Messages in this thread | | | From | Qi Wang 王起 (qiwang) <> | Subject | RE: [PATCH 0/3] An alternative to SPI NAND | Date | Wed, 21 Jan 2015 02:11:27 +0000 |
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On 01/20/2015 6:36 PM, Ezequiel Garcia wrote: > >On 01/12/2015 12:10 PM, Qi Wang 王起 (qiwang) wrote: >> Hi Ezequiel, >> >> On 01/08/2015 11:27 AM, Ezequiel Garcia wrote: >>> >>> Hi Qi Wang, >>> >>> On 01/07/2015 11:45 PM, Qi Wang 王起 (qiwang) wrote: >>>> Hi Brian, >>>> >>>> On Thu, Jan 08, 2015 at 9:03:24AM +0000, Brian Norris wrote: >>>>> >>>>> On Thu, Jan 08, 2015 at 12:47:24AM +0000, Peter Pan 潘栋 (peterpandong) >>>>> wrote: >>>>>> Documentation/devicetree/bindings/mtd/spi-nand.txt | 22 + >>>>>> drivers/mtd/Kconfig | 2 + >>>>>> drivers/mtd/Makefile | 1 + >>>>>> drivers/mtd/spi-nand/Kconfig | 7 + >>>>>> drivers/mtd/spi-nand/Makefile | 3 + >>>>>> drivers/mtd/spi-nand/spi-nand-base.c | 2034 >>>>> ++++++++++++++++++++ >>>>>> drivers/mtd/spi-nand/spi-nand-bbt.c | 1279 >++++++++++++ >>>>> >>>>> I can already tell by the diffstat that I don't like this. We probably >>>>> don't need 3000 new lines of code for this, but we especially don't >want >>>>> to duplicate nand_bbt.c. It won't take a lot of work to augment >>>>> nand_bbt.c to make it shareable. (I can whip that patch up if needed.) >>>> >>>> Yes, I agree with you, Nand_bbt.c do can be shared by Parallel NAND and >>>> SPI NAND. Actually, we are working at this now. Will send patches to >you >>>> Once we finished it. >>>> >>> >>> Thanks for the quick submission! >>> >>> However, Brian is right, this code duplication is a no go. >>> >>> Perhaps a more valid approach would be to first identify the code that >>> needs to be shared in nand_bbt.c and nand_base.c, and export those >>> symbols (or maybe do the required refactor). >> >> Yes, I agree Brian's suggestion in another mail. >> >> " The BBT code is something we definitely want to share, but it's >actually >> not very closely tied to nand_base.c, and it looks pretty easy to adapt >> to any MTD that implements mtd_read_oob()/mtd_write_oob(). We'd just >> need to parameterize a few relevant device details into a new nand_bbt >> struct, rather than using struct nand_chip directly." >> >> To abstract a new nand_bbt struct instead of nand_chip to make SPI NAND >> and parallel NAND can share nand_bbt.c file, I already begin to work on >> this. >> >> For code shared in nand_base.c, I agree it would be better if we can find >> a good method to share nand_base.c code between spi nand and parallel >nand. >> But frankly speaking, I'm not satisfied for the remap command method. >This >> method make code difficult to maintain when SPI NAND and Parallel NAND >> evolve much differently in the future. >> >> Take some example, >> If one new command (cache operation, multiple plane operation) >implemented >> in parallel NAND code, and is used in nand_read or nand_write, that will >> cause maintainer to modify SPI NAND code to remap this new command, >though >> this modification probably could be slight. That means modification on >> Parallel NAND flash need to consider SPI NAND as well. >> >> How do you think about this? >> >> For Peter Pan's patchset, if we do some modification to make nand_bbt.c >to >> make it shareable for Parallel and SPI NAND. The code line should be 2000. >> I believe I can review this spi-nand-base.c to remove some redundant code >> that may hundreds line. Is 1700 or 1800 code line is more acceptable? >> >> Let me know your opinions. >> > >Sounds good. > >Do you still plan to maintain the spi-nand-base.c and spi-nand-device.c >separation?
Yes, still plan to maintain the spi-nand-base.c and spi-nand-device.c separation. Abstract common code to spi-nand-base.c, and spi-nand-device.c is used for realize the different function for different SPI NAND, such as ecc layout, read ID etc.
Thanks -- Qi Wang
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