[PATCH 2/2] efi_loader: fix device-path for USB devices

[Simon Glass]

Hi Heinrich,

On Wed, 22 Mar 2023 at 02:21, Heinrich Schuchardt
<heinrich.schuchardt at canonical.com> wrote:
>
> On 3/20/23 19:39, Simon Glass wrote:
> > Hi Heinrich,
> >
> > On Mon, 20 Mar 2023 at 09:58, Heinrich Schuchardt
> > <heinrich.schuchardt at canonical.com> wrote:
> >>
> >>
> >>
> >> On 3/19/23 20:29, Simon Glass wrote:
> >>> Hi Heinrich,
> >>>
> >>> On Mon, 20 Mar 2023 at 04:25, Heinrich Schuchardt
> >>> <heinrich.schuchardt at canonical.com> wrote:
> >>>>
> >>>> EFI device paths for block devices must be unique. If a non-unique device
> >>>> path is discovered, probing of the block device fails.
> >>>>
> >>>> Currently we use UsbClass() device path nodes. As multiple devices may
> >>>> have the same vendor and product id these are non-unique. Instead we
> >>>> should use Usb() device path nodes. They include the USB port on the
> >>>> parent hub. Hence they are unique.
> >>>>
> >>>> A USB storage device may contain multiple logical units. These can be
> >>>> modeled as Ctrl() nodes.
> >>>>
> >>>> Reported-by: Patrick Delaunay <patrick.delaunay at foss.st.com>
> >>>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> >>>> ---
> >>>>    lib/efi_loader/efi_device_path.c | 45 +++++++++++++++++++++++---------
> >>>>    1 file changed, 33 insertions(+), 12 deletions(-)
> >>>
> >>> Reviewed-by: Simon Glass <sjg at chromium.org>
> >>>
> >>> [..]
> >>>
> >>>>
> >>>> diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
> >>>> index 3b267b713e..b6dd575b13 100644
> >>>> --- a/lib/efi_loader/efi_device_path.c
> >>>> +++ b/lib/efi_loader/efi_device_path.c
> >>>> @@ -147,7 +147,7 @@ struct efi_device_path *efi_dp_shorten(struct efi_device_path *dp)
> >>>>                    * in practice fallback.efi just uses MEDIA:HARD_DRIVE
> >>>>                    * so not sure when we would see these other cases.
> >>>>                    */
> >>>> -               if (EFI_DP_TYPE(dp, MESSAGING_DEVICE, MSG_USB_CLASS) ||
> >>>> +               if (EFI_DP_TYPE(dp, MESSAGING_DEVICE, MSG_USB) ||
> >>>>                       EFI_DP_TYPE(dp, MEDIA_DEVICE, HARD_DRIVE_PATH) ||
> >>>>                       EFI_DP_TYPE(dp, MEDIA_DEVICE, FILE_PATH))
> >>>>                           return dp;
> >>>> @@ -564,6 +564,11 @@ __maybe_unused static unsigned int dp_size(struct udevice *dev)
> >>>>                           return dp_size(dev->parent)
> >>>>                                   + sizeof(struct efi_device_path_vendor) + 1;
> >>>>    #endif
> >>>> +#ifdef CONFIG_USB
> >>>> +               case UCLASS_MASS_STORAGE:
> >>>
> >>> Can we do:
> >>>
> >>>                  case UCLASS_MASS_STORAGE:
> >>>                     if (IS_ENABLED(CONFIG_USB)) {
> >>>                              ...
> >>>                     }
> >>>
> >>> ?
> >>
> >> That should be possible too. Didn't you want to get rid of IS_ENABLED()?
> >> CONFIG_IS_ENABLED() would work here too.
> >
> > I was wanting to get rid of CONFIG_IS_ENABLED() for things that don't
> > have an SPL Kconfig, then eventually get rid of CONFIG_IS_ENABLED().
> > I've got a bit lost in all the problems though.
> >
> >>
> >> The whole way that we create device paths is not consistent. We should
> >> have a device path node for each DM device.
> >>
> >> With v2023.07 I want to add
> >>
> >>       struct efi_device_path *(*get_dp_node)(struct udevice *dev);
> >>
> >> to struct uclass_driver and move the generation of device path nodes to
> >> the individual uclass drivers.
> >
> > We could also send an event (EVT_EFI_GET_DP_NODE) and connect it that
> > way...ie would add less space to driver model. But yes it would be
> > good to line up EFI and DM a bit better.
>
> The type of device-path node to be created is uclass specific:
>
> For an NVMe device we will always create a NVMe() node.
> For a block device we will always create a Ctrl() node with the LUN number.
> ...
>
> For drivers that don't implement the method yet we can create a VenHw()
> node per default with uclass-id and device number encoded in the node.
>
> You suggested yourself that the DM and the EFI implementation should be
> tightly integrated.

I mean that EFI should make full use of DM rather than maintaining
parallel structures that need manual updating.

>
> I cannot see what the use of an event should be. Why should each udevice
> register to an event when all we need is a simple function like:
>
> #if CONFIG_IS_ENABLED(EFI_LOADER)
> struct efi_device_path *uclass_get_dp_node(struct udevice *dev)
> {
>         struct uclass *uc;
>         struct efi_device_path_uboot *dp;
>
>         uc = dev->uclass;
>         if (uc->uc_drv->get_dp_node)
>                 return uc->uc_drv->get_dp_node(dev);
>
>         dp = efi_alloc(sizeof(struct efi_device_path_uboot));
>         if (!dp)
>                 return NULL;
>
>         dp->dp.type = DEVICE_PATH_TYPE_HARDWARE_DEVICE;
>         dp->dp.sub_type = DEVICE_PATH_SUB_TYPE_VENDOR;
>         dp->dp.length = sizeof(struct efi_device_path_uboot);
>         dp->guid = efi_u_boot_guid;
>         dp->uclass_id = uc->uc_drv->id;
>         dp->seq_ = dev->seq_;
>
>         return &dp->dp;
> }
> #endif
>

I'll take a look at your series. Basically the idea with an event is
that it can tell EFI when action is needed, without requiring #ifdefs
and the like to build it into DM itself.

Regards,
Simon