The attached patch adds error detection for A53 and A57 cores. Hardware error injection is supported on A53. Software error injection is supported on both.
For hardware error injection on A53 to work, proper access to L2ACTLR_EL1,
CPUACTLR_EL1 needs to be granted by EL3 firmware. This is done by making an SMC call in the driver. Failure to enable access disables hardware error injection. For error interrupt to work, another SMC call enables access to L2ECTLR_EL1. Failure to enable access disables interrupt for error reporting.
CPU Memory Error Syndrome and L2 Memory Error Syndrome registers can be used for checking L1 and L2 memory errors. However, only A53 supports double-bit error injection to L1 and L2 memory. This driver uses the hardware error injection when available, but also provides a way to inject errors by software. Both A53 and A57 supports interrupt when multibit errors happen.
To use hardware error injection and the interrupt, proper access needs to be granted in ACTLR_EL3 (and/or ACTLR_EL2) register by EL3 firmware SMC call.
Correctable errors do not trigger such interrupt. This driver uses dynamic polling internal to check for errors. The more errors detected, the more frequently it polls. Combining with interrupt, this driver can detect correctable and uncorrectable errors. However, if the uncorrectable errors
cause system abort exception, this driver is not able to report errors in time.
