Call to switch_demux_using_fabric_ip() causes SDCARD boot issue for minimalistic FPGA design (MSS + Clocks only).

[ChrRudel]

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The switch_demux_using_fabric_ip() function always gets called at boot time inside the mmc_init_sdcard() function.
This creates a problem for boards which do not feature an external switch. The FPGA design also does not contain additional fabric logic to control it.

We observe a problem on the Discovery Kit when using a minimalistic FPGA design (FIC_3_PERIPHERALS_0 and FIC_0_PERIPHERALS_0 removed from the reference design).
With that design change the board would not boot from SD Card.
The HSS Boot is stuck at "Attempting to select SDCARD ..." and HSS is stuck in an endless restart cycle.

Commenting out Line #168 in hart-software-services/services/mmc/mmc_api.c resolved the problem and SDCARD boot is working again for that board+fpga design combination.

Please make sure to add all the information needed to understand the bug so that someone can help. If the info is missing we'll add the 'Needs more information' label and close the issue until there is enough information.

• Provide a minimal code snippet example that reproduces the bug where appropriate.
• Provide screenshots where appropriate
• Does this occur all of the time or is it intermittent? All the time
• Have you tried on another board? Tested on Two boards.

"MSS Only" FPGA Design (FIC_0_ / FIC_3_PERIPHERAL removed from 2024.04 MPFS-DISCO-KIT Refdesign):