Re: [PATCH v2 0/5] arm-cci400: PMU monitoring support on ARM64
From: Suzuki K. Poulose
Date: Wed Mar 04 2015 - 07:17:48 EST
On 03/03/15 16:00, Sudeep Holla wrote:
On 02/03/15 11:29, Suzuki K. Poulose wrote:
From: "Suzuki K. Poulose" <suzuki.poulose@xxxxxxx>
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 Juno.
For the series:
Tested-by: Sudeep Holla <sudeep.holla@xxxxxxx> (on secure/MCPM TC2)
Thanks a lot for the testing
Suzuki
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