Re: [PATCH v1 0/7] Add support to load QUP SE firmware from

Viken Dadhaniya
2024-12-10T05:06:48Z

On 12/5/2024 9:29 PM, Konrad Dybcio wrote:
> On 4.12.2024 4:03 PM, Viken Dadhaniya wrote:
>> In Qualcomm SoCs, firmware loading for Serial Engines (SE) in the QUP
>> hardware has traditionally been managed by TrustZone (TZ). This setup
>> handled Serial Engines(SE) assignments and access control permissions,
>> ensuring a high level of security but limiting flexibility and
>> accessibility.
>>
>> This limitation poses a significant challenge for developers who need more
>> flexibility to enable any protocol on any of the SEs within the QUP
>> hardware.
>>
>> To address this, we are introducing a change that opens the firmware
>> loading mechanism to the Linux environment. This enhancement increases
>> flexibility and allows for more streamlined and efficient management. We
>> can now handle SE assignments and access control permissions directly
>> within Linux, eliminating the dependency on TZ.
>>
>> We propose an alternative method for firmware loading and SE
>> ownership/transfer mode configuration based on device tree configuration.
>> This method does not rely on other execution environments, making it
>> accessible to all developers.
>>
>> For SEs used prior to the kernel, their firmware will be loaded by the
>> respective image drivers (e.g., Debug UART, Secure or trusted SE).
>> Additionally, the GSI firmware, which is common to all SEs per QUPV3 core,
>> will not be loaded by Linux driver but TZ only. At the kernel level, only
>> the SE protocol driver should load the respective protocol firmware.
>
> I think this is a great opportunity to rethink the SE node in general.
>
> Currently, for each supported protocol, we create a new node that
> differs in (possibly) interconnects and pinctrl states. These are really
> defined per-SE however and we can programmatically determine which ones
> are relevant.
>
> With the growing number of protocols supported, we would have to add
> 20+ nodes in some cases for each one of them. I think a good one would
> look like:
>
> geni_se10: serial-engine@abcdef {
> compatible = "qcom,geni-se";
>
> reg
> clocks
> power-domains
> interconnects
> ...
>
> status
>
> geni_se10_i2c: i2c {
> // i2c-controller.yaml
> };
>
> geni_se10_spi: spi {
> // spi-controller.yaml
> };
>
> ...
> }
>
> Or maybe even get rid of the subnodes and restrict that to a single
> se-protocol = <SE_PROTOCOL_xyz> property, if the bindings folks agree.
>
> We could extend the DMA APIs to dynamically determine the protocol
> ID and get rid of hardcoding it.
>
> And then we could spawn an instance of the spi, i2c, etc. driver from
> the GENI SE driver.
>
> Konrad

Thanks for the advice.
The above design suggested by you may add more code change into protocol
driver as well as common driver.
I am really interested to discuss more options and come to better
design. let me discuss with you on this.
Also do you think we can push the re-design of DTSI nodes as separate
change instead of clubbing with this FW load change ?