dt-bindings: sram: Add Baikal-T1 Boot SRAM bindingboot/bt1

Baikal-T1 is equipped with embedded SRAM of 64KB being accessed over the
AXI interconnect. It's normally used at the SoC startup procedure to
execute the system bootloader before the normal memory is initialized.
Alternatively the internal SRAM can be used to automatically pre-load a
bootloader code from external SPI-flash if corresponding Baikal-T1 Boot
mode is enabled, But functionally the later feature isn't that useful,
since SRAM is too small while the initial software can be XIP-ed right from
the SPI-flash and then download the system software from any place it
wants.

Baikal-T1 SRAM is clocked with a dedicated AXI-clock source and can be
reset by toggling the corresponding reset line. Due to the ability to
serve as a target of the system startup code pre-loading SRAM is connected
to the Baikal-T1 Boot Controller, which needs to be tuned in order to get
a direct access to the memory. The later is implemented in the framework
of the mux-controller functionality.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>

1 files changed, 42 insertions, 15 deletions

diff --git a/Documentation/devicetree/bindings/sram/sram.yaml b/Documentation/devicetree/bindings/sram/sram.yaml
index e9faffb64463..72bfd4cd78df 100644
--- a/Documentation/devicetree/bindings/sram/sram.yaml
+++ b/Documentation/devicetree/bindings/sram/sram.yaml
@@ -37,6 +37,7 @@ properties:
         - qcom,kaanapali-imem
         - qcom,rpm-msg-ram
         - rockchip,rk3288-pmu-sram
+        - baikal,bt1-sram
 
   reg:
     maxItems: 1
@@ -47,6 +48,15 @@ properties:
       A list of phandle and clock specifier pair that controls the single
       SRAM clock.
 
+  clock-names: true
+
+  resets:
+    description:
+      A list of phandle and reset specifier pair that controls the SRAM
+      state reset.
+
+  reset-names: true
+
   "#address-cells":
     const: 1
 
@@ -90,6 +100,7 @@ patternProperties:
             - arm,juno-scp-shmem
             - arm,scmi-shmem
             - arm,scp-shmem
+            - baikal,bt1-boot-sram
             - qcom,pil-reloc-info
             - renesas,smp-sram
             - rockchip,rk3066-smp-sram
@@ -144,21 +155,37 @@ required:
   - compatible
   - reg
 
-if:
-  not:
-    properties:
-      compatible:
-        contains:
-          enum:
-            - qcom,rpm-msg-ram
-            - rockchip,rk3288-pmu-sram
-then:
-  required:
-    - "#address-cells"
-    - "#size-cells"
-    - ranges
-
-additionalProperties: false
+allOf:
+  - $ref: /schemas/mux/mux-consumer.yaml#
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: baikal,bt1-sram
+    then:
+      properties:
+        mux-controls:
+          maxItems: 1
+      required:
+        - mux-controls
+    else:
+      properties:
+        mux-controls: false
+  - if:
+      properties:
+        compatible:
+          not:
+            contains:
+              enum:
+                - qcom,rpm-msg-ram
+                - rockchip,rk3288-pmu-sram
+    then:
+      required:
+        - "#address-cells"
+        - "#size-cells"
+        - ranges
+
+unevaluatedProperties: false
 
 examples:
   - |