OSPI Boot

An Octal Serial Peripheral Interface (OSPI) Flash is populated on the SOM as a programmable nonvolatile storage and can also be leveraged as boot media. This guide will walk through how to flash the SOM’s OSPI via U-boot, followed by booting from OSPI. For more information on OSPI, please see the phyCORE-AM64x Hardware Manual.

Flashing the OSPI

The easiest way to access the SOM’s OSPI is to boot the SOM into U-Boot from an SD card (you may already be doing this). This guide will require a “Bootable SD card”, an SD card that has been flashed with the development kit’s BSP image. For instructions on how to create a bootable SD card, see this guide SD Card.

  • Power on the development kit and hit any key to stop in U-Boot.

    Note

    Be sure that you are booting the kit from SD card!

  • Within U-Boot, flash both SPLs and the U-Boot image into the OSPI storage device.

    Target (U-Boot)
     sf probe

 fatload mmc 1 $loadaddr tiboot3.bin
 sf update  $loadaddr 0x0 $filesize

 fatload mmc 1 $loadaddr tispl.bin
 sf update  $loadaddr 0x100000 $filesize

 fatload mmc 1 $loadaddr u-boot.img
 sf update  $loadaddr 0x300000 $filesize

  • Unplug power from the kit. Follow the next section “Boot from OSPI” to configure the hardware.

Boot from OSPI

The phyCORE-AM64x development kit is configured to boot from an SD Card slot by default. This guide will serve to provide basic steps for booting from the SOM’s onboard OSPI flash memory after it has been flashed.

  • Keep the bootable SD card inserted in the kit if you want to boot all the way into Linux.

    Due to the OSPI NOR Flash’s limited size, the steps above only flash the bootloader. The SD card still contains the kernel and root filesystem for the BSP image.

  • S10 should be ON

../_images/pb-07225_boot-ospi.png phyCORE-AM64x Boot Switches

Note

Be mindful of the switch orientation!

Initramfs with OSPI

You can also include an initramfs and kernel on the OSPI NOR, which will allow you to boot into Linux using OSPI. Again, you will need to be booted into U-Boot with an SD card, and this guide also expects that you have a USB drive with an initramfs image on it. The name of the initramfs image will vary depending on what machine you are using.

Target (U-Boot)
sf probe

fatload mmc 1 $loadaddr tiboot3.bin
sf update $loadaddr 0x0 $filesize

fatload mmc 1 $loadaddr tispl.bin
sf update $loadaddr 0x100000 $filesize

fatload mmc 1 $loadaddr u-boot.img
sf update $loadaddr 0x300000 $filesize

fatload mmc 1 $loadaddr k3-am642-phyboard-electra-rdk.dtb
sf update $loadaddr 0x740000 $filesize
setenv size_fdt $filesize

fatload mmc 1 $loadaddr Image
sf update $loadaddr 0x800000 $filesize
setenv size_kern $filesize

usb start

fatload usb 0 $loadaddr phytec-initramfs-image-phyboard-electra-am64xx-2.cpio.xz
sf update $loadaddr 0x1e00000 $filesize
setenv size_fs $filesize

saveenv

env export -c $loadaddr
sf update $loadaddr 0x700000 $filesize
sf update $loadaddr 0x720000 $filesize

Now change your board to OSPI boot mode using the boot switches as shown above.

Once you boot into linux, in order to populate the /dev directory, you must run the following command. Once /dev is populated, you can write to the eMMC.

Target (Linux)
mount -t devtmpfs udev /dev

Limitations with OSPI

Unfortunatly, only SOMs with 64MB or more of NOR have space for a root filesystem. If you do not have space for a root file system, PHYTEC recommends to load a Kernel and root filesystem via Ethernet.