Re: [PATCH] efi: Call bootm_disable_interrupts earlier in efi_exit_boot_services

[Heinrich Schuchardt]

Am 19. November 2021 22:33:04 MEZ schrieb Tom Rini <trini at konsulko.com>:
>If we look at the path that bootm/booti take when preparing to boot the
>OS, we see that as part of (or prior to calling do_bootm_states,
>explicitly) the process, bootm_disable_interrupts() is called prior to
>announce_and_cleanup() which is where udc_disconnect() /
>board_quiesce_devices() / dm_remove_devices_flags() are called from.  In
>the EFI path, these are called afterwards.  In efi_exit_boot_services()
>however we have been calling bootm_disable_interrupts() after the above
>functions, as part of ensuring that we disable interrupts as required
>by the spec.  However, bootm_disable_interrupts() is also where we go
>and call usb_stop().  While this has been fine before, on the TI J721E
>platform this leads us to an exception.  This exception seems likely to
>be the case that we're trying to stop devices that we have already
>disabled clocks for.  The most direct way to handle this particular

This patch may hide an error on your board but obviously does not address the real problem.

If dependencies in the shut down sequence should exist, we need to consider them in the driver model.

What is your plan to analyze the problem?

Best regards

Heinrich 

>problem is to make EFI behave like the do_bootm_states() process and
>ensure we call bootm_disable_interrupts() prior to ending up in
>usb_stop().
>
>Cc: Ilias Apalodimas <ilias.apalodimas at linaro.org>
>Cc: Heinrich Schuchardt <xypron.glpk at gmx.de>
>Cc: Simon Glass <sjg at chromium.org>
>Suggested-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
>Signed-off-by: Tom Rini <trini at konsulko.com>
>---
>First up, as my wording above implies, I'm assuming rather than being
>100% confident in why calling usb_stop() is leading to the exception I
>get.  It's this call:
>                /* Locate root hub device */
>                device_find_first_child(bus, &rh);
>that causes the exception.  This board is also a little odd in that,
>borrowing from dm_dump_all():
> nop           5  [   ]   cdns-ti               |   |-- cdns-usb at 4114000
> usb           0  [ + ]   cdns-usb3-host        |   |   `-- usb at 6400000
> usb_hub       0  [ + ]   usb_hub               |   |       `-- usb_hub
> usb_hub       1  [ + ]   usb_hub               |   |           `-- usb_hub
> usb_mass_s    0  [ + ]   usb_mass_storage      |   |               `-- usb_mass_storage
> blk           2  [ + ]   usb_storage_blk       |   |                   `-- usb_mass_storage.lun0
>and physically, only that mass storage device is attached to the board
>itself, the rest is on-device.
>
>Second, while talking with Ilias he's said he'll see if there can be
>some common function / abstractions done here between the
>do_bootm_states() code and the efi_exit_boot_services() code as this
>change shows other common code that's in arch/*/lib/bootm.c.  The call
>to bootm_disable_interrupts() however I have tried to make clear is not
>handled in a common way as bootm/booti spell out the call as they don't
>use the BOOTM_STATE_LOADOS flag.
>
>Third, I'm not 100% sure that 3d71c81a9bb0 is still the correct / ideal
>thing to be doing, and that's what usb_stop() is all about, at that
>point in the boot cycle.  It might well be the kind of quirk that we
>have handled now, via DM.
>
>Fourth, I really would like to figure out a fix here appropriate to
>v2022.01 and I think this is the least invasive approach.
>---
> lib/efi_loader/efi_boottime.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
>diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
>index 1823990d9bd5..0485870d34d9 100644
>--- a/lib/efi_loader/efi_boottime.c
>+++ b/lib/efi_loader/efi_boottime.c
>@@ -2154,6 +2154,7 @@ static efi_status_t EFIAPI efi_exit_boot_services(efi_handle_t image_handle,
> 	}
> 
> 	if (!efi_st_keep_devices) {
>+		bootm_disable_interrupts();
> 		if (IS_ENABLED(CONFIG_USB_DEVICE))
> 			udc_disconnect();
> 		board_quiesce_devices();
>@@ -2166,9 +2167,6 @@ static efi_status_t EFIAPI efi_exit_boot_services(efi_handle_t image_handle,
> 	/* Fix up caches for EFI payloads if necessary */
> 	efi_exit_caches();
> 
>-	/* This stops all lingering devices */
>-	bootm_disable_interrupts();
>-
> 	/* Disable boot time services */
> 	systab.con_in_handle = NULL;
> 	systab.con_in = NULL;