Messages in this thread | | | From | Miquel Raynal <> | Subject | Re: [PATCH 2/8] mtd: rawnand: Let callers use the bare Hamming helpers | Date | Fri, 15 Oct 2021 12:33:13 +0200 |
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On Tue, 2021-09-28 at 22:15:01 UTC, Miquel Raynal wrote: > Before the introduction of the ECC framework infrastructure, many > drivers used the ->calculate/correct() Hamming helpers directly. The > point of this framework was to avoid this kind of hackish calls and use a > proper and generic API but it is true that in certain cases, drivers > still need to use these helpers in order to do ECC computations on > behalf of their limited hardware. > > Right after the introduction of the ECC engine core introduction, it was > spotted that it was not possible to use the shiny rawnand software ECC > helpers so easily because an ECC engine object should have been > allocated and initialized first. While this works well in most cases, > for these drivers just leveraging the power of a single helper in > conjunction with some pretty old and limited hardware, it did not fit. > > The idea back then was to declare intermediate helpers which would make > use of the exported software ECC engine bare functions while keeping the > rawnand layer compatibility. As there was already functions with the > rawnand_sw_hamming_ prefix it was decided to declare new local helpers > for this purpose in each driver needing one. > > Besides being far from optimal, this design choice was blamed by Linus > when he pulled the "fixes" pull request [1] so that is why now it is > time to clean this mess up. > > Enhancing the implementation of the rawnand_ecc_sw_* helpers to support > both cases, when the ECC object is instantiated and when it is not is a > quite elegant way to solve this situation. This way, we can still use > the existing and exported rawnand helpers while avoiding the need for > each driver to declare its own helper. > > Following this change, most of the fixes sent in [2] can now be safely > reverted. Only the fsmc fix will need to be kept because there is > actually something specific to the driver to do in its ->correct() > helper. > > [1] https://lore.kernel.org/lkml/CAHk-=wh_ZHF685Fni8V9is17mj=pFisUaZ_0=gq6nbK+ZcyQmg@mail.gmail.com/ > [2] https://lore.kernel.org/linux-mtd/20210413161840.345208-1-miquel.raynal@bootlin.com/ > > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next.
Miquel
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