Re: [PATCH v2] ArmPkg/PlatformBootManagerLib: connect non-discoverable USB hosts

["Laszlo Ersek" <lersek@redhat.com>]

On 05/22/20 10:40, Ard Biesheuvel wrote:
> The way the BDS handles the short-form USB device path of the console
> keyboard relies on USB host controllers to be locatable via their PCI
> metadata, which implies that these controllers already have a PCI I/O
> protocol installed on their handle.
> 
> This is not the case for non-discoverable USB host controllers that are
> supported by the NonDiscoverable PCI device driver. These controllers
> must be connected first, or the BDS will never notice their existence,
> and will not enable any USB keyboards connected through them.
> 
> Let's work around this by connecting these handles explicitly. This is
> a bit of a stopgap, but it is the cleanest way of dealing with this
> without violating the UEFI driver model entirely. This ensures that
> platforms that do not rely on ConnectAll() will keep working as
> expected.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
> ---
> 
> This is tagged as v2 since it is a followup to
> 
>   'MdeModulePkg/NonDiscoverablePciDeviceDxe: connect handles on registration'
> 
> that I sent out yesterday. Laslzo made the point that it would be
> unfortunate to add yet another hack that defeats the UEFI driver model
> entirely, so this time, the change is in the BDS where it belongs.
> 
> Note that only USB console devices are affected by this: short form
> block IO device paths used for booting are expanded and cached in a
> "HDDP" variable, and so they work as expected with fast boot without
> connect all.
> 
>  ArmPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf |  4 ++
>  ArmPkg/Library/PlatformBootManagerLib/PlatformBm.c               | 42 ++++++++++++++++++++
>  2 files changed, 46 insertions(+)
> 
> diff --git a/ArmPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf b/ArmPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
> index 87c9b1150c54..2f726d117d7d 100644
> --- a/ArmPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
> +++ b/ArmPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
> @@ -66,6 +66,9 @@ [Pcd]
>    gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut
>  
>  [Guids]
> +  gEdkiiNonDiscoverableEhciDeviceGuid
> +  gEdkiiNonDiscoverableUhciDeviceGuid
> +  gEdkiiNonDiscoverableXhciDeviceGuid
>    gEfiFileInfoGuid
>    gEfiFileSystemInfoGuid
>    gEfiFileSystemVolumeLabelInfoIdGuid
> @@ -74,6 +77,7 @@ [Guids]
>    gUefiShellFileGuid
>  
>  [Protocols]
> +  gEdkiiNonDiscoverableDeviceProtocolGuid
>    gEfiDevicePathProtocolGuid
>    gEfiGraphicsOutputProtocolGuid
>    gEfiLoadedImageProtocolGuid
> diff --git a/ArmPkg/Library/PlatformBootManagerLib/PlatformBm.c b/ArmPkg/Library/PlatformBootManagerLib/PlatformBm.c
> index 3411219fbfdb..4aca1382b042 100644
> --- a/ArmPkg/Library/PlatformBootManagerLib/PlatformBm.c
> +++ b/ArmPkg/Library/PlatformBootManagerLib/PlatformBm.c
> @@ -23,10 +23,12 @@
>  #include <Protocol/EsrtManagement.h>
>  #include <Protocol/GraphicsOutput.h>
>  #include <Protocol/LoadedImage.h>
> +#include <Protocol/NonDiscoverableDevice.h>
>  #include <Protocol/PciIo.h>
>  #include <Protocol/PciRootBridgeIo.h>
>  #include <Protocol/PlatformBootManager.h>
>  #include <Guid/EventGroup.h>
> +#include <Guid/NonDiscoverableDevice.h>
>  #include <Guid/TtyTerm.h>
>  #include <Guid/SerialPortLibVendor.h>
>  
> @@ -254,6 +256,37 @@ IsPciDisplay (
>  }
>  
>  
> +/**
> +  This FILTER_FUNCTION checks if a handle corresponds to a non-discoverable
> +  USB host controller.
> +**/
> +STATIC
> +BOOLEAN
> +EFIAPI
> +IsUsbHost (
> +  IN EFI_HANDLE   Handle,
> +  IN CONST CHAR16 *ReportText
> +  )
> +{
> +  NON_DISCOVERABLE_DEVICE   *Device;
> +  EFI_STATUS                Status;
> +
> +  Status = gBS->HandleProtocol (Handle,
> +                  &gEdkiiNonDiscoverableDeviceProtocolGuid,
> +                  (VOID **)&Device);
> +  if (EFI_ERROR (Status)) {
> +    return FALSE;
> +  }
> +
> +  if (CompareGuid (Device->Type, &gEdkiiNonDiscoverableUhciDeviceGuid) ||
> +      CompareGuid (Device->Type, &gEdkiiNonDiscoverableEhciDeviceGuid) ||
> +      CompareGuid (Device->Type, &gEdkiiNonDiscoverableXhciDeviceGuid)) {
> +    return TRUE;
> +  }
> +  return FALSE;
> +}
> +
> +
>  /**
>    This CALLBACK_FUNCTION attempts to connect a handle non-recursively, asking
>    the matching driver to produce all first-level child handles.
> @@ -574,6 +607,15 @@ PlatformBootManagerBeforeConsole (
>    //
>    FilterAndProcess (&gEfiGraphicsOutputProtocolGuid, NULL, AddOutput);
>  
> +  //
> +  // The core BDS code connects short-form USB device paths by explicitly
> +  // looking for handles with PCI I/O installed, and checking the PCI class
> +  // code whether it matches the one for a USB host controller. This means
> +  // non-discoverable USB host controllers need to have the non-discoverable
> +  // PCI driver attached first.
> +  //
> +  FilterAndProcess (&gEdkiiNonDiscoverableDeviceProtocolGuid, IsUsbHost, Connect);
> +
>    //
>    // Add the hardcoded short-form USB keyboard device path to ConIn.
>    //
> 

Awesome! So we don't mind the full proto stack on these handles, as long
as "these handles" means exactly the small set we want.

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Thanks!
Laszlo