[U-Boot-Users] RE: [PATCH v2] ARM: Davinci: Fix DM644x timer overflow handling and cleanup

[Pieter Voorthuijsen]

> Subject: [PATCH v2] ARM: Davinci: Fix DM644x timer overflow 
> handling and cleanup
> 
> Fix ARM based DaVinci DM644x timer overflow handling and 
> cleanup timer code.

Acked-by: Pieter Voorthuijsen <pieter.voorthuijsen at Prodrive.nl>

Please apply, tested on DaVinci DVEVM and other board, working OK!

> 
> Changes:
> 
> - Remove *_masked() functions as noted by Wolfgang
> 
> - Adapt register naming to recent TI spec (sprue26, March 2007)
> 
> - Fix reset_timer() handling
> 
> - As reported by Pieter [1] the overflow fix introduced a 
> delay of factor 16 (e.g 2 seconds became 32). While the 
> overflow fix is basically okay, it missed to divide udelay by 
> 16, too. Fix this.
> 
> [1] http://article.gmane.org/gmane.comp.boot-loaders.u-boot/38179
> 
> - Remove software division of timer count value (DIV(x) 
> macro) and do it in hardware (TIM_CLK_DIV).
> 
> Many thanks to Troy Kisky <troy.kisky at boundarydevices.com> 
> and Pieter Voorthuijsen <pieter.voorthuijsen at Prodrive.nl> for 
> the hints & testing!
> 
> Patch is compile tested with davinci_dvevm & sonata & 
> schmoogie configuration and tested by Pieter on DaVinci EVM hardware.
> 
> Signed-off-by: Dirk Behme <dirk.behme at gmail.com>
> 
> ---
> 
> This patch completely replaces first version of this patch
> 
> http://article.gmane.org/gmane.comp.boot-loaders.u-boot/38312/
> 
> Changes:
> 
> - Incorporate findings from testing on real HW: Don't change 
> CFG_HZ_CLOCK in config files, instead divide in udelay() and 
> get_timer() correctly.
> 
> Thanks to Pieter!
> 
> Index: uboot_davinci/cpu/arm926ejs/davinci/timer.c
> ===================================================================
> --- uboot_davinci.orig/cpu/arm926ejs/davinci/timer.c
> +++ uboot_davinci/cpu/arm926ejs/davinci/timer.c
> @@ -42,9 +42,9 @@
>  
>  typedef volatile struct {
>  	u_int32_t	pid12;
> -	u_int32_t	emumgt_clksped;
> -	u_int32_t	gpint_en;
> -	u_int32_t	gpdir_dat;
> +	u_int32_t	emumgt;
> +	u_int32_t	na1;
> +	u_int32_t	na2;
>  	u_int32_t	tim12;
>  	u_int32_t	tim34;
>  	u_int32_t	prd12;
> @@ -52,21 +52,12 @@ typedef volatile struct {
>  	u_int32_t	tcr;
>  	u_int32_t	tgcr;
>  	u_int32_t	wdtcr;
> -	u_int32_t	tlgc;
> -	u_int32_t	tlmr;
>  } davinci_timer;
>  
>  davinci_timer		*timer = (davinci_timer *)CFG_TIMERBASE;
>  
>  #define TIMER_LOAD_VAL	(CFG_HZ_CLOCK / CFG_HZ)
> -#define READ_TIMER	timer->tim34
> -
> -/*
> - * Timer runs with CFG_HZ_CLOCK, currently 27MHz. To avoid wrap
> - * around of timestamp already after min ~159s, divide it, 
> e.g. by 16.
> - * timestamp will then wrap around all min ~42min
> - */
> -#define DIV(x)		((x) >> 4)
> +#define TIM_CLK_DIV	16
>  
>  static ulong timestamp;
>  static ulong lastinc;
> @@ -76,63 +67,51 @@ int timer_init(void)
>  	/* We are using timer34 in unchained 32-bit mode, full speed */
>  	timer->tcr = 0x0;
>  	timer->tgcr = 0x0;
> -	timer->tgcr = 0x06;
> +	timer->tgcr = 0x06 | ((TIM_CLK_DIV - 1) << 8);
>  	timer->tim34 = 0x0;
>  	timer->prd34 = TIMER_LOAD_VAL;
>  	lastinc = 0;
> -	timer->tcr = 0x80 << 16;
>  	timestamp = 0;
> +	timer->tcr = 2 << 22;
>  
>  	return(0);
>  }
>  
>  void reset_timer(void)
>  {
> -	reset_timer_masked();
> -}
> -
> -ulong get_timer(ulong base)
> -{
> -	return(get_timer_masked() - base);
> -}
> -
> -void set_timer(ulong t)
> -{
> -	timestamp = t;
> -}
> -
> -void udelay(unsigned long usec)
> -{
> -	udelay_masked(usec);
> -}
> -
> -void reset_timer_masked(void)
> -{
> -	lastinc = DIV(READ_TIMER);
> +	timer->tcr = 0x0;
> +	timer->tim34 = 0;
> +	lastinc = 0;
>  	timestamp = 0;
> +	timer->tcr = 2 << 22;
>  }
>  
> -ulong get_timer_raw(void)
> +static ulong get_timer_raw(void)
>  {
> -	ulong now = DIV(READ_TIMER);
> +	ulong now = timer->tim34;
>  
>  	if (now >= lastinc) {
>  		/* normal mode */
>  		timestamp += now - lastinc;
>  	} else {
>  		/* overflow ... */
> -		timestamp += now + DIV(TIMER_LOAD_VAL) - lastinc;
> +		timestamp += now + TIMER_LOAD_VAL - lastinc;
>  	}
>  	lastinc = now;
>  	return timestamp;
>  }
>  
> -ulong get_timer_masked(void)
> +ulong get_timer(ulong base)
> +{
> +	return((get_timer_raw() / (TIMER_LOAD_VAL / 
> TIM_CLK_DIV)) - base); }
> +
> +void set_timer(ulong t)
>  {
> -	return(get_timer_raw() / DIV(TIMER_LOAD_VAL));
> +	timestamp = t;
>  }
>  
> -void udelay_masked(unsigned long usec)
> +void udelay(unsigned long usec)
>  {
>  	ulong tmo;
>  	ulong endtime;
> @@ -140,7 +119,7 @@ void udelay_masked(unsigned long usec)
>  
>  	tmo = CFG_HZ_CLOCK / 1000;
>  	tmo *= usec;
> -	tmo /= 1000;
> +	tmo /= (1000 * TIM_CLK_DIV);
>  
>  	endtime = get_timer_raw() + tmo;
>  
> @@ -165,8 +144,5 @@ unsigned long long get_ticks(void)
>   */
>  ulong get_tbclk(void)
>  {
> -	ulong tbclk;
> -
> -	tbclk = CFG_HZ;
> -	return(tbclk);
> +	return CFG_HZ;
>  }
>