Re: [PATCH 09/21] hw/arm/fsl-imx8mp: Add PCIe support

[Peter Maydell]

On Mon, 20 Jan 2025 at 20:38, Bernhard Beschow <shentey@gmail.com> wrote:
>
> Linux checks for the PLLs in the PHY to be locked, so implement a model
> emulating that.
>
> Signed-off-by: Bernhard Beschow <shentey@gmail.com>

> diff --git a/docs/system/arm/imx8mp-evk.rst b/docs/system/arm/imx8mp-evk.rst
> index 1514bc5864..8d48580cb4 100644
> --- a/docs/system/arm/imx8mp-evk.rst
> +++ b/docs/system/arm/imx8mp-evk.rst
> @@ -14,6 +14,7 @@ The ``imx8mp-evk`` machine implements the following devices:
>   * Generic Interrupt Controller (GICv3)
>   * 4 UARTs
>   * 3 USDHC Storage Controllers
> + * 1 Designware PCI Express Controller
>   * Secure Non-Volatile Storage (SNVS) including an RTC
>   * Clock Tree
>
> @@ -62,3 +63,15 @@ Now that everything is prepared the newly built image can 
> be run in the QEMU
>        -dtb imx8mp-evk-patched.dtb \
>        -append "root=/dev/mmcblk2p2" \
>        -drive file=sdcard.img,if=sd,bus=2,format=raw,id=mmcblk2
> +
> +Using PCI Devices
> +-----------------
> +
> +The PCI Express controller spawns two PCI buses, of which only one can be 
> used.
> +By default QEMU assigns the wrong bus, so the correct one has to be specified
> +manually by adding ``bus=dw-pcie``. For example, when adding an Intel e1000
> +network card, the command line looks like:
> +
> +.. code-block:: bash
> +
> +  $ qemu-system-aarch64 -M imximp-evk ... -device virtio-net-pci,bus=dw-pcie

Why does this happen? Isn't there some way to make QEMU default to
using the right bus? Otherwise there's likely to be a lot of
user confusion because PCI "doesn't work"...

thanks
-- PMM