[v2,1/9] clk: at91: pmc: Wait for clocks when resuming

Message ID 20170915140411.31716-2-romain.izard.pro@gmail.com
State Superseded
Headers show
Series
  • Various patches for SAMA5D2 backup mode
Related show

Commit Message

Romain Izard Sept. 15, 2017, 2:04 p.m.
Wait for the syncronization of all clocks when resuming, not only the
UPLL clock. Do not use regmap_read_poll_timeout, as it will call BUG()
when interrupts are masked, which is the case in here.

Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
---
 drivers/clk/at91/pmc.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

Comments

Ludovic Desroches Sept. 22, 2017, 12:05 p.m. | #1
On Fri, Sep 15, 2017 at 04:04:03PM +0200, Romain Izard wrote:
> Wait for the syncronization of all clocks when resuming, not only the
> UPLL clock. Do not use regmap_read_poll_timeout, as it will call BUG()
> when interrupts are masked, which is the case in here.
> 
> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>

I faced the same issue because of the use of regmap_read_poll_timeout
when timekeeping is not ready.


Ludovic

> ---
>  drivers/clk/at91/pmc.c | 24 ++++++++++++++++--------
>  1 file changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
> index 775af473fe11..5c2b26de303e 100644
> --- a/drivers/clk/at91/pmc.c
> +++ b/drivers/clk/at91/pmc.c
> @@ -107,10 +107,20 @@ static int pmc_suspend(void)
>  	return 0;
>  }
>  
> +static bool pmc_ready(unsigned int mask)
> +{
> +	unsigned int status;
> +
> +	regmap_read(pmcreg, AT91_PMC_SR, &status);
> +
> +	return ((status & mask) == mask) ? 1 : 0;
> +}
> +
>  static void pmc_resume(void)
>  {
> -	int i, ret = 0;
> +	int i;
>  	u32 tmp;
> +	u32 mask = AT91_PMC_MCKRDY | AT91_PMC_LOCKA;
>  
>  	regmap_read(pmcreg, AT91_PMC_MCKR, &tmp);
>  	if (pmc_cache.mckr != tmp)
> @@ -134,13 +144,11 @@ static void pmc_resume(void)
>  			     AT91_PMC_PCR_CMD);
>  	}
>  
> -	if (pmc_cache.uckr & AT91_PMC_UPLLEN) {
> -		ret = regmap_read_poll_timeout(pmcreg, AT91_PMC_SR, tmp,
> -					       !(tmp & AT91_PMC_LOCKU),
> -					       10, 5000);
> -		if (ret)
> -			pr_crit("USB PLL didn't lock when resuming\n");
> -	}
> +	if (pmc_cache.uckr & AT91_PMC_UPLLEN)
> +		mask |= AT91_PMC_LOCKU;
> +
> +	while (!pmc_ready(mask))
> +		cpu_relax();
>  }
>  
>  static struct syscore_ops pmc_syscore_ops = {
> -- 
> 2.11.0
> 
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Nicolas Ferre Sept. 22, 2017, 12:13 p.m. | #2
On 15/09/2017 at 16:04, Romain Izard wrote:
> Wait for the syncronization of all clocks when resuming, not only the
> UPLL clock. Do not use regmap_read_poll_timeout, as it will call BUG()
> when interrupts are masked, which is the case in here.
> 
> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>

And here is my:
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>

> ---
>  drivers/clk/at91/pmc.c | 24 ++++++++++++++++--------
>  1 file changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
> index 775af473fe11..5c2b26de303e 100644
> --- a/drivers/clk/at91/pmc.c
> +++ b/drivers/clk/at91/pmc.c
> @@ -107,10 +107,20 @@ static int pmc_suspend(void)
>  	return 0;
>  }
>  
> +static bool pmc_ready(unsigned int mask)
> +{
> +	unsigned int status;
> +
> +	regmap_read(pmcreg, AT91_PMC_SR, &status);
> +
> +	return ((status & mask) == mask) ? 1 : 0;
> +}
> +
>  static void pmc_resume(void)
>  {
> -	int i, ret = 0;
> +	int i;
>  	u32 tmp;
> +	u32 mask = AT91_PMC_MCKRDY | AT91_PMC_LOCKA;
>  
>  	regmap_read(pmcreg, AT91_PMC_MCKR, &tmp);
>  	if (pmc_cache.mckr != tmp)
> @@ -134,13 +144,11 @@ static void pmc_resume(void)
>  			     AT91_PMC_PCR_CMD);
>  	}
>  
> -	if (pmc_cache.uckr & AT91_PMC_UPLLEN) {
> -		ret = regmap_read_poll_timeout(pmcreg, AT91_PMC_SR, tmp,
> -					       !(tmp & AT91_PMC_LOCKU),
> -					       10, 5000);
> -		if (ret)
> -			pr_crit("USB PLL didn't lock when resuming\n");
> -	}
> +	if (pmc_cache.uckr & AT91_PMC_UPLLEN)
> +		mask |= AT91_PMC_LOCKU;
> +
> +	while (!pmc_ready(mask))
> +		cpu_relax();
>  }
>  
>  static struct syscore_ops pmc_syscore_ops = {
>

Patch

diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
index 775af473fe11..5c2b26de303e 100644
--- a/drivers/clk/at91/pmc.c
+++ b/drivers/clk/at91/pmc.c
@@ -107,10 +107,20 @@  static int pmc_suspend(void)
 	return 0;
 }
 
+static bool pmc_ready(unsigned int mask)
+{
+	unsigned int status;
+
+	regmap_read(pmcreg, AT91_PMC_SR, &status);
+
+	return ((status & mask) == mask) ? 1 : 0;
+}
+
 static void pmc_resume(void)
 {
-	int i, ret = 0;
+	int i;
 	u32 tmp;
+	u32 mask = AT91_PMC_MCKRDY | AT91_PMC_LOCKA;
 
 	regmap_read(pmcreg, AT91_PMC_MCKR, &tmp);
 	if (pmc_cache.mckr != tmp)
@@ -134,13 +144,11 @@  static void pmc_resume(void)
 			     AT91_PMC_PCR_CMD);
 	}
 
-	if (pmc_cache.uckr & AT91_PMC_UPLLEN) {
-		ret = regmap_read_poll_timeout(pmcreg, AT91_PMC_SR, tmp,
-					       !(tmp & AT91_PMC_LOCKU),
-					       10, 5000);
-		if (ret)
-			pr_crit("USB PLL didn't lock when resuming\n");
-	}
+	if (pmc_cache.uckr & AT91_PMC_UPLLEN)
+		mask |= AT91_PMC_LOCKU;
+
+	while (!pmc_ready(mask))
+		cpu_relax();
 }
 
 static struct syscore_ops pmc_syscore_ops = {