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[2/2] board: samsung: e850-96: Load LDFW in board_late_init()

Message ID 20250620022556.10363-3-semen.protsenko@linaro.org
State New
Headers show
Series board: samsung: e850-96: Fix MMC devices in EFI | expand

Commit Message

Sam Protsenko June 20, 2025, 2:25 a.m. UTC 
As stated in 5e847f7729b3 ("efi_loader: call efi_init_early() earlier"):

    efi_init_early() creates an event hook for block device probing.
    It has to be called before any block device is probed.

Indeed, efi_bl_init() registers EVT_DM_POST_PROBE event, which calls
efi_disk_probe() whenever any block device is probed. And to make that
hook work, the initialization of all block devices was put after
efi_init_early() in initcall_run_r():

    INITCALL(efi_init_early);
    INITCALL(initr_nand);
    INITCALL(initr_onenand);
    INITCALL(initr_mmc);

Because LDFW firmware is being read from MMC, attempt to load LDFW in
board_init() causes MMC driver to be probed. And because board_init() is
executed before efi_init_early(), the hook mentioned above won't work
for MMC devices anymore. So EFI disk objects won't be created, which in
turn makes the EFI subsystem non-functional, showing next symptoms:
  - 'efidebug dh' output is empty
  - attempt to add boot devices in 'eficonfig' shows this message:
    "No block device found!"
  - 'bootefi selftest $fdtcontroladdr' shows this warning:
    "Cannot persist EFI variables without system partition"
  - booting GRUB with 'bootefi' runs minimal GRUB shell which doesn't
    see any block devices as well, probably because EFI vars weren't
    passed

Load LDFW in board_late_init() instead, as it's called after
efi_init_early(). This fixes the described problem and makes it possible
to run EFI apps like GRUB correctly, add entries in 'eficonfig', and
makes 'efivar --list' command in Linux rootfs actually show EFI
variables.

The only user of LDFW at the moment is the TRNG driver, and it's probed
later, only when it's going to be used (e.g. on "rng" command). So it's
fine to load LDFW in board_late_init(). Now the corresponding call order
will look like this:

    efi_init_early()
    initr_mmc()
      mmc_probe()
        EVT_DM_POST_PROBE -> efi_disk_probe()
    board_late_init()
      load_ldfw() -> fs_read(), blk_dread()
    exynos_trng_probe()

Fixes: ccfd8de541a8 ("board: samsung: e850-96: Report LDFW loading failures")
Fixes: f04e58cc9788 ("board: samsung: e850-96: Load LDFW firmware on board init")
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
---
 board/samsung/e850-96/e850-96.c | 9 +++++++++
 1 file changed, 9 insertions(+)
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Patch

diff --git a/board/samsung/e850-96/e850-96.c b/board/samsung/e850-96/e850-96.c
index 0bef68d2fb20..3bbd95201b5f 100644
--- a/board/samsung/e850-96/e850-96.c
+++ b/board/samsung/e850-96/e850-96.c
@@ -18,9 +18,18 @@  int dram_init_banksize(void)
 }
 
 int board_init(void)
+{
+	return 0;
+}
+
+int board_late_init(void)
 {
 	int err;
 
+	/*
+	 * Do this in board_late_init() to make sure MMC is not probed before
+	 * efi_init_early().
+	 */
 	err = load_ldfw();
 	if (err)
 		printf("ERROR: LDFW loading failed (%d)\n", err);