[PATCH v9 00/13] Introduce STM32 Firewall framework

[Rob Herring]

On Mon, Apr 8, 2024 at 3:44 AM Alexandre TORGUE
<alexandre.torgue at foss.st.com> wrote:
>
> Hi Gatien,
>
> On 1/5/24 14:03, Gatien Chevallier wrote:
> > Introduce STM32 Firewall framework for STM32MP1x and STM32MP2x
> > platforms. STM32MP1x(ETZPC) and STM32MP2x(RIFSC) Firewall controllers
> > register to the framework to offer firewall services such as access
> > granting.
> >
> > This series of patches is a new approach on the previous STM32 system
> > bus, history is available here:
> > https://lore.kernel.org/lkml/20230127164040.1047583/
> >
> > The need for such framework arises from the fact that there are now
> > multiple hardware firewalls implemented across multiple products.
> > Drivers are shared between different products, using the same code.
> > When it comes to firewalls, the purpose mostly stays the same: Protect
> > hardware resources. But the implementation differs, and there are
> > multiple types of firewalls: peripheral, memory, ...
> >
> > Some hardware firewall controllers such as the RIFSC implemented on
> > STM32MP2x platforms may require to take ownership of a resource before
> > being able to use it, hence the requirement for firewall services to
> > take/release the ownership of such resources.
> >
> > On the other hand, hardware firewall configurations are becoming
> > more and more complex. These mecanisms prevent platform crashes
> > or other firewall-related incoveniences by denying access to some
> > resources.
> >
> > The stm32 firewall framework offers an API that is defined in
> > firewall controllers drivers to best fit the specificity of each
> > firewall.
> >
> > For every peripherals protected by either the ETZPC or the RIFSC, the
> > firewall framework checks the firewall controlelr registers to see if
> > the peripheral's access is granted to the Linux kernel. If not, the
> > peripheral is configured as secure, the node is marked populated,
> > so that the driver is not probed for that device.
> >
> > The firewall framework relies on the access-controller device tree
> > binding. It is used by peripherals to reference a domain access
> > controller. In this case a firewall controller. The bus uses the ID
> > referenced by the access-controller property to know where to look
> > in the firewall to get the security configuration for the peripheral.
> > This allows a device tree description rather than a hardcoded peripheral
> > table in the bus driver.
> >
> > The STM32 ETZPC device is responsible for filtering accesses based on
> > security level, or co-processor isolation for any resource connected
> > to it.
> >
> > The RIFSC is responsible for filtering accesses based on Compartment
> > ID / security level / privilege level for any resource connected to
> > it.
> >
> > STM32MP13/15/25 SoC device tree files are updated in this series to
> > implement this mecanism.
> >
>
> ...
>
> After minor cosmetic fixes, series applied on stm32-next.
> Seen with Arnd: it will be part on my next PR and will come through
> arm-soc tree.

And there's some new warnings in next with it:

      1  venc at 480e0000: 'access-controllers' does not match any of the
regexes: 'pinctrl-[0-9]+'
      1  vdec at 480d0000: 'access-controllers' does not match any of the
regexes: 'pinctrl-[0-9]+'

Rob