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

[Ilias Apalodimas]

On Sat, 15 Feb 2025 at 17:22, 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(-)
>
> 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
>

Acked-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>