[RFC] efi_driver: fix a parent issue in efi-created block devices
Simon Glass
sjg at chromium.org
Wed Jul 19 15:04:06 CEST 2023
Hi,
On Tue, 18 Jul 2023 at 19:54, AKASHI Takahiro
<takahiro.akashi at linaro.org> wrote:
>
> Hi Simon,
>
> On Tue, Jul 18, 2023 at 07:08:45PM -0600, Simon Glass wrote:
> > Hi AKASHI,
> >
> > On Tue, 18 Jul 2023 at 18:22, AKASHI Takahiro
> > <takahiro.akashi at linaro.org> wrote:
> > >
> > > An EFI application may create an EFI block device (EFI_BLOCK_IO_PROTOCOL) in
> > > EFI world, which in turn generates a corresponding U-Boot block device based on
> > > U-Boot's Driver Model.
> > > The latter device, however, doesn't work as U-Boot proper block device
> > > due to an issue in efi_driver's implementation. We saw discussions in the past,
> > > most recently in [1].
> > >
> > > [1] https://lists.denx.de/pipermail/u-boot/2023-July/522565.html
> > >
> > > This RFC patch tries to address (part of) the issue.
> > > If it is considered acceptable, I will create a formal patch.
> > >
> > > Withtout this patch,
> > > ===8<===
> > > => env set efi_selftest 'block device'
> > > => bootefi selftest
> > > ...
> > >
> > > Summary: 0 failures
> > >
> > > => dm tree
> > > Class Index Probed Driver Name
> > > -----------------------------------------------------------
> > > root 0 [ + ] root_driver root_driver
> > > ...
> > > bootmeth 7 [ ] vbe_simple | `-- vbe_simple
> > > blk 0 [ + ] efi_blk `-- efiblk#0
> > > partition 0 [ + ] blk_partition `-- efiblk#0:1
> > > => ls efiloader 0:1
> > > ** Bad device specification efiloader 0 **
> > > Couldn't find partition efiloader 0:1
> > > ===>8===
> > >
> > > With this patch applied, efiblk#0(:1) now gets accessible.
> > >
> > > ===8<===
> > > => env set efi_selftest 'block device'
> > > => bootefi selftest
> > > ...
> > >
> > > Summary: 0 failures
> > >
> > > => dm tree
> > > Class Index Probed Driver Name
> > > -----------------------------------------------------------
> > > root 0 [ + ] root_driver root_driver
> > > ...
> > > bootmeth 7 [ ] vbe_simple | `-- vbe_simple
> > > efi 0 [ + ] EFI block driver `-- /VenHw(dbca4c98-6cb0-694d-0872-819c650cb7b8)
> > > blk 0 [ + ] efi_blk `-- efiblk#0
> > > partition 0 [ + ] blk_partition `-- efiblk#0:1
> > > => ls efiloader 0:1
> > > 13 hello.txt
> > > 7 u-boot.txt
> > >
> > > 2 file(s), 0 dir(s)
> > > ===>8===
> > >
> > > Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> > > ---
> > > include/efi_driver.h | 2 +-
> > > lib/efi_driver/efi_block_device.c | 17 ++++++++++++-----
> > > lib/efi_driver/efi_uclass.c | 8 +++++++-
> > > lib/efi_selftest/efi_selftest_block_device.c | 2 ++
> > > 4 files changed, 22 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/include/efi_driver.h b/include/efi_driver.h
> > > index 63a95e4cf800..ed66796f3519 100644
> > > --- a/include/efi_driver.h
> > > +++ b/include/efi_driver.h
> > > @@ -42,7 +42,7 @@ struct efi_driver_ops {
> > > const efi_guid_t *child_protocol;
> > > efi_status_t (*init)(struct efi_driver_binding_extended_protocol *this);
> > > efi_status_t (*bind)(struct efi_driver_binding_extended_protocol *this,
> > > - efi_handle_t handle, void *interface);
> > > + efi_handle_t handle, void *interface, char *name);
> > > };
> > >
> > > #endif /* _EFI_DRIVER_H */
> > > diff --git a/lib/efi_driver/efi_block_device.c b/lib/efi_driver/efi_block_device.c
> > > index add00eeebbea..43b7ed7c973c 100644
> > > --- a/lib/efi_driver/efi_block_device.c
> > > +++ b/lib/efi_driver/efi_block_device.c
> > > @@ -115,9 +115,9 @@ static ulong efi_bl_write(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
> > > * Return: status code
> > > */
> > > static efi_status_t
> > > -efi_bl_create_block_device(efi_handle_t handle, void *interface)
> > > +efi_bl_create_block_device(efi_handle_t handle, void *interface, struct udevice *parent)
> > > {
> > > - struct udevice *bdev = NULL, *parent = dm_root();
> > > + struct udevice *bdev = NULL;
> > > efi_status_t ret;
> > > int devnum;
> > > char *name;
> > > @@ -181,7 +181,7 @@ err:
> > > */
> > > static efi_status_t efi_bl_bind(
> > > struct efi_driver_binding_extended_protocol *this,
> > > - efi_handle_t handle, void *interface)
> > > + efi_handle_t handle, void *interface, char *name)
> > > {
> > > efi_status_t ret = EFI_SUCCESS;
> > > struct efi_object *obj = efi_search_obj(handle);
> > > @@ -191,8 +191,15 @@ static efi_status_t efi_bl_bind(
> > > if (!obj || !interface)
> > > return EFI_INVALID_PARAMETER;
> > >
> > > - if (!handle->dev)
> > > - ret = efi_bl_create_block_device(handle, interface);
> > > + if (!handle->dev) {
> > > + struct udevice *parent;
> > > +
> > > + ret = device_bind_driver(dm_root(), "EFI block driver", name, &parent);
> >
> > Can you use a non-root device as the parent?
>
> I have no idea what else can be the parent in this case.
I suggest an EFI_MEDIA device.
>
> Please note:
> > > => dm tree
> > > Class Index Probed Driver Name
> > > -----------------------------------------------------------
> > > root 0 [ + ] root_driver root_driver
> > > ...
> > > bootmeth 7 [ ] vbe_simple | `-- vbe_simple
> > > efi 0 [ + ] EFI block driver `-- /VenHw(dbca4c98-6cb0-694d-0872-819c650cb7b8)
>
> This "efi" object is created by an EFI application (i.e. efi_selftest_block_device.c)
> and don't have any practical parent.
Block devices must have a media device as their parent. This seems to
be a persistent area of confusion...probably when the uclass ID goes
away from blk_desc it will be more obvious.
>
> > > blk 0 [ + ] efi_blk `-- efiblk#0
> > > partition 0 [ + ] blk_partition `-- efiblk#0:1
>
>
> > > + if (!ret)
> > > + ret = efi_bl_create_block_device(handle, interface, parent);
> > > + else
> > > + ret = EFI_DEVICE_ERROR;
> > > + }
> > >
> > > return ret;
> > > }
> > > diff --git a/lib/efi_driver/efi_uclass.c b/lib/efi_driver/efi_uclass.c
> > > index 45f935198874..bf669742783e 100644
> > > --- a/lib/efi_driver/efi_uclass.c
> > > +++ b/lib/efi_driver/efi_uclass.c
> > > @@ -145,7 +145,13 @@ static efi_status_t EFIAPI efi_uc_start(
> > > ret = check_node_type(controller_handle);
> > > if (ret != EFI_SUCCESS)
> > > goto err;
> > > - ret = bp->ops->bind(bp, controller_handle, interface);
> > > +
> > > + struct efi_handler *handler;
> > > + char tmpname[256] = "AppName";
> > > + ret = efi_search_protocol(controller_handle, &efi_guid_device_path,
> > > + &handler);
> > > + snprintf(tmpname, 256, "%pD", handler->protocol_interface);
> > > + ret = bp->ops->bind(bp, controller_handle, interface, strdup(tmpname));
> > > if (ret == EFI_SUCCESS)
> > > goto out;
> > >
> > > diff --git a/lib/efi_selftest/efi_selftest_block_device.c b/lib/efi_selftest/efi_selftest_block_device.c
> > > index a367e8b89d17..0ab8e4590dfe 100644
> > > --- a/lib/efi_selftest/efi_selftest_block_device.c
> > > +++ b/lib/efi_selftest/efi_selftest_block_device.c
> > > @@ -248,6 +248,7 @@ static int teardown(void)
> > > {
> > > efi_status_t r = EFI_ST_SUCCESS;
> > >
> > > +#if 0 /* Temporarily out for confirmation */
> > > if (disk_handle) {
> > > r = boottime->uninstall_protocol_interface(disk_handle,
> > > &guid_device_path,
> > > @@ -273,6 +274,7 @@ static int teardown(void)
> > > return EFI_ST_FAILURE;
> > > }
> > > }
> > > +#endif
> > > return r;
> > > }
> > >
> > > --
> > > 2.41.0
> > >
> >
> > Otherwise this looks good to me. We should have DM devices for all EFI
> > ones (in fact EFI ones should just be some extra data on top of DM
> > ones).
>
> Unfortunately, in this specific case (efi_block_device.c), UEFI object
> (handle) is set to be created first, then U-Boot device (efiblk#xxx).
> So "some extra data on top of DM ones" is not accurate (doesn't reflect
> the current implementation).
OK, so we should really sort that out :-)
>
> Please note again that efi_loader/efi_disk.c and efi_driver/efi_block_device.c
> are totally different things.
OK
Regards,
Simon
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