Re: [PATCHv2 5/6] OMAP: Powerdomains: Add support for checking if pwrdm/clkdm can idle

[Kevin Hilman <khilman@deeprootsystems.com>]

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

> From: Tero Kristo <tero.kristo@nokia.com>
>
> pwrdm_can_idle(pwrdm) will check if the specified powerdomain can enter
> idle. This is done by checking all clockdomains under the powerdomain
> if they can idle also.
>
> omap2_clkdm_can_idle(clkdm) will check if the specified clockdomain can
> enter idle. This checks the functional clock status in the clockdomain.
>
> These calls can be used e.g. inside cpuidle to decide which power states
> core and mpu should enter during idle, as there are certain dependencies
> between wakeup capabilities and reset logic.
>
> Signed-off-by: Tero Kristo <tero.kristo@nokia.com>

This looks good by me, but needs a review from Paul to go upstream with
the rest of his clockdomain/powerdomain updates for 2.6.34.

One question... I'm wondering if it might be good to also check the
CM_IDLEST_<pwrdm> register in the can_idle function.  Even if all
clocks are disabled, if the idle modes of the module are not set correctly,
it may not enter the target state.

Kevin

> ---
>  arch/arm/mach-omap2/clockdomain.c             |   24 ++++++++++++++++++++++++
>  arch/arm/mach-omap2/clockdomains.h            |   14 ++++++++++++++
>  arch/arm/mach-omap2/powerdomain.c             |   25 +++++++++++++++++++++++++
>  arch/arm/plat-omap/include/plat/clockdomain.h |   12 ++++++++++++
>  arch/arm/plat-omap/include/plat/powerdomain.h |    1 +
>  5 files changed, 76 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/clockdomain.c b/arch/arm/mach-omap2/clockdomain.c
> index fcd8232..9ddeb96 100644
> --- a/arch/arm/mach-omap2/clockdomain.c
> +++ b/arch/arm/mach-omap2/clockdomain.c
> @@ -474,6 +474,30 @@ int omap2_clkdm_wakeup(struct clockdomain *clkdm)
>  	return 0;
>  }
>  
> +
> +/**
> + * omap2_clkdm_can_idle - check if clockdomain has any active clocks or not
> + * @clkdm: struct clockdomain *
> + *
> + * Checks if the clockdomain has any active clock or not, i.e. whether it
> + * can enter idle. Returns -EINVAL if clkdm is NULL; 0 if unable to idle;
> + * 1 if can idle.
> + */
> +int omap2_clkdm_can_idle(struct clockdomain *clkdm)
> +{
> +	int i;
> +	const int fclk_regs[] = { CM_FCLKEN, OMAP3430ES2_CM_FCLKEN3 };
> +
> +	if (!clkdm)
> +		return -EINVAL;
> +
> +	for (i = 0; i < clkdm->fclk_reg_amt; i++)
> +		if (cm_read_mod_reg(clkdm->pwrdm.ptr->prcm_offs,
> +				    fclk_regs[i]) & ~clkdm->fclk_masks[i])
> +			return 0;
> +	return 1;
> +}
> +
>  /**
>   * omap2_clkdm_allow_idle - enable hwsup idle transitions for clkdm
>   * @clkdm: struct clockdomain *
> diff --git a/arch/arm/mach-omap2/clockdomains.h b/arch/arm/mach-omap2/clockdomains.h
> index c4ee076..2cde82a 100644
> --- a/arch/arm/mach-omap2/clockdomains.h
> +++ b/arch/arm/mach-omap2/clockdomains.h
> @@ -167,6 +167,7 @@ static struct clockdomain iva2_clkdm = {
>  	.flags		= CLKDM_CAN_HWSUP_SWSUP,
>  	.clktrctrl_mask = OMAP3430_CLKTRCTRL_IVA2_MASK,
>  	.omap_chip	= OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
> +	.fclk_reg_amt	= 1,
>  };
>  
>  static struct clockdomain gfx_3430es1_clkdm = {
> @@ -183,6 +184,7 @@ static struct clockdomain sgx_clkdm = {
>  	.flags		= CLKDM_CAN_HWSUP_SWSUP,
>  	.clktrctrl_mask = OMAP3430ES2_CLKTRCTRL_SGX_MASK,
>  	.omap_chip	= OMAP_CHIP_INIT(CHIP_GE_OMAP3430ES2),
> +	.fclk_reg_amt	= 1,
>  };
>  
>  /*
> @@ -206,6 +208,11 @@ static struct clockdomain core_l3_34xx_clkdm = {
>  	.flags		= CLKDM_CAN_HWSUP,
>  	.clktrctrl_mask = OMAP3430_CLKTRCTRL_L3_MASK,
>  	.omap_chip	= OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
> +	.fclk_reg_amt	= 2,
> +	.fclk_masks	= {
> +		[0] = OMAP3430_EN_UART2 | OMAP3430_EN_UART1,
> +		[1] = 0,
> +	},
>  };
>  
>  static struct clockdomain core_l4_34xx_clkdm = {
> @@ -222,6 +229,7 @@ static struct clockdomain dss_34xx_clkdm = {
>  	.flags		= CLKDM_CAN_HWSUP_SWSUP,
>  	.clktrctrl_mask = OMAP3430_CLKTRCTRL_DSS_MASK,
>  	.omap_chip	= OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
> +	.fclk_reg_amt	= 1,
>  };
>  
>  static struct clockdomain cam_clkdm = {
> @@ -230,6 +238,7 @@ static struct clockdomain cam_clkdm = {
>  	.flags		= CLKDM_CAN_HWSUP_SWSUP,
>  	.clktrctrl_mask = OMAP3430_CLKTRCTRL_CAM_MASK,
>  	.omap_chip	= OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
> +	.fclk_reg_amt	= 1,
>  };
>  
>  static struct clockdomain usbhost_clkdm = {
> @@ -238,6 +247,7 @@ static struct clockdomain usbhost_clkdm = {
>  	.flags		= CLKDM_CAN_HWSUP_SWSUP,
>  	.clktrctrl_mask = OMAP3430ES2_CLKTRCTRL_USBHOST_MASK,
>  	.omap_chip	= OMAP_CHIP_INIT(CHIP_GE_OMAP3430ES2),
> +	.fclk_reg_amt	= 1,
>  };
>  
>  static struct clockdomain per_clkdm = {
> @@ -246,6 +256,10 @@ static struct clockdomain per_clkdm = {
>  	.flags		= CLKDM_CAN_HWSUP_SWSUP,
>  	.clktrctrl_mask = OMAP3430_CLKTRCTRL_PER_MASK,
>  	.omap_chip	= OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
> +	.fclk_reg_amt	= 1,
> +	.fclk_masks	= {
> +		[0] = OMAP3430_EN_UART3,
> +	},
>  };
>  
>  /*
> diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
> index 1237717..2bef099 100644
> --- a/arch/arm/mach-omap2/powerdomain.c
> +++ b/arch/arm/mach-omap2/powerdomain.c
> @@ -1217,6 +1217,31 @@ int pwrdm_wait_transition(struct powerdomain *pwrdm)
>  	return 0;
>  }
>  
> +/**
> + * pwrdm_can_idle - check if the powerdomain can enter idle
> + * @pwrdm: struct powerdomain * the powerdomain to check status of
> + *
> + * Checks all associated clockdomains if they can idle or not.
> + * Returns 1 if the powerdomain can idle, 0 if not.
> + */
> +int pwrdm_can_idle(struct powerdomain *pwrdm)
> +{
> +	unsigned long flags;
> +	int i;
> +	int ret = 1;
> +
> +	read_lock_irqsave(&pwrdm_rwlock, flags);
> +
> +	for (i = 0; i < PWRDM_MAX_CLKDMS; i++)
> +		if (pwrdm->pwrdm_clkdms[i] &&
> +		    !omap2_clkdm_can_idle(pwrdm->pwrdm_clkdms[i]))
> +			ret = 0;
> +
> +	read_unlock_irqrestore(&pwrdm_rwlock, flags);
> +
> +	return ret;
> +}
> +
>  int pwrdm_state_switch(struct powerdomain *pwrdm)
>  {
>  	return _pwrdm_state_switch(pwrdm, PWRDM_STATE_NOW);
> diff --git a/arch/arm/plat-omap/include/plat/clockdomain.h b/arch/arm/plat-omap/include/plat/clockdomain.h
> index eb73482..4dfb820 100644
> --- a/arch/arm/plat-omap/include/plat/clockdomain.h
> +++ b/arch/arm/plat-omap/include/plat/clockdomain.h
> @@ -30,6 +30,12 @@
>  #define CLKDM_CAN_SWSUP		(CLKDM_CAN_FORCE_SLEEP | CLKDM_CAN_FORCE_WAKEUP)
>  #define CLKDM_CAN_HWSUP_SWSUP	(CLKDM_CAN_SWSUP | CLKDM_CAN_HWSUP)
>  
> +/*
> + * Maximum number of FCLK register masks that can be associated with a
> + * clockdomain. CORE powerdomain on OMAP3 is the worst case
> + */
> +#define CLKDM_MAX_FCLK				2
> +
>  /* OMAP24XX CM_CLKSTCTRL_*.AUTOSTATE_* register bit values */
>  #define OMAP24XX_CLKSTCTRL_DISABLE_AUTO		0x0
>  #define OMAP24XX_CLKSTCTRL_ENABLE_AUTO		0x1
> @@ -83,6 +89,10 @@ struct clockdomain {
>  	/* OMAP chip types that this clockdomain is valid on */
>  	const struct omap_chip_id omap_chip;
>  
> +	/* For idle checks */
> +	u8 fclk_reg_amt;
> +	u32 fclk_masks[CLKDM_MAX_FCLK];
> +
>  	/* Usecount tracking */
>  	atomic_t usecount;
>  
> @@ -108,4 +118,6 @@ int omap2_clkdm_sleep(struct clockdomain *clkdm);
>  int omap2_clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk);
>  int omap2_clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk);
>  
> +int omap2_clkdm_can_idle(struct clockdomain *clkdm);
> +
>  #endif
> diff --git a/arch/arm/plat-omap/include/plat/powerdomain.h b/arch/arm/plat-omap/include/plat/powerdomain.h
> index 55350d0..e6a227f 100644
> --- a/arch/arm/plat-omap/include/plat/powerdomain.h
> +++ b/arch/arm/plat-omap/include/plat/powerdomain.h
> @@ -177,6 +177,7 @@ int pwrdm_disable_hdwr_sar(struct powerdomain *pwrdm);
>  bool pwrdm_has_hdwr_sar(struct powerdomain *pwrdm);
>  
>  int pwrdm_wait_transition(struct powerdomain *pwrdm);
> +int pwrdm_can_idle(struct powerdomain *pwrdm);
>  
>  int pwrdm_state_switch(struct powerdomain *pwrdm);
>  int pwrdm_clkdm_state_switch(struct clockdomain *clkdm);
> -- 
> 1.5.4.3
>
> --
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