Help me in understanding of memory node in device tree

pavan krishna

Hi All,

In device tree of beagle bone black ti sdk-8 OS, could you please help me in understanding of below memory node

    memory {
        device_type = "memory";
        reg = <0x80000000 0x10000000>; /* 256 MB */

    };

In beagle bone black we are using 512MB of external DDR3, but if you see in the above configuration it saying 256 MB. Is this correct?

In our custom board we replaced with "MT41K128M16JT-125:K" DDR3 which is of 256MB of size, so what should I configure for this DDR3?

I referred so many docs, but I couldn't able to get success, so please kindly help me.

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

I will forward this to the SW team.

0 pavan krishna over 8 years ago in reply to Biser Gatchev-XID

Expert 1010 points

Thank you J,
Please

0 Yordan Kovachev over 8 years ago

TI__Guru**** 161600 points

Hi Pavan,

The following link describes the memory dts node:
android.googlesource.com/.../memory.txt

Hope this helps.

Best Regards,
Yordan

0 pavan krishna over 8 years ago in reply to Yordan Kovachev

Expert 1010 points

Thank you for your reply,

So as per the link "reg = <0x80000000 0x10000000>; /* 256 MB */", second cell should be of 512 MB instead of 256MB, am I correct? Since the DDR3 what ever we are using in beagle bone back is of 512 MB size.

Please clarify.

Thank you

0 Matthijs van Duin over 8 years ago

Mastermind 8020 points

The value is ignored, you can in fact delete the /memory node entirely: it is populated by u-boot.

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Help me in understanding of memory node in device tree