From: Georgi Djakov <georgi.djakov@linaro.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: vireshk@kernel.org, sboyd@kernel.org, nm@ti.com,
robh+dt@kernel.org, mark.rutland@arm.com, rjw@rjwysocki.net,
jcrouse@codeaurora.org, vincent.guittot@linaro.org,
bjorn.andersson@linaro.org, amit.kucheria@linaro.org,
seansw@qti.qualcomm.com, daidavid1@codeaurora.org,
evgreen@chromium.org, sibis@codeaurora.org,
linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH 1/4] dt-bindings: opp: Introduce opp-bw-MBs bindings
Date: Tue, 9 Apr 2019 17:36:01 +0300 [thread overview]
Message-ID: <e462c932-4789-4f59-ad58-98c62266d977@linaro.org> (raw)
In-Reply-To: <20190314062312.vwyu3ryeyc6iv55h@vireshk-i7>
Hi Viresh,
On 3/14/19 08:23, Viresh Kumar wrote:
> On 13-03-19, 11:00, Georgi Djakov wrote:
>> In addition to frequency and voltage, some devices may have bandwidth
>> requirements for their interconnect throughput - for example a CPU
>> or GPU may also need to increase or decrease their bandwidth to DDR
>> memory based on the current operating performance point.
>>
>> Extend the OPP tables with additional property to describe the bandwidth
>> needs of a device. The average and peak bandwidth values depend on the
>> hardware and its properties.
>>
>> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
>> ---
>> Documentation/devicetree/bindings/opp/opp.txt | 45 +++++++++++++++++++
>> 1 file changed, 45 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt
>> index 76b6c79604a5..fa598264615f 100644
>> --- a/Documentation/devicetree/bindings/opp/opp.txt
>> +++ b/Documentation/devicetree/bindings/opp/opp.txt
>> @@ -129,6 +129,9 @@ Optional properties:
>> - opp-microamp-<name>: Named opp-microamp property. Similar to
>> opp-microvolt-<name> property, but for microamp instead.
>>
>> +- opp-bw-MBs: The interconnect bandwidth is specified with an array containing
>> + the two integer values for average and peak bandwidth in megabytes per second.
>> +
>> - opp-level: A value representing the performance level of the device,
>> expressed as a 32-bit integer.
>>
>> @@ -546,3 +549,45 @@ Example 6: opp-microvolt-<name>, opp-microamp-<name>:
>> };
>> };
>> };
>> +
>> +Example 7: opp-bw-MBs:
>> +(example: average and peak bandwidth values are defined for each OPP and the
>> +interconnect between CPU and DDR memory is scaled together with CPU frequency)
>> +
>> +/ {
>> + cpus {
>> + CPU0: cpu@0 {
>> + compatible = "arm,cortex-a53", "arm,armv8";
>> + ...
>> + operating-points-v2 = <&cpu_opp_table>;
>> + /* path between the CPU and DDR memory */
>> + interconnects = <&rpm_bimc MASTER_AMPSS_M0
>> + &rpm_bimc SLAVE_EBI_CH0>;
>
> Can we have multiple paths for a device ?
I suppose that this is also a possible scenario. Will propose something
to handle multiple paths too.
>> + };
>> + };
>> +
>> + cpu_opp_table: cpu_opp_table {
>> + compatible = "operating-points-v2";
>> + opp-shared;
>> +
>> + opp-200000000 {
>> + opp-hz = /bits/ 64 <200000000>;
>> + /* 457 MB/s average and 1525 MB/s peak bandwidth */
>> + opp-bw-MBs = <457 1525>;
>
> In that case fixing this to just 2 entries in the array is incorrect
> and we should take care of that in the bindings here.
We can encode the path name into the property (when there are multiple
paths). We already have opp-microamp-<name> and opp-microamp-<name>, so
we can follow the same practice.
For example:
CPU0: cpu@0 {
compatible = "arm,cortex-a53", "arm,armv8";
...
operating-points-v2 = <&cpu_opp_table>;
/* path between the CPU and DDR and path between CPU and L3 */
interconnects = <&bimc MASTER_AMPSS_M0 &bimc SLAVE_EBI_CH0>,
<&bimc MASTER_AMPSS_M0 &bimc SLAVE_L3>;
interconnect-names "cpu-mem", "cpu-l3";
};
cpu_opp_table: cpu_opp_table {
compatible = "operating-points-v2";
opp-shared;
opp-200000000 {
opp-hz = /bits/ 64 <200000000>;
/* 457 MB/s average, 1525 MB/s peak bandwidth to DDR */
opp-bw-MBps-cpu-mem = <457 1525>;
/* 914 MB/s average, 3050 MB/s peak bandwidth to L3 */
opp-bw-MBps-cpu-l3 = <914 3050>;
};
};
Thanks,
Georgi
next prev parent reply other threads:[~2019-04-09 14:36 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-13 9:00 [PATCH 0/4] Introduce OPP bandwidth bindings Georgi Djakov
2019-03-13 9:00 ` [PATCH 1/4] dt-bindings: opp: Introduce opp-bw-MBs bindings Georgi Djakov
2019-03-14 6:23 ` Viresh Kumar
2019-04-09 14:36 ` Georgi Djakov [this message]
2019-04-10 4:05 ` Viresh Kumar
2019-04-10 9:52 ` Georgi Djakov
2019-03-28 15:12 ` Rob Herring
2019-04-09 14:39 ` Georgi Djakov
2019-03-13 9:00 ` [PATCH 2/4] OPP: Add support for parsing the interconnect bandwidth Georgi Djakov
2019-03-14 6:30 ` Viresh Kumar
2019-04-09 14:37 ` Georgi Djakov
2019-04-10 3:53 ` Viresh Kumar
2019-03-13 9:00 ` [PATCH 3/4] OPP: Update the bandwidth on OPP frequency changes Georgi Djakov
2019-03-13 9:00 ` [PATCH 4/4] cpufreq: dt: Add support for interconnect bandwidth scaling Georgi Djakov
2019-03-15 19:02 ` [PATCH 0/4] Introduce OPP bandwidth bindings Sibi Sankar
2019-03-28 15:16 ` Rob Herring
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=e462c932-4789-4f59-ad58-98c62266d977@linaro.org \
--to=georgi.djakov@linaro.org \
--cc=amit.kucheria@linaro.org \
--cc=bjorn.andersson@linaro.org \
--cc=daidavid1@codeaurora.org \
--cc=devicetree@vger.kernel.org \
--cc=evgreen@chromium.org \
--cc=jcrouse@codeaurora.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=nm@ti.com \
--cc=rjw@rjwysocki.net \
--cc=robh+dt@kernel.org \
--cc=sboyd@kernel.org \
--cc=seansw@qti.qualcomm.com \
--cc=sibis@codeaurora.org \
--cc=vincent.guittot@linaro.org \
--cc=viresh.kumar@linaro.org \
--cc=vireshk@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).