Hi,
Absolutely, I agree this approach.
But, I add some comments on below. please check them.
2019년 6월 22일 (토) 오전 9:36, Saravana Kannan <sarava...@google.com>님이 작성:
>
> Look at the required OPPs of the "parent" device to determine the OPP that
> is required from the slave device managed by the passive governor. This
> allows having mappings between a parent device and a slave device even when
> they don't have the same number of OPPs.
>
> Signed-off-by: Saravana Kannan <sarava...@google.com>
> ---
> drivers/devfreq/governor_passive.c | 25 +++++++++++++++++++++++--
> 1 file changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/devfreq/governor_passive.c
> b/drivers/devfreq/governor_passive.c
> index 3bc29acbd54e..bd4a98bb15b1 100644
> --- a/drivers/devfreq/governor_passive.c
> +++ b/drivers/devfreq/governor_passive.c
> @@ -21,8 +21,9 @@ static int devfreq_passive_get_target_freq(struct devfreq
> *devfreq,
> struct devfreq_passive_data *p_data
> = (struct devfreq_passive_data *)devfreq->data;
> struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
> + struct opp_table *opp_table = NULL, *c_opp_table = NULL;
In this function, the base device is passive devfreq device.
So, I think that better to define the 'parent_opp_table' instead of 'opp_table'
indicating the OPP table of parent devfreq device. And better to define
just 'opp_table' instead of 'c_opp_table' indicating the passive devfreq device.
- opp_table -> parent_opp_table
- c_opp_table -> opp_table
> unsigned long child_freq = ULONG_MAX;
> - struct dev_pm_opp *opp;
> + struct dev_pm_opp *opp = NULL, *c_opp = NULL;
Ditto. I think that better to define the variables as following:
- opp -> parent_opp
- c_cpp -> opp
> int i, count, ret = 0;
>
> /*
> @@ -65,7 +66,20 @@ static int devfreq_passive_get_target_freq(struct devfreq
> *devfreq,
> goto out;
> }
>
> - dev_pm_opp_put(opp);
> + opp_table = dev_pm_opp_get_opp_table(parent_devfreq->dev.parent);
devfreq_passive_get_target_freq() is called frequently for DVFS support.
I think that you have to add 'struct opp_table *opp_table' instance to
'struct devfreq'
and then get 'opp_table' instance in the devfreq_add_device().
devfreq_add_device() already get the OPP information by using
dev_pm_opp_get_suspend_opp_freq().
You can add following code nearby dev_pm_opp_get_suspend_opp_freq() in
devfreq_add_device().
- devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
> + if (IS_ERR_OR_NULL(opp_table)) {
> + ret = PTR_ERR(opp_table);
> + goto out;
> + }
> +
> + c_opp_table = dev_pm_opp_get_opp_table(devfreq->dev.parent);
> + if (!IS_ERR_OR_NULL(c_opp_table))
> + c_opp = dev_pm_opp_xlate_opp(opp_table, c_opp_table, opp);
> + if (c_opp) {
> + *freq = dev_pm_opp_get_freq(c_opp);
> + dev_pm_opp_put(c_opp);
> + goto out;
> + }
>
> /*
> * Get the OPP table's index of decided freqeuncy by governor
> @@ -92,6 +106,13 @@ static int devfreq_passive_get_target_freq(struct devfreq
> *devfreq,
> *freq = child_freq;
>
> out:
> + if (!IS_ERR_OR_NULL(opp_table))
> + dev_pm_opp_put_opp_table(opp_table);
> + if (!IS_ERR_OR_NULL(c_opp_table))
> + dev_pm_opp_put_opp_table(c_opp_table);
> + if (!IS_ERR_OR_NULL(opp))
> + dev_pm_opp_put(opp);
> +
> return ret;
> }
>
> --
> 2.22.0.410.gd8fdbe21b5-goog
>
--
Best Regards,
Chanwoo Choi
