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Message-ID: <54FF1AA8.8060102@arm.com>
Date: Tue, 10 Mar 2015 16:24:08 +0000
From: "Suzuki K. Poulose" <Suzuki.Poulose@....com>
To: Sudeep Holla <Sudeep.Holla@....com>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>
CC: Nicolas Pitre <nico@...aro.org>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
Kukjin Kim <kgene@...nel.org>,
Abhilash Kesavan <a.kesavan@...sung.com>,
Arnd Bergmann <arnd@...db.de>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Liviu Dudau <Liviu.Dudau@....com>,
Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
Olof Johansson <olof@...om.net>,
Pawel Moll <Pawel.Moll@....com>,
Punit Agrawal <Punit.Agrawal@....com>,
Will Deacon <Will.Deacon@....com>,
Catalin Marinas <Catalin.Marinas@....com>
Subject: Re: [PATCHv3 0/5] arm-cci400: PMU monitoring support on ARM64
On 10/03/15 16:21, Sudeep Holla wrote:
>
>
> On 10/03/15 15:18, Suzuki K. Poulose wrote:
>> From: "Suzuki K. Poulose" <suzuki.poulose@....com>
>>
>> This series enables the PMU monitoring support for CCI400 on ARM64.
>> The existing CCI400 driver code is a mix of PMU driver and the MCPM
>> driver code. The MCPM driver is only used on ARM(32) and contains
>> arm32 assembly and hence can't be built on ARM64. This patch splits
>> the code to
>>
>> - ARM_CCI400_PORT_CTRL driver - depends on ARM && V7
>> - ARM_CCI400_PMU driver
>>
>> Accessing the Peripheral ID2 register(PID2) on CCI-400, to detect
>> the revision of the chipset, is a secure operation. Hence, it prevents
>> us from running this on non-secure platforms. The issue is overcome by
>> explicitly mentioning the revision number of the CCI PMU in the device tree
>> binding. The device-tree binding has been updated with the new bindings.
>>
>> i.e, arm-cci-400-pmu,r0 => revision 0
>> arm-cci-400-pmu,r1 => revision 1
>> arm-cci-400-pmu => (old) DEPRECATED
>>
>> The old binding has been DEPRECATED and must be used only on ARM32
>> system with secure access. We don't have a reliable dynamic way to detect
>> if the system is running secure. This series tries to use the best safe
>> method by relying on the availability of MCPM(as it was prior to the series).
>> It is upto the MCPM platform driver to decide, if the system is secure before
>> it goes ahead and registers its drivers and pokes the CCI. This series doesn't
>> address/solve the problem of MCPM. I will be happy to use a better approach,
>> if there is any.
>>
>> Tested on (non-secure)TC2 and A53x2.
>>
>
> For the series,
> Tested-by: Sudeep Holla <sudeep.holla@....com>
> (Tested on secure TC2 using MCPM)
>
Thank you very much for the testing
Suzuki
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