On Wed, Oct 26, 2022 at 1:59 PM Elliot Berman [off-list ref] wrote:
.....

+
+        gunyah-resource-mgr@0 {
+            compatible = "gunyah-resource-manager-1-0", "gunyah-resource-manager";
+            interrupts = <GIC_SPI 3 IRQ_TYPE_EDGE_RISING>, /* TX full IRQ */
+                         <GIC_SPI 4 IRQ_TYPE_EDGE_RISING>; /* RX empty IRQ */
+            reg = <0x00000000 0x00000000>, <0x00000000 0x00000001>;
+                  /* TX, RX cap ids */
+        };

All these resources are used only by the mailbox controller driver.
So, this should be the mailbox controller node, rather than the
mailbox user.
One option is to load gunyah-resource-manager as a module that relies
on the gunyah-mailbox provider. That would also avoid the "Allow
direct registration to a channel" hack patch.

thanks.