Altera SoCFPGA
==============

Alteras SoCFPGA SoCs have a two-stage boot process. The first stage is
known as preloader which loads the second stage bootloader. barebox can act
as both the first and the second stage loader.
In barebox the preloader is called xload, so to build as a first stage loader,
build the ``socfpga-xload_defconfig``; for second stage use the normal
``socfpga_defconfig``.

Bootstrapping
-------------

The supported bootsource is a SD card. The Boot ROM searches for a partition of
type A2 and loads what it finds there. When barebox is placed in such a partition
it will then itself try and mount the second partition of the SD card, which must
be of type FAT32. On this partition barebox searches for a file called barebox.bin.

To boot barebox on a Terasic SoCkit, the procedure is as follows (sdb1 is the A2 and
sdb2 the FAT32 partition)::

  mount -t fat /dev/sdb2 /mnt
  make socfpga-xload_defconfig
  make
  make socfpga_defconfig
  make

barebox has now generated multiple files in the images directory. So for the SoCkit
proceed with::

  cat images/barebox-socfpga-sockit-xload.img > /dev/sdb1
  cp images/barebox-socfpga-sockit.img /mnt/barebox.bin
  umount /mnt

For the EBV Socrates use ``images/barebox-socfpga-socrates(-xload).img`` instead.

Updating handoff files
----------------------

(Tools needed: Quartus II + SoCEDS)

As barebox uses some of the autogenerated files from Quartus II, every
time Altera makes a new release, there might be some updates to the
handoff files. As these files are split up in the code base and generated
explicitely for some specific U-boot code base, some manual work might be
necessary.

The boardspecific files for `arch/arm/boards/<yourboard>` are:

* iocsr_config_cyclone5.c
* pinmux_config_cyclone5.c -> pinmux_config.c
* pll_config.h
* sdram/sdram_config.h -> sdram_config.h
* sequencer_auto.h
* sequencer_auto_ac_init.c
* sequencer_auto_inst_init.c
* sequencer_defines.h

To update the handoff files, the following procedure is necessary::

 1. Regenerate the project with Qsys
 2. Load up your project in Quartus II and assemble the design
 3. Go to the SoCEDS installation and run
    ``./embedded_command_shell.sh``
 4. Now run ``bsp-editor``
 5. Create a new BSP
 6. Select the directory `hps_isw_handoff/soc_system_hps_0` under the
    preloader settings directory
 7. Click ``Ok`` than ``Generate``

Now run the command::

  scripts/socfpga_import_preloader <SPL_GENERATED_DIR> <ISW_HANDOFF> <BOARD_DIRECTORY>

where `<SPL_GENERATED_DIR>` is the directory where the bsp-editor generated the files,
`<ISW_HANDOFF>` is the directory where Quartus generated the handoff files, and
`<BOARD_DIRECTORY>` is your board directory under `arch/arm/boards`.

The following files are generic and belong into the
`arch/arm/mach-socfpga` directory tree:

* sdram_io.h
* sequencer.c
* sequencer.h
* sequencer_defines.h
* system.h
* tclrpt.h

To add these files, run::

  scripts/socfpga_get_sequencer <UBOOT-SRC> scripts/socfpga_sequencer_defines_defaults

where `<UBOOT-SRC>` is the directory where the Altera bsp-editor generated the u-boot
directory. Refer to the Altera documentation for how to use the bsp-editor.