F2H Avalon Bridge f2h_sdram0_data_waitrequest got stuck

Well, I found something functional so far.

First, I have deactivated the fpga2sdram bridge in the device tree loaded with linux.

        fpgabridge1: fpgabridge@0xffc25080 {
            compatible = "altr,socfpga-fpga2sdram-bridge";
            reg = <0xffc25080 0x4>;
            bridge-enable = <0>;
        };

Then once in userland :

1- I force the fpga2sdram driver to unbind

echo -n "ffc25080.fpgabridge" > /sys/devices/platform/soc/ffc25080.fpgabridge/subsystem/drivers/altera_fpga2sdram_bridge/unbind

2- I load the FPGA with the device tree overlay method.

In the overlay, there is a fragment to enable the fpga2sdram bridge

        fragment@1 { 
            target = <&fpgabridge1>;
            __overlay__ { 
                bridge-enable = <1>;
            };
        };

3- I rebind the fpga2sdram driver

echo -n "ffc25080.fpgabridge" > /sys/devices/platform/soc/ffc25080.fpgabridge/subsystem/drivers/altera_fpga2sdram_bridge/bind

With this, I haven't see any issues anymore. I just hope it will last.