Hi Marc: How about this v7, if any suggestions very grateful. Thanks. Ding On 2017/1/7 15:07, Ding Tianhong wrote: > Erratum Hisilicon-161601 says that the ARM generic timer counter "has the > potential to contain an erroneous value when the timer value changes". > Accesses to TVAL (both read and write) are also affected due to the implicit counter > read. Accesses to CVAL are not affected. > > The workaround is to reread the system count registers until the value of the second > read is larger than the first one by less than 32, the system counter can be guaranteed > not to return wrong value twice by back-to-back read and the error value is always larger > than the correct one by 32. Writes to TVAL are replaced with an equivalent write to CVAL. > > v2: Introducing a new generic erratum handling mechanism for fsl,a008585 and hisilicon,161601. > Significant rework based on feedback, including seperate the fsl erratum a008585 > to another patch, update the erratum name and remove unwanted code. > > 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. > > Significant rework based on feedback, including fix some alignment problem, make the > #define __hisi_161601_read_reg to be private to the .c file instead of being globally > visible, add more accurate annotation and modify a bit of logical format to enable > arch_timer_read_ool_enabled, remove the kernel commandline parameter > clocksource.arm_arch_timer.hisilicon-161601. > > Introduce a generic aquick framework for erratum in ACPI mode. > > v4: rename the quirk handler parameter to make it more generic, and > avoid break loop when handling the quirk becasue it need to > support multi quirks handler. > > update some data structures for acpi mode. > > v5: Adapt the new kernel-parameters.txt for latest kernel version. > Set the retries of reread system counter to 50, because it is possible > that some interrupts may lead to more than twice read errors and break the loop, > it will trigger the warning, so we set the number of retries far beyond the number of > iterations the loop has been observed to take. > > v6: The last 2 patches in the previous version about the ACPI mode will conflict witch Fuwei's > GTDT patches, so remove the ACPI part and only support the DT base code for this patch set. > > We have trigger a bug when select the CONFIG_FUNCTION_GRAPH_TRACER and enable function_graph > to /sys/kernel/debug/tracing/current_tracer, the system will stall into an endless loop, it looks > like that the ftrace_graph_caller will be related to xxx.read_cntvct_el0 and read the system counter > again, so mark the xxx.read_cntvct_el0 with notrace to fix the problem. > > v7: Introduce a new general config symbol named CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND to enable the workaround > for any chips which has similar arch timer erratum just like "fsl,erratum_a008585" and "hisilicon,erratum_161601", > modify the struct arch_timer_erratum_workaround to be compatible different chip erratum more easily, and > reconstruction some code base on the new config symbol and struct, thanks to Marc's suggestion. > > Ding Tianhong (4): > arm64: arch_timer: Add device tree binding for hisilicon-161601 > erratum > arm64: arch_timer: Introduce a generic erratum handing mechanism for > fsl-a008585 > arm64: arch_timer: Work around Erratum Hisilicon-161601 > arm64: arch timer: Add timer erratum property for Hip05-d02 and > Hip06-d03 > > Documentation/admin-guide/kernel-parameters.txt | 9 -- > Documentation/arm64/silicon-errata.txt | 1 + > .../devicetree/bindings/arm/arch_timer.txt | 8 ++ > arch/arm64/boot/dts/hisilicon/hip05.dtsi | 1 + > arch/arm64/boot/dts/hisilicon/hip06.dtsi | 1 + > arch/arm64/include/asm/arch_timer.h | 38 ++---- > drivers/clocksource/Kconfig | 18 +++ > drivers/clocksource/arm_arch_timer.c | 150 +++++++++++++++------ > 8 files changed, 152 insertions(+), 74 deletions(-) > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
