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Registered: ‎02-12-2011

Supporting SRAM in Xilinx Linux

For a class, I've been working on trying to get Xilinx Linux up and working on MicroBlaze for an already built custom board with a Virtex-4 (XC4VLX40-12FF1148).  The board has an asynchronous SRAM module built into it that I want to use for system memory.


Right now I am trying to use the XPS_MCH_EMC driver to access it.


When generating the DTS file I get the following error. 


WARNING:MDT - : Bank 0 of EMC core sram_emc is used in asynchronous mode.  We

   assume this core is connected to a flash memory, although in some older

   designs this configuration may have been used to interface to a peripheral. 

   Current design recommendations suggest using an EPC core to interface to such


IP connected to bus: 

ERROR:MDT - device-tree () - No memory nodes found!

       while executing

   "error "No memory nodes found!""

       (procedure "gen_memories" line 134)

       invoked from within

   "gen_memories $toplevel $hwproc_handle"

       (procedure "generate_device_tree" line 154)

       invoked from within

   "generate_device_tree "xilinx.dts" $bootargs $consoleip"

       (procedure "::sw_device-tree_v0_00_x::generate" line 13)

       invoked from within

   "::sw_device-tree_v0_00_x::generate 38002400"  


Looking at gen_memories in the device-tree_v2_1_0.tcl file I can see the exact line where it is ignoring my memory module because it is asynchronous (and therefore assumed to be flash).


The warning above the error suggests I should interface with the SRAM using the EPC, but the I can see that the script file doesn't even look at EPC controllers as memory.  According to this post, I guess I should try and hack a DTS file by hand, but the task seems a little daunting.


I was wondering if instead it would be ok to hack the device-tree script to allow using the MCH EMC core asynchronously instead.


Are there any issues that might pop up if I were to try and do this?



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2 Replies
Registered: ‎02-12-2011

Sorry, I meant to mention that we still are using version 10.1 of the toolset.


Actually, now that I think of it, is the DTS generator even supposed to be compatible with 10.1?


Thanks again!

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Xilinx Employee
Xilinx Employee
Registered: ‎09-10-2008

Sorry for the delayed response.


You shouldn't even need a driver for SRAM I would think.



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