Re: [PATCH] mtd: fix timeout in M25P80 driver

[Peter Horton]

Artem Bityutskiy wrote:
> On Mon, 2009-04-13 at 15:26 +0100, Peter Horton wrote:
> > Extend erase timeout in M25P80 SPI Flash driver.
> >
> > The M25P80 drivers fails erasing sectors on a M25P128 because the ready
> > wait timeout is too short. Change the timeout from a simple loop count to a
> > suitable number of seconds.
> >
> > Signed-off-by: Peter Horton <zero@xxxxxxxxxxxxxxxxx>
> > ---
> > Index: linux-2.6.29-git12/drivers/mtd/devices/m25p80.c
> > ===================================================================
> > --- linux-2.6.29-git12.orig/drivers/mtd/devices/m25p80.c	2009-04-12 21:41:16.000000000 +0000
> > +++ linux-2.6.29-git12/drivers/mtd/devices/m25p80.c	2009-04-12 21:43:01.000000000 +0000
> > @@ -54,7 +54,7 @@
> >  #define	SR_SRWD			0x80	/* SR write protect */
> >  
> >  /* Define max times to check status register before we give up. */
> > -#define	MAX_READY_WAIT_COUNT	100000
> > +#define	MAX_READY_WAIT_JIFFIES	(10 * HZ)	/* eg. M25P128 specs 6s max sector erase */
> >  #define	CMD_SIZE		4
> >  
> >  #ifdef CONFIG_M25PXX_USE_FAST_READ
> > @@ -145,20 +145,20 @@
> >   */
> >  static int wait_till_ready(struct m25p *flash)
> >  {
> > -	int count;
> > +	unsigned long deadline;
> >  	int sr;
> >  
> > -	/* one chip guarantees max 5 msec wait here after page writes,
> > -	 * but potentially three seconds (!) after page erase.
> > -	 */
> Why did you remove the comment? Is it wrong or useless?

I moved the comment up to the definition of MAX_READY_WAIT_JIFFIES. 
Looking through the code I missed the fact the driver can generate "chip 
erase", on the M25P128 the maximum ready timeout for this is 250s !!!

P.
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