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i.mx6 memory dcd table only reporting 1/2 of memory in uboot/linux

Question asked by Dennis Muhlestein on Mar 26, 2019
Latest reply on Mar 26, 2019 by Dennis Muhlestein

This is a continuation of a couple other discussions:


1) Original problem booting custom board w/ dcd parameters.

i.mx6d pop dcd generation -> solution use updated script aid v1.3


Our memory configuration as input into the new script aid.


Device Information
Memory type:LPDDR2
Manufacturer:Micron - POP Package
Memory part number:EDB8164B4PT-1DAT-F-D
Density per chip select (Gb):4
Number of Chip Selects per channel used21
Number of Channels used22
DRAM density per channel (Gb)4
Total DRAM density (Gb)8
Number of ROW Addresses214
Number of COLUMN Addresses210
Number of BANKS28
Bus Width (input 16, 32, or 64 bits)232
Clock Cycle Freq (MHz)3400
Clock Cycle Time (ns)2.5


4Gb per channel X 2 Channels = 8Gb total. (1GiB)


This boots successfully in uboot/linux but the total ram reported available to the operating system is 512MiB instead of 1GiB.


I'm considering that maybe I misunderstood the data sheet and mixed up number of channels/chip selects or density but other combinations don't boot the device at all.


Any suggestions of where to look.  I don't know if this is a script aid error or a mis-configuration or if there is an additional step we need to be taking after boot to make available all memory.


Note: the ddr stress test tool can see 1GiB of memory and calibrate it.