On 02/26/13 09:37, Nishanth Menon wrote:
> Make Operating Performance Points (OPP) library introductory chapter
> a little more reader-friendly. Split the chapter into two sections
> and highlight the definition with an example.
>
> Reported-by: Linus Torvalds <[email protected]>
> Cc: "Rafael J. Wysocki" <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Nishanth Menon <[email protected]>
> ---
> based on v3.8 tag
> Documentation/power/opp.txt | 23 +++++++++++++++++++----
> 1 file changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/power/opp.txt b/Documentation/power/opp.txt
> index 3035d00..b4f1870 100644
> --- a/Documentation/power/opp.txt
> +++ b/Documentation/power/opp.txt
> @@ -1,6 +1,5 @@
> -*=============*
> -* OPP Library *
> -*=============*
> +Operating Performance Points (OPP) Library
> +==========================================
>
> (C) 2009-2010 Nishanth Menon <[email protected]>, Texas Instruments Incorporated
>
> @@ -16,15 +15,31 @@ Contents
>
> 1. Introduction
> ===============
> +1.1 What is an Operating Performance Point (OPP)?
> +
> Complex SoCs of today consists of a multiple sub-modules working in
> conjunction.
> In an operational system executing varied use cases, not all modules in the
> SoC
> need to function at their highest performing frequency all the time. To
> facilitate this, sub-modules in a SoC are grouped into domains, allowing some
> domains to run at lower voltage and frequency while other domains are loaded
> -more. The set of discrete tuples consisting of frequency and voltage pairs
> that
> +more.
huh???
> +
> +The set of discrete tuples consisting of frequency and voltage pairs that
> the device will support per domain are called Operating Performance Points or
> OPPs.
>
> +As an example:
> +Let us consider an MPU device which supports the following:
> +{300MHz at minimum voltage of 1V}, {800MHz at minimum voltage of 1.2V},
> +{1GHz at minimum voltage of 1.3V}
> +
> +We can represent these as three OPPs as the following {Hz, uV} tuples:
> +{300000000, 1000000}
> +{600000000, 1200000}
800000000
> +{100000000, 1300000}
1000000000 ??
> +
> +1.2 Operating Performance Points Library
> +
> OPP library provides a set of helper functions to organize and query the OPP
> information. The library is located in drivers/base/power/opp.c and the
> header
> is located in include/linux/opp.h. OPP library can be enabled by enabling
>
--
~Randy
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