76 lines
2.4 KiB
ReStructuredText
76 lines
2.4 KiB
ReStructuredText
.. _ipm_imx:
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i.MX IPM example
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################
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Overview
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********
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This simple example can be used with multicore i.MX SoCs containing a
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Messaging Unit peripheral. It reads the received data from the Messaging Unit
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using the IPM and transmits it back unchanged. The information about
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the received data is printed to the console. When sending the data back,
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it blocks until the data are read by the remote side.
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The i.MX Messaging Unit peripheral consists of four 32-bit transmit and receive
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registers. The sample uses the option :kconfig:`CONFIG_IPM_IMX_MAX_DATA_SIZE_4`,
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which effectively creates four IPM channels. Selecting the option
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:kconfig:`CONFIG_IPM_IMX_MAX_DATA_SIZE_8` or
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:kconfig:`CONFIG_IPM_IMX_MAX_DATA_SIZE_16` would result in two 64-bit channels
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or a single 128-bit channel respectively.
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Note that this is just a simple demo to demonstrate the i.MX IPM functionality
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and blocking sending of the data back is done in the interrupt handler, which
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would not be appropriate for a real world application.
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Building and Running the Zephyr Code
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************************************
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The sample requires that data are being sent by the remote core so it can echo
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it back. The other core is usually not running Zephyr but Linux on i.MX
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multicore processors.
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This project outputs data to the console.
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It can be built as follows:
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.. zephyr-app-commands::
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:zephyr-app: samples/subsys/ipc/ipm_imx
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:board: udoo_neo_full_m4
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:goals: build flash
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:compact:
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Follow the instructions in the :ref:`udoo_neo_full_m4` board documentation
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for how to load the Zephyr binary to the desired core and execute it.
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Building and Running the Linux Code
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***********************************
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The remote code is in the form of a loadable Linux kernel module. It creates
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four character devices /dev/mu0 till /dev/mu3, which are used to read data from
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and write data into the Messaging Unit.
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The remote code and the instructions how to build and run it are located at:
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https://source.codeaurora.org/external/imxsupport/imx-mu/
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Sample Output
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=============
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Typing this in the Linux console:
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.. code-block:: console
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# cat > /dev/mu0
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abcdefgh
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^D
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Results in the following output on the Zephyr side:
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.. code-block:: console
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***** Booting Zephyr OS v1.12.0-291-g8cc508b *****
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IPM initialized, data size = 4
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ipm_callback: id = 0, data = 0x03323130
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ipm_callback: id = 0, data = 0x03353433
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ipm_callback: id = 0, data = 0x03383736
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ipm_callback: id = 0, data = 0x02000a39
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