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diff --git a/doc/README.mpc83xx.ddrecc b/doc/README.mpc83xx.ddrecc new file mode 100644 index 0000000..0029f08 --- /dev/null +++ b/doc/README.mpc83xx.ddrecc @@ -0,0 +1,154 @@ +Overview +======== + +The overall usage pattern for ECC diagnostic commands is the following: + + * (injecting errors is initially disabled) + + * define inject mask (which tells the DDR controller what type of errors + we'll be injecting: single/multiple bit etc.) + + * enable injecting errors - from now on the controller injects errors as + indicated in the inject mask + +IMPORTANT NOTICE: enabling injecting multiple-bit errors is potentially +dangerous as such errors are NOT corrected by the controller. Therefore caution +should be taken when enabling the injection of multiple-bit errors: it is only +safe when used on a carefully selected memory area and used under control of +the 'ecc testdw' 'ecc testword' command (see example 'Injecting Multiple-Bit +Errors' below). In particular, when you simply set the multiple-bit errors in +inject mask and enable injection, U-Boot is very likely to hang quickly as the +errors will be injected when it accesses its code, data etc. + + +Use cases for DDR 'ecc' command: +================================ + +Before executing particular tests reset target board or clear status registers: + +=> ecc captureclear +=> ecc errdetectclr all +=> ecc sbecnt 0 + + +Injecting Single-Bit Errors +--------------------------- + +1. Set 1 bit in Data Path Error Inject Mask + +=> ecc injectdatahi 1 + +2. Run test over some memory region + +=> ecc testdw 200000 10 + +3. Check ECC status + +=> ecc status +... +Memory Data Path Error Injection Mask High/Low: 00000001 00000000 +... +Memory Single-Bit Error Management (0..255): + Single-Bit Error Threshold: 255 + Single Bit Error Counter: 16 +... +Memory Error Detect: + Multiple Memory Errors: 0 + Multiple-Bit Error: 0 + Single-Bit Error: 0 +... + +16 errors were generated, Single-Bit Error flag was not set as Single Bit Error +Counter did not reach Single-Bit Error Threshold. + +4. Make sure used memory region got re-initialized with 0x0123456789abcdef + +=> md 200000 +00200000: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200010: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200020: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200030: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200040: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200050: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200060: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200070: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200080: deadbeef deadbeef deadbeef deadbeef ................ +00200090: deadbeef deadbeef deadbeef deadbeef ................ + +Injecting Multiple-Bit Errors +----------------------------- + +1. Set more than 1 bit in Data Path Error Inject Mask + +=> ecc injectdatahi 1 +=> ecc injectdatalo 1 + +2. Run test over some memory region + +=> ecc testword 200000 1 + +3. Check ECC status + +=> ecc status +... +Memory Data Path Error Injection Mask High/Low: 00000001 00000001 +... +Memory Error Detect: + Multiple Memory Errors: 0 + Multiple-Bit Error: 1 + Single-Bit Error: 0 +... + +The Multiple Memory Errors flags not set and Multiple-Bit Error flags are set. + +4. Make sure used memory region got re-initialized with 0x0123456789abcdef + +=> md 200000 +00200000: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200010: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200020: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200030: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200040: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200050: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200060: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200070: 01234567 89abcdef 01234567 89abcdef .#Eg.....#Eg.... +00200080: deadbeef deadbeef deadbeef deadbeef ................ +00200090: deadbeef deadbeef deadbeef deadbeef ................ + + +Test Single-Bit Error Counter and Threshold +------------------------------------------- + +1. Set 1 bit in Data Path Error Inject Mask + +=> ecc injectdatahi 1 + +2. Enable error injection + +=> ecc inject en + +3. Let u-boot run for a with Single-Bit error injection enabled + +4. Disable error injection + +=> ecc inject dis + +4. Check status + +=> ecc status + +... +Memory Single-Bit Error Management (0..255): + Single-Bit Error Threshold: 255 + Single Bit Error Counter: 199 + +Memory Error Detect: + Multiple Memory Errors: 1 + Multiple-Bit Error: 0 + Single-Bit Error: 1 +... + +Observe that Single-Bit Error is 'on' which means that Single-Bit Error Counter +reached Single-Bit Error Threshold. Multiple Memory Errors bit is also 'on', that +is Counter reached Threshold more than one time (it wraps back after reaching +Threshold). |