Patchwork [U-Boot] imx-common: timer: fix 32-bit overflow

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Submitter Dirk Behme
Date March 4, 2013, 2:16 p.m.
Message ID <1362406562-17986-1-git-send-email-dirk.behme@de.bosch.com>
Download mbox | patch
Permalink /patch/224740/
State Awaiting Upstream
Delegated to: Stefano Babic
Headers show

Comments

Dirk Behme - March 4, 2013, 2:16 p.m.
From: Knut Wohlrab <knut.wohlrab@de.bosch.com>

The i.MX6 common timer uses the 32-bit variable tbl (time base lower)
to record the overflow of the 32-bit counter. I.e. if the counter
overflows, the variable tbl does overflow, too.

To capture this overflow, use the variable tbu (time base upper), too.
Return the combined value of tbl and tbu.

lastinc is unused then, remove it.

Signed-off-by: Knut Wohlrab <knut.wohlrab@de.bosch.com>
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
---
Note: This replaces the patch
      http://patchwork.ozlabs.org/patch/224646/

 arch/arm/imx-common/timer.c |   26 +++++++-------------------
 1 file changed, 7 insertions(+), 19 deletions(-)
Dirk Behme - March 11, 2013, 6:44 a.m.
On 04.03.2013 15:16, Dirk Behme wrote:
> From: Knut Wohlrab <knut.wohlrab@de.bosch.com>
> 
> The i.MX6 common timer uses the 32-bit variable tbl (time base lower)
> to record the overflow of the 32-bit counter. I.e. if the counter
> overflows, the variable tbl does overflow, too.
> 
> To capture this overflow, use the variable tbu (time base upper), too.
> Return the combined value of tbl and tbu.
> 
> lastinc is unused then, remove it.
> 
> Signed-off-by: Knut Wohlrab <knut.wohlrab@de.bosch.com>
> Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
> ---
> Note: This replaces the patch
>       http://patchwork.ozlabs.org/patch/224646/
> 
>  arch/arm/imx-common/timer.c |   26 +++++++-------------------
>  1 file changed, 7 insertions(+), 19 deletions(-)
> 
> Index: freescale-u-boot-imx.git/arch/arm/imx-common/timer.c
> ===================================================================
> --- freescale-u-boot-imx.git.orig/arch/arm/imx-common/timer.c
> +++ freescale-u-boot-imx.git/arch/arm/imx-common/timer.c
> @@ -48,9 +48,6 @@ static struct mxc_gpt *cur_gpt = (struct
>  
>  DECLARE_GLOBAL_DATA_PTR;
>  
> -#define timestamp (gd->arch.tbl)
> -#define lastinc (gd->arch.lastinc)
> -
>  static inline unsigned long long tick_to_time(unsigned long long tick)
>  {
>  	tick *= CONFIG_SYS_HZ;
> @@ -70,7 +67,6 @@ static inline unsigned long long us_to_t
>  int timer_init(void)
>  {
>  	int i;
> -	ulong val;
>  
>  	/* setup GP Timer 1 */
>  	__raw_writel(GPTCR_SWR, &cur_gpt->control);
> @@ -85,9 +81,8 @@ int timer_init(void)
>  	i = __raw_readl(&cur_gpt->control);
>  	__raw_writel(i | GPTCR_CLKSOURCE_32 | GPTCR_TEN, &cur_gpt->control);
>  
> -	val = __raw_readl(&cur_gpt->counter);
> -	lastinc = val / (MXC_CLK32 / CONFIG_SYS_HZ);
> -	timestamp = 0;
> +	gd->arch.tbl = __raw_readl(&cur_gpt->counter);
> +	gd->arch.tbu = 0;
>  
>  	return 0;
>  }
> @@ -96,18 +91,11 @@ unsigned long long get_ticks(void)
>  {
>  	ulong now = __raw_readl(&cur_gpt->counter); /* current tick value */
>  
> -	if (now >= lastinc) {
> -		/*
> -		 * normal mode (non roll)
> -		 * move stamp forward with absolut diff ticks
> -		 */
> -		timestamp += (now - lastinc);
> -	} else {
> -		/* we have rollover of incrementer */
> -		timestamp += (0xFFFFFFFF - lastinc) + now;
> -	}
> -	lastinc = now;
> -	return timestamp;
> +	/* increment tbu if tbl has rolled over */
> +	if (now < gd->arch.tbl)
> +		gd->arch.tbu++;
> +	gd->arch.tbl = now;
> +	return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl;
>  }
>  
>  ulong get_timer_masked(void)
> 

Any comments on this?

Many thanks

Dirk
Stefano Babic - March 20, 2013, 10:19 a.m.
On 11/03/2013 07:44, Dirk Behme wrote:
> On 04.03.2013 15:16, Dirk Behme wrote:
>> From: Knut Wohlrab <knut.wohlrab@de.bosch.com>
>>
>> The i.MX6 common timer uses the 32-bit variable tbl (time base lower)
>> to record the overflow of the 32-bit counter. I.e. if the counter
>> overflows, the variable tbl does overflow, too.
>>
>> To capture this overflow, use the variable tbu (time base upper), too.
>> Return the combined value of tbl and tbu.
>>
>> lastinc is unused then, remove it.
>>
>> Signed-off-by: Knut Wohlrab <knut.wohlrab@de.bosch.com>
>> Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
>> ---
>> Note: This replaces the patch
>>       http://patchwork.ozlabs.org/patch/224646/
>>
>>  arch/arm/imx-common/timer.c |   26 +++++++-------------------
>>  1 file changed, 7 insertions(+), 19 deletions(-)
>>
>> Index: freescale-u-boot-imx.git/arch/arm/imx-common/timer.c
>> ===================================================================
>> --- freescale-u-boot-imx.git.orig/arch/arm/imx-common/timer.c
>> +++ freescale-u-boot-imx.git/arch/arm/imx-common/timer.c
>> @@ -48,9 +48,6 @@ static struct mxc_gpt *cur_gpt = (struct
>>  
>>  DECLARE_GLOBAL_DATA_PTR;
>>  
>> -#define timestamp (gd->arch.tbl)
>> -#define lastinc (gd->arch.lastinc)
>> -
>>  static inline unsigned long long tick_to_time(unsigned long long tick)
>>  {
>>      tick *= CONFIG_SYS_HZ;
>> @@ -70,7 +67,6 @@ static inline unsigned long long us_to_t
>>  int timer_init(void)
>>  {
>>      int i;
>> -    ulong val;
>>  
>>      /* setup GP Timer 1 */
>>      __raw_writel(GPTCR_SWR, &cur_gpt->control);
>> @@ -85,9 +81,8 @@ int timer_init(void)
>>      i = __raw_readl(&cur_gpt->control);
>>      __raw_writel(i | GPTCR_CLKSOURCE_32 | GPTCR_TEN, &cur_gpt->control);
>>  
>> -    val = __raw_readl(&cur_gpt->counter);
>> -    lastinc = val / (MXC_CLK32 / CONFIG_SYS_HZ);
>> -    timestamp = 0;
>> +    gd->arch.tbl = __raw_readl(&cur_gpt->counter);
>> +    gd->arch.tbu = 0;
>>  
>>      return 0;
>>  }
>> @@ -96,18 +91,11 @@ unsigned long long get_ticks(void)
>>  {
>>      ulong now = __raw_readl(&cur_gpt->counter); /* current tick value */
>>  
>> -    if (now >= lastinc) {
>> -        /*
>> -         * normal mode (non roll)
>> -         * move stamp forward with absolut diff ticks
>> -         */
>> -        timestamp += (now - lastinc);
>> -    } else {
>> -        /* we have rollover of incrementer */
>> -        timestamp += (0xFFFFFFFF - lastinc) + now;
>> -    }
>> -    lastinc = now;
>> -    return timestamp;
>> +    /* increment tbu if tbl has rolled over */
>> +    if (now < gd->arch.tbl)
>> +        gd->arch.tbu++;
>> +    gd->arch.tbl = now;
>> +    return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl;
>>  }
>>  
>>  ulong get_timer_masked(void)
>>
> 
> Any comments on this?
> 
> Many thanks


Hi Dirk,

no thanks to fix this coherently with other SOCs. Checking your patch I
get convinced that we have a lot of duplicated code (get_ticks() for
example) in most SOCs, but let it for a further improvement.

Acked-by: Stefano Babic <sbabic@denx.de>

Best regards,
Stefano
Stefano Babic - March 20, 2013, 10:39 a.m.
On 11/03/2013 07:44, Dirk Behme wrote:
> On 04.03.2013 15:16, Dirk Behme wrote:
>> From: Knut Wohlrab <knut.wohlrab@de.bosch.com>
>>
>> The i.MX6 common timer uses the 32-bit variable tbl (time base lower)
>> to record the overflow of the 32-bit counter. I.e. if the counter
>> overflows, the variable tbl does overflow, too.
>>
>> To capture this overflow, use the variable tbu (time base upper), too.
>> Return the combined value of tbl and tbu.
>>
>> lastinc is unused then, remove it.
>>
>> Signed-off-by: Knut Wohlrab <knut.wohlrab@de.bosch.com>
>> Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
>> ---
>> Note: This replaces the patch
>>       http://patchwork.ozlabs.org/patch/224646/
>>
>>  arch/arm/imx-common/timer.c |   26 +++++++-------------------
>>  1 file changed, 7 insertions(+), 19 deletions(-)
>>
>> Index: freescale-u-boot-imx.git/arch/arm/imx-common/timer.c
>> ===================================================================

Applied to u-boot-imx, thanks.

Best regards,
Stefano Babic

Patch

Index: freescale-u-boot-imx.git/arch/arm/imx-common/timer.c
===================================================================
--- freescale-u-boot-imx.git.orig/arch/arm/imx-common/timer.c
+++ freescale-u-boot-imx.git/arch/arm/imx-common/timer.c
@@ -48,9 +48,6 @@  static struct mxc_gpt *cur_gpt = (struct
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#define timestamp (gd->arch.tbl)
-#define lastinc (gd->arch.lastinc)
-
 static inline unsigned long long tick_to_time(unsigned long long tick)
 {
 	tick *= CONFIG_SYS_HZ;
@@ -70,7 +67,6 @@  static inline unsigned long long us_to_t
 int timer_init(void)
 {
 	int i;
-	ulong val;
 
 	/* setup GP Timer 1 */
 	__raw_writel(GPTCR_SWR, &cur_gpt->control);
@@ -85,9 +81,8 @@  int timer_init(void)
 	i = __raw_readl(&cur_gpt->control);
 	__raw_writel(i | GPTCR_CLKSOURCE_32 | GPTCR_TEN, &cur_gpt->control);
 
-	val = __raw_readl(&cur_gpt->counter);
-	lastinc = val / (MXC_CLK32 / CONFIG_SYS_HZ);
-	timestamp = 0;
+	gd->arch.tbl = __raw_readl(&cur_gpt->counter);
+	gd->arch.tbu = 0;
 
 	return 0;
 }
@@ -96,18 +91,11 @@  unsigned long long get_ticks(void)
 {
 	ulong now = __raw_readl(&cur_gpt->counter); /* current tick value */
 
-	if (now >= lastinc) {
-		/*
-		 * normal mode (non roll)
-		 * move stamp forward with absolut diff ticks
-		 */
-		timestamp += (now - lastinc);
-	} else {
-		/* we have rollover of incrementer */
-		timestamp += (0xFFFFFFFF - lastinc) + now;
-	}
-	lastinc = now;
-	return timestamp;
+	/* increment tbu if tbl has rolled over */
+	if (now < gd->arch.tbl)
+		gd->arch.tbu++;
+	gd->arch.tbl = now;
+	return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl;
 }
 
 ulong get_timer_masked(void)