[PATCH 1/1] efi_driver: create a parent device for all EFI block devices

[Simon Glass]

Hi Heinrich,

On Sat, 15 Feb 2025 at 10:23, Simon Glass <sjg at chromium.org> wrote:
>
> Hi Heinrich,
>
> On Sat, 15 Feb 2025 at 08:22, Heinrich Schuchardt
> <heinrich.schuchardt at canonical.com> wrote:
> >
> > Up to now root has been the parent device for all block devices created via
> > calling ConnectController(). This does not work well together with the
> > implementation of bootstd.
> >
> > Add a dummy parent device for all EFI block devices.
> >
> > With this change EFI block devices are also accessible via commands like
> > 'cat', 'load', and 'ls'.
> >
> >     => dm tree
> >      Class     Seq    Probed  Driver                Name
> >     -----------------------------------------------------------
> >      efi           0  [ + ]   EFI block driver      `-- efi
> >      blk           3  [ + ]   efi_blk                   `-- efi.efiblk#0
> >      partition     0  [ + ]   blk_partition                 `-- efi.efiblk#0:1
> >
> >     => ls efiloader 0:1
> >            13   hello.txt
> >             7   u-boot.txt
> >     2 file(s), 0 dir(s)
> >
> >     => cat efiloader 0:1 hello.txt
> >     Hello world!
> >
> >     => efidebug dh
> >     0000000018df1700 (efi.efiblk#0:1)
> >       /VenHw(dbca4c98-6cb0-694d-0872-819c650cb7b8)/HD(1,MBR,0xd1535d21,0x1,0x7f)
> >       Block IO
> >       Simple File System
> >
> > Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> > ---
> >  lib/efi_driver/efi_block_device.c | 29 ++++++++++++++++++++++++++++-
> >  1 file changed, 28 insertions(+), 1 deletion(-)
>
> This looks very similar to this patch, which you shot down a few years back.
>
> https://lore.kernel.org/u-boot/30f22c59-c6ce-1cea-9ef0-bdc31f7d57c2@gmx.de/

In any case, we did and do need this, so this patch seems fine to me.


>
> >
> > diff --git a/lib/efi_driver/efi_block_device.c b/lib/efi_driver/efi_block_device.c
> > index d3c668dc183..070747de515 100644
> > --- a/lib/efi_driver/efi_block_device.c
> > +++ b/lib/efi_driver/efi_block_device.c
> > @@ -35,8 +35,10 @@
> >  #include <efi_driver.h>
> >  #include <malloc.h>
> >  #include <dm/device-internal.h>
> > +#include <dm/lists.h>
> >  #include <dm/root.h>
> >  #include <dm/tag.h>
> > +#include <dm/uclass-internal.h>
> >
> >  /**
> >   * struct efi_blk_plat - attributes of a block device
> > @@ -118,13 +120,18 @@ static ulong efi_bl_write(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
> >  static efi_status_t
> >  efi_bl_create_block_device(efi_handle_t handle, void *interface)
> >  {
> > -       struct udevice *bdev = NULL, *parent = dm_root();
> > +       struct udevice *bdev = NULL, *parent;
> >         efi_status_t ret;
> > +       int r;
> >         int devnum;
> >         char *name;
> >         struct efi_block_io *io = interface;
> >         struct efi_blk_plat *plat;
> >
> > +       r = uclass_find_first_device(UCLASS_EFI_LOADER, &parent);
> > +       if (r)
> > +               return EFI_OUT_OF_RESOURCES;
> > +
> >         devnum = blk_next_free_devnum(UCLASS_EFI_LOADER);
> >         if (devnum < 0)
> >                 return EFI_OUT_OF_RESOURCES;
> > @@ -221,6 +228,24 @@ efi_bl_init(struct efi_driver_binding_extended_protocol *this)
> >         return EFI_SUCCESS;
> >  }
> >
> > +/**
> > + * efi_block_device_create() - create parent for EFI block devices
> > + *
> > + * Create a device that serves as parent for all block devices created via
> > + * ConnectController().
> > + *
> > + * Return:     0 for success
> > + */
> > +static int efi_block_device_create(void)
> > +{
> > +       int ret;
> > +       struct udevice *dev;
> > +
> > +       ret = device_bind_driver(gd->dm_root, "EFI block driver", "efi", &dev);
> > +
> > +       return ret;
> > +}
> > +
> >  /* Block device driver operators */
> >  static const struct blk_ops efi_blk_ops = {
> >         .read   = efi_bl_read,
> > @@ -249,3 +274,5 @@ U_BOOT_DRIVER(efi_block) = {
> >         .id             = UCLASS_EFI_LOADER,
> >         .ops            = &driver_ops,
> >  };
> > +
> > +EVENT_SPY_SIMPLE(EVT_LAST_STAGE_INIT, efi_block_device_create);
> > --
> > 2.47.1
> >

Regards,
Simon