[PATCH v2 1/2] dt-bindings: remoteproc: document AMD BRAM-based rproc

[Ben Levinsky <ben.levinsky@amd.com>]

Describe an AMD BRAM-based soft-core processor subsystem instantiated in
programmable logic and using dual-port BRAM for firmware storage and
execution.

The binding models a soft-core processor subsystem instantiated in AMD
programmable logic and using dual-port BRAM for firmware storage and
execution. The remoteproc device is represented as a child node whose
reg property describes the firmware memory window in the processor-local
address space. The parent bus node provides standard devicetree address
translation through ranges so Linux can access the same BRAM through the
system physical address space.

A clock input feeds the soft-core processor subsystem, and an active-low
reset GPIO holds the processor in reset until firmware loading
completes. The firmware-name property is optional.

Signed-off-by: Ben Levinsky <ben.levinsky@amd.com>
---
 .../bindings/remoteproc/amd,bram-rproc.yaml   | 98 +++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/remoteproc/amd,bram-rproc.yaml

diff --git a/Documentation/devicetree/bindings/remoteproc/amd,bram-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/amd,bram-rproc.yaml
new file mode 100644
index 000000000000..f16657dc0d9f
--- /dev/null
+++ b/Documentation/devicetree/bindings/remoteproc/amd,bram-rproc.yaml
@@ -0,0 +1,98 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/remoteproc/amd,bram-rproc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: AMD BRAM-based Remote Processor
+
+maintainers:
+  - Ben Levinsky <ben.levinsky@amd.com>
+
+description: |
+  Soft-core processor subsystem instantiated in AMD programmable logic and
+  using dual-port BRAM for firmware storage and execution.
+
+  Hardware Architecture:
+
+    Host (PS)                        Programmable Logic (PL)
+    =========                        ======================
+
+    AXI Interface -----------------> AXI BRAM Controller (Host Port)
+                                             |
+                                             | Port A
+                                             v
+                                     +-----------------+
+                                     |  Dual-Port BRAM |
+                                     | (shared memory) |
+                                     +-----------------+
+                                             ^
+                                             | Port B
+                                             |
+                                     AXI BRAM Controller (Soft-core Port)
+                                             ^
+                                             | LMB
+                                             |
+                                     Soft-core CPU (MicroBlaze/V)
+
+    GPIO --------------------------> Proc Sys Reset ----> CPU Reset Signal
+
+    Clock -------------------------> Clock Distribution -> CPU Clock
+
+  Memory Architecture:
+
+    The dual-port BRAM allows simultaneous access from both processors:
+      - Port A: Connected to the host AXI BRAM controller for firmware loading
+      - Port B: Connected to the soft-core local memory bus for execution
+
+  The reg property describes the executable BRAM window in the processor-local
+  address space. The parent bus node translates that window to the system
+  physical address space by using standard devicetree address translation
+  through ranges. A clock input and a reset GPIO control the subsystem.
+
+properties:
+  compatible:
+    const: amd,bram-rproc
+
+  reg:
+    maxItems: 1
+    description:
+      Processor-local address and size of the BRAM firmware memory window,
+      as seen by the soft-core processor (typically 0x0 for reset vector).
+      The parent bus ranges property must translate this window to the
+      corresponding system physical address.
+
+  clocks:
+    maxItems: 1
+    description:
+      Clock input for the soft-core processor subsystem.
+
+  firmware-name:
+    maxItems: 1
+    description:
+      Name of the firmware ELF file to load.
+
+  reset-gpios:
+    maxItems: 1
+    description:
+      GPIO specifier controlling the soft-core reset input.
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - reset-gpios
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    remoteproc@0 {
+      compatible = "amd,bram-rproc";
+      reg = <0x0 0x40000>;
+      clocks = <&pl_clk>;
+      firmware-name = "firmware.elf";
+      reset-gpios = <&gpio0 0 GPIO_ACTIVE_LOW>;
+    };
+...
-- 
2.34.1