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rshal2's avatar
rshal2
Icon for Occasional Contributor rankOccasional Contributor
6 years ago
Solved

When do we need to customize preloader?

Hello, The general scheme of building preloader is composed of: handoff -> preloader config + u-boot-spl source code -> binary So it is usually "automatic" build without any customization. Yet, ...
  • EBERLAZARE_I_Intel's avatar
    EBERLAZARE_I_Intel
    6 years ago

    Hi ranran,

    Here is an example; for enabling HPS-to-FPGA Bridges from the preloader, the preloader will check the status of the FPGA then automatically enables bridges that are configured in Qsys/platform designer (Standard) and the BSP if the FPGA is configured.

    For more information, I reckon you refer to GSRD v13.1 - Programming FPGA from HPS.

    Regards.

EBERLAZARE_I_Intel's avatar
EBERLAZARE_I_Intel
Icon for Regular Contributor rankRegular Contributor
6 years ago

Hi,

Apologize for that, here is an updated version doc that could guide you thoroughly:

https://rocketboards.org/foswiki/Documentation/AVCVGSRDLTS

Jump straight to Cyclone V Getting Started Guides.

The answer to your question is that, that FPGA can be configure from uboot by using an .rbf image. I suggest you run through the guides in the above link.

It means that if you decide to have hardware utilizing the bridges between HPS and FPGA, then the command is need to enable the bridges. Again I highly recommend that you check out the above guidelines which might help you.

Regards.

rshal2's avatar
rshal2
Icon for Occasional Contributor rankOccasional Contributor
6 years ago

Hello,

I have followed this guide.

Yet, I don't understand the issue of enabling bridge:

From the reading I assumed that preloader enables the bridge.

So, I don't understand why this command is needed.

Also note that some system run baremetal application immediately after preloader (no u-boot in the middle).

In those cases there is no such u-boot command.

I still haven't find from this document why we need to enable bridge if they are already enabled.

Thank you for the time,

ran