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).