Re: [PATCH v3 5/5] mtd: rawnand: brcmnand: Fix mtd oobsize

William Zhang
2023-07-05T00:52:19Z

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Hi Miquel,

On 07/04/2023 08:30 AM, Miquel Raynal wrote:
> Hi William,
>
> william.zhang@broadcom.com wrote on Tue, 27 Jun 2023 12:37:38 -0700:
>
>> brcmnand controller can only access the flash spare area up to certain
>> bytes based on the ECC level. It can be less than the actual flash spare
>> area size. For example, for many NAND chip supporting ECC BCH-8, it has
>> 226 bytes spare area. But controller can only uses 218 bytes. So brcmand
>> driver overrides the mtd oobsize with the controller's accessible spare
>> area size. When the nand base driver utilizes the nand_device object, it
>> resets the oobsize back to the actual flash spare aprea size from
>> nand_memory_organization structure and controller may not able to access
>> all the oob area as mtd advises.
>>
>> This change fixes the issue by overriding the oobsize in the
>> nand_memory_organization structure to the controller's accessible spare
>> area size.
>
> I am clearly not a big fan of this solution. memorg should be and
> remain a read only object. Can you please find another solution?
>
I was debating on this too but I don't see option because there is no
other hooks after nanddev_init to set the mtd->oobsize as far as I can
see and I see there were similar fixes for other controller drivers
after the nand device object init was committed, for example:
Fixes: 629a442cad5f ("mtd: rawnand: Fill memorg during detection")

I will think through this again but I am open to any suggestion.

>>
>> Fixes: a7ab085d7c16 ("mtd: rawnand: Initialize the nand_device object")
>> Signed-off-by: William Zhang <william.zhang@broadcom.com>
>>
>> ---
>>
>> Changes in v3: None
>> Changes in v2: None
>>
>> drivers/mtd/nand/raw/brcmnand/brcmnand.c | 7 +++++--
>> 1 file changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
>> index 407bf79cbaf4..39c7f547db1f 100644
>> --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
>> +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
>> @@ -2647,6 +2647,8 @@ static int brcmnand_setup_dev(struct brcmnand_host *host)
>> struct nand_chip *chip = &host->chip;
>> const struct nand_ecc_props *requirements =
>> nanddev_get_ecc_requirements(&chip->base);
>> + struct nand_memory_organization *memorg =
>> + nanddev_get_memorg(&chip->base);
>> struct brcmnand_controller *ctrl = host->ctrl;
>> struct brcmnand_cfg *cfg = &host->hwcfg;
>> char msg[128];
>> @@ -2668,10 +2670,11 @@ static int brcmnand_setup_dev(struct brcmnand_host *host)
>> if (cfg->spare_area_size > ctrl->max_oob)
>> cfg->spare_area_size = ctrl->max_oob;
>> /*
>> - * Set oobsize to be consistent with controller's spare_area_size, as
>> - * the rest is inaccessible.
>> + * Set mtd and memorg oobsize to be consistent with controller's
>> + * spare_area_size, as the rest is inaccessible.
>> */
>> mtd->oobsize = cfg->spare_area_size * (mtd->writesize >> FC_SHIFT);
>> + memorg->oobsize = mtd->oobsize;
>>
>> cfg->device_size = mtd->size;
>> cfg->block_size = mtd->erasesize;
>
>
> Thanks,
> Miquèl