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From:   Naga Sureshkumar Relli <nagasure@xilinx.com>
To:     Helmut Grohne <helmut.grohne@intenta.de>
CC:     "bbrezillon@kernel.org" <bbrezillon@kernel.org>,
        "miquel.raynal@bootlin.com" <miquel.raynal@bootlin.com>,
        "richard@nod.at" <richard@nod.at>,
        "dwmw2@infradead.org" <dwmw2@infradead.org>,
        "computersforpeace@gmail.com" <computersforpeace@gmail.com>,
        "marek.vasut@gmail.com" <marek.vasut@gmail.com>,
        "linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Michal Simek <michals@xilinx.com>,
        "nagasureshkumarrelli@gmail.com" <nagasureshkumarrelli@gmail.com>
Subject: RE: [LINUX PATCH v14] mtd: rawnand: pl353: Add basic driver for arm
 pl353 smc nand interface
Thread-Topic: [LINUX PATCH v14] mtd: rawnand: pl353: Add basic driver for arm
 pl353 smc nand interface
Thread-Index: AQHU83vggkxmg2rBCEyEcIHuXS/Vp6ZJveKAgAEOs2A=
Date:   Wed, 24 Apr 2019 05:04:38 +0000
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Hi Helmut,

> -----Original Message-----
> From: Helmut Grohne <helmut.grohne@intenta.de>
> Sent: Tuesday, April 23, 2019 6:15 PM
> To: Naga Sureshkumar Relli <nagasure@xilinx.com>
> Cc: bbrezillon@kernel.org; miquel.raynal@bootlin.com; richard@nod.at;
> dwmw2@infradead.org; computersforpeace@gmail.com; marek.vasut@gmail.com; =
linux-
> mtd@lists.infradead.org; linux-kernel@vger.kernel.org; Michal Simek <mich=
als@xilinx.com>;
> nagasureshkumarrelli@gmail.com
> Subject: Re: [LINUX PATCH v14] mtd: rawnand: pl353: Add basic driver for =
arm pl353 smc
> nand interface
>=20
> WARNING: This driver might brick the hardware. See below.
>=20
> Hi Naga,
>=20
> On Mon, Apr 15, 2019 at 04:40:13PM +0530, Naga Sureshkumar Relli wrote:
> > Changes in v14:
> >  - Removed legacy hooks as per Miquel comments
>=20
> Thank you for the update.
>=20
> > +static inline int pl353_wait_for_dev_ready(struct nand_chip *chip) {
> > +	unsigned long timeout =3D jiffies + PL353_NAND_DEV_BUSY_TIMEOUT;
> > +
> > +	do {
> > +		if (pl353_smc_get_nand_int_status_raw()) {
> > +			pl353_smc_clr_nand_int();
> > +			break;
>=20
> A closing brace is missing here. This causes a compilation failure.
While cleaning up the warnings reported by checkpatch,  this happened.
sorry for that. I will correct it.=20
>=20
> > +
> > +		cpu_relax();
>=20
> You previously used cond_resched (via nand_wait_ready) here. Why did you =
change it to
> cpu_relax()?
I just replicated the pl353_wait_for_ecc_done() API definition.
But did you see any issue with this?
Anyway I will replace it with cond_resched(), instead of cpu_releax()
>=20
> > +	} while (!time_after_eq(jiffies, timeout));
> > +
> > +	if (time_after_eq(jiffies, timeout)) {
> > +		pr_err("%s timed out\n", __func__);
> > +		return -ETIMEDOUT;
> > +	}
> > +
> > +	return 0;
> > +}
>=20
>=20
> > +static int pl353_nand_read_page_hwecc(struct nand_chip *chip,
> > +				      u8 *buf, int oob_required, int page) {
> > +	int i, stat, eccsize =3D chip->ecc.size;
> > +	int eccbytes =3D chip->ecc.bytes;
> > +	int eccsteps =3D chip->ecc.steps;
> > +	u8 *p =3D buf;
> > +	u8 *ecc_calc =3D chip->ecc.calc_buf;
> > +	u8 *ecc =3D chip->ecc.code_buf;
> > +	unsigned int max_bitflips =3D 0;
> > +	u8 *oob_ptr;
> > +	u32 ret;
> > +	unsigned long data_phase_addr;
> > +	unsigned long nand_offset =3D (unsigned long __force)xnfc->regs;
>=20
> The variable xnfc is undeclared here. Consider swapping the line with the=
 next one.
>=20
> > +	struct pl353_nand_controller *xnfc =3D to_pl353_nand(chip);
> > +	struct mtd_info *mtd =3D nand_to_mtd(chip);
>=20
> After loading the driver, the device does not work. The dmesg output is:
>=20
> nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xda
> nand: Micron MT29F2G08ABAEAWP
> nand: 256 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB size: 64 Ba=
d block table not
> found for chip 0 Bad block table not found for chip 0 Scanning device for=
 bad blocks
> nand_bbt: error while writing BBT block -524
> nand_bbt: error while writing BBT block -524
> nand_bbt: error while writing BBT block -524
> nand_bbt: error while writing BBT block -524 No space left to write bad b=
lock table
> nand_bbt: error while writing bad block table -28 pl353-nand e1000000.fla=
sh: could not scan
> the nand chip
> pl353-nand: probe of e1000000.flash failed with error -28
Did you follow the same thing that you tried earlier?
i.e. updated "nand-bus-width" property and "nand-ecc-mode" ?
I haven't seen any issue in BBT scanning, with this patch.

>=20
> After trying the driver, the flash chip was bricked. Neither the old driv=
er nor the uboot-xlnx
> driver nor the Xilinx fsbl are able to talk to the chip afterwards. This =
behaviour persists even
> after a full power cycle. I'll try reinitializing the flash chip next. I'=
ve only seen this behaviour
> once, so there is a slight chance that the cause is something else.
Sometimes I also faced the same problem during driver development.
What I did is, in standalone nandps driver example,  I forcibly created BBT=
 in the init and once
 it is done. I just reloaded the actual example. Then after wards u-boot an=
d Linux are able to scan
the BBT.

Thanks,
Naga Sureshkumar Relli
>=20
> Helmut