact, I was thinking we could go further and clean up the directories a bit >> > >> >> by separating core code, from controllers code, from SPI NAND code: >> > >> >> >> > >> >> drivers/mtd/nand/ >> > >> >> drivers/mtd/nand/controllers >> > >> >> drivers/mtd/nand/spi >> > >> >> >> > >> >> Makes any sense? >> > >> > >> > >> > Actually I had the secret plan of moving all (raw) NAND controller >> > >> > drivers into the drivers/mtd/nand/controllers directory, though this >> > >> > was for a different reason: I'd like to create another directory for >> > >> > manufacturer specific code in order to support some advanced features >> > >> > on NANDs that do not implement (or only partially implement) the ONFI >> > >> > standard. >> > >> > >> > >> > The separation you're talking about here is more related to the >> > >> > interface used to communicate with the NAND chip. >> > >> > >> > >> > How about using the following hierarchy? >> > >> > >> > >> > drivers/mtd/nand/<nand-core-code> >> > >> > drivers/mtd/nand/interfaces/raw/<raw-nand-core-code> >> > >> > drivers/mtd/nand/interfaces/raw/controllers/<raw-nand-controller-drivers> >> > >> > drivers/mtd/nand/interfaces/spi/<spi-nand-code> >> > >> > drivers/mtd/nand/interfaces/onenand/<onenand-code> >> > >> > drivers/mtd/nand/chips/<manufacturer-spcific-code> >> > >> > >> > >> > What do you think? >> > >> > >> > >> >> > >> I believe we are bikeshedding here, but what the heck. >> > >> >> > >> That seems too involved. A simpler hierarchy could be clear enough, >> > >> and seems to follow what other subsystems do: >> > >> >> > >> drivers/mtd/nand/<all-nand-core-code> >> > >> drivers/mtd/nand/raw/<raw-nand-controller-drivers> >> > > >> > > And probably some common logic in there too. >> > > >> > >> drivers/mtd/nand/spi/<spi-nand-code> >> > >> drivers/mtd/nand/onenand/<onenand-code> >> > >> drivers/mtd/nand/chips/<manufacturer-spcific-code> >> > >> >> > > >> > > I'm fine with this one too ;-). >> > >> > I'm fine with this structure too. drivers/mtd/nand folder becomes top folder for >> > all NAND based devices. Because (raw)NAND, SPI-NAND and ONENAND have >> > different command set and feature, each has its own core - nand_base.c >> > spi-nand-base.c >> > and onenand_base.c. So maybe it'll take a lot effort to abstract a >> > all-nand-core-code >> > (of course BBT should be one of them). What's your opinion? >> >> Absolutely, that was the idea: move everything into the >> drivers/mtd/nand directory (with the structure described above), keep >> some specific logic for each interface type, and see if we can factor >> out some common code (I noticed that SPI NAND devices have a parameter >> page which looks similar to the one exposed by ONFI compliant devices, >> except this parameter page is retrieved using a different command, the >> same goes for the ->{set,get}_features() functions). >> But let's focus on the nand_bbt code for now. >> >> > >> > Also, please review the BBT patch if you have time. I think it's >> > helpful on the new NAND code >> > hierarchy. >> >> I'll try to review it this week. > > I'm a bit late, but I think I've reviewed most of it now.
I already go through your comments. They are very precious and instructive. Thank you a lot for taking time to do the review. I'll remake the patches and send the v3 out soon.
> > > -- > Boris Brezillon, Free Electrons > Embedded Linux and Kernel engineering > http://free-electrons.com
Thanks, Peter Pan
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