| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <CAGTfZH18SQXj_2TpUf7iQPzWrZ5RP8-OCb_t6fp7qhuutGWz5A@mail.gmail.com>
Date: Sat, 22 Jun 2019 20:49:59 +0900
From: Chanwoo Choi <cwchoi00@...il.com>
To: Saravana Kannan <saravanak@...gle.com>
Cc: MyungJoo Ham <myungjoo.ham@...sung.com>,
Kyungmin Park <kyungmin.park@...sung.com>,
Chanwoo Choi <cw00.choi@...sung.com>,
Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
Stephen Boyd <sboyd@...nel.org>,
"Rafael J. Wysocki" <rjw@...ysocki.net>, kernel-team@...roid.com,
Linux PM list <linux-pm@...r.kernel.org>,
linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 2/3] OPP: Add function to look up required OPP's for a
given OPP
Hi,
Absolutely, I like this approach. I think that it is necessary to make
the connection
between frequencies of devices. But, I have a question on below.
2019년 6월 22일 (토) 오전 9:35, Saravana Kannan <saravanak@...gle.com>님이 작성:
>
> Add a function that allows looking up required OPPs given a source OPP
> table, destination OPP table and the source OPP.
>
> Signed-off-by: Saravana Kannan <saravanak@...gle.com>
> ---
> drivers/opp/core.c | 54 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/pm_opp.h | 11 +++++++++
> 2 files changed, 65 insertions(+)
>
> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> index 74c7bdc6f463..4f7870bffbf8 100644
> --- a/drivers/opp/core.c
> +++ b/drivers/opp/core.c
> @@ -1830,6 +1830,60 @@ void dev_pm_opp_put_genpd_virt_dev(struct opp_table *opp_table,
> dev_err(virt_dev, "Failed to find required device entry\n");
> }
>
> +/**
> + * dev_pm_opp_xlate_opp() - Find required OPP for src_table OPP.
> + * @src_table: OPP table which has dst_table as one of its required OPP table.
> + * @dst_table: Required OPP table of the src_table.
> + * @pstate: OPP of the src_table.
> + *
> + * This function returns the OPP (present in @dst_table) pointed out by the
> + * "required-opps" property of the OPP (present in @src_table).
> + *
> + * The callers are required to call dev_pm_opp_put() for the returned OPP after
> + * use.
> + *
> + * Return: destination table OPP on success, otherwise NULL on errors.
> + */
> +struct dev_pm_opp *dev_pm_opp_xlate_opp(struct opp_table *src_table,
> + struct opp_table *dst_table,
> + struct dev_pm_opp *src_opp)
> +{
> + struct dev_pm_opp *opp, *dest_opp = NULL;
> + int i;
> +
> + if (!src_table || !dst_table || !src_opp)
> + return NULL;
> +
> + for (i = 0; i < src_table->required_opp_count; i++) {
> + if (src_table->required_opp_tables[i]->np == dst_table->np)
> + break;
> + }
> +
> + if (unlikely(i == src_table->required_opp_count)) {
> + pr_err("%s: Couldn't find matching OPP table (%p: %p)\n",
> + __func__, src_table, dst_table);
> + return NULL;
> + }
> +
> + mutex_lock(&src_table->lock);
> +
> + list_for_each_entry(opp, &src_table->opp_list, node) {
> + if (opp == src_opp) {
> + dest_opp = opp->required_opps[i];
Correct me if I am wrong. This patch assume that 'i' index is same on between
[1] and [2]. But in order to guarantee this assumption, all OPP entries
in the same opp_table have to have the same number of 'required-opps' properties
and keep the sequence among 'required-opps' entries.
[1] src_table->required_opp_tables[i]->np
[2] opp->required_opps[I];
For example, three OPP entries in the 'parent_bus_opp'
have the different sequence of 'required-opps' and the different
number of 'required-opps'. Is it no problem?
parent_bus_opp: opp_table {
compatible = "operating-points-v2";
opp2 {
opp-hz = /bits/ 64 <200000>;
required-opps = <&child_bus_a_opp2>, <&child_bus_b_opp2>,
<&child_bus_c_opp2>;
};
opp1 {
opp-hz = /bits/ 64 <200000>;
// change the sequence between child_bus_b_opp2 and child_bus_c_opp2
required-opps = <&child_bus_a_opp2>, <&child_bus_c_opp2>,
<&child_bus_b_opp2>
};
opp0 {
opp-hz = /bits/ 64 <200000>;
// missing 'child_bus_a_opp2'
required-opps = <&child_bus_c_opp2>, <&child_bus_b_opp2>
};
}
> + dev_pm_opp_get(dest_opp);
> + goto unlock;
> + }
> + }
> +
> + pr_err("%s: Couldn't find matching OPP (%p: %p)\n", __func__, src_table,
> + dst_table);
> +
> +unlock:
> + mutex_unlock(&src_table->lock);
> +
> + return dest_opp;
> +}
> +
> /**
> * dev_pm_opp_xlate_performance_state() - Find required OPP's pstate for src_table.
> * @src_table: OPP table which has dst_table as one of its required OPP table.
> diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
> index b150fe97ce5a..bc5c68bdfc8d 100644
> --- a/include/linux/pm_opp.h
> +++ b/include/linux/pm_opp.h
> @@ -134,6 +134,9 @@ void dev_pm_opp_unregister_set_opp_helper(struct opp_table *opp_table);
> struct opp_table *dev_pm_opp_set_genpd_virt_dev(struct device *dev, struct device *virt_dev, int index);
> void dev_pm_opp_put_genpd_virt_dev(struct opp_table *opp_table, struct device *virt_dev);
> int dev_pm_opp_xlate_performance_state(struct opp_table *src_table, struct opp_table *dst_table, unsigned int pstate);
> +struct dev_pm_opp *dev_pm_opp_xlate_opp(struct opp_table *src_table,
> + struct opp_table *dst_table,
> + struct dev_pm_opp *src_opp);
> int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq);
> int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, const struct cpumask *cpumask);
> int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask);
> @@ -307,6 +310,14 @@ static inline int dev_pm_opp_xlate_performance_state(struct opp_table *src_table
> return -ENOTSUPP;
> }
>
> +static inline struct dev_pm_opp *dev_pm_opp_xlate_opp(
> + struct opp_table *src_table,
> + struct opp_table *dst_table,
> + struct dev_pm_opp *src_opp)
> +{
> + return NULL;
> +}
> +
> static inline int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
> {
> return -ENOTSUPP;
> --
> 2.22.0.410.gd8fdbe21b5-goog
>
--
Best Regards,
Chanwoo Choi
Powered by blists - more mailing lists