OPAL Flash calls
================

There are three OPAL calls for interacting with flash devices: ::

 #define OPAL_FLASH_READ	110
 #define OPAL_FLASH_WRITE	111
 #define OPAL_FLASH_ERASE	112

Multiple flash devices are supported by OPAL - each of these calls takes an id
parameter, which must match an ID found in the corresponding ``ibm,opal/flash@n``
device tree node. See :ref:`device-tree/ibm,opal/flash` for details of
the device tree bindings.

All operations on the flash device must be aligned to the block size of the
flash. This applies to both offset and size arguments.

This interface is asynchronous; all calls require a 'token' argument. On
success, the calls will return ``OPAL_ASYNC_COMPLETION``, and an
opal_async_completion message will be sent (with the appropriate token
argument) when the operation completes.

All calls share the same return values:

``OPAL_ASYNC_COMPLETION``
  operation started, an async completion will be triggered with the ``token`` argument

``OPAL_PARAMETER``
  invalid flash id

``OPAL_PARAMETER``
  invalid size or offset (alignment, or access beyond end of device)

``OPAL_BUSY``
  flash in use

``OPAL_HARDWARE``
  error accessing flash device

OPAL_FLASH_READ
---------------

Parameters: ::

	uint64_t id
	uint64_t offset
	uint64_t buffer
	uint64_t size
	uint64_t token

Reads from the specified flash id, at the specified offset, into the buffer.
Will trigger an async completion with token when completed.

OPAL_FLASH_ERASE
----------------

Parameters: ::

	uint64_t id
	uint64_t offset
	uint64_t size
	uint64_t token

Erases the specified flash id, at the specified offset and size.  Will trigger
an async completion with token when completed.

OPAL_FLASH_WRITE
----------------

Parameters: ::

	uint64_t id
	uint64_t offset
	uint64_t buffer
	uint64_t size
	uint64_t token

Writes buffer to the specified flash id, at the specified offset and size. The
flash must be erased before being written. Will trigger an async completion with
token when completed.