No need to keep these out in sysfs.c, move them into the
interface_block.c file so that we can see them easier, and remove some
variable definitions by taking advantage of the attribute group macro.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Documentation, what, really?

Yes.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

The sysfs files for an interface block should not have 'module' in them.
This was a hold-over from when we thought we were going to have
all attributes of a "module" in one directory.  Remove the prefix as
it's not needed, and is confusing considering modules can not have
strings or any of these attributes.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Rename struct gb_module to struct gb_interface_block

It's a complex rename, some functions got their name changed where
needed, but primarily this change is focused on the structure and where
it is used.  Future changes will clean up the remaining usages of the
term "module" in individual changes, this one spanned the whole
subsystem so do it all at once.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

"modules" in the driver model here, are really "interface blocks" as
that is what they are physically tied to.  So rename the files before we
start changing the code to make it obvious what is going on.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

We aren't using this anymore, so remove gb_tty from struct gb_module.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

We removed the module version from the spec, so remove them from the
code as well.  It's still in the manifest as we need to sync with gbsim
/ firmware when we do that, which will happen sometime in the next
weeks.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

No need to specifically include the greybus module.h here, greybus.h
already does so and we will be renaming it soon.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

In talking with Perry today I learned that the CPort id expected to
supplied over the HSIC interface to the APB is different from the
way I understood it.

My understanding was that the CPort id to supply always specified
the CPort id on the other end of a connection.  However, Perry says
the mapping between local CPort id and remote CPort id (and device
id) is done by the host UniPro interface.

So whether sending or receiving data, the CPort id that the Greybus
code should supply to the AP Bridge is the one representing the AP
side of a connection.

This patch fixes this.  The receive side already used that CPort id;
it's only the sending code that needed to be changed.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

When probing for i2c devices, a read transfer operation can be used.
In this case, it is expected that some devices will not be found, so
ENODEV is an expected failure.  Don't issue a warning if the return
value is -ENODEV.

Note:  I anticipate we might have to be more precise in identifying
this specific case, but for now this eliminates a bogus warning when
probing i2c devices.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

The i2c protocol needs a way to indicate an i2c device doesn't exist
(which is not necessarily an error).  Define GB_OP_NONEXISTENT to
indicate this, and updating the status<->errno mapping functions
accordingly.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

The version field is going to go away, but after the demo, not before.
Note that in the header file.
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

I've gone back and forth on this, but now that I'm looking at
asynchronous operations I know that the asynchronous callback will
want to know what type of operation it is handling, and right now
that's only available in the message header.

So record an operation's type in the operation structure, and use
it in a few spots where the header type was being used previously.
Pass the type to gb_operation_create_incoming() so it can fill
it in after the operation has been created.

Clean up the crap comments above the definition of the operation
structure.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Currently message->payload always points to the address immediately
following the header in a message.  If the payload length is 0, this
is not a valid pointer.

Change the code to assign a null pointer to the payload in this
case.  I have verified that no code dereferences the payload pointer
unless the payload is known to have non-zero size.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

An asynchronous operation will want to know how big the response
message it receives is.  Rather than require the sender to record
that information, expose a new field "payload_size" available to
the protocol code for this purpose.

An operation message consists of a header and a payload.  The size
of the message can be derived from the size of the payload, so
record only the payload size and not the size of the whole message.
Reorder the fields in a message structure.

Update the description of the message header structure.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

This is in preparation for an upcoming patch, which makes the
payload pointer be NULL when a message has zero bytes of payload.

It ensures a null payload pointer never gets dereferenced.  To do
this we pass the response structure to gb_i2c_transfer_response()
rather than just its data, and if it's null, returning immediately.

Rearrange the logic in gb_i2c_transfer_operation() a bit.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

The connection->private pointer should refer to a protocol-specific
data structure.  Change two protocol drivers (USB and vibrator) so
they now set this.

In addition, because the setup routine may need access to the
data structure, the private pointer should be set early--as
early as possible.  Make the UART, i2c, and GPIO protocol drivers
set the private pointer earlier.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

The error message printed by gb_operation_sync() if the operation
fails is wrong.  Fix it.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Define a new function used to initiate a synchronous operation.
It sends the operation request message and doesn't return until
the response has been received and/or the operation's result
has been set.

This gets rid of the convention that a null callback pointer
signifies a synchronous operation.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

There's no need to protect updating a connections operation id cycle
counter with the operations spinlock.   That spinlock protects
connection lists, which do not interact with the cycle counter.
All that we require is that it gets updated atomically, and we
can express that requirement in its type.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

A connection has two lists of operations, and an operation is always
on one or the other of them.  One of them contains the operations
that are currently "in flight".

We really don't expect to have very many in-flight operations on any
given connection (in fact, at the moment it's always exactly one).
So there's no significant performance benefit to keeping these in a
separate list.  An in-flight operation can also be distinguished by
its errno field holding -EINPROGRESS.

Get rid of the pending list, and search all operations rather than
the pending list when looking up a response message's operation.
Rename gb_pending_operation_find() accordingly.

There's no longer any need to remove operations from the pending
list, and the insertion function no longer has anything to do with a
pending list.  Just open code what was the insertion function (it
now has only to do with assigning the operation id).
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Stop allowing 0x0000 to be used as an operation id.  That id will be
reserved for use by operations that will return no response message.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Use a symbolic constant (rather than just "0") to represent an
explicitly invalid operation type.  The protocols have all reserved
that value for that purpose--this just makes it explicit in the core
code (since we now leverage its existence).  Fix the code so it uses
the new symbolic value.

Define it in "operation.h" for all to see.  Move the common
definition of the GB_OPERATION_TYPE_RESPONSE flag mask there
as well.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

The memcpy of request data into the request payload was
copying the data into the wrong location.  Fix that.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

The PWM config request defines two 32-bit values using u32. All
over-the-wire values have to be in little-endian format.  Fix this.
Signed-off-by: Alex Elder <elder@linaro.org>
Acked-by: Matt Porter <mporter@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Define a helper function gb_operation_response_alloc() and use it
to allocate the response buffer for outgoing operations in
gb_operation_create_common(.

Use it also in  gb_operation_response_send() if the caller has not
allocated a response buffer.

Once a response buffer is allocated, fill in its result code and
send it.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Define gb_operation_errno_map(), which maps an operation->errno
into the u8 value that represents it in the status field of an
operation response header.  It'll be used in an upcoming patch.

Make gb_operation_status_map() a private function.  It's not used
outside "operation.c" and I don't believe it ever should be.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Un-comment gb_operation_request_handle(), which was recently
disabled to avoid distraction.

In gb_connection_recv_request(), activate handling incoming
requests by defining gb_operation_request_handle() as an
incoming operation's callback function.

Incoming operation requests have
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Change gb_operation_response_send() so it takes an errno to assign
as an operation's result.  This emphasizes that setting the result
should be the last thing done to an incoming operation before
sending its response.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

A large number of request and response message types have no payload.
Such "simple" messages have a known, fixed maximum size, so we can
preallocate and use a pool (slab cache) of them.

Here are two benefits to doing this:
    - There can be (small) performance and memory utilization
      benefits to using a slab cache.
    - Error responses can be sent with no payload; the cache is
      likely to have a free entry to use for an error response even
      in a low memory situation.

The plan here is that an incoming request handler that has no
response payload to fill will not need to allocate a response
message.  If no message has been allocated when a response is to be
sent, one will be allocated from the cache by the core code.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Define a maximum size that a host device can use for its private
area ahead of the payload space used by Greybus in a message buffer.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Separate the allocation of a message structure from its basic
initialization.  This will allow very common fixed-size operation
response buffers to be allocated from a slab cache.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

When incoming data is going to be handled as a request, we create a
new operation whose request buffer will hold the received data.
There is no need to initialize the message header in such a request
buffer because it will be immediately overwritten.

Use operation type value of 0x00 in gb_operation_create_common()
to signal that we are creating an incoming operation, and therefore
do not need to initialize the request message header.  This allows
us to get rid of the Boolean "outgoing" parameter.

As a result, we can stop supplying the "type" parameter to both
gb_operation_create_incoming() and gb_connection_recv_request().

Update the header comments for gb_operation_message_alloc() and
gb_operation_create_common().
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

The operation type 0x00 is reserved as an explicitly invalid
operation type in all protocols.  Enforce this.

Add a check for callers who erroneously have the RESPONSE message
type flag set in the operation type passed in gb_operation_create().
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Pass the operation result to gb_connection_recv_response() as a
parameter.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

We enforce a rule that a response message must completely fill the
buffer that's been allocated to hold it.  However, if an error
occurs, the payload is off limits, so we should allow a short
message to convey an error result.

Change gb_connection_recv_response() to require the right message
size only if there's no error.

One other thing:  The arriving data is only being copied into the
response buffer if the request was successful.  That means the
response message header is assumed to have been initialized.  That
isn't a valid assumption.  So change it so that if an error is
seen, the header portion of the message is copied into the
response buffer--but only the header.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Currently incoming request data is copied into a request message
buffer in gb_connection_recv_request().  Move that--along with the
assignment of the message id--into gb_operation_create_incoming().
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

gb_connection_recv_request should be static, so mark it as such.
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Currently we issue a warning in gb_operation_work() if an operation
has no callback function defined.  But we return without dropping
the reference to the operation as we should.

Stop warning if there's no callback, call it only if it's defined,
and always drop the operation reference before returning.

This means we're now treating a NULL callback pointer as a normal
condition.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>