From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Date: Sun, 4 Jan 2009 08:40:04 +0100
Subject: [U-Boot] [PATCH] IXP425: Fixing timer code Part 1/1
In-Reply-To: <gim47r$3uf$1@ger.gmane.org>
References: <49384728.LMggwd1oTzMugOAp%stefan.althoefer@web.de>
	<20081215232625.2BBDC832E8A1@gemini.denx.de>
	<gim47r$3uf$1@ger.gmane.org>
Message-ID: <20090104074004.GD6960@game.jcrosoft.org>
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On 20:08 Sun 21 Dec     , Stefan Althoefer wrote:
> This fixes bugs in non-interupt timer code for IXP425
> 
> Fixed udelay() implementation to be more accurate.
> The timing error of udelay() was caused by
> too much looping overhead. The actual timing routine
> was called repeatedly for each microsecond. When
> bigger slices are used, it becomes more accurate.
> CONFIG_SYS_TIMER_CLK_FREQ can be set by config file
> if clock speed differs from IXP425 default (66,666MHz).
> 
> Fixed get_timer() to return correct time in units
> of CONFIG_SYS_HZ. The code now works for times
> in execess of 64 seconds (the timer overflow
> limit), assumed get_timer() is called with a period
> < 64 seconds.
> 
> do_sleep() now works correctly.
> 

some general comments
please check the coding style
and please use the readx/writex accessors

> Signed-off-by: Stefan Althoefer <stefan.althoefer@web.de>
> ---
>  cpu/ixp/timer.c |   64 ++++++++++++++++++++++++++++++++++++++++++-------------
>  1 files changed, 49 insertions(+), 15 deletions(-)
> 
> diff --git a/cpu/ixp/timer.c b/cpu/ixp/timer.c
> index 09d8ad5..d30adbc 100644
> --- a/cpu/ixp/timer.c
> +++ b/cpu/ixp/timer.c
> @@ -33,18 +33,28 @@
>  #include <asm/arch/ixp425.h>
> 
>  #ifndef CONFIG_USE_IRQ
> +
> +#ifndef CONFIG_SYS_TIMER_CLK_FREQ
> +#define CONFIG_SYS_TIMER_CLK_FREQ 66666666
> +#endif
> +
>  ulong get_timer (ulong base)
>  {
> -       return get_timer_masked () - base;
> +	return get_timer_masked () - base;
>  }
> 
> -void ixp425_udelay(unsigned long usec)
> +/* udelay uses timer 1 */
> +
> +void ixp425_udelay (unsigned long usec)
>  {
>  	/*
>  	 * This function has a max usec, but since it is called from udelay
>  	 * we should not have to worry... be happy
>  	 */
> -	unsigned long usecs = CONFIG_SYS_HZ/1000000L & ~IXP425_OST_RELOAD_MASK;
> +	unsigned long usecs = CONFIG_SYS_TIMER_CLK_FREQ/1000000L
please add a space before and after '/'
> +		& ~IXP425_OST_RELOAD_MASK;
> +
> +	usecs *= usec;
> 
>  	*IXP425_OSST = IXP425_OSST_TIMER_1_PEND;
>  	usecs |= IXP425_OST_ONE_SHOT | IXP425_OST_ENABLE;
> @@ -54,30 +64,54 @@ void ixp425_udelay(unsigned long usec)
> 
>  void udelay (unsigned long usec)
>  {
> -	while (usec--) ixp425_udelay(1);
> +	/* ipx425_udelay has big overhead, so call it in bigger slices */
> +	while (usec>1000) {
please add a space before and after '>'
> +		ixp425_udelay (1000);
> +		usec -= 1000;
> +	}
> +	/* and now the rest */
> +	ixp425_udelay (usec);
>  }
> 
Best Regards,
J.