greybus: move copy of incoming request data

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>
greybus: short message is OK for errors

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>
greybus: pass result in gb_connection_recv_response()

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>
greybus: enforce non-zero operation type requirement

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>