Re: [PATCH] mtd: cfi_cmdset_0001: Fix max timeout for locking operations

[David Woodhouse <dwmw2@infradead.org>]

On Fri, 2010-02-26 at 21:54 +0100, Anders Grafström wrote:
> The max timeout is currently too short for some flash chips.
> This patch increases it to 10 seconds. The typical timeout
> remains unchanged (the tick period, 1000000/HZ).
> 
> Specification change #11 in '5 Volt Intel StrataFlash Memory Specification Update'
> (297848-15) specifies an increase of Clear Block Lock-Bit Time Max to 7 sec.
> This is contradicted by the table in Specification Change #8 which says .70 sec
> but a 10 sec timeout doesn't hurt so play it safe.
> 
> Signed-off-by: Anders Grafström <anders.grafstrom@netinsight.net>
> ---
>  drivers/mtd/chips/cfi_cmdset_0001.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/mtd/chips/cfi_cmdset_0001.c b/drivers/mtd/chips/cfi_cmdset_0001.c
> index 9253043..83e4ae2 100644
> --- a/drivers/mtd/chips/cfi_cmdset_0001.c
> +++ b/drivers/mtd/chips/cfi_cmdset_0001.c
> @@ -2077,7 +2077,7 @@ static int __xipram do_xxlock_oneblock(struct map_info *map, struct flchip *chip
>          */
>         udelay = (!extp || !(extp->FeatureSupport & (1 << 5))) ? 1000000/HZ : 0;
>  
> -       ret = WAIT_TIMEOUT(map, chip, adr, udelay, udelay * 100);
> +       ret = WAIT_TIMEOUT(map, chip, adr, udelay, udelay * HZ * 10); 

I don't see how this makes any sense. What is the _unit_ of the argument
you're changing? Is it µs, is it ticks? You aren't just changing the
value here; you're actually changing the units. The dimensional analysis
doesn't make sense.

AFAICT this really is supposed to be µs, so multiplying by HZ has to be
wrong.

-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse@intel.com                              Intel Corporation