From: Viresh Kumar <viresh.kumar@linaro.org>
To: Saravana Kannan <saravanak@google.com>
Cc: Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
Stephen Boyd <sboyd@kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Georgi Djakov <georgi.djakov@linaro.org>,
vincent.guittot@linaro.org, seansw@qti.qualcomm.com,
daidavid1@codeaurora.org, adharmap@codeaurora.org,
Rajendra Nayak <rnayak@codeaurora.org>,
sibis@codeaurora.org, bjorn.andersson@linaro.org,
evgreen@chromium.org, kernel-team@android.com,
linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 0/3] Introduce Bandwidth OPPs for interconnects
Date: Mon, 29 Jul 2019 15:05:45 +0530 [thread overview]
Message-ID: <20190729093545.kvnqxjkyx4nogddk@vireshk-i7> (raw)
In-Reply-To: <20190726231558.175130-1-saravanak@google.com>
On 26-07-19, 16:15, Saravana Kannan wrote:
> Interconnects and interconnect paths quantify their performance levels in
> terms of bandwidth and not in terms of frequency. So similar to how we have
> frequency based OPP tables in DT and in the OPP framework, we need
> bandwidth OPP table support in DT and in the OPP framework.
>
> So with the DT bindings added in this patch series, the DT for a GPU
> that does bandwidth voting from GPU to Cache and GPU to DDR would look
> something like this:
>
> gpu_cache_opp_table: gpu_cache_opp_table {
> compatible = "operating-points-v2";
>
> gpu_cache_3000: opp-3000 {
> opp-peak-KBps = <3000000>;
> opp-avg-KBps = <1000000>;
> };
> gpu_cache_6000: opp-6000 {
> opp-peak-KBps = <6000000>;
> opp-avg-KBps = <2000000>;
> };
> gpu_cache_9000: opp-9000 {
> opp-peak-KBps = <9000000>;
> opp-avg-KBps = <9000000>;
> };
> };
>
> gpu_ddr_opp_table: gpu_ddr_opp_table {
> compatible = "operating-points-v2";
>
> gpu_ddr_1525: opp-1525 {
> opp-peak-KBps = <1525000>;
> opp-avg-KBps = <452000>;
> };
> gpu_ddr_3051: opp-3051 {
> opp-peak-KBps = <3051000>;
> opp-avg-KBps = <915000>;
> };
> gpu_ddr_7500: opp-7500 {
> opp-peak-KBps = <7500000>;
> opp-avg-KBps = <3000000>;
> };
> };
>
> gpu_opp_table: gpu_opp_table {
> compatible = "operating-points-v2";
> opp-shared;
>
> opp-200000000 {
> opp-hz = /bits/ 64 <200000000>;
> };
> opp-400000000 {
> opp-hz = /bits/ 64 <400000000>;
> };
> };
>
> gpu@7864000 {
> ...
> operating-points-v2 = <&gpu_opp_table>, <&gpu_cache_opp_table>, <&gpu_ddr_opp_table>;
> ...
> };
One feedback I missed giving earlier. Will it be possible to get some
user code merged along with this ? I want to make sure anything we add
ends up getting used.
That also helps understanding the problems you are facing in a better
way, i.e. with real examples.
--
viresh
next prev parent reply other threads:[~2019-07-29 9:35 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-26 23:15 [PATCH v4 0/3] Introduce Bandwidth OPPs for interconnects Saravana Kannan
2019-07-26 23:15 ` [PATCH v4 1/3] dt-bindings: opp: Introduce opp-peak-KBps and opp-avg-KBps bindings Saravana Kannan
2019-07-29 17:23 ` Stephen Boyd
2019-07-26 23:15 ` [PATCH v4 2/3] OPP: Add support for bandwidth OPP tables Saravana Kannan
2019-08-07 12:53 ` Georgi Djakov
2019-08-07 20:46 ` Saravana Kannan
2019-07-26 23:15 ` [PATCH v4 3/3] OPP: Add helper function " Saravana Kannan
2019-07-29 9:35 ` Viresh Kumar [this message]
2019-07-29 20:16 ` [PATCH v4 0/3] Introduce Bandwidth OPPs for interconnects Saravana Kannan
2019-07-30 2:46 ` Viresh Kumar
2019-07-30 5:28 ` Sibi Sankar
2019-07-30 5:53 ` Saravana Kannan
2019-07-30 16:43 ` Sibi Sankar
2019-08-06 15:27 ` Georgi Djakov
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