ERR005187
Chip Errata for the i.MX 6Dual/6Quad and i.MX 6DualPlus/6QuadPlus, Rev. 6.1, 06/2016
NXP Semiconductors
59
Description:
PARITYFAIL signal bits [7] and [6] are expected to report parity errors occurring on the BTAC
and GHB RAMs, when the parity error detection logic is enabled (ACTLR[9]=1’b1).
The erratum is that the Parity Enable bit, ACTLR[9], is not taken into account by the logic driving
PARITYFAIL[7:6]. As a consequence, any parity error on the BTAC or GHB RAM will be
reported on PARITYFAIL[7] or [6], even when parity error detection is not enabled.
Conditions:
The erratum happens on all configurations that have implemented parity support on the BTAC or
GHB RAMs when dynamic branch prediction is enabled (SCTLR[11]=1’b1).
Projected Impact:
Due to the erratum, unexpected parity errors might be reported when parity is not enabled, if any
parity error happens on the BTAC or GHB RAMs.
Note that implementing parity error detection is not mandatory on the BTAC and GHB RAMs
because such errors might cause a branch mispredict, but no functional failure.
In systems which are implementing parity error detection on the BTAC and GHB RAMs, the
erratum is not expected to cause any significant issue because parity is likely to be enabled very
soon in the boot process.
Workarounds:
Because parity errors on the BTAC and GHB RAMs are not reported when the dynamic branch
prediction is not enabled, the workaround consists in enabling parity error detection (ACTLR[9]),
prior to enabling dynamic branch prediction (SCTLR[11]).
In systems where branch prediction is enabled while parity error detection remains disabled, the
workaround consists in ignoring any assertion on the PARITYFAIL[7:6] bits.
Proposed Solution:
No fix scheduled
Linux BSP Status:
Software workaround not needed in the BSP. Functionality or mode of operation in which the
erratum may manifest itself is not used. BSP ignores any assertion on the PARITYFAIL[7:6] bits
by masking the ARM -GIC parity interrupt 125.
Please note that the i.MX6 does not support the parity feature and hence should not be enabled.
ERR005187
ARM/MP: 771223—Parity errors on BTAC and GHB are reported on
PARITYFAIL[7:6], regardless of the Parity Enable bit value
