On 19/01/17 11:14, Ding Tianhong wrote:
> The workaround for hisilicon,161010101 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.
>
> After discussion with Marc and Will, a consensus decision was made to remove the commandline
> parameter for enabling fsl,erratum-a008585 erratum.
>
> Signed-off-by: Ding Tianhong <dingtianhong@xxxxxxxxxx>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 9 --
> arch/arm64/include/asm/arch_timer.h | 38 +++------
> drivers/clocksource/Kconfig | 8 ++
> drivers/clocksource/arm_arch_timer.c | 105 ++++++++++++++----------
> 4 files changed, 84 insertions(+), 76 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 21e2d88..76437ad 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -539,15 +539,6 @@
> loops can be debugged more effectively on production
> systems.
>
> - clocksource.arm_arch_timer.fsl-a008585=
> - [ARM64]
> - Format: <bool>
> - Enable/disable the workaround of Freescale/NXP
> - erratum A-008585. This can be useful for KVM
> - guests, if the guest device tree doesn't show the
> - erratum. If unspecified, the workaround is
> - enabled based on the device tree.
> -
> clearcpuid=BITNUM [X86]
> Disable CPUID feature X for the kernel. See
> arch/x86/include/asm/cpufeatures.h for the valid bit
> diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
> index eaa5bbe..b4b3400 100644
> --- a/arch/arm64/include/asm/arch_timer.h
> +++ b/arch/arm64/include/asm/arch_timer.h
> @@ -29,41 +29,29 @@
>
> #include <clocksource/arm_arch_timer.h>
>
> -#if IS_ENABLED(CONFIG_FSL_ERRATUM_A008585)
> +#if IS_ENABLED(CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND)
> extern struct static_key_false arch_timer_read_ool_enabled;
> -#define needs_fsl_a008585_workaround() \
> +#define needs_unstable_timer_counter_workaround() \
> static_branch_unlikely(&arch_timer_read_ool_enabled)
> #else
> -#define needs_fsl_a008585_workaround() false
> +#define needs_unstable_timer_counter_workaround() false
> #endif
>
> -u32 __fsl_a008585_read_cntp_tval_el0(void);
> -u32 __fsl_a008585_read_cntv_tval_el0(void);
> -u64 __fsl_a008585_read_cntvct_el0(void);
>
> -/*
> - * The number of retries is an arbitrary value well beyond the highest number
> - * of iterations the loop has been observed to take.
> - */
> -#define __fsl_a008585_read_reg(reg) ({ \
> - u64 _old, _new; \
> - int _retries = 200; \
> - \
> - do { \
> - _old = read_sysreg(reg); \
> - _new = read_sysreg(reg); \
> - _retries--; \
> - } while (unlikely(_old != _new) && _retries); \
> - \
> - WARN_ON_ONCE(!_retries); \
> - _new; \
> -})
> +struct arch_timer_erratum_workaround {
> + const char *id; /* Indicate the Erratum ID */
> + u32 (*read_cntp_tval_el0)(void);
> + u32 (*read_cntv_tval_el0)(void);
> + u64 (*read_cntvct_el0)(void);
> +};
> +
> +extern const struct arch_timer_erratum_workaround *timer_unstable_counter_workaround;
>
> #define arch_timer_reg_read_stable(reg) \
> ({ \
> u64 _val; \
> - if (needs_fsl_a008585_workaround()) \
> - _val = __fsl_a008585_read_##reg(); \
> + if (needs_unstable_timer_counter_workaround()) \
> + _val = timer_unstable_counter_workaround->read_##reg();\
> else \
> _val = read_sysreg(reg); \
> _val; \
> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> index 4866f7a..04c2b93 100644
> --- a/drivers/clocksource/Kconfig
> +++ b/drivers/clocksource/Kconfig
> @@ -325,10 +325,18 @@ config ARM_ARCH_TIMER_EVTSTREAM
> This must be disabled for hardware validation purposes to detect any
> hardware anomalies of missing events.
>
> +config ARM_ARCH_TIMER_OOL_WORKAROUND
> + bool "Workaround for arm arch timer unstable counter"
Please drop the message. We don't want that option to be selectable by a
user, but only selected if an erratum that depends on it is enabled.
> + depends on FSL_ERRATUM_A008585
> + help
> + This option would only be enabled by Freescale/NXP Erratum A-008585
> + or something else chip has similar erratum.
> +
> config FSL_ERRATUM_A008585
> bool "Workaround for Freescale/NXP Erratum A-008585"
> default y
> depends on ARM_ARCH_TIMER && ARM64
> + select ARM_ARCH_TIMER_OOL_WORKAROUND
> help
> This option enables a workaround for Freescale/NXP Erratum
> A-008585 ("ARM generic timer may contain an erroneous
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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