[U-Boot] [PATCH 01/11] imx: Add bootcmd to load and run UEFI from mmc

[Alexander Graf]

On 08/08/2018 04:24 AM, Henry Beberman wrote:
>
>> -----Original Message-----
>> From: Alexander Graf <agraf at suse.de>
>> Sent: Tuesday, August 7, 2018 6:46 AM
>> To: Tom Rini <trini at konsulko.com>
>> Cc: Stefano Babic <sbabic at denx.de>; Henry Beberman
>> <Henry.Beberman at microsoft.com>; u-boot at lists.denx.de; Fabio Estevam
>> <fabio.estevam at nxp.com>
>> Subject: Re: [PATCH 01/11] imx: Add bootcmd to load and run UEFI from
>> mmc
>>
>>
>>
>>> Am 07.08.2018 um 12:16 schrieb Tom Rini <trini at konsulko.com>:
>>>
>>>> On Tue, Aug 07, 2018 at 01:11:11PM +0200, Stefano Babic wrote:
>>>> Hi Henry,
>>>>
>>>>> On 14/07/2018 02:11, Henry Beberman wrote:
>>>>> From: Henry Beberman <henry.beberman at microsoft.com>
>>>>>
>>>>> This patch enables i.MX platforms to easily add a boot script to
>>>>> their U-Boot Proper environment to automatically load and execute an
>>>>> EFI firmware from the first FAT partition of an MMC device.
>>>>>
>>>>> This is a portion of enabling the Windows 10 IoT Core boot path.
>>>>>
>>>>> The go command is overridden when CONFIG_UEFI_BOOT is specified.
>>>>> This new go will perform a cache flush/disable, disable interrupts,
>>>>> then jump to the address where UEFI was loaded.
>>>>>
>>>>> This patch adds two new Kconfig options:
>>>>> CONFIG_UEFI_BOOT: Selects the UEFI bootcmd and overrides go to
>> flush
>>>>> caches and disable interrupts.
>>>>> CONFIG_UEFI_LOAD_ADDR: Specifies the load address for the UEFI
>> image
>>>>> Signed-off-by: Henry Beberman <henry.beberman at microsoft.com>
>>>>> Cc: Stefano Babic <sbabic at denx.de>
>>>>> Cc: Fabio Estevam <fabio.estevam at nxp.com>
>>>>> Cc: Tom Rini <trini at konsulko.com>
>>>>> ---
>>>>> arch/arm/mach-imx/Makefile    |  1 +
>>>>> arch/arm/mach-imx/boot.c      | 19 +++++++++++++++++++
>>>>> common/Kconfig                | 17 +++++++++++++++++
>>>>> include/config_uefi_bootcmd.h | 29
>> +++++++++++++++++++++++++++++
>>>>> 4 files changed, 66 insertions(+)
>>>>> create mode 100644 arch/arm/mach-imx/boot.c create mode 100644
>>>>> include/config_uefi_bootcmd.h
>>>>>
>>>> I am really missing why we need this specially for i.MX. There is
>>>> nothing special to i.MX, and if this command is necessary, we should
>>>> put it in common code.
>>>>
>>>> Anyway, should we not try to merge it with the general support for
>>>> UEFI in U-Boot ? We have already a "bootefi" command (aarch64 and
>>>> x86, currently).
>>> Agreed, this should be folded in with our existing UEFI support, thanks!
>> Yes, please just use distro boot. Bootefi (which distro boot calls) already
>> supports running UEFI binaries for real even on armv7.
>>
>>
>> Alex
>>
> Running Windows directly on U-Boot through bootefi is definitely appealing, but
> we're dependent on a number of features provided by our full UEFI firmware.
>
> * Several ACPI tables that are unimplemented in U-Boot: CSRT, DBG2, SPCR, TPM2, GTDT
> * Some DSDT elements that require the Microsoft ASL compiler (for now)
> * UEFI Authenticated Variables that are writeable at runtime.
> * UEFI Secure Boot
> * Launching and communicating with a Firmware TPM running as an OP-TEE Trusted Application
>
> I'd be happy to break down this patch's changes into more generic steps rather than
> creating confusion by adding CONFIG_UEFI_BOOT.
>
> I can move the UEFI binary into our FIT to eliminate the custom binary load script.
> How should I cleanly add an alternate CONFIG_BOOTCOMMAND to an existing board.h file?

I think ideally you just integrate into whatever distro boot supports. 
It already gives you plenty options such as extboot, boot.scr and real 
generic bootefi support. I'm sure your specially crafted FIT image can 
by loaded by at least one of the existing mechanisms.

> Where is the best place to define an alternate do_go_exec that calls
> cleanup_before_linux() before jumping?

Do you really really need that? The ARM calling convention for bootz is 
trivial and sounds like pretty much what you need already, no?


Alex