Hi,

On Tue, May 05, 2026 at 04:05:10PM +0200, Ketil Johnsen wrote:

From: Florent Tomasin florent.tomasin@arm.com

This patch allows Panthor to allocate buffer objects from a protected heap. The Panthor driver should be seen as a consumer of the heap and not an exporter.

Protected memory buffers needed by the Panthor driver:

• On CSF FW load, the Panthor driver must allocate a protected buffer object to hold data to use by the FW when in protected mode. This protected buffer object is owned by the device and does not belong to a process.
• On CSG creation, the Panthor driver must allocate a protected suspend buffer object for the FW to store data when suspending the CSG while in protected mode. The kernel owns this allocation and does not allow user space mapping. The format of the data in this buffer is only known by the FW and does not need to be shared with other entities.

The driver will retrieve the protected heap using the name of the heap provided to the driver as module parameter.

I know it's what dma_heap_find asks for, but I wonder if it wouldn't be better in the device tree and lookup through the device node? heaps are going to have a node anyway, right?

This would allow you to have a default that works and not mess to much with the kernel parameters that aren't always easy to change for end-users.

Maxime