Messages in this thread | ![/](/images/icornerl.gif) | | Date | Tue, 20 Jan 2015 07:35:39 -0300 | From | Ezequiel Garcia <> | Subject | Re: [PATCH 0/3] An alternative to SPI NAND |
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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? -- Ezequiel
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