OSPI Flash
==========

An Octal Serial Peripheral Interface (OSPI) Flash is populated on the SOM as a programmable nonvolatile storage. The OSPI interface supports single, dual, quad, or octal read/write access to the flash device. This guide will walk through how to read and write from the OSPI. The OSPI Flash can be used for a fast boot source, see the guide :ref:`FlashOSPI-62A` for more on booting from OSPI. For more information on the OSPI interface, see section 6.1.4 in the `Hardware Manual <https://www.phytec.com/product/phycore-am62a/#section-hardware-documentation>`_.


View Available NOR Partitions
-------------------------------

* Verify that the NOR interface was initialized properly.

.. code-block:: none
        :caption: Target (Linux)

        mtdinfo

.. code-block:: none
        :caption: Expected Output

        Count of MTD devices:           1
        Present MTD devices:            mtd0
        Sysfs interface supported:      yes

* View basic partition information.

.. code-block:: none
        :caption: Target (Linux)

        cat /proc/mtd

.. code-block:: none
        :caption: Expected Output

        dev: size erasesize name
        mtd0: 04000000 00020000 "fc40000.spi.0"

* More detailed information can be viewed using the "mtdinfo" command on a specific partition.

.. code-block:: none
        :caption: Target (Linux)

        mtdinfo /dev/mtd0

.. code-block:: none
        :caption: Expected Output

        mtd0
        Name:                           fc40000.spi.0
        Type:                           nor
        Eraseblock size:                131072 bytes, 128.0 KiB
        Amount of eraseblocks:          512 (67108864 bytes, 64.0 MiB)
        Minimum input/output unit size: 1 byte
        Sub-page size:                  1 byte
        Character device major/minor:   90:0
        Bad blocks are allowed:         false
        Device is writable:             true

Write to OSPI
---------------

* Create a random file equal to the size of the /dev/mtd0 partition (512 kBytes).

.. code-block:: none
        :caption: Target (Linux)

        dd if=/dev/urandom of=test.dat bs=1k count=512

.. code-block:: none
        :caption: Expected Output

        512+0 records in
        512+0 records out
        524288 bytes (524 kB, 512 KiB) copied, 0.0152006 s, 34.5 MB/s

* Copy the generated file to the mtd0 partition.

.. code-block:: none
        :caption: Target (Linux)

        flashcp -v test.dat /dev/mtd0

.. code-block:: none
        :caption: Expected Output

        Erasing blocks: 4/4 (100%)
        Writing data: 512k/512k (100%)
        Verifying data: 512k/512k (100%)

Read from OSPI
----------------

* Dump the contents of /dev/mtd0 partition to a new file:

.. code-block:: none
        :caption: Target (Linux)

        dd if=/dev/mtd0 of=read.dat bs=1k count=512


.. code-block:: none
        :caption: Expected Output

        512+0 records in
        512+0 records out
        524288 bytes (524 kB, 512 KiB) copied, 0.167633 s, 3.1 MB/s

* Verify that the output files were not corrupted during the transfer using md5sum.

.. code-block:: none
        :caption: Target (Linux)

        md5sum test.dat read.dat

.. code-block:: none
        :caption: Expected Output

        3497f295076c7ef96443b109ab9be333  test.dat
        3497f295076c7ef96443b109ab9be333  read.dat