boards: nordic: ipc: added dcache alignement

The nRF54 and nRF92 chips has data cache, which means the ICMsg and ICBMsg must be configured to follow required cache alignment of the shared memory. The `dcache-alignement` needs to be defined for that. Signed-off-by: Dominik Kilian <[email protected]>
zephyrproject-rtos · Oct 23, 2024 · bd932d1 · bd932d1
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diff --git a/boards/nordic/nrf54h20dk/nrf54h20dk_nrf54h20-ipc_conf.dtsi b/boards/nordic/nrf54h20dk/nrf54h20dk_nrf54h20-ipc_conf.dtsi
@@ -24,6 +24,7 @@
 
 		cpuapp_cpurad_ipc: ipc-2-3 {
 			compatible = "zephyr,ipc-icbmsg";
+			dcache-alignment = <32>;
 			status = "disabled";
 			mboxes = <&cpuapp_bellboard 18>,
 				 <&cpurad_bellboard 12>;

diff --git a/boards/nordic/nrf9280pdk/nrf9280pdk_nrf9280-ipc_conf.dtsi b/boards/nordic/nrf9280pdk/nrf9280pdk_nrf9280-ipc_conf.dtsi
@@ -24,6 +24,7 @@
 
 		cpuapp_cpurad_ipc: ipc-2-3 {
 			compatible = "zephyr,ipc-icbmsg";
+			dcache-alignment = <32>;
 			status = "disabled";
 			mboxes = <&cpuapp_bellboard 18>,
 				 <&cpurad_bellboard 12>;

diff --git a/doc/services/ipc/ipc_service/backends/ipc_service_icbmsg.rst b/doc/services/ipc/ipc_service/backends/ipc_service_icbmsg.rst
@@ -40,12 +40,21 @@ Configuration
 The backend is configured using Kconfig and devicetree.
 When configuring the backend, do the following:
 
+* If at least one of the cores uses data cache on shared memory, set the ``dcache-alignment`` value.
+  This must be the largest value of the invalidation or the write-back size for both sides of the communication.
+  You can skip it if none of the communication sides is using data cache on shared memory.
 * Define two memory regions and assign them to ``tx-region`` and ``rx-region`` of an instance.
   Ensure that the memory regions used for data exchange are unique (not overlapping any other region) and accessible by both domains (or CPUs).
 * Define the number of allocable blocks for each region with ``tx-blocks`` and ``rx-blocks``.
 * Define MBOX devices for sending a signal that informs the other domain (or CPU) of the written data.
   Ensure that the other domain (or CPU) can receive the signal.
 
+.. caution::
+
+    Make sure that you set correct value of the ``dcache-alignment``.
+    At first, wrong value may not show any signs, which may give a false impression that everything works.
+    Unstable behavior will appear sooner or later.
+
 See the following configuration example for one of the instances:
 
 .. code-block:: devicetree
@@ -63,6 +72,7 @@ See the following configuration example for one of the instances:
    ipc {
       ipc0: ipc0 {
          compatible = "zephyr,ipc-icbmsg";
+         dcache-alignment = <32>;
          tx-region = <&tx>;
          rx-region = <&rx>;
          tx-blocks = <16>;

diff --git a/doc/services/ipc/ipc_service/backends/ipc_service_icmsg.rst b/doc/services/ipc/ipc_service/backends/ipc_service_icmsg.rst
@@ -24,6 +24,9 @@ Configuration
 The  backend is configured via Kconfig and devicetree.
 When configuring the backend, do the following:
 
+* If at least one of the cores uses data cache on shared memory, set the ``dcache-alignment`` value.
+  This must be the largest value of the invalidation or the write-back size for both sides of the communication.
+  You can skip it if none of the communication sides is using data cache on shared memory.
 * Define two memory regions and assign them to ``tx-region`` and ``rx-region``
   of an instance. Ensure that the memory regions used for data exchange are
   unique (not overlapping any other region) and accessible by both domains
@@ -32,6 +35,12 @@ When configuring the backend, do the following:
   domain (or CPU) that data has been written. Ensure that the other domain
   (or CPU) is able to receive the signal.
 
+.. caution::
+
+    Make sure that you set correct value of the ``dcache-alignment``.
+    At first, wrong value may not show any signs, which may give a false impression that everything works.
+    Unstable behavior will appear sooner or later.
+
 See the following configuration example for one of the instances:
 
 .. code-block:: devicetree
@@ -49,6 +58,7 @@ See the following configuration example for one of the instances:
       ipc {
          ipc0: ipc0 {
             compatible = "zephyr,ipc-icmsg";
+            dcache-alignment = <32>;
             tx-region = <&tx>;
             rx-region = <&rx>;
             mboxes = <&mbox 0>, <&mbox 1>;

diff --git a/dts/bindings/ipc/zephyr,ipc-icmsg.yaml b/dts/bindings/ipc/zephyr,ipc-icmsg.yaml
@@ -32,7 +32,7 @@ properties:
       For example:
         Side A: no data cache
         Side B: 32 Bytes write-back size, 16 Bytes invalidation size
-        dcache-alignment = 32; for both
+        dcache-alignment = <32>; for both
 
   mboxes:
     description: phandle to the MBOX controller (TX and RX are required)

diff --git a/samples/subsys/ipc/ipc_service/icmsg/boards/nrf54l15dk_nrf54l15_cpuapp.overlay b/samples/subsys/ipc/ipc_service/icmsg/boards/nrf54l15dk_nrf54l15_cpuapp.overlay
@@ -23,6 +23,7 @@
 	ipc {
 		ipc0: ipc0 {
 			compatible = "zephyr,ipc-icmsg";
+			dcache-alignment = <32>;
 			tx-region = <&sram_tx>;
 			rx-region = <&sram_rx>;
 			mboxes = <&cpuapp_vevif_rx 20>, <&cpuapp_vevif_tx 21>;

diff --git a/samples/subsys/ipc/ipc_service/icmsg/boards/nrf54l15dk_nrf54l15_cpuapp_icbmsg.overlay b/samples/subsys/ipc/ipc_service/icmsg/boards/nrf54l15dk_nrf54l15_cpuapp_icbmsg.overlay
@@ -23,6 +23,7 @@
 	ipc {
 		ipc0: ipc0 {
 			compatible = "zephyr,ipc-icbmsg";
+			dcache-alignment = <32>;
 			tx-region = <&sram_tx>;
 			rx-region = <&sram_rx>;
 			tx-blocks = <16>;

diff --git a/samples/subsys/ipc/ipc_service/icmsg/remote/boards/nrf54l15dk_nrf54l15_cpuflpr.overlay b/samples/subsys/ipc/ipc_service/icmsg/remote/boards/nrf54l15dk_nrf54l15_cpuflpr.overlay
@@ -23,6 +23,7 @@
 	ipc {
 		ipc0: ipc0 {
 			compatible = "zephyr,ipc-icmsg";
+			dcache-alignment = <32>;
 			tx-region = <&sram_tx>;
 			rx-region = <&sram_rx>;
 			mboxes = <&cpuflpr_vevif_rx 21>, <&cpuflpr_vevif_tx 20>;

diff --git a/...les/subsys/ipc/ipc_service/icmsg/remote/boards/nrf54l15dk_nrf54l15_cpuflpr_icbmsg.overlay b/...les/subsys/ipc/ipc_service/icmsg/remote/boards/nrf54l15dk_nrf54l15_cpuflpr_icbmsg.overlay
@@ -23,6 +23,7 @@
 	ipc {
 		ipc0: ipc0 {
 			compatible = "zephyr,ipc-icbmsg";
+			dcache-alignment = <32>;
 			tx-region = <&sram_tx>;
 			rx-region = <&sram_rx>;
 			tx-blocks = <18>;

diff --git a/subsys/ipc/ipc_service/backends/ipc_icbmsg.c b/subsys/ipc/ipc_service/backends/ipc_icbmsg.c
@@ -1434,11 +1434,11 @@ const static struct ipc_service_backend backend_ops = {
 	};										\
 	BUILD_ASSERT(IS_POWER_OF_TWO(GET_CACHE_ALIGNMENT(i)),				\
 		     "This module supports only power of two cache alignment");		\
-	BUILD_ASSERT((GET_BLOCK_SIZE_INST(i, tx, rx) > GET_CACHE_ALIGNMENT(i)) &&	\
+	BUILD_ASSERT((GET_BLOCK_SIZE_INST(i, tx, rx) >= GET_CACHE_ALIGNMENT(i)) &&	\
 		     (GET_BLOCK_SIZE_INST(i, tx, rx) <					\
 		      GET_MEM_SIZE_INST(i, tx)),					\
 		     "TX region is too small for provided number of blocks");		\
-	BUILD_ASSERT((GET_BLOCK_SIZE_INST(i, rx, tx) > GET_CACHE_ALIGNMENT(i)) &&	\
+	BUILD_ASSERT((GET_BLOCK_SIZE_INST(i, rx, tx) >= GET_CACHE_ALIGNMENT(i)) &&	\
 		     (GET_BLOCK_SIZE_INST(i, rx, tx) <					\
 		      GET_MEM_SIZE_INST(i, rx)),					\
 		     "RX region is too small for provided number of blocks");		\