linux-kernel - Re: [PATCH v6 3/3] OPP: Add helper function for bandwidth OPP tables

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Date:   Wed, 8 Jan 2020 16:49:47 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Saravana Kannan <saravanak@...gle.com>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Georgi Djakov <georgi.djakov@...aro.org>,
        vincent.guittot@...aro.org, seansw@....qualcomm.com,
        daidavid1@...eaurora.org, adharmap@...eaurora.org,
        Rajendra Nayak <rnayak@...eaurora.org>, sibis@...eaurora.org,
        bjorn.andersson@...aro.org, evgreen@...omium.org,
        kernel-team@...roid.com, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 3/3] OPP: Add helper function for bandwidth OPP tables

On 06-12-19, 16:24, Saravana Kannan wrote:
> The frequency OPP tables have helper functions to search for entries in the
> table based on frequency and get the frequency values for a given (or
> suspend) OPP entry.
> 
> Add similar helper functions for bandwidth OPP tables to search for entries
> in the table based on peak bandwidth and to get the peak and average
> bandwidth for a given (or suspend) OPP entry.
> 
> Signed-off-by: Saravana Kannan <saravanak@...gle.com>
> ---
>  drivers/opp/core.c     | 301 +++++++++++++++++++++++++++++++++++------
>  include/linux/pm_opp.h |  43 ++++++
>  2 files changed, 305 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> index c79bbfac7289..3ff33a08198e 100644
> --- a/drivers/opp/core.c
> +++ b/drivers/opp/core.c
> @@ -127,6 +127,29 @@ unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
>  }
>  EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
>  
> +/**
> + * dev_pm_opp_get_bw() - Gets the bandwidth corresponding to an available opp
> + * @opp:	opp for which peak bandwidth has to be returned for

s/peak //

> + * @avg_bw:	Pointer where the corresponding average bandwidth is stored.
> + *		Can be NULL.
> + *
> + * Return: Peak bandwidth in kBps corresponding to the opp, else
> + * return 0
> + */
> +unsigned long dev_pm_opp_get_bw(struct dev_pm_opp *opp, unsigned long *avg_bw)
> +{
> +	if (IS_ERR_OR_NULL(opp) || !opp->available) {
> +		pr_err("%s: Invalid parameters\n", __func__);
> +		return 0;
> +	}
> +
> +	if (avg_bw)

Do you see this being NULL in practice ? If no, then we can make it
mandatory for now ?

> +		*avg_bw = opp->avg_bw;
> +
> +	return opp->peak_bw;
> +}
> +EXPORT_SYMBOL_GPL(dev_pm_opp_get_bw);
> +
>  /**
>   * dev_pm_opp_get_level() - Gets the level corresponding to an available opp
>   * @opp:	opp for which level value has to be returned for
> @@ -299,6 +322,34 @@ unsigned long dev_pm_opp_get_suspend_opp_freq(struct device *dev)
>  }
>  EXPORT_SYMBOL_GPL(dev_pm_opp_get_suspend_opp_freq);
>  
> +/**
> + * dev_pm_opp_get_suspend_opp_bw() - Get peak bandwidth of suspend opp in kBps

Hmm, I wasn't expecting this. So the interconnects will also have a
suspend OPP ?

> + * @dev:	device for which we do this operation
> + * @avg_bw:	Pointer where the corresponding average bandwidth is stored.
> + *		Can be NULL.
> + *
> + * Return: This function returns the peak bandwidth of the OPP marked as
> + * suspend_opp if one is available, else returns 0;
> + */
> +unsigned long dev_pm_opp_get_suspend_opp_bw(struct device *dev,
> +					    unsigned long *avg_bw)
> +{
> +	struct opp_table *opp_table;
> +	unsigned long peak_bw = 0;
> +
> +	opp_table = _find_opp_table(dev);
> +	if (IS_ERR(opp_table))
> +		return 0;
> +
> +	if (opp_table->suspend_opp && opp_table->suspend_opp->available)
> +		peak_bw = dev_pm_opp_get_bw(opp_table->suspend_opp, avg_bw);
> +
> +	dev_pm_opp_put_opp_table(opp_table);
> +
> +	return peak_bw;
> +}
> +EXPORT_SYMBOL_GPL(dev_pm_opp_get_suspend_opp_bw);
> +
>  int _get_opp_count(struct opp_table *opp_table)
>  {
>  	struct dev_pm_opp *opp;
> @@ -343,6 +394,40 @@ int dev_pm_opp_get_opp_count(struct device *dev)
>  }
>  EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
>  

I think we should add function header here instead of the helpers
which get exact match for freq, bw or level. And then pass a enum
value to it, which tells what we are looking to compare. After that
rest of the routines will be just one liners, make them macros in
header file itself.

> +struct dev_pm_opp *dev_pm_opp_find_opp_exact(struct device *dev,
> +					      struct dev_pm_opp *opp_key,
> +					      bool available)

-- 
viresh