RE: [LINUX PATCH v9 4/4] mtd: rawnand: pl353: Add basic driver for arm pl353 smc nand interface

[Naga Sureshkumar Relli]

Hi Miquel,

> -----Original Message-----
> From: Miquel Raynal [mailto:miquel.raynal@xxxxxxxxxxx]
> Sent: Friday, June 8, 2018 6:06 PM
> To: Naga Sureshkumar Relli <nagasure@xxxxxxxxxx>
> Cc: boris.brezillon@xxxxxxxxxxx; richard@xxxxxx; wmw2@xxxxxxxxxxxxx;
> computersforpeace@xxxxxxxxx; marek.vasut@xxxxxxxxx; f.fainelli@xxxxxxxxx;
> mmayer@xxxxxxxxxxxx; rogerq@xxxxxx; ladis@xxxxxxxxxxxxxx; ada@xxxxxxxxxxx;
> honghui.zhang@xxxxxxxxxxxx; linux-mtd@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> nagasureshkumarrelli@xxxxxxxxx
> Subject: Re: [LINUX PATCH v9 4/4] mtd: rawnand: pl353: Add basic driver for arm pl353
> smc nand interface
> 
> Hi Naga,
> 
> > > > +		ecc->read_page = pl353_nand_read_page_hwecc;
> > > > +		ecc->size = PL353_NAND_ECC_SIZE;
> > > > +		ecc->write_page = pl353_nand_write_page_hwecc;
> > > > +		pl353_smc_set_ecc_pg_size(mtd->writesize);
> > > > +		switch (mtd->writesize) {
> > > > +		case SZ_512:
> > > > +		case SZ_1K:
> > > > +		case SZ_2K:
> > > > +			pl353_smc_set_ecc_mode(PL353_SMC_ECCMODE_APB);
> > > > +			break;
> > > > +		default:
> > > > +			/*
> > > > +			 * The software ECC routines won't work with the
> > > > +			 * SMC controller
> > > > +			 */
> > > > +			ecc->calculate = nand_calculate_ecc;
> > > > +			ecc->correct = nand_correct_data;
> > > > +			ecc->size = 256;
> > > > +			break;
> > > > +		}
> > > > +		if (mtd->writesize <= SZ_512)
> > > > +			xnand->addr_cycles = 1;
> > > > +		else
> > > > +			xnand->addr_cycles = 2;
> > > > +
> > > > +		if (chip->options & NAND_ROW_ADDR_3)
> > > > +			xnand->addr_cycles += 3;
> > > > +		else
> > > > +			xnand->addr_cycles += 2;
> > > > +
> > > > +		if (mtd->oobsize == 16)
> > > > +			mtd_set_ooblayout(mtd, &pl353_ecc_ooblayout16_ops);
> > > > +		else if (mtd->oobsize == 64)
> > > > +			mtd_set_ooblayout(mtd, &pl353_ecc_ooblayout64_ops);
> > >
> > > else?
> > You mean to say, add an error condition?
> 
> I do.
Ok, I will add it in next version.
> 
> > >
> > > > +	}
> > > > +}
> > > > +
> > > > +/**
> > > > + * pl353_nand_probe - Probe method for the NAND driver
> > > > + * @pdev:	Pointer to the platform_device structure
> > > > + *
> > > > + * This function initializes the driver data structures and the hardware.
> > > > + *
> > > > + * Return:	0 on success or error value on failure
> > > > + */
> > > > +static int pl353_nand_probe(struct platform_device *pdev) {
> > > > +	struct pl353_nand_info *xnand;
> > >
> > > xnand is a strange name, more and more because its a bout NAND
> > > controller data, not NAND chip.
> > We added this name to represent Xilinx Nand(xnand),
> > >
> 
> I see where the x comes from.
> 
> Maybe just nfc (for NAND flash controller) or xnfc if you prefer. What
> I want is to clearly make the distinction between what is a NAND chip,
> what is a NAND controller.
Ok, got it. I will update like xnfc.
> 
> > > > +	struct mtd_info *mtd;
> > > > +	struct nand_chip *nand_chip;
> > >
> > > This one you can call it just "nand" or "chip".
> > Ok, I will update.
> >
> > >
> > > > +	struct resource *res;
> > > > +
> > > > +	xnand = devm_kzalloc(&pdev->dev, sizeof(*xnand), GFP_KERNEL);
> > > > +	if (!xnand)
> > > > +		return -ENOMEM;
> > > > +
> > > > +	/* Map physical address of NAND flash */
> > > > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > > +	xnand->nand_base = devm_ioremap_resource(&pdev->dev, res);
> > > > +	if (IS_ERR(xnand->nand_base))
> > > > +		return PTR_ERR(xnand->nand_base);
> > > > +
> > > > +	nand_chip = &xnand->chip;
> > > > +	mtd = nand_to_mtd(nand_chip);
> > > > +	nand_chip->exec_op = pl353_nfc_exec_op;
> > > > +	nand_set_controller_data(nand_chip, xnand);
> > > > +	mtd->priv = nand_chip;
> > > > +	mtd->owner = THIS_MODULE;
> > > > +	mtd->name = PL353_NAND_DRIVER_NAME;
> > >
> > > A label property in the DT might overwrite this value.
> > Could you please explain a bit more ?
> >
> 
> I meant something like this:
> 
> https://elixir.bootlin.com/linux/latest/source/drivers/mtd/nand/raw/marvell_nand.c#L251
> 5
Understood. Thanks.
I will update in next version.

Thanks,
Naga Sureshkumar Relli.
> 
> Thanks,
> MiquÃl