This adds a code for turning on chicken bit 11, which appears to avoid a potential CPU deadlock that could occur. The exact set of instruction needed to trigger this errata is not totaly known but we have a high level of confidence that the problem is fixed by setting chicken bit 11.
All details are in http://crbug.com/711784 This erratum has no known number and thus I have tagged it CR711784 (after the Chrome OS bug number). I have created separate A12 / A17 configs to match how the rest of the A12 / A17 errata is handled. Signed-off-by: Douglas Anderson <diand...@chromium.org> --- arch/arm/Kconfig | 18 ++++++++++++++++++ arch/arm/mm/proc-v7.S | 10 ++++++++++ 2 files changed, 28 insertions(+) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 4376fe74f95e..34ec9039206b 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1181,6 +1181,13 @@ config ARM_ERRATA_857271 hang. The workaround is expected to have a negligible performance impact. +config ARM_ERRATA_CR711784_A12 + bool "ARM errata: A12: conditional instructions can lead to a CPU hang" + depends on CPU_V7 + help + This option enables the workaround for a Cortex-A12 erratum without a + number. The problems are best described in https://crbug.com/711784 + config ARM_ERRATA_852421 bool "ARM errata: A17: DMB ST might fail to create order between stores" depends on CPU_V7 @@ -1212,6 +1219,17 @@ config ARM_ERRATA_857272 config option from the A12 erratum due to the way errata are checked for and handled. +config ARM_ERRATA_CR711784_A17 + bool "ARM errata: A17: conditional instructions can lead to a CPU hang" + depends on CPU_V7 + help + This option enables the workaround for a Cortex-A17 erratum without a + number. The problems are best described in https://crbug.com/711784 + This erratum is not known to be fixed in any A17 revision. + This is identical to Cortex-A12 erratum CR711784. It is a separate + config option from the A12 erratum due to the way errata are checked + for and handled. + endmenu source "arch/arm/common/Kconfig" diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index cd2accbab844..a5156ea734ee 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -396,6 +396,11 @@ __ca12_errata: mrc p15, 0, r10, c15, c0, 1 @ read diagnostic register orr r10, r10, #1 << 10 @ set bit #10 mcr p15, 0, r10, c15, c0, 1 @ write diagnostic register +#endif +#ifdef CONFIG_ARM_ERRATA_CR711784_A12 + mrc p15, 0, r10, c15, c0, 1 @ read diagnostic register + orr r10, r10, #1 << 11 @ set bit #11 + mcr p15, 0, r10, c15, c0, 1 @ write diagnostic register #endif b __errata_finish @@ -416,6 +421,11 @@ __ca17_errata: mrc p15, 0, r10, c15, c0, 1 @ read diagnostic register orr r10, r10, #1 << 10 @ set bit #10 mcr p15, 0, r10, c15, c0, 1 @ write diagnostic register +#endif +#ifdef CONFIG_ARM_ERRATA_CR711784_A17 + mrc p15, 0, r10, c15, c0, 1 @ read diagnostic register + orr r10, r10, #1 << 11 @ set bit #11 + mcr p15, 0, r10, c15, c0, 1 @ write diagnostic register #endif b __errata_finish -- 2.21.0.593.g511ec345e18-goog
