[RFC] zephyr: virtio i2c ram example

examples/zephyr/virtio_i2c_ram/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.13.1)
+# Copyright (c) 2023  STMicroelectronics
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+include($ENV{ZEPHYR_BASE}/cmake/app/boilerplate.cmake NO_POLICY_SCOPE)
+
+project(virtio_i2c_ram)
+
+zephyr_compile_definitions(
+  -DMETAL_MAX_DEVICE_REGIONS=2
+  -DVIRTIO_SLAVE_ONLY
+  )
+
+target_include_directories(app PRIVATE $ENV{ZEPHYR_BASE}/drivers)
+target_include_directories(app PRIVATE ${LIBMETAL_INCLUDE_DIR} ${OPENAMP_INCLUDE_DIR} ${PLATFORM_DIR})
+
+target_sources(app PRIVATE src/main_remote.c)
+target_sources(app PRIVATE src/mmio_table.c)
+
+target_include_directories(app PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/..)

examples/zephyr/virtio_i2c_ram/README.rst

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+.. _openAMP_sample:
+
+OpenAMP Sample Application
+##########################
+
+Overview
+********
+
+This application demonstrates how to use of virtio mmio to share an I2C bus between
+Zephyr and a remote processor. It is designed to implement an memory device
+connected on an I2C virtio bus.
+
+Currently this implementation don't use the OpenAMP virtio as not ready.
+
+requested Hardware
+*************************
+
+- compatible with:
+  - STM32MP115c-dk2 board
+
+Zephyr
+======
+
+.. code-block:: console
+
+   west build -b <target board> openamp-system-reference/examples/zephyr/virtio_i2c_ram
+
+Copy the binary file on the SDCard
+
+Linux console
+=============
+
+Open a serial Linux terminal (minicom, putty, etc.) and connect the board with the
+following settings:
+
+- Speed: 115200
+- Data: 8 bits
+- Parity: odd
+- Stop bits: 1
+
+Load and start the firmware:
+
+.. code-block:: console
+
+  echo -n <firmware_name.elf> > /sys/class/remoteproc/remoteproc0/firmware
+  echo start >/sys/class/remoteproc/remoteproc0/state
+
+
+This is the Linux console:
+
+1. Verify that the virtio I2C bus is preent
+
+.. code-block:: console
+
+  root@stm32mp1-disco-oss:~# i2cdetect -l
+  i2c-0   i2c             STM32F7 I2C(0x40012000)                 I2C adapter
+  i2c-1   i2c             STM32F7 I2C(0x5c002000)                 I2C adapter
+  i2c-2   i2c             i2c-0-mux (chan_id 0)                   I2C adapter
+  i2c-3   i2c             i2c_virtio at virtio bus 0              I2C adapter
+
+2. list devices on the virtio bus
+
+Two memory devices should be connected:
+- one 20 bytes memory at address 0x54 initialized with "123456789abcdefghij"
+- one 20 bytes memory at address 0x56 initialized with "klmnopqrstuvwxyz!:;"
+Verify that the virtio I2C bus is present
+
+.. code-block:: console
+
+  root@stm32mp1-disco-oss:~# i2cdetect -y 3
+       0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
+  00:                         -- -- -- -- -- -- -- --
+  10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+  20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+  30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+  40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+  50: -- -- -- -- 54 -- 56 -- -- -- -- -- -- -- -- --
+  60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+  70: -- -- -- -- -- -- -- --
+
+3. Update RAM device 0x54 at address 0x14 with value 4
+
+.. code-block:: console
+
+  root@stm32mp1-disco-oss:~# i2cget -y 3 0x54 14
+  0x66
+  root@stm32mp1-disco-oss:~# i2cset -y 3 0x54 14 0x25
+  root@stm32mp1-disco-oss:~# i2cget -y 3 0x54 14
+  0x25

examples/zephyr/virtio_i2c_ram/boards/stm32mp157c_dk2.overlay

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+/*
+ * Copyright (c) 2023, STMICROLECTRONICS
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	chosen {
+		/*
+		 * shared memory reserved for the inter-processor communication
+		 */
+		zephyr,ipc_shm = &mcusram3;
+		zephyr,ipc = &mailbox;
+	};
+
+	mcusram3: memory1@10050000 {
+		compatible = "mmio-sram";
+		reg = <0x10050000 DT_SIZE_K(64)>;
+	};
+};
+
+&mcusram {
+	reg = <0x10000000 DT_SIZE_K(256)>;
+};

examples/zephyr/virtio_i2c_ram/prj.conf

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+CONFIG_KERNEL_BIN_NAME="zephyr_virtio_i2c_eeprom"
+CONFIG_PRINTK=n
+CONFIG_IPM=y
+CONFIG_PLATFORM_SPECIFIC_INIT=n
+CONFIG_MAIN_STACK_SIZE=4096
+CONFIG_HEAP_MEM_POOL_SIZE=16384
+CONFIG_OPENAMP=y
+CONFIG_OPENAMP_MASTER=n
+CONFIG_OPENAMP_RSC_TABLE=y