[PATCH 02/10] firmware: firmware-zynqmp: Probe driver before use

[Stefan Herbrechtsmeier]

Am 20.06.2022 um 08:51 schrieb Michal Simek:
> Hi,
> 
> On 6/20/22 08:40, Stefan Herbrechtsmeier wrote:
>> Am 16.06.2022 um 16:22 schrieb Michal Simek:
>>> On 6/8/22 18:20, Stefan Herbrechtsmeier wrote:
>>>> [CAUTION: External Email]
>>>>
>>>> From: Stefan Herbrechtsmeier <stefan.herbrechtsmeier at weidmueller.com>
>>>>
>>>> Probe the driver before use to ensure that the global data are valid.
>>>
>>> It is not clear what the issue is. And this function is called in SPL 
>>> or EL3 and likely multiple times.
>>> Can you please clarify?
>>
>> The driver only works if it is used after u-boot,dm-pre-reloc. This 
>> change is needed to support a usage by other drivers like 
>> xlnx,zynqmp-firmware.
> 
> Can you please describe the case, execution path where it is used before?

I released the problem with the soc_xilinx_zynqmp driver. The driver was 
probed before the firmware-zynqmp driver.

At the moment every user of xilinx_pm_request function have to ensure 
that the firmware-zynqmp driver was probed.

> 
> Also that calling multiple times is just adding overhead for boot up 
> time. We should try to avoid it as much as possible.

Should I zero zynqmp_power and only probe if it is zero?

The solution is based on the psci driver.

Regards
   Stefan