On Tue, Mar 17, 2015 at 09:51:41AM +0000, Suzuki K. Poulose wrote: > From: "Suzuki K. Poulose" <[email protected]> > > A minor change, fixed missplled 'DEPRECATED' in the dev_warn(). > > Thanks > Suzuki > > ----8>---- > Avoid secure transactions while probing the CCI PMU. The > existing code makes use of the Peripheral ID2 (PID2) register > to determine the revision of the CCI400, which requires a > secure transaction. This puts a limitation on the usage of the > driver on systems running non-secure Linux(e.g, ARM64). > > Updated the device-tree binding for cci pmu node to add the explicit > revision number for the compatible field. > > The supported strings are : > arm,cci-400-pmu,r0 > arm,cci-400-pmu,r1 > arm,cci-400-pmu - DEPRECATED. See NOTE below > > NOTE: If the revision is not mentioned, we need to probe the cci revision, > which could be fatal on a platform running non-secure. We need a reliable way > to know if we can poke the CCI registers at runtime on ARM32. We depend on > 'mcpm_is_available()' when it is available. mcpm_is_available() returns true > only when there is a registered driver for mcpm. Otherwise, we assume that we > don't have secure access, and skips probing the revision number(ARM64 case). > > The MCPM should figure out if it is safe to access the CCI. Unfortunately > there isn't a reliable way to indicate the same via dtb. This patch doesn't > address/change the current situation. It only deals with the CCI-PMU, leaving > the assumptions about the secure access as it has been, prior to this patch. > > Changes since V2: > - Use 'bool' instead of 'int' for platform_has_secure_cci_access(). > (Suggested-by: Sudeep Holla) > > Cc: [email protected] > Cc: Punit Agrawal <[email protected]> > Signed-off-by: Suzuki K. Poulose <[email protected]> > Tested-by: Sudeep Holla <[email protected]> > Acked-by: Nicolas Pitre <[email protected]> > --- > Documentation/devicetree/bindings/arm/cci.txt | 7 +++-- > arch/arm/include/asm/arm-cci.h | 42 > +++++++++++++++++++++++++ > arch/arm64/include/asm/arm-cci.h | 27 ++++++++++++++++ > drivers/bus/arm-cci.c | 17 +++++++++- > include/linux/arm-cci.h | 2 ++ > 5 files changed, 92 insertions(+), 3 deletions(-) > create mode 100644 arch/arm/include/asm/arm-cci.h > create mode 100644 arch/arm64/include/asm/arm-cci.h > > diff --git a/Documentation/devicetree/bindings/arm/cci.txt > b/Documentation/devicetree/bindings/arm/cci.txt > index f28d82b..0e4b6a7 100644 > --- a/Documentation/devicetree/bindings/arm/cci.txt > +++ b/Documentation/devicetree/bindings/arm/cci.txt > @@ -94,8 +94,11 @@ specific to ARM. > - compatible > Usage: required > Value type: <string> > - Definition: must be "arm,cci-400-pmu" > - > + Definition: Supported strings are :
I'd prefer we said "Must contain one of:". > + "arm,cci-400-pmu,r0" > + "arm,cci-400-pmu,r1" > + "arm,cci-400-pmu" - DEPRECATED, permitted > only where OS has > + secure acces to CCI > registers Otherwise, the binding change looks fine to me, so: Acked-by: Mark Rutland <[email protected]> [DT binding] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
