From: ppvk@codeaurora.org
To: Georgi Djakov <georgi.djakov@linaro.org>
Cc: adrian.hunter@intel.com, ulf.hansson@linaro.org,
robh+dt@kernel.org, asutoshd@codeaurora.org,
vbadigan@codeaurora.org, stummala@codeaurora.org,
sayalil@codeaurora.org, rampraka@codeaurora.org,
linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
Subhash Jadavani <subhashj@codeaurora.org>,
Andy Gross <agross@kernel.org>,
linux-mmc-owner@vger.kernel.org
Subject: Re: [RFC 1/2] mmc: sdhci-msm: Add support for bus bandwidth voting
Date: Wed, 25 Sep 2019 11:54:11 +0530 [thread overview]
Message-ID: <d10c21360d4830c864374a57c491c21c@codeaurora.org> (raw)
In-Reply-To: <616c7a8c-a1cf-2043-4ea4-f452ee90f083@linaro.org>
On 2019-09-12 18:26, Georgi Djakov wrote:
> Hi Pradeep,
>
> Thanks for the patch!
>
> On 9/6/19 15:47, Pradeep P V K wrote:
>> Vote for the MSM bus bandwidth required by SDHC driver
>> based on the clock frequency and bus width of the card.
>> Otherwise,the system clocks may run at minimum clock speed
>> and thus affecting the performance.
>>
>> This change is based on Georgi Djakov [RFC]
>> (https://lkml.org/lkml/2018/10/11/499)
>
> I am just wondering whether do we really need to predefine the
> bandwidth values
> in DT? Can't we use the computations from the above patch or is there
> any
> problem with that approach?
>
> Thanks,
> Georgi
Hi Georgi,
By using the direct required bandwidth(bw / 1000) values, it will not
guarantee
that all the NOC clocks are running in the same voltage corner as
required,
which is very crucial for power concern devices like Mobiles etc.
Also, it will not guarantee that the value passed is in proper Clock
Plans domain
there by effecting the requested Bandwidth.
I think, you already aware of these consequences on using direct
bandwidth values for
RPMh based devices.
The value the we passed in DT will make sure that all the NOC clocks
between the end points
are running in the same voltage corners as required and also it will
guarantee that
the requested BW's for the clients are obtained.
Hence the reason for passing the predefined bandwidth values in DT.
Thanks and Regards,
Pradeep
next prev parent reply other threads:[~2019-09-25 6:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-06 12:47 [RFC 0/2] Add Support for SDHC bus bandwidth voting Pradeep P V K
2019-09-06 12:47 ` [RFC 1/2] mmc: sdhci-msm: Add support for " Pradeep P V K
2019-09-06 12:51 ` ppvk
2019-09-06 21:02 ` Stephen Boyd
2019-09-12 15:01 ` ppvk
2019-09-12 12:56 ` Georgi Djakov
2019-09-25 6:24 ` ppvk [this message]
2019-09-12 16:45 ` Bjorn Andersson
2019-09-25 11:27 ` ppvk
2019-10-03 10:00 ` Ulf Hansson
2019-09-06 12:47 ` [RFC 2/2] dt-bindings: mmc: sdhci-msm: Add Bus BW vote supported strings Pradeep P V K
2019-09-13 14:36 ` Rob Herring
2019-09-30 14:32 ` ppvk
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