| Message ID | 20210928221507.199198-3-miquel.raynal@bootlin.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Cleanup series about Hamming helpers | expand |
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
diff --git a/drivers/mtd/nand/ecc-sw-hamming.c b/drivers/mtd/nand/ecc-sw-hamming.c index a7655b668f32..254db2e7f8bb 100644 --- a/drivers/mtd/nand/ecc-sw-hamming.c +++ b/drivers/mtd/nand/ecc-sw-hamming.c @@ -364,9 +364,9 @@ int nand_ecc_sw_hamming_calculate(struct nand_device *nand, { struct nand_ecc_sw_hamming_conf *engine_conf = nand->ecc.ctx.priv; unsigned int step_size = nand->ecc.ctx.conf.step_size; + bool sm_order = engine_conf ? engine_conf->sm_order : false; - return ecc_sw_hamming_calculate(buf, step_size, code, - engine_conf->sm_order); + return ecc_sw_hamming_calculate(buf, step_size, code, sm_order); } EXPORT_SYMBOL(nand_ecc_sw_hamming_calculate); @@ -457,9 +457,10 @@ int nand_ecc_sw_hamming_correct(struct nand_device *nand, unsigned char *buf, { struct nand_ecc_sw_hamming_conf *engine_conf = nand->ecc.ctx.priv; unsigned int step_size = nand->ecc.ctx.conf.step_size; + bool sm_order = engine_conf ? engine_conf->sm_order : false; return ecc_sw_hamming_correct(buf, read_ecc, calc_ecc, step_size, - engine_conf->sm_order); + sm_order); } EXPORT_SYMBOL(nand_ecc_sw_hamming_correct);
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> --- drivers/mtd/nand/ecc-sw-hamming.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)