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Message-ID: <54FF19F5.1020309@arm.com>
Date: Tue, 10 Mar 2015 16:21:09 +0000
From: Sudeep Holla <sudeep.holla@....com>
To: "Suzuki K. Poulose" <suzuki.poulose@....com>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>
CC: Sudeep Holla <sudeep.holla@....com>,
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 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)
Regards,
Sudeep
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