Code Update on FSP based machine
================================

There are three OPAL calls for code update on FSP based machine: ::

 #define OPAL_FLASH_VALIDATE	76
 #define OPAL_FLASH_MANAGE	77
 #define OPAL_FLASH_UPDATE	78

OPAL_FLASH_VALIDATE
-------------------

Validate new image is valid for this platform or not. We do below
validation in OPAL:

   - We do below sys parameters validation to confirm inband
     update is allowed.
     - Platform is managed by HMC or not?.
     - Code update policy (inband code update allowed?).

   - We parse candidate image header (first 4k bytes) to perform
     below validations.
     - Image magic number.
     - Image version to confirm image is valid for this platform.

Input
^^^^^
buffer
  First 4k bytes of new image

size
  Input buffer size

Output
^^^^^^

buffer
  Output result (current and new image version details)

size
  Output buffer size

result
  Token to identify what will happen if update is attempted
  See hw/fsp/fsp-codeupdate.h for token values.

Return value
^^^^^^^^^^^^
Validation status


OPAL_FLASH_MANAGE
-----------------
Commit/Reject image.

  - We can commit new image (T -> P), if system is running with T side image.
  - We can reject T side image, if system is running with P side image.

**Note:** If a platform is running from a T side image when an update is to be
applied, then the platform may automatically commit the current T side
image to the P side to allow the new image to be updated to the
temporary image area.

Input
^^^^^
op
  Operation (1 : Commit /0 : Reject)

Return value
    Commit operation status (0 : Success)

OPAL_FLASH_UPDATE
------------------
Update new image. It only sets the flag, actual update happens
during system reboot/shutdown.

Host splits FW image to scatter/gather list and sends it to OPAL.
OPAL parse the image to get indivisual LID and passes it to FSP
via MBOX command.

FW update flow :

    - if (running side == T)
        Swap P & T side
    - Start code update
    - Delete T side LIDs
    - Write LIDs
    - Code update complete
    - Deep IPL

Input
^^^^^
list
  Real address of image scatter/gather list of the FW image

Return value:
  Update operation status (0: update requested)