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Date:   Wed, 20 Jun 2018 10:31:03 +0530
From:   Gautham R Shenoy <ego@linux.vnet.ibm.com>
To:     Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        linux-pm@vger.kernel.org, rjw@rjwysocki.net,
        svaidy@linux.vnet.ibm.com, ego@linux.vnet.ibm.com,
        npiggin@gmail.com, mpe@ellerman.id.au
Subject: Re: [PATCH 3/3] powernv/cpuidle: Use parsed device tree values for
 cpuidle_init
Reply-To: ego@linux.vnet.ibm.com
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 <1529384668-27548-4-git-send-email-akshay.adiga@linux.vnet.ibm.com>
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Hi Akshay,

On Tue, Jun 19, 2018 at 10:34:28AM +0530, Akshay Adiga wrote:
> Export pnv_idle_states and nr_pnv_idle_states so that its accessible to
> cpuidle driver. Use properties from pnv_idle_states structure for powernv
> cpuidle_init.
> 
> Signed-off-by: Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
> ---
>  arch/powerpc/include/asm/cpuidle.h |  2 ++
>  drivers/cpuidle/cpuidle-powernv.c  | 49 +++++++++++++++++++++++---------------
>  2 files changed, 32 insertions(+), 19 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/cpuidle.h b/arch/powerpc/include/asm/cpuidle.h
> index 55ee7e3..1446747 100644
> --- a/arch/powerpc/include/asm/cpuidle.h
> +++ b/arch/powerpc/include/asm/cpuidle.h
> @@ -93,6 +93,8 @@ struct pnv_idle_states_t {
>  	u32 flags;
>  };
> 
> +extern struct pnv_idle_states_t *pnv_idle_states;
> +extern int nr_pnv_idle_states;
>  extern u32 pnv_fastsleep_workaround_at_entry[];
>  extern u32 pnv_fastsleep_workaround_at_exit[];
> 
> diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
> index d29e4f0..de8ba26 100644
> --- a/drivers/cpuidle/cpuidle-powernv.c
> +++ b/drivers/cpuidle/cpuidle-powernv.c
> @@ -285,6 +285,11 @@ static int powernv_add_idle_states(void)
>  		goto out;
>  	}
> 
> +	if (nr_pnv_idle_states <= 0) {
> +		pr_warn("opal: No idle states found\n");

We would have a warning of this type in the powernv/idle.c right ? We
don't need to warn again. Or at least have a different warning
something like: 

      	         pr_warn("cpuidle: Only snooze state is available\n");
> +		goto out;
> +	}

> +
>  	/* Read values of any property to determine the num of idle states */
>  	dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags");


We don't need to get dt_idle_states from the device tree now that we
have nr_pnv_idle_states. 


>  	if (dt_idle_states < 0) {
> @@ -338,7 +343,7 @@ static int powernv_add_idle_states(void)
>  	 * If the idle states use stop instruction, probe for psscr values
>  	 * and psscr mask which are necessary to specify required stop level.
>  	 */
> -	has_stop_states = (flags[0] &
> +	has_stop_states = (pnv_idle_states[0].flags &
>  			   (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP));
>  	if (has_stop_states) {
>  		count = of_property_count_u64_elems(power_mgt,
> @@ -387,51 +392,55 @@ static int powernv_add_idle_states(void)
>  						residency_ns, dt_idle_states);
>  	}
> 
> -	for (i = 0; i < dt_idle_states; i++) {
> +	for (i = 0; i < nr_pnv_idle_states; i++) {
>  		unsigned int exit_latency, target_residency;
>  		bool stops_timebase = false;
> +		struct pnv_idle_states_t *state = &pnv_idle_states[i];
> 
>  		/*
>  		 * Skip the platform idle state whose flag isn't in
> -		 * the supported_cpuidle_states flag mask.
> +		 * the supported_pnv_idle_states flag mask.
>  		 */
> -		if ((flags[i] & supported_flags) != flags[i])
> +		if ((state->flags & supported_flags) !=
> +				state->flags)
>  			continue;
>  		/*
>  		 * If an idle state has exit latency beyond
>  		 * POWERNV_THRESHOLD_LATENCY_NS then don't use it
>  		 * in cpu-idle.
>  		 */
> -		if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS)
> +		if (state->latency_ns > POWERNV_THRESHOLD_LATENCY_NS)
>  			continue;
>  		/*
>  		 * Firmware passes residency and latency values in ns.
>  		 * cpuidle expects it in us.
>  		 */
> -		exit_latency = DIV_ROUND_UP(latency_ns[i], 1000);
> +		exit_latency = DIV_ROUND_UP(state->latency_ns, 1000);
>  		if (!rc)
> -			target_residency = DIV_ROUND_UP(residency_ns[i], 1000);
> +			target_residency = DIV_ROUND_UP(state->residency_ns, 1000);
>  		else
>  			target_residency = 0;
> 
>  		if (has_stop_states) {
> -			int err = validate_psscr_val_mask(&psscr_val[i],
> -							  &psscr_mask[i],
> -							  flags[i]);

> +			int err;
> +			err = validate_psscr_val_mask(&state->pm_ctrl_reg_val,
> +						      &state->pm_ctrl_reg_mask,
> +						      state->flags);
>  			if (err) {
> -				report_invalid_psscr_val(psscr_val[i], err);
> +				report_invalid_psscr_val(state->pm_ctrl_reg_val,
> +							 err);
>  				continue;
>  			}

We have already validated the states once. We should simply use the
result here.


>  		}
> 
> -		if (flags[i] & OPAL_PM_TIMEBASE_STOP)
> +		if (state->flags & OPAL_PM_TIMEBASE_STOP)
>  			stops_timebase = true;
> 
>  		/*
>  		 * For nap and fastsleep, use default target_residency
>  		 * values if f/w does not expose it.
>  		 */
> -		if (flags[i] & OPAL_PM_NAP_ENABLED) {
> +		if (state->flags & OPAL_PM_NAP_ENABLED) {
>  			if (!rc)
>  				target_residency = 100;
>  			/* Add NAP state */
> @@ -439,10 +448,11 @@ static int powernv_add_idle_states(void)
>  					  CPUIDLE_FLAG_NONE, nap_loop,
>  					  target_residency, exit_latency, 0, 0);
>  		} else if (has_stop_states && !stops_timebase) {
> -			add_powernv_state(nr_idle_states, names[i],
> +			add_powernv_state(nr_idle_states, state->name,
>  					  CPUIDLE_FLAG_NONE, stop_loop,
>  					  target_residency, exit_latency,
> -					  psscr_val[i], psscr_mask[i]);
> +					  state->pm_ctrl_reg_val,
> +					  state->pm_ctrl_reg_mask);
>  		}
> 
>  		/*
> @@ -450,8 +460,8 @@ static int powernv_add_idle_states(void)
>  		 * within this config dependency check.
>  		 */
>  #ifdef CONFIG_TICK_ONESHOT
> -		else if (flags[i] & OPAL_PM_SLEEP_ENABLED ||
> -			 flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) {
> +		else if (state->flags & OPAL_PM_SLEEP_ENABLED ||
> +			 state->flags & OPAL_PM_SLEEP_ENABLED_ER1) {
>  			if (!rc)
>  				target_residency = 300000;
>  			/* Add FASTSLEEP state */
> @@ -460,10 +470,11 @@ static int powernv_add_idle_states(void)
>  					  fastsleep_loop,
>  					  target_residency, exit_latency, 0, 0);
>  		} else if (has_stop_states && stops_timebase) {
> -			add_powernv_state(nr_idle_states, names[i],
> +			add_powernv_state(nr_idle_states, state->name,
>  					  CPUIDLE_FLAG_TIMER_STOP, stop_loop,
>  					  target_residency, exit_latency,
> -					  psscr_val[i], psscr_mask[i]);
> +					  state->pm_ctrl_reg_val,
> +					  state->pm_ctrl_reg_mask);
>  		}
>  #endif
>  		else
> -- 
> 2.5.5
>