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mqx uncached mem alloc

Question asked by johannesstuttner on Feb 8, 2016
Latest reply on Feb 29, 2016 by johannesstuttner

Hi,

 

for using the DMA mapped TDSR Register (pointer to Buffer desc start)  for Enet useage, the Buffer Descriptor Data must be stored in the uncached address space. right? Mapping an normal allocated struct with _mem_alloc_align() function kills the Enet controler and terminates with an EBERR interrupt. I assumed that this is a caching problem, because the DMA has no access to the virtual address space allocated by MQX.

 

So now how can I allocate uncached adressspace in MQX? The function _mem_alloc_asign_uncached() returns the same address like _mem_alloc_asign(). Now when I enable MQX_USE_UNCACHED_MEM in the user_cnfg.h to support the uncached memory functions the compiler terminates with the Error:

/home/nexus/imx6solox/mqx/mcc/examples/pingpong/mcc.c:398: undefined reference to `_mem_alloc_align_uncached'

 

is there no uncached memory support in the MQX release for the imx6SX?

 

greets

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