Hi David, dregan@xxxxxxxxxxxx wrote on Fri, 26 Jan 2024 11:57:39 -0800: > Hi Miquèl, > > On Thu, Jan 25, 2024 at 10:19 PM Miquel Raynal > <miquel.raynal@xxxxxxxxxxx> wrote: > > > > Hi David, > > > > dregan@xxxxxxxxxxxx wrote on Thu, 25 Jan 2024 11:47:46 -0800: > > > > > Hi Miquèl, > > > > > > On Wed, Jan 24, 2024 at 9:40 AM Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote: > > > > > > > > Hi David, > > > > > > > > dregan@xxxxxxxxxxxx wrote on Tue, 23 Jan 2024 19:04:58 -0800: > > > > > > > > > Allow settings for on-die ecc such that if on-die ECC is selected > > > > > don't error out but require ECC strap setting of zero > > > > > > > > > > Signed-off-by: David Regan <dregan@xxxxxxxxxxxx> > > > > > Reviewed-by: William Zhang <william.zhang@xxxxxxxxxxxx> > > > > > --- > > > > > Changes in v3: None > > > > > --- > > > > > Changes in v2: > > > > > - Added to patch series > > > > > --- > > > > > drivers/mtd/nand/raw/brcmnand/brcmnand.c | 14 ++++++++++---- > > > > > 1 file changed, 10 insertions(+), 4 deletions(-) > > > > > > > > > > diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c > > > > > index a4e311b6798c..42526f3250c9 100644 > > > > > --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c > > > > > +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c > > > > > @@ -2727,9 +2727,11 @@ static int brcmnand_setup_dev(struct brcmnand_host *host) > > > > > cfg->blk_adr_bytes = get_blk_adr_bytes(mtd->size, mtd->writesize); > > > > > > > > > > if (chip->ecc.engine_type != NAND_ECC_ENGINE_TYPE_ON_HOST) { > > > > > - dev_err(ctrl->dev, "only HW ECC supported; selected: %d\n", > > > > > - chip->ecc.engine_type); > > > > > - return -EINVAL; > > > > > + if (chip->ecc.strength) { > > > > > + dev_err(ctrl->dev, "ERROR!!! HW ECC must be set to zero for non-hardware ECC; selected: %d\n", > > > > > + chip->ecc.strength); > > > > > > > > Can you use a more formal string? Also clarify it because I don't > > > > really understand what it leads to. > > > > > > How about: > > > > > > dev_err(ctrl->dev, "HW ECC set to %d, must be zero for on-die ECC\n", > > > > Actually I am wondering how legitimate this is. Just don't enable the > > on host ECC engine if it's not in use. No need to check the core's > > choice. > > Our chip ECC engine will either be on if it's needed or off if it's not. > Either I can do that in one place or put checks in before each > read/write to turn on/off the ECC engine, which seems a lot more > work and changes and possible issues/problems. > Turning it on/off as needed has not been explicitly tested and > could cause unforeseen consequences. This > is a minimal change which should have minimal impact. > > > > > > > > > > > > > > > + return -EINVAL; > > > > > + } > > > > > } > > > > > > > > > > if (chip->ecc.algo == NAND_ECC_ALGO_UNKNOWN) { > > > > > @@ -2797,7 +2799,11 @@ static int brcmnand_setup_dev(struct brcmnand_host *host) > > > > > if (ret) > > > > > return ret; > > > > > > > > > > - brcmnand_set_ecc_enabled(host, 1); > > > > > + if (chip->ecc.engine_type == NAND_ECC_ENGINE_TYPE_ON_DIE) { > > > > > + dev_dbg(ctrl->dev, "Disable HW ECC for on-die ECC\n"); > > > > > > > > Not needed. > > > > > > Will remove. > > > > > > > > > > > > + brcmnand_set_ecc_enabled(host, 0); > > > > > + } else > > > > > + brcmnand_set_ecc_enabled(host, 1); > > > > > > > > Style is wrong, but otherwise I think ECC should be kept disabled while > > > > not in active use, so I am a bit surprised by this line. > > > > > > This is a double check to turn on/off our hardware ECC. > > > > I expect the engine to be always disabled. Enable it only when you > > need (may require an additional patch before this one). > > We are already turning on the ECC enable at this point, > this is just adding the option to turn it off if the NAND chip > itself will be doing the ECC instead of our controller. Sorry if I have not been clear. This sequence: - init - enable hw ECC engine Is broken. It *cannot* work as any operation going through exec_op now may perform page reads which should be unmodified by the ECC engine. You driver *must* follow the following sequence: - init and disable (or keep disabled) the hw ECC engine - when you perform a page operation with correction you need to - enable the engine - perform the operation - disable the engine Thanks, Miquèl