Re: [PATCH v2] xen: arm64: Add support for Renesas RCar Gen3 H3 Salvator-X platform

[Andre Przywara <andre.przywara@arm.com>]

Hi,

On 05/07/16 14:34, Julien Grall wrote:
> (CC Andre)
> 
> On 05/07/16 14:04, Dirk Behme wrote:
>> On 05.07.2016 14:45, Julien Grall wrote:
>>>
>>>
>>> On 05/07/16 13:09, Dirk Behme wrote:
>>>> Hi Julien,
>>>>
>>>> On 05.07.2016 13:39, Julien Grall wrote:
>>>>> Hi Dirk,
>>>>>
>>>>> On 05/07/16 07:37, Dirk Behme wrote:
>>>>>> Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
>>>>>
>>>>> This patch looks good to me, however I would like to see the
>>>>> documentation on the wiki page (see [1]) before giving any formal ack.
>>>>
>>>>
>>>> Ok, many thanks for your review!
>>>>
>>>> Yes, I understood that something more is needed.
>>>>
>>>>
>>>> I just wonder if we keep the patch on the mailing list for a moment.
>>>> With this it's publically available and we can see how's the public
>>>> interest for this board.
>>>>
>>>> Additionally, getting Xen running on this board and describe all
>>>> this in
>>>> the wiki isn't that easy. You either need to modify the flashed
>>>> firmware. Or, like me, load everything via a JTAG debugger ...
>>>
>>> Can you details why you think it is not easy? Why do you have to modify
>>> the firmware? Is it because it does not boot the hypervisor in EL2?
>>
>>
>> The board boots via ATF, which starts U-Boot in EL1, then. You have to
>> find a way to load Xen into memory (e.g. U-Boot TFTP) and then switch to
>> EL2 to start Xen.
> 
> But ATF is running in EL3, right? If so, can ATF just starts U-boot in EL2?
> 
> I have a board at home (pine64) which also uses ATF and U-Boot and is
> able to boot Xen without any SMC call because the U-Boot is entered in EL2.

From having a very quick look into the rcar ATF port on github[1] I see:

+#elif (RCAR_BL33_EXECUTION_EL == BL33_EL2)
+	return (uint32_t)SPSR_64(MODE_EL2, MODE_SP_ELX, DISABLE_ALL_EXCEPTIONS);

So if you rebuild ATF with RCAR_BL33_EXECUTION_EL set to BL33_EL2 that
should enter U-Boot in EL2.

The fix for the Pine64 was equally simple and works fine since then.

Cheers,
Andre.

[1]
https://github.com/renesas-rcar/meta-renesas/tree/jethro/meta-rcar-gen3/recipes-bsp/arm-trusted-firmware/arm-trusted-firmware

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel