Subject: [PATCHv4 3/8] ARM: OMAP3+: voltage: add support for voltagedomain usecounts

From: [email-masked] (Rajendra Nayak)
Date: Mon, 16 Jul 2012 15:53:05 +0530

On Friday 13 July 2012 07:49 PM, Tero Kristo wrote:
> These are updated based on powerdomain usecounts. Also added support
> for voltdm->sleep and voltdm->wakeup calls that will be invoked once
> voltagedomain enters sleep or wakes up based on usecount numbers. These
> will be used for controlling voltage scaling functionality.
>
> Signed-off-by: Tero Kristo<[email-masked]>
> Cc: Paul Walmsley<[email-masked]>
> Cc: Kevin Hilman<[email-masked]>

Reviewed-by: Rajendra Nayak <[email-masked]>

I am working on a series to cleanup CPUidle, on top of this series,
where I add similar callbacks at the pwrdm level too. Something like
pwrdm->power_on and pwrdm->power_down. Helps get rid of a lot of
code stuffed inside idle/suspend.

>   arch/arm/mach-omap2/powerdomain.c |    6 +++-
>   arch/arm/mach-omap2/voltage.c     |   56 +++++++++++++++++++++++++++++++++++++
>   arch/arm/mach-omap2/voltage.h     |   11 +++++++
>   3 files changed, 72 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
> index 68bdf36..3b4b15d 100644
> --- a/arch/arm/mach-omap2/powerdomain.c
> +++ b/arch/arm/mach-omap2/powerdomain.c
> @@ -994,7 +994,8 @@ void pwrdm_clkdm_enable(struct powerdomain *pwrdm)
>   	if (!pwrdm)
>   		return;
>
> -	atomic_inc(&pwrdm->usecount);
> +	if (atomic_inc_return(&pwrdm->usecount) == 1)
> +		voltdm_pwrdm_enable(pwrdm->voltdm.ptr);
>   }
>
>   /**
> @@ -1013,6 +1014,9 @@ void pwrdm_clkdm_disable(struct powerdomain *pwrdm)
>
>   	val = atomic_dec_return(&pwrdm->usecount);
>
> +	if (!val)
> +		voltdm_pwrdm_disable(pwrdm->voltdm.ptr);
> +
>   	BUG_ON(val<  0);
>   }
>
> diff --git a/arch/arm/mach-omap2/voltage.c b/arch/arm/mach-omap2/voltage.c
> index 4dc60e8..8c6439b 100644
> --- a/arch/arm/mach-omap2/voltage.c
> +++ b/arch/arm/mach-omap2/voltage.c
> @@ -38,6 +38,7 @@
>
>   #include "voltage.h"
>   #include "powerdomain.h"
> +#include "smartreflex.h"
>
>   #include "vc.h"
>   #include "vp.h"
> @@ -340,6 +341,61 @@ int voltdm_add_pwrdm(struct voltagedomain *voltdm, struct powerdomain *pwrdm)
>   }
>
>   /**
> + * voltdm_pwrdm_enable - increase usecount for a voltagedomain
> + * @voltdm: struct voltagedomain * to increase count for
> + *
> + * Increases usecount for a given voltagedomain. If the usecount reaches
> + * 1, the domain is awakened from idle and the function will call the
> + * voltagedomain->wakeup callback for this domain.
> + */
> +void voltdm_pwrdm_enable(struct voltagedomain *voltdm)
> +{
> +	if (!voltdm)
> +		return;
> +
> +	if (atomic_inc_return(&voltdm->usecount) == 1) {
> +		if (voltdm->wakeup)
> +			voltdm->wakeup(voltdm);
> +	}
> +}
> +
> +/**
> + * voltdm_pwrdm_disable - decrease usecount for a voltagedomain
> + * @voltdm: struct voltagedomain * to decrease count for
> + *
> + * Decreases the usecount for a given voltagedomain. If the usecount
> + * reaches zero, the domain can idle and the function will call the
> + * voltagedomain->sleep callback, and calculate the overall target
> + * state for the voltagedomain.
> + */
> +void voltdm_pwrdm_disable(struct voltagedomain *voltdm)
> +{
> +	u8 target_state = PWRDM_POWER_OFF;
> +	int state;
> +	struct powerdomain *pwrdm;
> +	int val;
> +
> +	if (!voltdm)
> +		return;
> +
> +	val = atomic_dec_return(&voltdm->usecount);
> +
> +	BUG_ON(val<  0);
> +
> +	if (val == 0) {
> +		/* Determine target state for voltdm */
> +		list_for_each_entry(pwrdm,&voltdm->pwrdm_list, voltdm_node) {
> +			state = pwrdm_read_next_pwrst(pwrdm);
> +			if (state>  target_state)
> +				target_state = state;
> +		}
> +		voltdm->target_state = target_state;
> +		if (voltdm->sleep)
> +			voltdm->sleep(voltdm);
> +	}
> +}
> +
> +/**
>    * voltdm_for_each_pwrdm - call function for each pwrdm in a voltdm
>    * @voltdm: struct voltagedomain * to iterate over
>    * @fn: callback function *
> diff --git a/arch/arm/mach-omap2/voltage.h b/arch/arm/mach-omap2/voltage.h
> index 16a1b09..c1f4ae8 100644
> --- a/arch/arm/mach-omap2/voltage.h
> +++ b/arch/arm/mach-omap2/voltage.h
> @@ -54,10 +54,14 @@ struct omap_vfsm_instance {
>    * @pwrdm_list: list_head linking all powerdomains in this voltagedomain
>    * @vc: pointer to VC channel associated with this voltagedomain
>    * @vp: pointer to VP associated with this voltagedomain
> + * @usecount: number of users for this voltagedomain
> + * @target_state: calculated target state for the children of this domain
>    * @read: read a VC/VP register
>    * @write: write a VC/VP register
>    * @read: read-modify-write a VC/VP register
>    * @sys_clk: system clock name/frequency, used for various timing calculations
> + * @sleep: function to call once the domain enters idle
> + * @wakeup: function to call once the domain wakes up from idle
>    * @scale: function used to scale the voltage of the voltagedomain
>    * @nominal_volt: current nominal voltage for this voltage domain
>    * @volt_data: voltage table having the distinct voltages supported
> @@ -73,6 +77,9 @@ struct voltagedomain {
>   	struct omap_vp_instance *vp;
>   	struct omap_voltdm_pmic *pmic;
>
> +	atomic_t usecount;
> +	u8 target_state;
> +
>   	/* VC/VP register access functions: SoC specific */
>   	u32 (*read) (u8 offset);
>   	void (*write) (u32 val, u8 offset);
> @@ -83,6 +90,8 @@ struct voltagedomain {
>   		u32 rate;
>   	} sys_clk;
>
> +	void (*sleep) (struct voltagedomain *voltdm);
> +	void (*wakeup) (struct voltagedomain *voltdm);
>   	int (*scale) (struct voltagedomain *voltdm,
>   		      unsigned long target_volt);
>
> @@ -161,6 +170,8 @@ extern void omap44xx_voltagedomains_init(void);
>   struct voltagedomain *voltdm_lookup(const char *name);
>   void voltdm_init(struct voltagedomain **voltdm_list);
>   int voltdm_add_pwrdm(struct voltagedomain *voltdm, struct powerdomain *pwrdm);
> +void voltdm_pwrdm_enable(struct voltagedomain *voltdm);
> +void voltdm_pwrdm_disable(struct voltagedomain *voltdm);
>   int voltdm_for_each(int (*fn)(struct voltagedomain *voltdm, void *user),
>   		    void *user);
>   int voltdm_for_each_pwrdm(struct voltagedomain *voltdm,