Re: [PATCH 8/9] mtd: nand: mxc: implement onfi get/set features

[Boris Brezillon <boris.brezillon@free-electrons.com>]

On Tue, 22 Nov 2016 11:52:53 +0100
Sascha Hauer <s.hauer@pengutronix.de> wrote:

> Hi Boris,
> 
> On Mon, Nov 21, 2016 at 02:56:43PM +0100, Boris Brezillon wrote:
> > Hi Sascha,
> > 
> > On Thu, 15 Sep 2016 10:32:52 +0200
> > Sascha Hauer <s.hauer@pengutronix.de> wrote:
> >   
> > > To be able to support different ONFI timing modes we have to implement
> > > the onfi_set_features and onfi_get_features. Tested on an i.MX25 SoC.
> > > 
> > > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> > > ---
> > >  drivers/mtd/nand/mxc_nand.c | 53 +++++++++++++++++++++++++++++++++++++++++++++
> > >  1 file changed, 53 insertions(+)
> > > 
> > > diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
> > > index 5173fad..1db8299 100644
> > > --- a/drivers/mtd/nand/mxc_nand.c
> > > +++ b/drivers/mtd/nand/mxc_nand.c
> > > @@ -1239,6 +1239,57 @@ static void mxc_nand_command(struct mtd_info *mtd, unsigned command,
> > >  	}
> > >  }
> > >  
> > > +static int mxc_nand_onfi_set_features(struct mtd_info *mtd, struct nand_chip *chip,
> > > +			int addr, uint8_t *subfeature_param)
> > > +{
> > > +	struct nand_chip *nand_chip = mtd_to_nand(mtd);
> > > +	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
> > > +	int i;
> > > +
> > > +	if (!chip->onfi_version ||
> > > +	    !(le16_to_cpu(chip->onfi_params.opt_cmd)
> > > +	      & ONFI_OPT_CMD_SET_GET_FEATURES))
> > > +		return -EINVAL;
> > > +
> > > +	host->buf_start = 0;
> > > +
> > > +	for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i)
> > > +		chip->write_byte(mtd, subfeature_param[i]);
> > > +
> > > +	memcpy32_toio(host->main_area0, host->data_buf, mtd->writesize);
> > > +	host->devtype_data->send_cmd(host, NAND_CMD_SET_FEATURES, false);
> > > +	mxc_do_addr_cycle(mtd, addr, -1);
> > > +	host->devtype_data->send_page(mtd, NFC_INPUT);  
> > 
> > I've been working with an mx27 board embedding a NAND device lately,
> > and had a closer look at the NAND controller IP.
> > With this IP, you're not able to send only 4 bytes of data, and I'm
> > sure sure what you're doing here (sending a full page of data) works
> > for a SET_FEATURE command.
> > 
> > Do you have a way to test it (my NAND is not ONFI compliant)? By test
> > it, I mean, set a timing mode using SET_FEATURE and check if the new
> > mode has been applied using GET_FEATURE.  
> 
> I have an i.MX27 board with ONFI flash, but this one does not have the
> ONFI_OPT_CMD_SET_GET_FEATURES bit set, so I can't test it there.
> However, I can confirm that it works on an i.MX25. With the attached
> patch applied on vanilla v4.9-rc5 I get:
> 
> GET FEATURES. chip->onfi_timing_mode_default: 4
> timing before: 0x00
> timing after: 0x04

Okay, cool. I guess most NANDs are more tolerant than what's strictly
required in the ONFI spec.

Thanks for testing.

Boris