[U-Boot] [U-Boot, v4, 07/11] spl: add support to booting with OP-TEE

[Bryan O'Donoghue]

On 15/01/18 04:48, Peng Fan wrote:
> On Mon, Jan 15, 2018 at 11:25:00AM +0800, Kever Yang wrote:
>> Bryan,
>>
>>
>> On 01/12/2018 11:10 PM, Bryan O'Donoghue wrote:
>>>
>>>
>>> On 12/01/18 11:27, Philipp Tomsich wrote:
>>>>> OP-TEE is an open source trusted OS, in armv7, its loading and
>>>>> running are like this:
>>>>> loading:
>>>>> - SPL load both OP-TEE and U-Boot
>>>>> running:
>>>>> - SPL run into OP-TEE in secure mode;
>>>>> - OP-TEE run into U-Boot in non-secure mode;
>>>>>
>>>>> More detail:
>>>>> https://github.com/OP-TEE/optee_os
>>>>> and search for 'boot arguments' for detail entry parameter in:
>>>>> core/arch/arm/kernel/generic_entry_a32.S
>>>>>
>>>>> Signed-off-by: Kever Yang <kever.yang at rock-chips.com>
>>>>> ---
>>>>>
>>>>> Changes in v4:
>>>>> - use NULL instead of '0'
>>>>> - add fdt_addr as arg2 of entry
>>>>>
>>>>> Changes in v3: None
>>>>> Changes in v2:
>>>>> - Using new image type for op-tee
>>>>>
>>>>>   common/spl/Kconfig     |  7 +++++++
>>>>>   common/spl/Makefile    |  1 +
>>>>>   common/spl/spl.c       |  9 +++++++++
>>>>>   common/spl/spl_optee.S | 13 +++++++++++++
>>>>>   include/spl.h          | 13 +++++++++++++
>>>>>   5 files changed, 43 insertions(+)
>>>>>   create mode 100644 common/spl/spl_optee.S
>>>>>
>>>>
>>>> Acked-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
>>>> _______________________________________________
>>>> U-Boot mailing list
>>>> U-Boot at lists.denx.de
>>>> https://lists.denx.de/listinfo/u-boot
>>>>
>>>
>>> Kever, Philipp
>>>
>>> I have patches that define a IH_TYPE_OPTEE as a bootable OPTEE
>>> image (one that never returns to u-boot).
>>
>> I don't understand how you use OP-TEE in your project.
>> You are using U-Boot 'bootm' cmd to run into OP-TEE and 'PC' never
>> get out of the OP-TEE os?
>> The upstream OP-TEE will always be back to the pointer in 'lr'.
>>
>> We are using boot flow like ARMv8 for OP-TEE in armv7, could you
>> introduce your flow?
> 
> The flow is ROM->U-Boot->OP-TEE->Linux.

Hi Kever, this got buried in my mailbox...

Which I believe is the preferred flow for armv7

That said - if you look at the TI commits for IH_TYPE_TEE I believe 
*that* is the appropriate type for what you are doing with SPL.

As I read the TI code the TEE is installed into memory - jumped into and 
returned out of, which is the model you are using with SPL here.

Basically that's what 
arch/arm/mach-omap2/sec-common.c::secure_tee_install() does.

So, I think the SPL solution you have can co-exist quite easily with the 
model we have described above for imx7.

My only suggestion here is that you probably don't need to define a new 
image type for SPL - you can reuse IH_TYPE_TEE for SPL as below.

Other than that I think the SPL/bootm or indeed the TI method of 
installing a TEE are entirely able to (and should) live side-by-side.

>>> +#if CONFIG_IS_ENABLED(OPTEE)
>>> +    case IH_TYPE_TEE:
>>> +        debug("Jumping to U-Boot via OP-TEE\n");
>>> +        spl_optee_entry(NULL, NULL, spl_image->fdt_addr,
>>> +                (void *)spl_image.entry_point);
>>> +        break;
>>> +#endif