[PATCH] imx8m: set sane default value for SPL_LOAD_FIT_ADDRESS

[Marek Vasut]

On 10/24/24 5:20 PM, Tom Rini wrote:
> On Thu, Oct 24, 2024 at 04:06:03PM +0200, Marek Vasut wrote:
>> On 10/24/24 3:18 PM, Rasmus Villemoes wrote:
>>> On Thu, Oct 24 2024, Marek Vasut <marex at denx.de> wrote:
>>>
>>>> On 10/24/24 12:01 PM, Rasmus Villemoes wrote:
>>>>> I enabled IMX_HAB on an imx8mp board, but even though I knew about the
>>>>> implementation, I forgot that I had to provide a sane value for
>>>>> SPL_LOAD_FIT_ADDRESS. The help text for IMX_HAB doesn't mention this
>>>>> implicit requirement, and there's no build-time warning; the default
>>>>> 0x0 value just ends up being returned from
>>>>> board_spl_fit_buffer_addr(), obviously resulting in a non-booting
>>>>> board.
>>>>> The existing imx8m* board configs that set a non-zero value
>>>>> currently
>>>>> all use 0x44000000. The actual value doesn't matter too much, but 0 is
>>>>> always wrong for imx8m platforms. So just use 0x44000000 as default
>>>>> for those platforms.
>>>>> Signed-off-by: Rasmus Villemoes <ravi at prevas.dk>
>>>>> ---
>>>>>     boot/Kconfig | 1 +
>>>>>     1 file changed, 1 insertion(+)
>>>>> diff --git a/boot/Kconfig b/boot/Kconfig
>>>>> index 940389d4882..72d1f69afcd 100644
>>>>> --- a/boot/Kconfig
>>>>> +++ b/boot/Kconfig
>>>>> @@ -231,6 +231,7 @@ config SPL_LOAD_FIT
>>>>>     config SPL_LOAD_FIT_ADDRESS
>>>>>     	hex "load address of fit image"
>>>>>     	depends on SPL_LOAD_FIT
>>>>> +	default 0x44000000 if ARCH_IMX8M
>>>> This only applies to HAB , for non-HAB the fitImage can be loaded at
>>>> arbitrary location, do you need:
>>>>
>>>> default 0x44000000 if ARCH_IMX8M && IMX_HAB
>>>>
>>>> right ?
>>>
>>> On IMX8 without HAB, the value is not used at all AFAICT (otherwise the
>>> value of 0x0 would have caused trouble already). I don't see the harm of
>>> setting some sane value that's actually within DRAM space independent of
>>> HAB.
>>>
>>> Making the default depend on IMX_HAB has the UX problem that if I do
>>> "make imx8mp_evk_defconfig", then go about tweaking stuff, then do "make
>>> menuconfig" and enable IMX_HAB, SPL_LOAD_FIT_ADDRESS already has the
>>> bogus 0x0 value and nothing forces or asks that to be changed. Making the
>>> default depend only on SOC (or SOC family or whatever IMX8M is in this
>>> context) makes that problem go away.
>> Looking at this closely, common/spl/spl_ram.c does make use of
>> CONFIG_SPL_LOAD_FIT_ADDRESS too, so I think yes, we should have a default
>> for this.
>>
>> iMX6 should have 0x14000000
>> iMX7 should have 0x84000000
>> iMX8M should have 0x44000000
> 
> These differ, slightly, from the value used in CONFIG_SYS_LOAD_ADDR.
> Could that not be used (and the overall option changed to default
> SYS_LOAD_ADDR ?
If I recall it right, no ... these addresses are where the fitImage is 
loaded and where HAB does its authentication stuff on the fitImage, that 
address has to be fixed and well aligned. The SYS_LOAD_ADDR is the 
destination address where the u-boot-nodtb.bin is copied from the 
fitImage AFTER the fitImage was authenticated. Maybe Rasmus can correct 
me here, I might be wrong ...