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From: Scott Wood <scottwood@freescale.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] nand_base: Add timeout for NAND reset command
Date: Wed, 04 Feb 2009 13:54:02 -0600	[thread overview]
Message-ID: <4989F25A.6090400@freescale.com> (raw)
In-Reply-To: <1233776842-23379-1-git-send-email-ptyser@xes-inc.com>

Peter Tyser wrote:
> +/*
> + * CONFIG_SYS_NAND_RESET_CNT is used as a timeout mechanism when resetting
> + * a flash.  NAND flash is initialized prior to interrupts so standard timers
> + * can't be used.  CONFIG_SYS_NAND_RESET_CNT should be set to a value
> + * which is greater than (max NAND reset time / NAND status read time).
> + * A conservative default of 200000 (500 us / 25 ns) is used as a default.
> + */
> +#ifndef CONFIG_SYS_NAND_RESET_CNT
> +#define CONFIG_SYS_NAND_RESET_CNT 200000
> +#endif

Where does 25 ns come from?  Should the timeout be in terms of real time 
rather than iterations (we use get_ticks() for this purpose in 
fsl_elbc_nand.c)?

-Scott

  reply	other threads:[~2009-02-04 19:54 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-04 19:47 [U-Boot] [PATCH] nand_base: Add timeout for NAND reset command Peter Tyser
2009-02-04 19:54 ` Scott Wood [this message]
2009-02-04 20:22   ` Peter Tyser
2009-02-04 20:45     ` Scott Wood
2009-02-04 21:22       ` Wolfgang Denk
2009-02-04 21:29         ` Peter Tyser
2009-02-04 21:53           ` Wolfgang Denk
2009-02-04 21:31         ` Scott Wood
2009-02-04 21:54           ` Wolfgang Denk
2009-02-05 16:33             ` Peter Tyser
2009-02-05 16:37               ` Scott Wood
2009-02-06 23:30 ` Scott Wood

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