HI3520D uses 512M of RAM

The original memory of the board is 256m, feel too small, so switch to 512m chip, the manual is supported.

Confirm Chip Circuit

256M memory and 512M memory are 8 bank,10bit row addresses, different 256M is 14bit column address, 512M is 15bit column address
calculation method for 2^ (14+10) * 8 * 2 = 256M
2^ (15+10) * 8 * 2 = 5 12M

Note that multiplying by 2 is because the data line is 16bit, which means that each address space is 2Bytes

From the above you can see that 512M of memory than 256M more than one with the address line, so you need to check the circuit has not been properly connected.

Modify Uboot

Description: From the above, you can know that the most important thing to upgrade memory is to configure the address and pin, because more than one with the address line AH

Description: The official SDK for Uboot is provided by 2 parts, part of the initialization of basic registers, including but not limited to DDRC initialization. This part of the code (presumably 4800B) can be loaded into the in-chip RAM to execute, and then initialize the DDRC, while the external physical memory can be accessed happily. (Detailed mechanism I also is not very clear, so please welcome the Great God can feel free) compile uboot

This should be all right, ready Uboot.bin file

part of processing basic registers

Description here HiSilicon is using the Excel table to successfully bin file, open Uboot-hi3520d-bvt_no1_660_330_660_ddr_innerfephy.xls file, modify the inside 2 places:
  switch to Ddrc_init Table
      Ddrc_rnkcfg changed to 0x142 
      ddrc_timing1    
  to 0xff637a6a switch to Main Table  ->  Click Generate Reg Bin File
  Uboot.bin CP to the current directory, using the command:


./mkboot-hi3520d.sh Reg_info_hi3520d.bin Reg_info_hi3515a.bin U-boot-hi3520d-t16063003.bin 

 Generate Uboot ...

Follow-up work

In fact, there is nothing special to say in the back. TFTP burn write, start parameter settings, and test memory is not effective, etc., are very common.

PostScript

DDRC register a lot, is not easy to modify, from the Official SDK with Excel table to modify it can be seen, how to change the value of how to modify the register. I don't know about that either. ╮(╯3╰)╭
I learned from http://www.ebaina.com/bbs/thread-10333-1-1.html posts the value of the register to be changed.