| Message ID | 1478264794-14652-1-git-send-email-dingtianhong@huawei.com |
|---|---|
| State | Superseded |
| Headers | show |
On Fri, Nov 04, 2016 at 09:06:30PM +0800, Ding Tianhong wrote: > The workaround for hisilicon,161601 will check the return value of the system counter > by different way, in order to distinguish with the fsl-a008585 workaround, introduce > a new generic erratum handing mechanism for fsl-a008585 and rename some functions. > > v2: Introducing a new generic erratum handling mechanism for fsl erratum a008585. > > v3: Introducing the erratum_workaround_set_sne generic function for fsl erratum a008585 > and make the #define __fsl_a008585_read_reg to be private to the .c file instead of > being globally visible. After discussion with Marc and Will, a consensus decision was > made to remove the commandline parameter for enabling fsl,erratum-a008585 erratum, > and make some generic name more specific, export timer_unstable_counter_workaround > for module access. The command line paramter was added at Marc's request to provide a way of enbaling the workaround in a KVM guest, until API is added to allow QEMU to discover the need to set the property in the guest device tree. Is there an alternative? -Scott -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Nov 04, 2016 at 01:20:50PM -0500, Scott Wood wrote: > On Fri, Nov 04, 2016 at 09:06:30PM +0800, Ding Tianhong wrote: > > The workaround for hisilicon,161601 will check the return value of the system counter > > by different way, in order to distinguish with the fsl-a008585 workaround, introduce > > a new generic erratum handing mechanism for fsl-a008585 and rename some functions. > > > > v2: Introducing a new generic erratum handling mechanism for fsl erratum a008585. > > > > v3: Introducing the erratum_workaround_set_sne generic function for fsl erratum a008585 > > and make the #define __fsl_a008585_read_reg to be private to the .c file instead of > > being globally visible. After discussion with Marc and Will, a consensus decision was > > made to remove the commandline parameter for enabling fsl,erratum-a008585 erratum, > > and make some generic name more specific, export timer_unstable_counter_workaround > > for module access. > > The command line paramter was added at Marc's request to provide a way of > enbaling the workaround in a KVM guest, until API is added to allow QEMU to > discover the need to set the property in the guest device tree. Is there an > alternative? Yes -- generate the device-tree property to indicate that there's an issue. Will -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/devicetree/bindings/arm/arch_timer.txt b/Documentation/devicetree/bindings/arm/arch_timer.txt index ef5fbe9..c27b2c4 100644 --- a/Documentation/devicetree/bindings/arm/arch_timer.txt +++ b/Documentation/devicetree/bindings/arm/arch_timer.txt @@ -31,6 +31,14 @@ to deliver its interrupts via SPIs. This also affects writes to the tval register, due to the implicit counter read. +- hisilicon,erratum-161601 : A boolean property. Indicates the presence of + erratum 161601, which says that reading the counter is unreliable unless + reading twice on the register and the value of the second read is larger + than the first by less than 32. If the verification is unsuccessful, then + discard the value of this read and repeat this procedure until the verification + is successful. This also affects writes to the tval register, due to the + implicit counter read. + ** Optional properties: - arm,cpu-registers-not-fw-configured : Firmware does not initialize