RTOS/AM5726: Using L3 shared memory to share data between ARM, DSP and M4

Tool/software: TI-RTOS

Hi, 

We are currently investigating using the Sitara AM5726 in one of our products. Right now, I am testing different audio codecs performance on the DSP. The ARM (which is running Linux) is sending encode/decode request to the DSP cores using IPC MessageQ. The ARM allocates a CMEM shared region that is used by both the ARM and the DSP to share the audio data (encoded or PCM). 

Now, that CMEM region is currently in DDR. I would like to put that CMEM region in the L3 shared memory (OCMC). 

I see in the am57xx-evm-cmem.dtsi that we do have a CMEM block region in OCMC3 :

/ {
        reserved-memory {
                #address-cells = <2>;
                #size-cells = <2>;
                ranges;

                cmem_block_mem_0: cmem_block_mem@a0000000 {
                        reg = <0x0 0xa0000000 0x0 0x0c000000>;
                        no-map;
                        status = "okay";
                };

		cmem_block_mem_1_ocmc3: cmem_block_mem@40500000 {
			reg = <0x0 0x40500000 0x0 0x100000>;
			no-map;
			status = "okay";
		};
        };

        cmem {
                compatible = "ti,cmem";
                #address-cells = <1>;
                #size-cells = <0>;

		#pool-size-cells = <2>;

                status = "okay";

                cmem_block_0: cmem_block@0 {
                        reg = <0>;
                        memory-region = <&cmem_block_mem_0>;
                        cmem-buf-pools = <1 0x0 0x0c000000>;
                };

		cmem_block_1: cmem_block@1 {
			reg = <1>;
			memory-region = <&cmem_block_mem_1_ocmc3>;
		};
        };

However, I can't seem to allocate in CMEM block 1.

Can this be done? Or is this block already in use by another part in the system?

Regards,

- David