133 lines
4.1 KiB
ReStructuredText
133 lines
4.1 KiB
ReStructuredText
.. zephyr:code-sample:: ipm-ivshmem
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:name: IPM over IVSHMEM
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:relevant-api: ipm_interface
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Implement inter-processor mailbox (IPM) over IVSHMEM (Inter-VM shared memory)
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Prerequisites
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*************
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* QEMU needs to available.
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ivshmem-server needs to be available and running. The server is available in
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Zephyr SDK or pre-built in some distributions. Otherwise, it is available in
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QEMU source tree.
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ivshmem-client needs to be available as it is employed in this sample as an
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external application. The same conditions of ivshmem-server apply to the
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ivshmem-server, as it is also available via QEMU.
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Preparing IVSHMEM server
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************************
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#. The ivshmem-server utility for QEMU can be found into the Zephyr SDK
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directory, in:
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``/path/to/your/zephyr-sdk/zephyr-<version>/sysroots/x86_64-pokysdk-linux/usr/xilinx/bin/``
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#. You may also find ivshmem-client utility, it can be useful to check if everything works
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as expected.
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#. Run ivshmem-server. For the ivshmem-server, both number of vectors and
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shared memory size are decided at run-time (when the server is executed).
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For Zephyr, the number of vectors and shared memory size of ivshmem are
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decided at compile-time and run-time, respectively. For Arm64 we use
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vectors == 2 for the project configuration in this sample. Here is an example:
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.. code-block:: console
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# n = number of vectors
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$ sudo ivshmem-server -n 2
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$ *** Example code, do not use in production ***
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#. Appropriately set ownership of ``/dev/shm/ivshmem`` and
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``/tmp/ivshmem_socket`` for your deployment scenario. For instance:
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.. code-block:: console
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$ sudo chgrp $USER /dev/shm/ivshmem
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$ sudo chmod 060 /dev/shm/ivshmem
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$ sudo chgrp $USER /tmp/ivshmem_socket
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$ sudo chmod 060 /tmp/ivshmem_socket
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Building and Running
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********************
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After getting QEMU ready to go, first create two output folders, so open two terminals
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and create them, these folders will receive the output of Zephyr west commands:
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.. code-block:: console
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$ mkdir -p path/to/instance_1
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On another terminal window do:
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.. code-block:: console
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$ mkdir -p path/to/instance_2
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Then build the sample as follows, don't forget, two builds are necessary
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to test this sample, so append the option ``-d path/to/instance_1`` and
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on the other terminal window do the same, that is it ``-d path/to/instance_2``
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.. zephyr-app-commands::
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:zephyr-app: samples/drivers/ipm/ipm_ivshmem
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:board: qemu_cortex_a53
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:goals: build
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:compact:
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To run both QEMU sides, repeat the west build command followed
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by ``-d path/to/instance_x`` where x is 1 or 2 depending on the
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terminal window, using the run target:
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.. zephyr-app-commands::
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:zephyr-app: samples/drivers/ipm/ipm_ivshmem
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:board: qemu_cortex_a53
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:goals: run
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:compact:
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Expected output
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***************
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On the console just use the ``ivshmem_ipm_send`` command
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followed by the destination peer-id, to get the peer-id destination
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go to the other terminal window and check with ``ivshmem`` command:
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.. code-block:: console
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*** Booting Zephyr OS build zephyr-v3.4.0-974-g7fba7d395750 ***
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uart:~$ ivshmem
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IVshmem up and running:
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Shared memory: 0xafa00000 of size 4194304 bytes
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Peer id: 12
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Notification vectors: 2
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uart:~$
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For example one of the instances has the peer-id 12, so go the other
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instance and use the command to send the IPM notification followed
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by this peer-id:
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.. code-block:: console
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*** Booting Zephyr OS build zephyr-v3.4.0-974-g7fba7d395750 ***
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uart:~$ ivshmem
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IVshmem up and running:
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Shared memory: 0xafa00000 of size 4194304 bytes
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Peer id: 11
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Notification vectors: 2
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uart:~$ ivshmem_ipm_send 12
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Then go back to the other terminal window where user may see the reception
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of the notification on the terminal:
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.. code-block:: console
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uart:~$ ivshmem
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IVshmem up and running:
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Shared memory: 0xafa00000 of size 4194304 bytes
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Peer id: 12
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Notification vectors: 2
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uart:~$ Received IPM notification over IVSHMEM
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