OSPI NOR Flash

A 64 MB OSPI NOR Flash is populated on the phyCORE-AM65x development kit and is available for use as volatile or non-volatile memory. The NOR Flash is accessible through the OSPI interface and can also be used as an alternative boot source.

This guide will show you how to read from and write to the OSPI NOR.

Partition Information

To view the software-defined partitions for the OSPI NOR Flash, enter the following commands:
Target (Linux)
```
mtdinfo
cat /proc/mtd
```

You can expect an output similar to the one below. In this example the OSPI NOR Flash has 7 partitions.

Expected Output

root@am65xx-phycore-kit:~# mtdinfo
Count of MTD devices:           7
Present MTD devices:            mtd0, mtd1, mtd2, mtd3, mtd4, mtd5, mtd6
Sysfs interface supported:      yes

root@am65xx-phycore-rdk:~# cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00080000 00020000 "ospi.tiboot3"
mtd1: 00200000 00020000 "ospi.tispl"
mtd2: 00400000 00020000 "ospi.u-boot"
mtd3: 00020000 00020000 "ospi.env"
mtd4: 00020000 00020000 "ospi.env.backup"
mtd5: 00100000 00020000 "ospi.sysfw"
mtd6: 03800000 00020000 "ospi.rootfs"

If you would like to take a closer look at each partition you can run the following command:
Target (Linux)
```
mtdinfo /dev/mtd0
```

Below is the expected output. In this case you can see that the first partition of the OSPI NOR is named ospi.tiboot3 and is 512 kBytes.

Expected Output

root@am65xx-phycore-kit:~# mtdinfo /dev/mtd0
mtd0
Name:                           ospi.tiboot3
Type:                           nor
Eraseblock size:                131072 bytes, 128.0 KiB
Amount of eraseblocks:          4 (524288 bytes, 512.0 KiB)
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

Using this example you can create a random file equal in size to the /dev/mtd0 partition (512 kBytes) and transfer it to the OSPI NOR using the flashcp command. Run the following from the command line:
Target (Linux)
```
dd if=/dev/urandom of=test.dat bs=1k count=512
flashcp -v test.dat /dev/mtd0
```

Below is the expected output:

Expected Output

root@am65xx-phycore-kit:~# dd if=/dev/urandom of=test.dat bs=1k count=512
512+0 records in
512+0 records out

root@am65xx-phycore-kit:~# flashcp -v test.dat /dev/mtd0
Erasing blocks: 4/4 (100%)
Writing data: 512k/512k (100%)
Verifying data: 512k/512k (100%)

Read from OSPI

Going the opposite direction of the previous example, to read the OSPI NOR flash, you can dump the contents of /dev/mtd0 to a new file:
Target (Linux)
```
dd if=/dev/mtd0 of=read.dat bs=1k count=512
```
The file read (read.dat) should be identical to the file written in the previous example (test.dat). Use md5sum to compare and verify the data transfer was successful:
Target (Linux)
```
md5sum test.dat && md5sum read.dat
```

Below is the expected output:

Expected Output

root@am65xx-phycore-kit:~# dd if=/dev/mtd0 of=read.dat bs=1k count=512
512+0 records in
512+0 records out

root@am65xx-phycore-kit:~# md5sum test.dat && md5sum read.dat
066206f95d3d324048c55b6840998e0c  test.dat
066206f95d3d324048c55b6840998e0c  read.dat