From: Sudeep Holla <sudeep.holla@arm.com>
To: Amit Kucheria <amit.kucheria@verdurent.com>,
Taniya Das <tdas@codeaurora.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux PM list <linux-pm@vger.kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Viresh Kumar <viresh.kumar@linaro.org>,
Stephen Boyd <sboyd@kernel.org>,
Rajendra Nayak <rnayak@codeaurora.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>, Rob Herring <robh@kernel.org>,
Saravana Kannan <skannan@codeaurora.org>
Subject: Re: [PATCH v4 1/2] dt-bindings: cpufreq: Introduce QCOM CPUFREQ FW bindings
Date: Fri, 15 Jun 2018 14:27:15 +0100 [thread overview]
Message-ID: <ce75662b-20ee-a879-5004-57d6cc2c29a5@arm.com> (raw)
In-Reply-To: <CAHLCerMCM1qf1MJ3bz+ZwBQMjshKSCWKXjHCiuqxJTDBdauamQ@mail.gmail.com>
On 15/06/18 12:59, Amit Kucheria wrote:
> On Thu, Jun 14, 2018 at 9:24 PM, Taniya Das <tdas@codeaurora.org> wrote:
>
[...]
>>
>> Yes I do understand the intent of mapping the whole register space, but as
>> per the HW specs these 3 registers would be the only ones required for now.
>> I do not think this hardware engine has any information on the power
>> numbers.
>
> "For now" - I think this is exactly the point that Sudeep is trying to make.
>
> A future version of the HW engine, or more likely, a firmware
> revision, will make more functionality available. Say, this needs
> access to another register or two. This will require changing the DT
> bindings. Instead, if you map the entire address space, you can just
> add offsets to the new registers.
>
> So in this case, I think you should define the following addresses
> (size 0x1400) for the two frequency domains
>
> 0x17d43000, 0x1400 (power cluster)
> 0x17d45800, 0x1400 (perf cluster)
>
> And in the driver simply add offsets as follows:
>
> #define ENABLE_OFFSET 0x0
> #define LUT_OFFSET 0x110
> #define PERF_DESIRED_OFFSET 0x920
>
> This will allow you add any new registers in the future w/o modifying
> the DT binding and reduce qcom_cpu_resources_init() to a handful of
> lines since you no longer need so many OF string matches, and
> devm_ioremap()s.
>
Thanks Amit for such nice and detailed explanation. I was lazy to write
in such details, but was hoping Taniya to understand the point. Anyways
thanks again for doing this.
--
Regards,
Sudeep
next prev parent reply other threads:[~2018-06-15 13:27 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-12 11:02 [PATCH v4 0/2] cpufreq: qcom-fw: Add support for QCOM cpufreq FW driver Taniya Das
2018-06-12 11:02 ` [PATCH v4 1/2] dt-bindings: cpufreq: Introduce QCOM CPUFREQ FW bindings Taniya Das
2018-06-13 11:26 ` Sudeep Holla
2018-06-13 18:13 ` Taniya Das
2018-06-14 10:47 ` Sudeep Holla
2018-06-14 18:24 ` Taniya Das
2018-06-15 11:59 ` Amit Kucheria
2018-06-15 13:27 ` Sudeep Holla [this message]
2018-06-15 17:40 ` Taniya Das
2018-06-15 17:45 ` Sudeep Holla
2018-06-17 9:03 ` Amit Kucheria
2018-06-18 9:21 ` Sudeep Holla
2018-06-19 7:53 ` Taniya Das
2018-06-19 9:21 ` Viresh Kumar
2018-06-19 9:34 ` Sudeep Holla
2018-06-19 10:44 ` Taniya Das
2018-06-15 13:23 ` Sudeep Holla
2018-06-15 17:31 ` Taniya Das
2018-06-15 17:42 ` Sudeep Holla
2018-06-15 13:07 ` Amit Kucheria
2018-06-12 11:02 ` [PATCH v4 2/2] cpufreq: qcom-fw: Add support for QCOM cpufreq FW driver Taniya Das
2018-06-15 12:02 ` Amit Kucheria
2018-06-19 9:30 ` Viresh Kumar
2018-07-11 20:37 ` Matthias Kaehlcke
2018-07-12 18:06 ` Taniya Das
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