Re: [PATCH 3/3] mtd/nand : workaround for Freescale FCM to supportlarge-page Nand chip

[LiuShuo]

ä 2011å11æ24æ 16:16, Artem Bityutskiy åé:
> On Thu, 2011-11-24 at 07:49 +0000, Li Yang-R58472 wrote:
> > > Subject: Re: [PATCH 3/3] mtd/nand : workaround for Freescale FCM to support
> > > large-page Nand chip
> > >
> > > On Thu, 2011-11-24 at 08:41 +0800, b35362@xxxxxxxxxxxxx wrote:
> > > > +               /*
> > > > +                * Freescale FCM controller has a 2K size limitation of buffer
> > > > +                * RAM, so elbc_fcm_ctrl->buffer have to be used if writesize
> > > > +                * of chip is greater than 2048.
> > > > +                * We malloc a large enough buffer (maximum page size is
> > > 16K).
> > > > +                */
> > > > +               elbc_fcm_ctrl->buffer = kmalloc(1024 * 16 + 1024,
> > > GFP_KERNEL);
> > >
> > > Are there NANDs with 16KiB page size?
> > We are not sure, but are there possibility that chip with 16K page will appear?  Or maybe we can add a MACRO for the maximum page size?
> I do not know, but I know that allocating 32KiB of contiguous physical
> RAM may cause unneeded memory pressure and even fail if the memory is
> too fragmented. So I would not go for this unless this is necessary.
What is your suggestion ? 8k is enough ?
> Did you try to look how the NAND base interface could be changed to
> avoid re-allocation altogether, BTW?
This buffer is a controller-wide resource( as Scott said), I only 
allocate buffer one time in this version.
It should be a large enough buffer for all chips.

-Liu Shuo

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/