Re: [PATCH 5/6] ARM: OMAP4: CLKDM: Update supported transition modes

[Santosh Shilimkar <santosh.shilimkar@ti.com>]

On Thursday 10 May 2012 03:06 AM, Jon Hunter wrote:
> From: Jon Hunter <jon-hunter@ti.com>
> 
> For OMAP3+ devices, the clock domains (CLKDMs) support one or more of the
> following transition modes ...
> 
> NO_SLEEP (0x0) - A clock domain sleep transition is never initiated,
> 		 irrespective of the hardware conditions.
> SW_SLEEP (0x1) - A software-forced sleep transition. The transition is initiated
> 		 when the associated hardware conditions are satisfied
> SW_WKUP  (0x2) - A software-forced clock domain wake-up transition is initiated,
> 		 irrespective of the hardware conditions.
> HW_AUTO  (0x3) - Hardware-controlled automatic sleep and wake-up transition is
> 		 initiated by the PRCM module when the associated hardware
> 		 conditions are satisfied.
> 
> For OMAP4 devices, SW_SLEEP is equivalent to HW_AUTO and NO_SLEEP is equivalent
> to SW_WKUP. For OMAP4 devices, all CLKDMs support HW_AUTO and therefore we can
> place the CLKDMs in the HW_AUTO state instead of the SW_SLEEP mode. Hence, we
> do not need to use the SW_SLEEP mode. With regard to NO_SLEEP and SW_WKUP it is
> preferred to use SW_WKUP mode if the CLKDM supports it and so use this mode
> instead of NO_SLEEP where possible.
> 
> For a software perspective the above 4 modes are represented by the following
> flags to indicate what modes are supported by each of the CLKDMs.
> 
> CLKDM_CAN_DISABLE_AUTO	--> NO_SLEEP
> CLKDM_CAN_ENABLE_AUTO	--> HW_AUTO
> CLKDM_CAN_FORCE_SLEEP	--> SW_SLEEP
> CLKDM_CAN_FORCE_WAKEUP	--> SW_WKUP
> 
> By eliminating the SW_SLEEP mode the the mapping of the flags for OMAP4 devices
> can becomes ...
> 
> CLKDM_CAN_DISABLE_AUTO	--> NO_SLEEP
> CLKDM_CAN_ENABLE_AUTO	--> HW_AUTO
> CLKDM_CAN_FORCE_SLEEP	--> HW_AUTO
Not sure if this can be entirely correct for OMAP4.
Because HW_AUTO = "Sleep and wakeup transition are
based upon hardware conditions"
Where as SW_SLEEP = "Start a software forced sleep
transition on the domain."

I will reply on the the thread where this is being discussed.

> CLKDM_CAN_FORCE_WAKEUP	--> SW_WKUP
> 
> Cc: Ming Lei <ming.lei@canonical.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Benoit Cousson <b-cousson@ti.com>
> Cc: Paul Walmsley <paul@pwsan.com>
> Cc: Kevin Hilman <khilman@ti.com>
> 
> Signed-off-by: Jon Hunter <jon-hunter@ti.com>
> ---
>  arch/arm/mach-omap2/clockdomain44xx.c |    7 +++++--
>  arch/arm/mach-omap2/cminst44xx.c      |   14 --------------
>  2 files changed, 5 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/clockdomain44xx.c b/arch/arm/mach-omap2/clockdomain44xx.c
> index 4f04dd1..99ce556 100644
> --- a/arch/arm/mach-omap2/clockdomain44xx.c
> +++ b/arch/arm/mach-omap2/clockdomain44xx.c
> @@ -70,7 +70,7 @@ static int omap4_clkdm_clear_all_wkup_sleep_deps(struct clockdomain *clkdm)
>  
>  static int omap4_clkdm_sleep(struct clockdomain *clkdm)
>  {
> -	omap4_cminst_clkdm_force_sleep(clkdm->prcm_partition,
> +	omap4_cminst_clkdm_enable_hwsup(clkdm->prcm_partition,
>  					clkdm->cm_inst, clkdm->clkdm_offs);
In case SW_SLEEP != HW_AUTO, something like below can be done

if (clkdm->flags & CLKDM_CAN_FORCE_SLEEP )
	omap4_cminst_clkdm_force_sleep(clkdm->prcm_partition,
				clkdm->cm_inst, clkdm->clkdm_offs);
else
	omap4_cminst_clkdm_enable_hwsup(clkdm->prcm_partition,
				clkdm->cm_inst, clkdm->clkdm_offs);

>  	return 0;
>  }
> @@ -90,7 +90,10 @@ static void omap4_clkdm_allow_idle(struct clockdomain *clkdm)
>  
>  static void omap4_clkdm_deny_idle(struct clockdomain *clkdm)
>  {
> -	omap4_cminst_clkdm_disable_hwsup(clkdm->prcm_partition,
> +	if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
> +		omap4_clkdm_wakeup(clkdm);
> +	else
> +		omap4_cminst_clkdm_disable_hwsup(clkdm->prcm_partition,
>  					clkdm->cm_inst, clkdm->clkdm_offs);
>  }
>  
> diff --git a/arch/arm/mach-omap2/cminst44xx.c b/arch/arm/mach-omap2/cminst44xx.c
> index bd8810c..a44456c 100644
> --- a/arch/arm/mach-omap2/cminst44xx.c
> +++ b/arch/arm/mach-omap2/cminst44xx.c
> @@ -227,20 +227,6 @@ void omap4_cminst_clkdm_disable_hwsup(u8 part, s16 inst, u16 cdoffs)
>  }
>  
>  /**
> - * omap4_cminst_clkdm_force_sleep - try to put a clockdomain into idle
> - * @part: PRCM partition ID that the clockdomain registers exist in
> - * @inst: CM instance register offset (*_INST macro)
> - * @cdoffs: Clockdomain register offset (*_CDOFFS macro)
> - *
> - * Put a clockdomain referred to by (@part, @inst, @cdoffs) into idle
> - * No return value.
> - */
> -void omap4_cminst_clkdm_force_sleep(u8 part, s16 inst, u16 cdoffs)
> -{
> -	_clktrctrl_write(OMAP34XX_CLKSTCTRL_FORCE_SLEEP, part, inst, cdoffs);
> -}
> -
> -/**
>   * omap4_cminst_clkdm_force_sleep - try to take a clockdomain out of idle
>   * @part: PRCM partition ID that the clockdomain registers exist in
>   * @inst: CM instance register offset (*_INST macro)