Re: [PATCH v3 06/10] mtd: rawnand: brcmnand: Add support for getting ecc setting from strap

From: William Zhang <william.zhang@broadcom.com>
To: Miquel Raynal <miquel.raynal@bootlin.com>,
	David Regan <dregan@broadcom.com>
Cc: dregan@mail.com, richard@nod.at, vigneshr@ti.com,
	robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
	conor+dt@kernel.org, computersforpeace@gmail.com,
	kdasu.kdev@gmail.com, linux-mtd@lists.infradead.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	joel.peshkin@broadcom.com, tomer.yacoby@broadcom.com,
	dan.beygelman@broadcom.com, anand.gore@broadcom.com,
	kursad.oney@broadcom.com, florian.fainelli@broadcom.com,
	rafal@milecki.pl, bcm-kernel-feedback-list@broadcom.com,
	andre.przywara@arm.com, baruch@tkos.co.il,
	linux-arm-kernel@lists.infradead.org, dan.carpenter@linaro.org
Subject: Re: [PATCH v3 06/10] mtd: rawnand: brcmnand: Add support for getting ecc setting from strap
Date: Wed, 24 Jan 2024 19:13:45 -0800	[thread overview]
Message-ID: <48f3c65f-4e27-42d8-b32a-3889329303c2@broadcom.com> (raw)
In-Reply-To: <20240124183207.5898cbfd@xps-13>

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Hi Miquel,

On 1/24/24 09:32, Miquel Raynal wrote:
> Hi David,
> 
>> @@ -2622,19 +2667,43 @@ static int brcmnand_setup_dev(struct brcmnand_host *host)
>>   		nanddev_get_memorg(&chip->base);
>>   	struct brcmnand_controller *ctrl = host->ctrl;
>>   	struct brcmnand_cfg *cfg = &host->hwcfg;
>> -	char msg[128];
>> +	struct device_node *np = nand_get_flash_node(chip);
>>   	u32 offs, tmp, oob_sector;
>> -	int ret;
>> +	int ret, sector_size_1k = 0;
>> +	bool use_strap = false;
>> +	char msg[128];
>>   
>>   	memset(cfg, 0, sizeof(*cfg));
>> +	use_strap = of_property_read_bool(np, "brcm,nand-ecc-use-strap");
>>   
>> -	ret = of_property_read_u32(nand_get_flash_node(chip),
>> -				   "brcm,nand-oob-sector-size",
>> +	/*
>> +	 * Set ECC size and strength based on hw configuration from strap
>> +	 * if device tree does not specify them and use strap property is set
>> +	 * If ecc strength is set in dts, don't use strap setting.
>> +	 */
> 
> You would have to use the strap settings only if the property is set.
> If not property is set, the default from the core should apply I guess.
> 
Maybe the comment confuse you... I will make it more clear.  But the 
logic here is exactly what you said.  If no properties are set, the core 
value is already set in chip->ecc.strength and chip->ecc.size and it 
clear the use_strap flag too.

>> +	if (chip->ecc.strength)
>> +		use_strap = 0;
>> +
>> +	if (use_strap) {
>> +		chip->ecc.strength = brcmnand_get_ecc_strength(host);
>> +		sector_size_1k = brcmnand_get_sector_size_1k(host);
>> +		if (chip->ecc.size == 0) {
>> +			if (sector_size_1k < 0)
>> +				chip->ecc.size = 512;
>> +			else
>> +				chip->ecc.size = 512 << sector_size_1k;
>> +		}
>> +	}
>> +
>> +	ret = of_property_read_u32(np, "brcm,nand-oob-sector-size",
>>   				   &oob_sector);
>>   	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;
>>   	}
> 
> 
> Thanks,
> Miquèl

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