[U-Boot] how to trigger DM rescan ?

[Simon Glass]

Hi Hannes,

On 13 February 2017 at 05:53, Hannes Schmelzer <hannes at schmelzer.or.at> wrote:
>
> Hi Simon,
>
> forwarding this directly to you since nobody did response on the mailinglist.
> Maybe you have some suggestion to me.

Yes, I tend to notice things that are cc'd to me :-)

>
> many thanks,
> Hannes
>
>
>
> -------- Forwarded Message --------
> Subject: how to trigger DM rescan ?
> Date: Wed, 8 Feb 2017 08:05:31 +0100
> From: Hannes Schmelzer <hannes at schmelzer.or.at>
> To: u-boot at lists.denx.de <u-boot at lists.denx.de>
>
>
> 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 ?

You can call lists_bind_fdt() to handle this manually. Perhaps we
should have a function like dm_node_enable() ?

>
> many thanks for your help and
> best regards,
> Hannes
>
>
>

Regards,
Simon