about SDRAM

[figoarzaki]

what is actually

dram_zq = 0x7b
dram_tpr0 = 0x42d899b7
dram_tpr1 = 0xa090
dram_tpr2 = 0x22a00
dram_tpr3 = 0x0
dram_tpr4 = 0x0
dram_tpr5 = 0x0
dram_emr1 = 0x0
dram_emr2 = 0x10
dram_emr3 = 0x0

did they are on datasheet?, if yes, which repositories is that, because i did'nt see em. If not, what is that and how we set it?,
if i use 1 RAM Chip (4Gb) what dram fex i should set?
did Allwinner A13 only support Hynix and Samsung RAM chip?, or we can use any ram chip from any manufacturer?