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Date: Tue, 19 Jun 2018 11:07:41 +0200
From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Martin Kaiser <martin@kaiser.cx>
Cc: Boris Brezillon <boris.brezillon@bootlin.com>, David Woodhouse
 <dwmw2@infradead.org>, Sascha Hauer <s.hauer@pengutronix.de>, Fabio Estevam
 <fabio.estevam@nxp.com>, linux-mtd@lists.infradead.org,
 linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v3] mtd: rawnand: mxc: set spare area size register
 explicitly
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On Mon, 18 Jun 2018 22:41:03 +0200, Martin Kaiser <martin@kaiser.cx>
wrote:

> The v21 version of the NAND flash controller contains a Spare Area Size
> Register (SPAS) at offset 0x10. Its setting defaults to the maximum
> spare area size of 218 bytes. The size that is set in this register is
> used by the controller when it calculates the ECC bytes internally in
> hardware.
>=20
> Usually, this register is updated from settings in the IIM fuses when
> the system is booting from NAND flash. For other boot media, however,
> the SPAS register remains at the default setting, which may not work for
> the particular flash chip on the board. The same goes for flash chips
> whose configuration cannot be set in the IIM fuses (e.g. chips with 2k
> sector size and 128 bytes spare area size can't be configured in the IIM
> fuses on imx25 systems).
>=20
> Set the SPAS register explicitly during the preset operation. Derive the
> register value from mtd->oobsize that was detected during probe by
> decoding the flash chip's ID bytes.
>=20
> While at it, rename the define for the spare area register's offset to
> NFC_V21_RSLTSPARE_AREA. The register at offset 0x10 on v1 controllers is
> different from the register on v21 controllers.
>=20
> Signed-off-by: Martin Kaiser <martin@kaiser.cx>
> Cc: stable@vger.kernel.org
> Fixes: d484018 ("mtd: mxc_nand: set NFC registers after reset")

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>

Thanks,
Miqu=C3=A8l