linux-kernel - Re: [PATCH v5 39/50] mtd: nand: omap2: switch to mtd_ooblayout

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Date:	Tue, 19 Apr 2016 15:30:39 +0300
From:	Roger Quadros <rogerq@...com>
To:	Boris Brezillon <boris.brezillon@...e-electrons.com>
CC:	David Woodhouse <dwmw2@...radead.org>,
	Brian Norris <computersforpeace@...il.com>,
	<linux-mtd@...ts.infradead.org>,
	Richard Weinberger <richard@....at>,
	<linux-mips@...ux-mips.org>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Harvey Hunt <harvey.hunt@...tec.com>,
	Nicolas Ferre <nicolas.ferre@...el.com>,
	Stefan Agner <stefan@...er.ch>, <linux-sunxi@...glegroups.com>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	punnaiah choudary kalluri <punnaia@...inx.com>,
	Robert Jarzmik <robert.jarzmik@...e.fr>,
	<devel@...verdev.osuosl.org>,
	Archit Taneja <architt@...eaurora.org>,
	<linux-samsung-soc@...r.kernel.org>,
	Kamal Dasu <kdasu.kdev@...il.com>,
	Josh Wu <rainyfeeling@...look.com>,
	Chen-Yu Tsai <wens@...e.org>, Kukjin Kim <kgene@...nel.org>,
	<bcm-kernel-feedback-list@...adcom.com>,
	Ezequiel Garcia <ezequiel.garcia@...e-electrons.com>,
	Huang Shijie <shijie.huang@....com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Haojian Zhuang <haojian.zhuang@...il.com>,
	Han Xu <b45815@...escale.com>,
	<linux-arm-kernel@...ts.infradead.org>,
	Priit Laes <plaes@...es.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	<linux-kernel@...r.kernel.org>, Ralf Baechle <ralf@...ux-mips.org>,
	Wenyou Yang <wenyou.yang@...el.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	<linux-api@...r.kernel.org>,
	Maxime Ripard <maxime.ripard@...e-electrons.com>,
	Daniel Mack <daniel@...que.org>
Subject: Re: [PATCH v5 39/50] mtd: nand: omap2: switch to mtd_ooblayout_ops

On 19/04/16 14:22, Boris Brezillon wrote:
> Hi Roger,
> 
> On Tue, 19 Apr 2016 13:28:50 +0300
> Roger Quadros <rogerq@...com> wrote:
> 
>>> @@ -1921,6 +1927,9 @@ static int omap_nand_probe(struct platform_device *pdev)
>>>  		nand_chip->ecc.correct          = omap_correct_data;
>>>  		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
>>>  		oobbytes_per_step		= nand_chip->ecc.bytes;
>>> +
>>> +		if (nand_chip->options & NAND_BUSWIDTH_16)
>>> +			min_oobbytes		= 1;
>>
>> Shouldn't this have been
>> 		if (!(nand_chip->options & NAND_BUSWIDTH_16)
>> 			min_oobbytes		= 1;
>> ?
> 
> Yep.
> 
>>
>>>  		break;
>>>  
>>>  	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
>>> @@ -2038,10 +2047,8 @@ static int omap_nand_probe(struct platform_device *pdev)
>>>  	}
>>>  
>>>  	/* check if NAND device's OOB is enough to store ECC signatures */
>>> -	min_oobbytes = (oobbytes_per_step *
>>> -			(mtd->writesize / nand_chip->ecc.size)) +
>>> -		       (nand_chip->options & NAND_BUSWIDTH_16 ?
>>> -			BADBLOCK_MARKER_LENGTH : 1);
>>> +	min_oobbytes += (oobbytes_per_step *
>>> +			 (mtd->writesize / nand_chip->ecc.size));
>>>  	if (mtd->oobsize < min_oobbytes) {
>>>  		dev_err(&info->pdev->dev,
>>>  			"not enough OOB bytes required = %d, available=%d\n",
>>>
>>
>> After the above changes BCH with HW ECC worked fine but BCH with SW ECC still failed.
>> I had to fix it up with the below patch. This is mainly because chip->ecc.steps wasn't
>> yet initialized before calling nand_bch_init().
>>
>> After the below patch it worked fine with bch4 (hw & sw), bch8 (hw & sw) and ham1.
>> I couldn't yet verify bch16 though.
> 

I just verified that bch16 works as well.

> Thanks for the fix, but I'd prefer fixing the bug for all soft BCH
> users.
> 
> Could you try this patch?

I tried your patch and it worked fine.
You will still need the below change to omap2.c

--
cheers,
-roger

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 0abfba6..33c8fde 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -1715,7 +1715,7 @@ static int omap_sw_ooblayout_free(struct mtd_info *mtd, int section,
 	struct nand_chip *chip = mtd_to_nand(mtd);
 	int off = BADBLOCK_MARKER_LENGTH;
 
-	if (section)
+	if (section >= chip->ecc.steps)
 		return -ERANGE;
 
 	/*
-- 
2.5.0