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Subject: Re: [PATCH] Add driver for M-sys / Sandisk diskonchip G4 nand flash
From: Artem Bityutskiy <dedekind1@gmail.com>
To: Mike Dunn <mikedunn@newsguy.com>
Date: Thu, 20 Oct 2011 19:31:04 +0300
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On Mon, 2011-10-17 at 14:45 -0700, Mike Dunn wrote:
> Not sure.  I'm currently not too knowlegeable on timers, and I'm not usin=
g this
> config option in my kernel.  Will look into this.  Meantime, suggestions,
> pointers to reference docs, etc greatly appreciated!

Jiffies do work fine in NO_HZ.

>=20
>=20
> > Why not use a loop of mdelay() or msleep() or doc_nops() bellow ?
> > I would prefer doc nops, as the time of these is controlled by the chip=
 itself,
> > and thus less dependant on the CPU frequency.
>=20
>=20
> I'm not simply delaying, I'm polling register 0x1038 (I'm calling it
> DOCG4_CONTROL_STATUS).  The diskonchip P3 uses this same register in exac=
tly the
> same way, so it's likely the G3 does as well.  With regard to the diskonc=
hip nop
> register, I was careful to preserve the same number of reads of that regi=
ster in
> the same places as was observed during reverse engineering, to prevent
> timing-related failures.

But use cpu_relax() in the polling loop.


--=20
Best Regards,
Artem Bityutskiy

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