Some question about AIE+PL

[kkenshin1]

Hi,

I notice your repo about controlling AIE through PL side rather than PS

From your code, I understand that the data_mover_mm2mm could choose different operating mode, it could not only transfer the data from ddr to bram, but also transfer the aie configuration through setting the ADDR_INT_OFFSET address

And I understand that when aie want to transfer configuration to aie, it will call PL_Write32 function, is it correct?

But I don't know when and where the function PL_Write32 in common.cpp would be called?

I also want to implement this function, to control the AIE without PS, and have so many questions, is there any docs to describe this working flow?

Thanks!

[nqdtan]

Hi @kkenshin1

Sorry for the late response. I missed the issue notification. Yes, your understanding is correct. PL_XXX functions defined in common.c are called under methods defined in XAie Debug Backend

https://github.com/nqdtan/embeddedsw/blob/aiev2_custom/XilinxProcessorIPLib/drivers/aienginev2/src/io_backend/ext/xaie_debug.c

Those IO methods are invoked by higher-level, more abstract XAie methods. The XAie API defines several IO backends to support different target platforms (e.g., bare-metal on ARM, linux on ARM, etc.), and you need to select your target backend when you compile libxaiengine. See here:

https://github.com/nqdtan/embeddedsw/blob/2203d9057b67b75719d2b26308af85278a2926e3/XilinxProcessorIPLib/drivers/aienginev2/src/io_backend/xaie_io.c#L32-L46

This corresponds to the flag EXTRA_CFLAGS += -D__AIE$(AIEBACKEND)__ in embeddedsw/XilinxProcessorIPLib/drivers/aienginev2/src/Makefile. If you follow Step 1 in General Setup, it will generate a libxaiengine with Debug as IO Backend, because we use Makefile.Linux in this case (Makefile compiles with Baremetal backend). Hence, the methods in xaie_debug will be called under the hood of the high-level XAie calls (DMA, Stream Switch configs, etc.). I modified xaie_debug a bit to invoke the PL_XXX methods for reading/writing AIE config data via the PL module data_mover, instead of printing out configuration data as it is originally intended. This is just a quick hack to make things work. A more proper way is to define a new backend for these new methods (e.g., PL backend).

I'm not sure if I will write more documentation for this repository in the near future, but feel free to let me know or follow up if you have any questions.