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2.2 Management Path
This topic discusses programming interface between the device and the host. The management information
is encapsulated by means of the 'Proprietary Integrated Mechanism For Object Relay' (PIMFOR) and
conveyed between the host and device.
2.2.1 PIMFOR
Management information is modeled as a set of variables (or managed objects) residing in an internal
management information base (MIB). These objects can be queried for their value and/or can be set. Each
managed object is uniquely identified by an Object Identifier (OID). Each variable has an associated type that
has specific syntax and semantics with respect to the values it can take. For PIMFOR, however, these values
are opaque. PIMFOR simply conveys the value of the variable as an octet string; it doesn't convey type
information. It is the responsibility of senders and receivers of PIMFOR packets to know the type of a
variable, how to encode this type in an octet string, and syntactical and/or semantic constraints (if any) of
the variable when performing operations on it. The protocol purely acts as a transport of management
information. PIMFOR peers may assume correctly formatted packets and mutual understanding of the MIB.
This design decision is justified by the assumption that PIMFOR is meant to be a management interface
internal to a product (for example, between host driver and firmware). It is not meant to be used by third-
party applications directly. The generic packet interface of PIMFOR makes it suitable for a variety of other
situations where a simple form of management and control is desired.
2.2.1.1 PIMFOR Packet Format
Proprietary Integrated Mechanism For Object Relay (PIMFOR) was devised to fill the need for simple
management and configuration of NIC firmware through host driver.
The MAC implements a wealth of configurable objects, which are accessed by sm_conf() function to
configure the MAC. PIMFOR is also used by sm_trap() which is used for sending async traps from the MAC
to the driver. To access these objects from the host, the PIMFOR frame format is used over Mgmt queues of
the PCI protocol. In case of a get operation, the driver waits for the firmware to respond for the value and
then passes the response encapsulated in PIMFOR frame to the host.
2.2.1.2 PIMFOR Header Format
PIMFOR is a proprietary format. The PIMFOR header format is shown in below:
2-5
SHoC Driver Design
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