[U-Boot] [PATCH v2 09/11] S3C24XX: Add NAND Flash driver

Scott Wood
2012-09-14T20:29:56Z

On Fri, Sep 14, 2012 at 01:20:32PM -0700, Tom Rini wrote:
> On Fri, Sep 14, 2012 at 02:24:48PM -0500, Scott Wood wrote:
> > On Fri, Sep 14, 2012 at 08:21:11PM +0200, Marek Vasut wrote:
> > > Dear Jos? Miguel Gon?alves,
> > >
> > > > NAND Flash driver with HW ECC for the S3C24XX SoCs.
> > > > Currently it only supports SLC NAND chips.
> > > >
> > > > Signed-off-by: Jos? Miguel Gon?alves <jose.goncalves@inov.pt>
> [snip]
> > > > +/*
> > > > + * Hardware specific access to control-lines function
> > > > + */
> > > > +static void s3c_nand_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int
> > > > ctrl) +{
> > > > + struct s3c24xx_nand *const nand = s3c24xx_get_base_nand();
> > > > + struct nand_chip *this = mtd->priv;
> > > > +
> > > > + if (ctrl & NAND_CTRL_CHANGE) {
> > > > + if (ctrl & NAND_CLE)
> > > > + this->IO_ADDR_W = &nand->nfcmmd;
> > > > + else if (ctrl & NAND_ALE)
> > > > + this->IO_ADDR_W = &nand->nfaddr;
> > > > + else
> > > > + this->IO_ADDR_W = &nand->nfdata;
> > >
> > > Why don't you use local variable here?
> >
> > Because then you'll access the wrong data when the function is called
> > again without NAND_CTRL_CHANGE. This is a common way of writing the
> > hwcontrol function, though the way ndfc.c does it is simpler (you can use
> > a local variable if you ignore NAND_CTRL_CHANGE altogether).
> >
> > > > + if (ctrl & NAND_NCE)
> > > > + s3c_nand_select_chip(mtd, *(int *)this->priv);
> > >
> > > Uh, how's this *(int *) supposed to work?
> >
> > Usually driver-private data is a struct; apparently in this driver it's
> > an int.
>
> Shall we take both of these comments as requests to do things
> differently (struct like everyone else does, simpiler code like ndfc.c
> does) unless there's good reason to not change?

Sure. :-)

-Scott