[U-Boot] how to trigger DM rescan ?

[Hannes Schmelzer]

Hello,

i've following trouble on a new custom zynq board:

There is a axi4pcie root-complex implemented within the FPGA, i added 
this to my devicetree:

     pci_express: axi-pcie at 90000000 {
         #address-cells = <3>;
         #size-cells = <2>;
         #interrupt-cells = <1>;
         status = "disabled";
         compatible = "xlnx,axi-pcie-host-1.00.a";
         reg = < 0x90000000 0x1000000 >;
         device_type = "pci";
         interrupts = < 0 116 4 >;
         interrupt-map-mask = <0 0 0 7>;
         interrupt-map = <0 0 0 1 &pcie_intc 1>,
                 <0 0 0 2 &pcie_intc 2>,
                 <0 0 0 3 &pcie_intc 3>,
                 <0 0 0 4 &pcie_intc 4>;
         ranges = < 0x02000000 0 0x80000000 0x80000000 0 0x10000000 >;

         pcie_intc: interrupt-controller {
             interrupt-controller;
             #address-cells = <0>;
             #interrupt-cells = <1>;
         };
     };

As you can see the node is "disabled". For me this makes sense since 
during very first come up of u-boot the FPGA is not configured yet and 
the registers of the root-complex aren't accessible.
Later on, during "board_init(...)" i bring up the FPGA (load bitstream 
from spi flash into FPGA) and set the fdt-node property status to "okay".

Trouble is that dm-scan, probe, ... is already done at this point and 
the root-complex is left ofter uninitialized and is not in the dm-tree 
at all (since it was disabled through first scan).

=> dm tree
  Class       Probed   Name
----------------------------------------
  root        [ + ]    root_driver
  simple_bus  [ + ]    `-- amba
  gpio        [ + ]        |-- gpio at e000a000
  i2c         [   ]        |-- i2c at e0004000
  i2c         [ + ]        |-- i2c at e0005000
  i2c_generic [ + ]        |   `-- generic_60
  serial      [ + ]        |-- serial at e0000000
  serial      [   ]        |-- serial at e0001000
  spi         [ + ]        |-- spi at e000d000
  spi_flash   [ + ]        |   `-- spiflash at 0
  eth         [   ]        |-- ethernet at e000b000
  mmc         [ + ]        |-- sdhci at e0100000
  blk         [   ]        |   `-- sdhci at e0100000.blk
  mmc         [ + ]        |-- sdhci at e0101000
  blk         [   ]        |   `-- sdhci at e0101000.blk
  simple_bus  [   ]        |-- slcr at f8000000
  usb         [   ]        `-- usb at e0003000
=>

Is there a possibility to trigger a dm-scan after bringing up such new 
devices ?
Or is it the wrong way having the node "disabled" first and enabled it 
later ? are there better ways to prevent accessing not yet ready devices 
from access ?

many thanks for your help and
best regards,
Hannes