Re: [PATCH v3 2/6] OPP: Add support for bandwidth OPP tables

Sibi Sankar
2019-07-16T17:33:22Z

Hey Saravana,

On 7/3/19 6:40 AM, Saravana Kannan wrote:
> Not all devices quantify their performance points in terms of frequency.
> Devices like interconnects quantify their performance points in terms of
> bandwidth. We need a way to represent these bandwidth levels in OPP. So,
> add support for parsing bandwidth OPPs from DT.
>
> Signed-off-by: Saravana Kannan <saravanak@google.com>
> ---
> drivers/opp/of.c | 34 ++++++++++++++++++++++++++++++++--
> drivers/opp/opp.h | 4 +++-
> 2 files changed, 35 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/opp/of.c b/drivers/opp/of.c
> index c10c782d15aa..54fa70ed2adc 100644
> --- a/drivers/opp/of.c
> +++ b/drivers/opp/of.c
> @@ -552,6 +552,35 @@ void dev_pm_opp_of_remove_table(struct device *dev)
> }
> EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
>
> +static int _read_opp_key(struct dev_pm_opp *new_opp, struct device_node *np)
> +{
> + int ret;
> + u64 rate;
> + u32 bw;
> +
> + ret = of_property_read_u64(np, "opp-hz", &rate);
> + if (!ret) {
> + /*
> + * Rate is defined as an unsigned long in clk API, and so
> + * casting explicitly to its type. Must be fixed once rate is 64
> + * bit guaranteed in clk API.
> + */
> + new_opp->rate = (unsigned long)rate
now that the rate gets set here, please remove the rate assignment in
_opp_add_static_v2

> + return 0;
> + }
> +
> + ret = of_property_read_u32(np, "opp-peak-KBps", &bw);
> + if (ret)
> + return ret;
> + new_opp->rate = (unsigned long) &bw;

should be bw instead

> +
> + ret = of_property_read_u32(np, "opp-avg-KBps", &bw);
> + if (!ret)
> + new_opp->avg_bw = (unsigned long) &bw;

ditto

> +
> + return 0;
> +}
> +
> /**
> * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
> * @opp_table: OPP table
> @@ -589,11 +618,12 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
> if (!new_opp)
> return ERR_PTR(-ENOMEM);
>
> - ret = of_property_read_u64(np, "opp-hz", &rate);
> + ret = _read_opp_key(new_opp, np);
> if (ret < 0) {
> /* "opp-hz" is optional for devices like power domains. */
> if (!opp_table->is_genpd) {
> - dev_err(dev, "%s: opp-hz not found\n", __func__);
> + dev_err(dev, "%s: opp-hz or opp-peak-bw not found\n",
> + __func__);

please remove the else part where rate value will be reset.

> goto free_opp;
> }
>
> diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
> index 569b3525aa67..ead2cdafe957 100644
> --- a/drivers/opp/opp.h
> +++ b/drivers/opp/opp.h
> @@ -59,7 +59,8 @@ extern struct list_head opp_tables;
> * @turbo: true if turbo (boost) OPP
> * @suspend: true if suspend OPP
> * @pstate: Device's power domain's performance state.
> - * @rate: Frequency in hertz
> + * @rate: Frequency in hertz OR Peak bandwidth in kilobytes per second
> + * @avg_bw: Average bandwidth in kilobytes per second
> * @level: Performance level
> * @supplies: Power supplies voltage/current values
> * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
> @@ -81,6 +82,7 @@ struct dev_pm_opp {
> bool suspend;
> unsigned int pstate;
> unsigned long rate;
> + unsigned long avg_bw;
> unsigned int level;
>
> struct dev_pm_opp_supply *supplies;
>

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