[PATCH] [MTD] Adjust the NOR CFI flash timeouts to round better
Artem Bityutskiy
dedekind1 at gmail.com
Mon Oct 15 15:28:19 EDT 2012
On Mon, 2012-10-15 at 09:09 -0700, David Woodhouse wrote:
> On Mon, 2012-10-15 at 16:42 +0300, Artem Bityutskiy wrote:
> > On Fri, 2012-10-05 at 12:32 -0600, Jason Gunthorpe wrote:
> > > - /* see comments in do_write_oneword() regarding uWriteTimeo. */
> > > - unsigned long uWriteTimeout = ( HZ / 1000 ) + 1;
> > > + /* see comments in do_write_oneword() regarding uWriteTimeo.
> > > + Note: write_buffer commands take longer so we use a higher
> > > + time. The AMD 29LV256M for instance has a datasheet max
> > > + of 1.2ms for page and 600us for byte */
> > > + unsigned long uWriteTimeout = (HZ / 1500) + 2;
> >
> > What does HZ / 1500 mean? HZ is amount of timer interrupts per second,
> > which may be 1/100, or 1/1000, or 1/300, depending on the system.
>
> If HZ is the amount of timer interrupts per second, then HZ/1500 is the
> amount of timer interrupts in 1/1500 of a second, aka 666.7µs.¹
First of all, yes, my e-mail was not very clear, I guess I just wanted
to express that it is not very readable. Also, HZ / 1500 would be 0 for
HZ < 1500, since we are using integer arithmetic.
--
Best Regards,
Artem Bityutskiy
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