S32G3 DDR size change

[FlaviuNistor]

Hello,

I need to change to DDR size from the default 4G to 2G for a custom ECU using S32g3. For BSP 46.00 I know this is part of the BL2 (TFA) and there a is chapter in the BSP user manual, BUT...

the steps described there are "manual", meaning the TFA should be build as an independent binary.

I am using Yocto with BSP46.00 and took as a start reference s32g399aevb3. I have created my own custom MACHINE and meta layer and can successfully do the bitbake and run the image on the EVB (still 4G as original MACHINE).

Now I want to integrate the DDR size change (4G -> 2G) in my Yocto flow. For now I am thinking to add the new ddr files as a patch in a bbapend for TFA recipe, but the issue is that Yocto build will fail if NXP_FIRMWARE_LOCAL_DIR is not provided.

My questions are:

1. Is the "manual" option the only one (I hope not)?

2. Is my intended approach correct?

3. If using a patch for TFA (or even pointing to a local repo) in the bbapend, how can I avoid the build fail caused by removing NXP_FIRMWARE_LOCAL_DIR? I expect that I can't create my own binaries and also makes no sense to have my changes for ddr and also the ddr_firmware intended for the EVB (that is why I need to remove NXP_FIRMWARE_LOCAL_DIR).

[chenyin_h]

Hello, @FlaviuNistor 

Thanks for your post.

1. The DDR_FW_BIN_PATH parameter must be set to specify the path to the NXP board-specific DDR firmware binary file, so it is only for building images for NXP board(RDB, EVB, etc.)

2. For building TFA for custom board, it is suggested using the  CUSTOM_DDR_DRV parameter for make. It must be set to a path (relative to the TF-A root folder) where all the DDR source and header files are, in the state they were generated by DDR Tool.

3. Once the TFA could be build correctly, you may make the changes to the Yocto accordingly to have further test.

I hope it will help.

BR

Chenyin

[FlaviuNistor]

Hello Chenyin,

1. This is clear now.
2. Since I do not have yet some generated custom files, can you please provide the needed files for the NXP EVB board (S32G-VNP-EVB) so I can test my build flow?
3. A bbappend for arm-trusted-firmware containing: EXTRA_OEMAKE:append:s32g = " CUSTOM_DDR_DRV=$(realpath --relative-to=${S} $(pwd)/../../../../../../../linuxbsp_ddr_config)" should be the right solution.

As a new question:
4. If I have to change the DDR size, do I have to also modify something in U-boot or is the TFA change enough?

[chenyin_h]

Hello, @FlaviuNistor 

Thanks for your reply.

1. Sorry that I do not have such files for EVB, you may try generating them via DDR tools with your EVB.

2. Let me summarize the possible steps:

a. Connect your custom board with PC, and run ddr tools to generate corresponding files

b. Once generated, copy all the files generated to  your TFA code base.

c. Try building it with CUSTOM_DDR_DRV=$(Generated_Code)

3. There may also be modifications needed for U-boot to run the BSP code correctly on your custom board.

BR

Chenyin