RE: [PATCH v2 7/7] mtd: rawnand: brcmnand: Add support for getting ecc setting from strap

[William Zhang <william.zhang@broadcom.com>]

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> -----Original Message-----
> From: Linus Walleij <linus.walleij@linaro.org>
> Sent: Monday, September 16, 2024 2:59 AM
> To: u-boot@lists.denx.de; Dario Binacchi
> <dario.binacchi@amarulasolutions.com>; Michael Trimarchi
> <michael@amarulasolutions.com>; Anand Gore
> <anand.gore@broadcom.com>; William Zhang
> <william.zhang@broadcom.com>; Kursad Oney
> <kursad.oney@broadcom.com>; Philippe Reynes
> <philippe.reynes@softathome.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>; David Regan
> <dregan@broadcom.com>; Miquel Raynal <miquel.raynal@bootlin.com>
> Subject: [PATCH v2 7/7] mtd: rawnand: brcmnand: Add support for getting
> ecc setting from strap
>
> From: William Zhang <william.zhang@broadcom.com>
>
> Backport from the upstream Linux kernel
> commit c2cf7e25eb2a3c915a420fb8ceed8912add7f36c
> "mtd: rawnand: brcmnand: Add support for getting ecc setting from strap"
>
> Note: the upstream kernel introduces a new
> bool brcmnand_get_sector_size_1k() function because the int
> version in U-Boot has been removed in Linux. I kept the old
> int-returning version that is already in U-Boot as we depend
> on that in other code.
>
> BCMBCA broadband SoC based board design does not specify ecc setting in
> dts but rather use the SoC NAND strap info to obtain the ecc strength
> and spare area size setting. Add brcm,nand-ecc-use-strap dts propety for
> this purpose and update driver to support this option. However these two
> options can not be used at the same time.
>
> Signed-off-by: William Zhang <william.zhang@broadcom.com>
> Reviewed-by: David Regan <dregan@broadcom.com>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> Link: https://lore.kernel.org/linux-mtd/20240301173308.226004-1-
> william.zhang@broadcom.com
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>  drivers/mtd/nand/raw/brcmnand/brcmnand.c | 70
> ++++++++++++++++++++++++++++++--
>  1 file changed, 66 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> index 071b33951648..749553c9df90 100644
> --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> @@ -980,6 +980,43 @@ static void brcmnand_set_sector_size_1k(struct
> brcmnand_host *host, int val)
>  	nand_writereg(ctrl, acc_control_offs, tmp);
>  }
>
> +static int brcmnand_get_spare_size(struct brcmnand_host *host)
> +{
> +	struct brcmnand_controller *ctrl = host->ctrl;
> +	u16 acc_control_offs = brcmnand_cs_offset(ctrl, host->cs,
> +
> BRCMNAND_CS_ACC_CONTROL);
> +	u32 acc = nand_readreg(ctrl, acc_control_offs);
> +
> +	return (acc & brcmnand_spare_area_mask(ctrl));
> +}
> +
> +static void brcmnand_get_ecc_settings(struct brcmnand_host *host,
> struct nand_chip *chip)
> +{
> +	struct brcmnand_controller *ctrl = host->ctrl;
> +	u16 acc_control_offs = brcmnand_cs_offset(ctrl, host->cs,
> +
> BRCMNAND_CS_ACC_CONTROL);
> +	bool sector_size_1k = brcmnand_get_sector_size_1k(host);
> +	int spare_area_size, ecc_level;
> +	u32 acc;
> +
> +	spare_area_size = brcmnand_get_spare_size(host);
> +	acc = nand_readreg(ctrl, acc_control_offs);
> +	ecc_level = (acc & brcmnand_ecc_level_mask(ctrl)) >> ctrl-
> >ecc_level_shift;
> +	if (sector_size_1k)
> +		chip->ecc.strength = ecc_level * 2;
> +	else if (spare_area_size == 16 && ecc_level == 15)
> +		chip->ecc.strength = 1; /* hamming */
> +	else
> +		chip->ecc.strength = ecc_level;
> +
> +	if (chip->ecc.size == 0) {
> +		if (sector_size_1k)
> +			chip->ecc.size = 1024;
> +		else
> +			chip->ecc.size = 512;
> +	}
> +}
> +
>
> /**********************************************************
> *************
>   * CS_NAND_SELECT
>
> **********************************************************
> *************/
> @@ -2323,12 +2360,33 @@ static int brcmnand_setup_dev(struct
> brcmnand_host *host)
>  	struct nand_memory_organization *memorg =
> nanddev_get_memorg(nanddev);
>  	struct brcmnand_controller *ctrl = host->ctrl;
>  	struct brcmnand_cfg *cfg = &host->hwcfg;
> -	char msg[128];
>  	u32 offs, tmp, oob_sector;
> +	bool use_strap = false;
> +	char msg[128];
>  	int ret;
>
>  	memset(cfg, 0, sizeof(*cfg));
>
> +#ifndef __UBOOT__
> +	use_strap = of_property_read_bool(nand_get_flash_node(chip),
> +					  "brcm,nand-ecc-use-strap"):
> +#else
> +	use_strap = ofnode_read_bool(nand_get_flash_node(chip),
> +				     "brcm,nand-ecc-use-strap");
> +#endif /* __UBOOT__ */
> +	/*
> +	 * Either nand-ecc-xxx or brcm,nand-ecc-use-strap can be set. Error
> out
> +	 * if both exist.
> +	 */
> +	if (chip->ecc.strength && use_strap) {
> +		dev_err(ctrl->dev,
> +			"ECC strap and DT ECC configuration properties are
> mutually exclusive\n");
> +		return -EINVAL;
> +	}
> +
> +	if (use_strap)
> +		brcmnand_get_ecc_settings(host, chip);
> +
>  #ifndef __UBOOT__
>  	ret = of_property_read_u32(nand_get_flash_node(chip),
>  				   "brcm,nand-oob-sector-size",
> @@ -2338,10 +2396,14 @@ static int brcmnand_setup_dev(struct
> brcmnand_host *host)
>  			      "brcm,nand-oob-sector-size",
>  			      &oob_sector);
>  #endif /* __UBOOT__ */
> +
>  	if (ret) {
> -		/* Use detected size */
> -		cfg->spare_area_size = mtd->oobsize /
> -					(mtd->writesize >> FC_SHIFT);
> +		if (use_strap)
> +			cfg->spare_area_size =
> brcmnand_get_spare_size(host);
> +		else
> +			/* Use detected size */
> +			cfg->spare_area_size = mtd->oobsize /
> +						(mtd->writesize >> FC_SHIFT);
>  	} else {
>  		cfg->spare_area_size = oob_sector;
>  	}
>
> --
> 2.46.0

Reviewed-by: William Zhang <william.zhang@broadcom.com>
Tested-by: William Zhang <william.zhang@broadcom.com>

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