QSPI NOR Flash
================

This guide will show you how to access the 16 MiB QSPI NOR Flash populated on the phyCORe-i.MX7 SOM. The NOR Flash is accessible through the QSPI interface and can also be used as an alternative boot source. This guide will show how to read from and write to the QSPI NOR.

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

* Make sure 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: 01000000 00010000 "30bb0000.spi"

* 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:                           30bb0000.spi
   Type:                           nor
   Eraseblock size:                65536 bytes, 64.0 KiB
   Amount of eraseblocks:          256 (16777216 bytes, 16.0 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

* Copy the generated file to the mtd0 partition using the "flashcp" command.

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

    flashcp -v test.dat /dev/mtd0

Reading 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

* Make sure the output file was not corrupted during the transfer using md5sum.

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

    md5sum test.dat read.dat

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

   90ba5a74fa335d7aef3af63d9b93070a  test.dat
   90ba5a74fa335d7aef3af63d9b93070a  read.dat