Why RPMSG size is changed on A9 core in latest BSP imx-5.4.24-2.1.0.xml from 0x8000 to 0x10000 ?

[rakesh_patel]

Old BSP with kernel 4.1.15

============

&rpmsg{
compatible = "fsl,imx6sx-rpmsg";
reg = <0x9FFF0000 0x8000>;
status = "okay";
};

New BSP with kernel 5.4

============

&rpmsg{
vdev-nums = <1>;
compatible = "fsl,imx6sx-rpmsg";
reg = <0x9FFF0000 0x10000>;
status = "okay";
};

Query:

================

1) Why RPMSG size change on A9 core only? Does it not required on M4 side as well?

2) What is the calculation to change size from 0x8000 to 0x10000?

[igorpadykov]

Hi rakesh_patel

size may affect transfer rate from M4 to A7. For changes one can refer  to:

https://developer.toradex.com/knowledge-base/freertos-on-the-cortex-m4-of-a-colibri-imx7#Change_RPms...

https://www.toradex.com/community/questions/35761/how-to-change-the-size-of-rpmsg-buffer.html?childT...

Best regards
igor

[rakesh_patel]

@igorpadykov :

Thanks for sharing the open-forum links.

But, I want some useful information from NXP's documents for changing size in A9 core in new BSP and no change in M4 side.

Please do needful for the same.

[igorpadykov · Accepted solution]

Hi rakesh_patel

usually for bsp changes no additional documents provided except on official nxp linux link:

https://www.nxp.com/design/software/embedded-software/i-mx-software/embedded-linux-for-i-mx-applicat...

Also nxp official L4.1.15 bsp (from codeaurora.org/external/imx/linux-imx repository) has not such entry :

https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm/boot/dts/imx6sx-sdb-m4.dts?h=imx_...

Old BSP with kernel 4.1.15

============

&rpmsg{
compatible = "fsl,imx6sx-rpmsg";
reg = <0x9FFF0000 0x8000>;
status = "okay";
};

Best regards
igor