How to increase DDR on B4860QDS to 6G?

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How to increase DDR on B4860QDS to 6G?

981 Views
jorhai
Contributor II

I found that there are two DDR3 controler in B4860QDS. Ten DDR parts on DDRC1 are arranged in two rank of 4GB with ECC. The second DDR controller DDRC2 has 2GB memory in five DDR3 parts including ECC. So there is 6GB DDR available in B4860QDS. Howerver, Only 4GB DDR used in SDK1.6, DDRC1 is used by DSP side and DDRC2 is used by PA side, but 2GB DDR is unmapped.

However, We have to distribute 256M HUGEPAGE memory for IPC and 256M for USDPAA DMA memory, and the ramdisk filesystem will aslo take almost 150M memory.

By accounting for these factors, we could only have 1.3G memory for our linux software.

How to increase the memory on PA side by using the unmapped DDR ?

3 Replies

802 Views
lunminliang
NXP Employee
NXP Employee

Hello sf dong

I am afraid it's not safe to change this in SPD.

Currently Linux kernel o B4860QDS SDK1.6 is using 4G memory on PA side, not 2G, u-boot uses only 2G memory. Actually on all our platforms SDK supports, the u-boot only maps 2G memory.

root@b4860qds:~# cat /proc/meminfo

MemTotal: 4064100 kB

MemFree: 3878576 kB

So there's no problem. Do you see any error report?


Have a great day,
Lunmin

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802 Views
Bulat
NXP Employee
NXP Employee

The problem is with SPD of the DDRC1, it defines the size of the memory to be 2GB instead of 4GB. Uboot sets up the memory based on this SPD data.

You can try to change SPD content. Required parameter is located at the I2C EEPROM with bus address 0x51. Within the EEPROM you need to change 0x4 address location from 0x3 (corresponds to 2Gb device configuration) to 0x4 (corresponds to 4Gb device configuration).

Note also that CRC of the SPD will be corrupted, however uboot can hint at correct CRC value.

Regards,

Bulat

802 Views
jorhai
Contributor II

Thanks Bulat,I will try as you said.

But, I am also confused by the memory map.

need I change the memory map of the whole PA and DSP's DDR, and how to change memory map?

Thanks again.

Regards,

Dongsf

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