[U-Boot] [PATCH v3] NAND: add support for reading ONFI page table

[Florian Fainelli]

Hello Scott,

(sorry for the lag in answering)

On Tuesday 15 February 2011 00:46:07 Scott Wood wrote:
> On Mon, 14 Feb 2011 16:48:01 +0100
> 
> Florian Fainelli <florian at openwrt.org> wrote:
> > From: Florian Fainelli <florian at openwrt.org>
> > 
> > This patch adds support for reading an ONFI page parameter from a NAND
> > device supporting it. If this is the case, struct nand_chip onfi_version
> > member contains the supported ONFI version, 0 otherwise.
> > 
> > This allows NAND drivers past nand_scan_ident to set the best timings for
> > the NAND chip.
> > 
> > Signed-off-by: Florian Fainelli <florian at openwrt.org>
> > ---
> > Patch against your 'next' branch
> 
> The 'next' branch is old, since I haven't pushed anything to it yet this
> cycle.  Base it on Wolfgang's 'next'.
> 
> > Changes since v1:
> > - ifdef out ONFI detection code around CONFIG_SYS_NAND_ONFI_DETECTION
> > - removed bogus comment
> > - fixed busw variable usage
> > - move non-ONFI detection code to its own function
> > - fixed stylistic issues spotted by Scott
> > 
> > Changes since v2:
> > - reduce lenght of some lines down to 80 columns
> > - change chip->options consistently wrt to ONFI detected or not
> > - removed extra spaces
> > 
> > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> > index 5239c1f..7becb99 100644
> > --- a/drivers/mtd/nand/nand_base.c
> > +++ b/drivers/mtd/nand/nand_base.c
> > @@ -2409,15 +2409,137 @@ static void nand_set_defaults(struct nand_chip
> > *chip, int busw)
> > 
> >  		chip->controller = &chip->hwcontrol;
> >  
> >  }
> > 
> > +#ifdef CONFIG_SYS_NAND_ONFI_DETECTION
> > +static u16 onfi_crc16(u16 crc, u8 const *p, size_t len)
> > +{
> > +	int i;
> > +
> > +	while (len--) {
> > +		crc ^= *p++ << 8;
> > +		for (i = 0; i < 8; i++)
> > +			crc = (crc << 1) ^ ((crc & 0x8000) ? 0x8005 : 0);
> > +	}
> > +
> > +	return crc;
> > +}
> 
> Is this different from what's in lib/crc16.c (other than appearing to have
> made a different speed/size tradeoff)?

Yes it is a different version of the CRC16 function.

> 
> > +#define ONFI_CRC_BASE	0x4F4E
> 
> Is this ONFI-specific, or standard for crc16?
> 
> > +
> > +/*
> > + * Check if the NAND chip is ONFI compliant, returns 1 if it is, 0
> > otherwise + */
> > +static int nand_flash_detect_onfi(struct mtd_info *mtd,
> > +					struct nand_chip *chip,
> > +					int *busw)
> > +{
> 
> [snip]
> 
> > +	chip->options &= ~NAND_CHIPOPTIONS_MSK;
> > +	chip->options |= NAND_NO_READRDY & NAND_CHIPOPTIONS_MSK;
> 
> Won't this get overwritten by this later?

It will, thanks for spotting.
--
Florian