can: flexcan: initialize all flexcan memory for ECC function
One issue was reported at a baremetal environment, which is used for FPGA verification. "The first transfer will fail for extended ID format(for both 2.0B and FD format), following frames can be transmitted and received successfully for extended format, and standard format don't have this issue. This issue occurred randomly with high possiblity, when it occurs, the transmitter will detect a BIT1 error, the receiver a CRC error. According to the spec, a non-correctable error may cause this transfer failure." With FLEXCAN_QUIRK_DISABLE_MECR quirk, it supports correctable errors, disable non-correctable errors interrupt and freeze mode. Platform has ECC hardware support, but select this quirk, this issue may not come to light. Initialize all FlexCAN memory before accessing them, at least it can avoid non-correctable errors detected due to memory uninitialized. The internal region can't be initialized when the hardware doesn't support ECC. According to IMX8MPRM, Rev.C, 04/2020. There is a NOTE at the section 11.8.3.13 Detection and correction of memory errors: "All FlexCAN memory must be initialized before starting its operation in order to have the parity bits in memory properly updated. CTRL2[WRMFRZ] grants write access to all memory positions that require initialization, ranging from 0x080 to 0xADF and from 0xF28 to 0xFFF when the CAN FD feature is enabled. The RXMGMASK, RX14MASK, RX15MASK, and RXFGMASK registers need to be initialized as well. MCR[RFEN] must not be set during memory initialization." Memory range from 0x080 to 0xADF, there are reserved memory (unimplemented by hardware, e.g. only configure 64 MBs), these memory can be initialized or not. In this patch, initialize all flexcan memory which includes reserved memory. In this patch, create FLEXCAN_QUIRK_SUPPORT_ECC for platforms which has ECC feature. If you have a ECC platform in your hand, please select this qurik to initialize all flexcan memory firstly, then you can select FLEXCAN_QUIRK_DISABLE_MECR to only enable correctable errors. Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com> Link: https://lore.kernel.org/r/20200929211557.14153-2-qiangqing.zhang@nxp.com [mkl: wrap long lines] Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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