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

[Viken Dadhaniya]

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 ?