[PATCH] PM OMAP3: Change omap3_save_secure_ram to be called only during init

[PATCH] PM OMAP3: Change omap3_save_secure_ram to be called only during init

[Tero Kristo]

This function is now called only once during the initialization of the device
and consequent sleep cycles will re-use the same saved contents for secure
RAM. Users who need secure services should do secure RAM saving before
entering off-mode, if a secure service has been accessed after last save.

Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
---
 arch/arm/mach-omap2/pm34xx.c |   19 ++++++++++++++++++-
 1 files changed, 18 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index 4223622..b8cf5f2 100644
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -127,6 +127,12 @@ static void omap3_core_restore_context(void)
 	omap_dma_global_context_restore();
 }
 
+/*
+ * FIXME: This function should be called before entering off-mode after
+ * OMAP3 secure services have been accessed. Currently it is only called
+ * once during boot sequence, but this works as we are not using secure
+ * services.
+ */
 static void omap3_save_secure_ram_context(u32 target_mpu_state)
 {
 	u32 ret;
@@ -349,7 +355,6 @@ void omap_sram_idle(void)
 					     OMAP3_PRM_VOLTCTRL_OFFSET);
 			omap3_core_save_context();
 			omap3_prcm_save_context();
-			omap3_save_secure_ram_context(mpu_next_state);
 		}
 		/* Enable IO-PAD wakeup */
 		prm_set_mod_reg_bits(OMAP3430_EN_IO, WKUP_MOD, PM_WKEN);
@@ -923,6 +928,18 @@ int __init omap3_pm_init(void)
 	}
 	omap3_save_scratchpad_contents();
 
+	if (omap_type() != OMAP2_DEVICE_TYPE_GP) {
+		local_irq_disable();
+		local_fiq_disable();
+
+		omap_dma_global_context_save();
+		omap3_save_secure_ram_context(PWRDM_POWER_ON);
+		omap_dma_global_context_restore();
+
+		local_irq_enable();
+		local_fiq_enable();
+	}
+
 err1:
 	return ret;
 err2:
-- 
1.5.4.3

Re: [PATCH] PM OMAP3: Change omap3_save_secure_ram to be called only during init

[Kevin Hilman]

Tero Kristo <tero.kristo@nokia.com> writes:

> This function is now called only once during the initialization of the device
> and consequent sleep cycles will re-use the same saved contents for secure
> RAM. Users who need secure services should do secure RAM saving before
> entering off-mode, if a secure service has been accessed after last save.
>
> Signed-off-by: Tero Kristo <tero.kristo@nokia.com>

Thanks, applied to PM branch.

Kevin

> ---
>  arch/arm/mach-omap2/pm34xx.c |   19 ++++++++++++++++++-
>  1 files changed, 18 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index 4223622..b8cf5f2 100644
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -127,6 +127,12 @@ static void omap3_core_restore_context(void)
>  	omap_dma_global_context_restore();
>  }
>  
> +/*
> + * FIXME: This function should be called before entering off-mode after
> + * OMAP3 secure services have been accessed. Currently it is only called
> + * once during boot sequence, but this works as we are not using secure
> + * services.
> + */
>  static void omap3_save_secure_ram_context(u32 target_mpu_state)
>  {
>  	u32 ret;
> @@ -349,7 +355,6 @@ void omap_sram_idle(void)
>  					     OMAP3_PRM_VOLTCTRL_OFFSET);
>  			omap3_core_save_context();
>  			omap3_prcm_save_context();
> -			omap3_save_secure_ram_context(mpu_next_state);
>  		}
>  		/* Enable IO-PAD wakeup */
>  		prm_set_mod_reg_bits(OMAP3430_EN_IO, WKUP_MOD, PM_WKEN);
> @@ -923,6 +928,18 @@ int __init omap3_pm_init(void)
>  	}
>  	omap3_save_scratchpad_contents();
>  
> +	if (omap_type() != OMAP2_DEVICE_TYPE_GP) {
> +		local_irq_disable();
> +		local_fiq_disable();
> +
> +		omap_dma_global_context_save();
> +		omap3_save_secure_ram_context(PWRDM_POWER_ON);
> +		omap_dma_global_context_restore();
> +
> +		local_irq_enable();
> +		local_fiq_enable();
> +	}
> +
>  err1:
>  	return ret;
>  err2:
> -- 
> 1.5.4.3
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] PM OMAP3: Change omap3_save_secure_ram to be called only during init

[Kevin Hilman]

Tero Kristo <tero.kristo@nokia.com> writes:

> This function is now called only once during the initialization of the device
> and consequent sleep cycles will re-use the same saved contents for secure
> RAM. Users who need secure services should do secure RAM saving before
> entering off-mode, if a secure service has been accessed after last save.
>
> Signed-off-by: Tero Kristo <tero.kristo@nokia.com>

You explain what you're doing, but you don't explain why.

Is there a large latency involved in this save/restore that you're
trying to eliminate for the no-secure-services case?

Kevin

> ---
>  arch/arm/mach-omap2/pm34xx.c |   19 ++++++++++++++++++-
>  1 files changed, 18 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index 4223622..b8cf5f2 100644
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -127,6 +127,12 @@ static void omap3_core_restore_context(void)
>  	omap_dma_global_context_restore();
>  }
>  
> +/*
> + * FIXME: This function should be called before entering off-mode after
> + * OMAP3 secure services have been accessed. Currently it is only called
> + * once during boot sequence, but this works as we are not using secure
> + * services.
> + */
>  static void omap3_save_secure_ram_context(u32 target_mpu_state)
>  {
>  	u32 ret;
> @@ -349,7 +355,6 @@ void omap_sram_idle(void)
>  					     OMAP3_PRM_VOLTCTRL_OFFSET);
>  			omap3_core_save_context();
>  			omap3_prcm_save_context();
> -			omap3_save_secure_ram_context(mpu_next_state);
>  		}
>  		/* Enable IO-PAD wakeup */
>  		prm_set_mod_reg_bits(OMAP3430_EN_IO, WKUP_MOD, PM_WKEN);
> @@ -923,6 +928,18 @@ int __init omap3_pm_init(void)
>  	}
>  	omap3_save_scratchpad_contents();
>  
> +	if (omap_type() != OMAP2_DEVICE_TYPE_GP) {
> +		local_irq_disable();
> +		local_fiq_disable();
> +
> +		omap_dma_global_context_save();
> +		omap3_save_secure_ram_context(PWRDM_POWER_ON);
> +		omap_dma_global_context_restore();
> +
> +		local_irq_enable();
> +		local_fiq_enable();
> +	}
> +
>  err1:
>  	return ret;
>  err2:
> -- 
> 1.5.4.3
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

RE: [PATCH] PM OMAP3: Change omap3_save_secure_ram to be called only during init

[Tero.Kristo]

 

>-----Original Message-----
>From: ext Kevin Hilman [mailto:khilman@deeprootsystems.com] 
>Sent: 13 August, 2009 17:17
>To: Kristo Tero (Nokia-D/Tampere)
>Cc: linux-omap@vger.kernel.org
>Subject: Re: [PATCH] PM OMAP3: Change omap3_save_secure_ram to 
>be called only during init
>
>Tero Kristo <tero.kristo@nokia.com> writes:
>
>> This function is now called only once during the 
>initialization of the device
>> and consequent sleep cycles will re-use the same saved 
>contents for secure
>> RAM. Users who need secure services should do secure RAM 
>saving before
>> entering off-mode, if a secure service has been accessed 
>after last save.
>>
>> Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
>
>You explain what you're doing, but you don't explain why.
>
>Is there a large latency involved in this save/restore that you're
>trying to eliminate for the no-secure-services case?

There are both latency and reliability issues. The context save uses a hardware resource which takes an order of hundreds of milliseconds to initialize after a wake up from off-mode, and also there is no way of checking whether it is ready from kernel side or not. It just crashes if you use it too quickly.

>
>Kevin
>
>> ---
>>  arch/arm/mach-omap2/pm34xx.c |   19 ++++++++++++++++++-
>>  1 files changed, 18 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/pm34xx.c 
>b/arch/arm/mach-omap2/pm34xx.c
>> index 4223622..b8cf5f2 100644
>> --- a/arch/arm/mach-omap2/pm34xx.c
>> +++ b/arch/arm/mach-omap2/pm34xx.c
>> @@ -127,6 +127,12 @@ static void omap3_core_restore_context(void)
>>  	omap_dma_global_context_restore();
>>  }
>>  
>> +/*
>> + * FIXME: This function should be called before entering 
>off-mode after
>> + * OMAP3 secure services have been accessed. Currently it 
>is only called
>> + * once during boot sequence, but this works as we are not 
>using secure
>> + * services.
>> + */
>>  static void omap3_save_secure_ram_context(u32 target_mpu_state)
>>  {
>>  	u32 ret;
>> @@ -349,7 +355,6 @@ void omap_sram_idle(void)
>>  					     OMAP3_PRM_VOLTCTRL_OFFSET);
>>  			omap3_core_save_context();
>>  			omap3_prcm_save_context();
>> -			omap3_save_secure_ram_context(mpu_next_state);
>>  		}
>>  		/* Enable IO-PAD wakeup */
>>  		prm_set_mod_reg_bits(OMAP3430_EN_IO, WKUP_MOD, PM_WKEN);
>> @@ -923,6 +928,18 @@ int __init omap3_pm_init(void)
>>  	}
>>  	omap3_save_scratchpad_contents();
>>  
>> +	if (omap_type() != OMAP2_DEVICE_TYPE_GP) {
>> +		local_irq_disable();
>> +		local_fiq_disable();
>> +
>> +		omap_dma_global_context_save();
>> +		omap3_save_secure_ram_context(PWRDM_POWER_ON);
>> +		omap_dma_global_context_restore();
>> +
>> +		local_irq_enable();
>> +		local_fiq_enable();
>> +	}
>> +
>>  err1:
>>  	return ret;
>>  err2:
>> -- 
>> 1.5.4.3
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe 
>linux-omap" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: [PATCH] PM OMAP3: Change omap3_save_secure_ram to be called only during init

[Kevin Hilman]

<Tero.Kristo@nokia.com> writes:

>  
>
>>-----Original Message-----
>>From: ext Kevin Hilman [mailto:khilman@deeprootsystems.com]
>>Sent: 13 August, 2009 17:17
>>To: Kristo Tero (Nokia-D/Tampere)
>>Cc: linux-omap@vger.kernel.org
>>Subject: Re: [PATCH] PM OMAP3: Change omap3_save_secure_ram to
>>be called only during init
>>
>>Tero Kristo <tero.kristo@nokia.com> writes:
>>
>>> This function is now called only once during the
>>initialization of the device
>>> and consequent sleep cycles will re-use the same saved
>>contents for secure
>>> RAM. Users who need secure services should do secure RAM
>>saving before
>>> entering off-mode, if a secure service has been accessed
>>after last save.
>>> Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
>>
>>You explain what you're doing, but you don't explain why.
>>
>>Is there a large latency involved in this save/restore that you're
>>trying to eliminate for the no-secure-services case?
>
> There are both latency and reliability issues. The context save uses a
> hardware resource which takes an order of hundreds of milliseconds to
> initialize after a wake up from off-mode, and also there is no way of
> checking whether it is ready from kernel side or not. It just crashes
> if you use it too quickly.

Tero,

OK, makes sense.  Thanks or the clarification.  I'll add this to the
changelog and push to PM branch.

Kevin

>>
>>Kevin
>>
>>> --- arch/arm/mach-omap2/pm34xx.c | 19 ++++++++++++++++++- 1 files
>>> changed, 18 insertions(+), 1 deletions(-)
>>> diff --git a/arch/arm/mach-omap2/pm34xx.c
>>b/arch/arm/mach-omap2/pm34xx.c
>>> index 4223622..b8cf5f2 100644 --- a/arch/arm/mach-omap2/pm34xx.c
>>> +++ b/arch/arm/mach-omap2/pm34xx.c
>>> @@ -127,6 +127,12 @@ static void omap3_core_restore_context(void)
>>> omap_dma_global_context_restore(); }
>>>  
>>> +/* * FIXME: This function should be called before entering
>>off-mode after
>>> + * OMAP3 secure services have been accessed. Currently it
>>is only called
>>> + * once during boot sequence, but this works as we are not
>>using secure
>>> + * services.  */
>>>  static void omap3_save_secure_ram_context(u32 target_mpu_state) {
>>> u32 ret; @@ -349,7 +355,6 @@ void omap_sram_idle(void)
>>> OMAP3_PRM_VOLTCTRL_OFFSET); omap3_core_save_context();
>>> omap3_prcm_save_context(); -
>>> omap3_save_secure_ram_context(mpu_next_state); } /* Enable IO-PAD
>>> wakeup */ prm_set_mod_reg_bits(OMAP3430_EN_IO, WKUP_MOD, PM_WKEN);
>>> @@ -923,6 +928,18 @@ int __init omap3_pm_init(void) }
>>> omap3_save_scratchpad_contents();
>>>  
>>> +	if (omap_type() != OMAP2_DEVICE_TYPE_GP) {
>>> +		local_irq_disable();
>>> +		local_fiq_disable();
>>> +
>>> +		omap_dma_global_context_save();
>>> +		omap3_save_secure_ram_context(PWRDM_POWER_ON);
>>> +		omap_dma_global_context_restore();
>>> +
>>> +		local_irq_enable();
>>> +		local_fiq_enable();
>>> +	}
>>> +
>>>  err1: return ret; err2: -- 1.5.4.3
>>> -- To unsubscribe from this list: send the line "unsubscribe
>>linux-omap" in
>>> the body of a message to majordomo@vger.kernel.org More majordomo
>>> info at http://vger.kernel.org/majordomo-info.html
>>