rocker: add register programming guide

This is the register programming guide for the Rocker device.  It's intended
for driver writers and device writers.  It covers the device's PCI space,
the register set, DMA interface, and interrupts.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Message-id: 1426306173-24884-4-git-send-email-sfeldma@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 1009 insertions, 0 deletions

diff --git a/docs/specs/rocker.txt b/docs/specs/rocker.txt
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+Rocker Network Switch Register Programming Guide
+Copyright (c) Scott Feldman <sfeldma@gmail.com>
+Copyright (c) Neil Horman <nhorman@tuxdriver.com>
+Version 0.11, 12/29/2014
+
+LICENSE
+=======
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+SECTION 1: Introduction
+=======================
+
+Overview
+--------
+
+This document describes the hardware/software interface for the Rocker switch
+device.  The intended audience is authors of OS drivers and device emulation
+software.
+
+Notations and Conventions
+-------------------------
+
+o In register descriptions, [n:m] indicates a range from bit n to bit m,
+inclusive.
+o Use of leading 0x indicates a hexadecimal number.
+o Use of leading 0b indicates a binary number.
+o The use of RSVD or Reserved indicates that a bit or field is reserved for
+future use.
+o Field width is in bytes, unless otherwise noted.
+o Register are (R) read-only, (R/W) read/write, (W) write-only, or (COR) clear
+on read
+o TLV values in network-byte-order are designated with (N).
+
+
+SECTION 2: PCI Configuration Registers
+======================================
+
+PCI Configuration Space
+-----------------------
+
+Each switch instance registers as a PCI device with PCI configuration space:
+
+	offset	width	description		value
+	---------------------------------------------
+	0x0	2	Vendor ID		0x1b36
+	0x2	2	Device ID		0x0006
+	0x4	4	Command/Status
+	0x8	1	Revision ID		0x01
+	0x9	3	Class code		0x2800
+	0xC	1	Cache line size
+	0xD	1	Latency timer
+	0xE	1	Header type
+	0xF	1	Built-in self test
+	0x10	4	Base address low
+	0x14	4	Base address high
+	0x18-28		Reserved
+	0x2C	2	Subsystem vendor ID	*
+	0x2E	2	Subsystem ID		*
+	0x30-38		Reserved
+	0x3C	1	Interrupt line
+	0x3D	1	Interrupt pin		0x00
+	0x3E	1	Min grant		0x00
+	0x3D	1	Max latency		0x00
+	0x40	1	TRDY timeout
+	0x41	1	Retry count
+	0x42	2	Reserved
+
+
+* Assigned by sub-system implementation
+
+SECTION 3: Memory-Mapped Register Space
+=======================================
+
+There are two memory-mapped BARs.  BAR0 maps device register space and is
+0x2000 in size.  BAR1 maps MSI-X vector and PBA tables and is also 0x2000 in
+size, allowing for 256 MSI-X vectors.
+
+All registers are 4 or 8 bytes long.  It is assumed host software will access 4
+byte registers with one 4-byte access, and 8 byte registers with either two
+4-byte accesses or a single 8-byte access.  In the case of two 4-byte accesses,
+access must be lower and then upper 4-bytes, in that order.
+
+BAR0 device register space is organized as follows:
+
+	offset		description
+	------------------------------------------------------
+	0x0000-0x000f	Bogus registers to catch misbehaving
+			drivers.  Writes do nothing.  Reads
+			back as 0xDEADBABE.
+	0x0010-0x00ff	Test registers
+	0x0300-0x03ff	General purpose registers
+	0x1000-0x1fff	Descriptor control
+
+Holes in register space are reserved.  Writes to reserved registers do nothing.
+Reads to reserved registers read back as 0.
+
+No fancy stuff like write-combining is enabled on any of the registers.
+
+BAR1 MSI-X register space is organized as follows:
+
+	offset		description
+	------------------------------------------------------
+	0x0000-0x0fff	MSI-X vector table (256 vectors total)
+	0x1000-0x1fff	MSI-X PBA table
+
+
+SECTION 4: Interrupts, DMA, and Endianness
+==========================================
+
+PCI Interrupts
+--------------
+
+The device supports only MSI-X interrupts.  BAR1 memory-mapped region contains
+the MSI-X vector and PBA tables, with support for up to 256 MSI-X vectors.
+
+The vector assignment is:
+
+	vector		description
+	-----------------------------------------------------
+	0		Command descriptor ring completion
+	1		Event descriptor ring completion
+	2		Test operation completion
+	3		RSVD
+	4-255		Tx and Rx descriptor ring completion
+			  Tx vector is even
+			  Rx vector is odd
+
+A MSI-X vector table entry is 16 bytes:
+
+	field		offset	width	description
+	-------------------------------------------------------------
+	lower_addr	0x0	4	[31:2] message address[31:2]
+					[1:0] Rsvd (4 byte alignment
+						    required)
+	upper_addr	0x4	4	[31:19] Rsvd
+					[14:0] message address[46:32]
+	data		0x8	4	message data[31:0]
+	control		0xc	4	[31:1] Rsvd
+					[0] mask (0 = enable,
+						  1 = masked)
+
+Software should install the Interrupt Service Routine (ISR) before any ports
+are enabled or any commands are issued on the command ring.
+
+DMA Operations
+--------------
+
+DMA operations are used for packet DMA to/from the CPU, command and event
+processing.  Command processing includes statistical counters and table dumps,
+table insertion/deletion, and more.  Event processing provides an async
+notification method for device-originating events.  Each DMA operation has a
+set of control registers to manage a descriptor ring.  The descriptor rings are
+allocated from contiguous host DMA-able memory and registers specify the rings
+base address, size and current head and tail indices.  Software always writes
+the head, and hardware always writes the tail.
+
+The higher-order bit of DMA_DESC_COMP_ERR is used to mark hardware completion
+of a descriptor.  Software will clear this bit when posting a descriptor to the
+ring, and hardware will set this bit when the descriptor is complete.
+
+Descriptor ring sizes must be a power of 2 and range from 2 to 64K entries.
+Descriptor rings' base address must be 8-byte aligned.  Descriptors must be
+packed within ring.  Each descriptor in each ring must also be aligned on an 8
+byte boundary.  Each descriptor ring will have these registers:
+
+	DMA_DESC_xxx_BASE_ADDR, offset 0x1000 + (x * 32), 64-bit, (R/W)
+	DMA_DESC_xxx_SIZE, offset 0x1008 + (x * 32), 32-bit, (R/W)
+	DMA_DESC_xxx_HEAD, offset 0x100c + (x * 32), 32-bit, (R/W)
+	DMA_DESC_xxx_TAIL, offset 0x1010 + (x * 32), 32-bit, (R)
+	DMA_DESC_xxx_CTRL, offset 0x1014 + (x * 32), 32-bit, (W)
+	DMA_DESC_xxx_CREDITS, offset 0x1018 + (x * 32), 32-bit, (R/W)
+	DMA_DESC_xxx_RSVD1, offset 0x101c + (x * 32), 32-bit, (R/W)
+
+Where x is descriptor ring index:
+
+	index		ring
+	--------------------
+	0		CMD
+	1		EVENT
+	2		TX (port 0)
+	3		RX (port 0)
+	4		TX (port 1)
+	5		RX (port 1)
+	.
+	.
+	.
+	124		TX (port 61)
+	125		RX (port 61)
+	126		Resv
+	127		Resv
+
+Writing BASE_ADDR or SIZE will reset HEAD and TAIL to zero.  HEAD cannot be
+written past TAIL.  To do so would wrap the ring.  An empty ring is when HEAD
+== TAIL.  A full ring is when HEAD is one position behind TAIL.  Both HEAD and
+TAIL increment and modulo wrap at the ring size.
+
+CTRL register bits:
+
+	bit	name		description
+	------------------------------------------------------------------------
+	[0]	CTRL_RESET	Reset the descriptor ring
+	[1:31]	Reserved
+
+All descriptor types share some common fields:
+
+	field			width	description
+	-------------------------------------------------------------------
+	DMA_DESC_BUF_ADDR	8	Phys addr of desc payload, 8-byte
+					aligned
+	DMA_DESC_COOKIE		8	Desc cookie for completion matching,
+					upper-most bit is reserved
+	DMA_DESC_BUF_SIZE	2	Desc payload size in bytes
+	DMA_DESC_TLV_SIZE	2	Desc payload total size in bytes
+					used for TLVs.  Must be <=
+					DMA_DESC_BUF_SIZE.
+	DMA_DESC_COMP_ERR	2	Completion status of associated
+					desc payload.  High order bit is
+					clear on new descs, toggled by
+					hw for completed items.
+
+To support forward- and backward-compatibility, descriptor and completion
+payloads are specified in TLV format.  Fields are packed with Type=field name,
+Length=field length, and Value=field value.  Software will ignore unknown fields
+filled in by the switch.  Likewise, the switch will ignore unknown fields
+filled in by software.
+
+Descriptor payload buffer is 8-byte aligned and TLVs are 8-byte aligned.  The
+value within a TLV is also 8-byte aligned.  The (packed, 8 byte) TLV header is:
+
+	field	width	description
+	-----------------------------
+	type	4	TLV type
+	len	2	TLV value length
+	pad	2	Reserved
+
+The alignment requirements for descriptors and TLVs are to avoid unaligned
+access exceptions in software.  Note that the payload for each TLV is also
+8 byte aligned.
+
+Figure 1 shows an example descriptor buffer with two TLVs.
+
+                  <------- 8 bytes ------->
+
+  8-byte  +––––+  +–––––––––––+–––––+–––––+                     +–+
+  align           |   type    | len | pad |    TLV#1 hdr          |
+                  +–––––––––––+–––––+–––––+    (len=22)           |
+                  |                       |                       |
+                  |  value                |    TVL#1 value        |
+                  |                       |    (padded to 8-byte  |
+                  |                 +–––––+     alignment)        |
+                  |                 |/////|                       |
+   8-byte +––––+  +–––––––––––+–––––––––––+                       |
+   align          |   type    | len | pad |    TLV#2 hdr    DESC_BUF_SIZE
+                  +–––––+–––––+–––––+–––––+    (len=2)            |
+                  |value|/////////////////|    TLV#2 value        |
+                  +–––––+/////////////////|                       |
+                  |///////////////////////|                       |
+                  |///////////////////////|                       |
+                  |///////////////////////|                       |
+                  |////////unused/////////|                       |
+                  |////////space//////////|                       |
+                  |///////////////////////|                       |
+                  |///////////////////////|                       |
+                  |///////////////////////|                       |
+                  +–––––––––––––––––––––––+                     +–+
+
+				fig. 1
+
+TLVs can be nested within the NEST TLV type.
+
+Interrupt credits
+^^^^^^^^^^^^^^^^^
+
+MSI-X vectors used for descriptor ring completions use a credit mechanism for
+efficient device, PCIe bus, OS and driver operations.  Each descriptor ring has
+a credit count which represents the number of outstanding descriptors to be
+processed by the driver.  As the device marks descriptors complete, the credit
+count is incremented.  As the driver processes those outstanding descriptors,
+it returns credits back to the device.  This way, the device knows the driver's
+progress and can make decisions about when to fire the next interrupt or not.
+When the credit count is zero, and the first descriptors are posted for the
+driver, a single interrupt is fired.  Once the interrupt is fired, the
+interrupt is disabled (auto-masked*).  In response to the interrupt, the driver
+will process descriptors and PIO write a returned credit value for that
+descriptor ring.  If the driver returns all credits (the driver caught up with
+the device and there is no outstanding work), then the interrupt is unmasked,
+but not fired.  If only partial credits are returned, the interrupt remains
+masked but the device generates an interrupt, signaling the driver that more
+outstanding work is available.
+
+(* this masking is unrelated to to the MSI-X interrupt mask register)
+
+Endianness
+----------
+
+Device registers are hard-coded to little-endian (LE).  The driver should
+convert to/from host endianess to LE for device register accesses.
+
+Descriptors are LE.  Descriptor buffer TLVs will have LE type and length
+fields, but the value field can either be LE or network-byte-order, depending
+on context.  TLV values containing network packet data will be in network-byte
+order.  A TLV value containing a field or mask used to compare against network
+packet data is network-byte order.  For example, flow match fields (and masks)
+are network-byte-order since they're matched directly, byte-by-byte, against
+network packet data.  All non-network-packet TLV multi-byte values will be LE.
+
+TLV values in network-byte-order are designated with (N).
+
+
+SECTION 5: Test Registers
+=========================
+
+Rocker has several test registers to support troubleshooting register access,
+interrupt generation, and DMA operations:
+
+	TEST_REG, offset 0x0010, 32-bit (R/W)
+	TEST_REG64, offset 0x0018, 64-bit (R/W)
+	TEST_IRQ, offset 0x0020, 32-bit (R/W)
+	TEST_DMA_ADDR, offset 0x0028, 64-bit (R/W)
+	TEST_DMA_SIZE, offset 0x0030, 32-bit (R/W)
+	TEST_DMA_CTRL, offset 0x0034, 32-bit (R/W)
+
+Reads to TEST_REG and TEST_REG64 will read a value equal to twice the last
+value written to the register.  The 32-bit and 64-bit versions are for testing
+32-bit and 64-bit host accesses.
+
+A vector can be written to TEST_IRQ and the device will generate an interrupt
+for that vector.
+
+To test basic DMA operations, allocate a DMA-able host buffer and put the
+buffer address into TEST_DMA_ADDR and size into TEST_DMA_SIZE.  Then, write to
+TEST_DMA_CTRL to manipulate the buffer contents.  TEST_DMA_CTRL operations are:
+
+	operation		value	description
+	-----------------------------------------------------------
+	TEST_DMA_CTRL_CLEAR	1	clear buffer
+	TEST_DMA_CTRL_FILL	2	fill buffer bytes with 0x96
+	TEST_DMA_CTRL_INVERT	4	invert bytes in buffer
+
+Various buffer address and sizes should be tested to verify no address boundary
+issue exists.  In particular, buffers that start on odd-8-byte boundary and/or
+span multiple PAGE sizes should be tested.
+
+
+SECTION 6: Ports
+================
+
+Physical and Logical Ports
+------------------------------------
+
+The switch supports up to 62 physical (front-panel) ports.  Register
+PORT_PHYS_COUNT returns the actual number of physical ports available:
+
+	PORT_PHYS_COUNT, offset 0x0304, 32-bit, (R)
+
+In addition to front-panel ports, the switch supports logical ports for
+tunnels.
+
+Front-panel ports and logical tunnel ports are mapped into a single 32-bit port
+space.  A special CPU port is assigned port 0.  The front-panel ports are
+mapped to ports 1-62.  A special loopback port is assigned port 63.  Logical
+tunnel ports are assigned ports 0x0001000-0x0001ffff.
+To summarize the port assignments:
+
+	port			mapping
+	-------------------------------------------------------
+	0			CPU port (for packets to/from host CPU)
+	1-62			front-panel physical ports
+	63			loopback port
+	64-0x0000ffff		RSVD
+	0x00010000-0x0001ffff	logical tunnel ports
+	0x00020000-0xffffffff	RSVD
+
+Physical Port Mode
+------------------
+
+Switch front-panel ports operate in a mode.  Currently, the only mode is
+OF-DPA.  OF-DPA[1] mode is based on OpenFlow Data Plane Abstraction (OF-DPA)
+Abstract Switch Specification, Version 1.0, from Broadcom Corporation.  To
+set/get the mode for front-panel ports, see port settings, below.
+
+Port Settings
+-------------
+
+Link status for all front-panel ports is available via PORT_PHYS_LINK_STATUS:
+
+	PORT_PHYS_LINK_STATUS, offset 0x0310, 64-bit, (R)
+
+	Value is port bitmap.  Bits 0 and 63 always read 0.  Bits 1-62
+	read 1 for link UP and 0 for link DOWN for respective front-panel ports.
+
+Other properties for front-panel ports are available via DMA CMD descriptors:
+
+	Get PORT_SETTINGS descriptor:
+
+		field		width	description
+		----------------------------------------------
+		PORT_SETTINGS	2	CMD_GET
+		PPORT		4	Physical port #
+
+	Get PORT_SETTINGS completion:
+
+		field		width	description
+		----------------------------------------------
+		PPORT		4	Physical port #
+		SPEED		4	Current port interface speed, in Mbps
+		DUPLEX		1	1 = Full, 0 = Half
+		AUTONEG		1	1 = enabled, 0 = disabled
+		MACADDR		6	Port MAC address
+		MODE		1	0 = OF-DPA
+		LEARNING	1	MAC address learning on port
+						1 = enabled
+						0 = disabled
+
+	Set PORT_SETTINGS descriptor:
+
+		field		width	description
+		----------------------------------------------
+		PORT_SETTINGS	2	CMD_SET
+		PPORT		4	Physical port #
+		SPEED		4	Port interface speed, in Mbps
+		DUPLEX		1	1 = Full, 0 = Half
+		AUTONEG		1	1 = enabled, 0 = disabled
+		MACADDR		6	Port MAC address
+		MODE		1	0 = OF-DPA
+
+Port Enable
+-----------
+
+Front-panel ports are initially disabled, which means port ingress and egress
+packets will be dropped.  To enable or disable a port, use PORT_PHYS_ENABLE:
+
+	PORT_PHYS_ENABLE: offset 0x0318, 64-bit, (R/W)
+
+	Value is bitmap of first 64 ports.  Bits 0 and 63 are ignored
+	and always read as 0.  Write 1 to enable port; write 0 to disable it.
+	Default is 0.
+
+
+SECTION 7: Switch Control
+=========================
+
+This section covers switch-wide register settings.
+
+Control
+-------
+
+This register is used for low level control of the switch.
+
+	CONTROL: offset 0x0300, 32-bit, (W)
+
+	bit	name		description
+	------------------------------------------------------------------------
+	[0]	CONTROL_RESET	If set, device will perform reset
+	[1:31]	Reserved
+
+Switch ID
+---------
+
+The switch has a SWITCH_ID to be used by software to uniquely identify the
+switch:
+
+	SWITCH_ID: offset 0x0320, 64-bit, (R)
+
+	Value is opaque to switch software and no special encoding is implied.
+
+
+SECTION 8: Events
+=================
+
+Non-I/O asynchronous events from the device are notified to the host using the
+event ring.  The TLV structure for events is:
+
+	field		width	description
+	---------------------------------------------------
+	TYPE		4	Event type, one of:
+					1: LINK_CHANGED
+					2: MAC_VLAN_SEEN
+	INFO		<nest>	Event info (details below)
+
+Link Changed Event
+------------------
+
+When link status changes on a physical port, this event is generated.
+
+	field		width	description
+	---------------------------------------------------
+	INFO		<nest>
+	  PPORT		4	Physical port
+	  LINKUP	1	Link status:
+					0: down
+					1: up
+
+MAC VLAN Seen Event
+-------------------
+
+When a packet ingresses on a port and the source MAC/VLAN isn't known to the
+device, the device will generate this event.  In response to the event, the
+driver should install to the device the MAC/VLAN on the port into the bridge
+table.  Once installed, the MAC/VLAN is known on the port and this event will
+no longer be generated.
+
+	field		width	description
+	---------------------------------------------------
+	INFO		<nest>
+	  PPORT		4	Physical port
+	  MAC		6	MAC address
+	  VLAN		2	VLAN ID
+
+
+SECTION 9: CPU Packet Processing
+================================
+
+Ingress packets directed to the host CPU for further processing are delivered
+in the DMA RX ring.  Likewise, host CPU originating packets destined to egress
+on switch ports are scheduled by software using the DMA TX ring.
+
+Tx Packet Processing
+--------------------
+
+Software schedules packets for egress on switch ports using the DMA TX ring.  A
+TX descriptor buffer describes the packet location and size in host DMA-able
+memory, the destination port, and any hardware-offload functions (such as L3
+payload checksum offload).  Software then bumps the descriptor head to signal
+hardware of new Tx work.  In response, hardware will DMA read Tx descriptors up
+to head, DMA read descriptor buffer and packet data, perform offloading
+functions, and finally frame packet on wire (network).  Once packet processing
+is complete, hardware will writeback status to descriptor(s) to signal to
+software that Tx is complete and software resources (e.g. skb) backing packet
+can be released.
+
+Figure 2 shows an example 3-fragment packet queued with one Tx descriptor.  A
+TLV is used for each packet fragment.
+
+	                                           pkt frag 1
+	                                           +–––––––+  +–+
+	                                       +–––+       |    |
+	                         desc buf      |   |       |    |
+	                        +––––––––+     |   |       |    |
+	        Tx ring     +–––+        +–––––+   |       |    |
+	      +–––––––––+   |   |  TLVs  |         +–––––––+    |
+	      |         +–––+   +––––––––+         pkt frag 2   |
+	      | desc 0  |       |        +–––––+   +–––––––+    |
+	      +–––––––––+       |  TLVs  |     +–––+       |    |
+	head+–+         |       +––––––––+         |       |    |
+	      | desc 1  |       |        +–––––+   +–––––––+    |pkt
+	      +–––––––––+       |  TLVs  |     |                |
+	      |         |       +––––––––+     |   pkt frag 3   |
+	      |         |                      |   +–––––––+    |
+	      +–––––––––+                      +–––+       |    |
+	      |         |                          |       |    |
+	      |         |                          |       |    |
+	      +–––––––––+                          |       |    |
+	      |         |                          |       |    |
+	      |         |                          |       |    |
+	      +–––––––––+                          |       |    |
+	      |         |                          +–––––––+  +–+
+	      |         |
+	      +–––––––––+
+
+				fig 2.
+
+The TLVs for Tx descriptor buffer are:
+
+	field			width	description
+	---------------------------------------------------------------------
+	PPORT			4	Destination physical port #
+	TX_OFFLOAD		1	Hardware offload modes:
+					  0: no offload
+					  1: insert IP csum (ipv4 only)
+					  2: insert TCP/UDP csum
+					  3: L3 csum calc and insert
+                        	             into csum offset (TX_L3_CSUM_OFF)
+                 	                    16-bit 1's complement csum value.
+                                	     IPv4 pseudo-header and IP
+                        	             already calculated by OS
+                  	                   and inserted.
+					  4: TSO (TCP Segmentation Offload)
+	TX_L3_CSUM_OFF		2	For L3 csum offload mode, the offset,
+					from the beginning of the packet,
+					of the csum field in the L3 header
+	TX_TSO_MSS		2	For TSO offload mode, the
+					Maximum Segment Size in bytes
+        TX_TSO_HDR_LEN		2	For TSO offload mode, the
+					length of ethernet, IP, and
+					TCP/UDP headers, including IP
+					and TCP options.
+	TX_FRAGS		<array>	Packet fragments
+	  TX_FRAG		<nest>	Packet fragment
+	    TX_FRAG_ADDR	8	DMA address of packet fragment
+	    TX_FRAG_LEN		2	Packet fragment length
+
+Possible status return codes in descriptor on completion are:
+
+	DESC_COMP_ERR	reason
+	--------------------------------------------------------------------
+	0		OK
+	-ROCKER_ENXIO	address or data read err on desc buf or packet
+			fragment
+	-ROCKER_EINVAL	bad pport or TSO or csum offloading error
+	-ROCKER_ENOMEM	no memory for internal staging tx fragment
+
+Rx Packet Processing
+--------------------
+
+For packets ingressing on switch ports that are not forwarded by the switch but
+rather directed to the host CPU for further processing are delivered in the DMA
+RX ring.  Rx descriptor buffers are allocated by software and placed on the
+ring.  Hardware will fill Rx descriptor buffers with packet data, write the
+completion, and signal to software that a new packet is ready.  Since Rx packet
+size is not known a-priori, the Rx descriptor buffer must be allocated for
+worst-case packet size.  A single Rx descriptor will contain the entire Rx
+packet data in one RX_FRAG.  Other Rx TLVs describe and hardware offloads
+performed on the packet, such as checksum validation.
+
+The TLVs for Rx descriptor buffer are:
+
+	field		width	description
+	---------------------------------------------------
+	PPORT		4	Source physical port #
+	RX_FLAGS	2	Packet parsing flags:
+				  (1 << 0): IPv4 packet
+				  (1 << 1): IPv6 packet
+				  (1 << 2): csum calculated
+				  (1 << 3): IPv4 csum good
+				  (1 << 4): IP fragment
+				  (1 << 5): TCP packet
+				  (1 << 6): UDP packet
+				  (1 << 7): TCP/UDP csum good
+	RX_CSUM		2	IP calculated checksum:
+				  IPv4: IP payload csum
+				  IPv6: header and payload csum
+				(Only valid is RX_FLAGS:csum calc is set)
+	RX_FRAG_ADDR	8	DMA address of packet fragment
+	RX_FRAG_MAX_LEN	2	Packet maximum fragment length
+	RX_FRAG_LEN	2	Actual packet fragment length after receive
+
+Possible status return codes in descriptor on completion are:
+
+	DESC_COMP_ERR	reason
+	--------------------------------------------------------------------
+	0		OK
+	-ROCKER_ENXIO	address or data read err on desc buf
+	-ROCKER_ENOMEM	no memory for internal staging desc buf
+	-ROCKER_EMSGSIZE Rx descriptor buffer wasn't big enough to contain
+			packet data TLV and other TLVs.
+
+
+SECTION 10: OF-DPA Mode
+======================
+
+OF-DPA mode allows the switch to offload flow packet processing functions to
+hardware.  An OpenFlow controller would communicate with an OpenFlow agent
+installed on the switch.  The OpenFlow agent would (directly or indirectly)
+communicate with the Rocker switch driver, which in turn would program switch
+hardware with flow functionality, as defined in OF-DPA.  The block diagram is:
+
+		+–––––––––––––––----–––+
+		|        OF            |
+		|  Remote Controller   |
+		+––––––––+––----–––––––+
+		         |
+		         |
+		+––––––––+–––––––––+
+		|       OF         |
+		|   Local Agent    |
+		+––––––––––––––––––+
+		|                  |
+		|   Rocker Driver  |
+		+––––––––––––––––––+
+		    <this spec>
+		+––––––––––––––––––+
+		|                  |
+		|   Rocker Switch  |
+		+––––––––––––––––––+
+
+To participate in flow functions, ports must be configure for OF-DPA mode
+during switch initialization.
+
+OF-DPA Flow Table Interface
+---------------------------
+
+There are commands to add, modify, delete, and get stats of flow table entries.
+The commands are issued using the DMA CMD descriptor ring.  The following
+commands are defined:
+
+	CMD_ADD:		add an entry to flow table
+	CMD_MOD:		modify an entry in flow table
+	CMD_DEL:		delete an entry from flow table
+	CMD_GET_STATS:		get stats for flow entry
+
+TLVs for add and modify commands are:
+
+	field			width	description
+	----------------------------------------------------
+	OF_DPA_CMD		2	CMD_[ADD|MOD]
+	OF_DPA_TBL		2	Flow table ID
+					  0: ingress port
+					  10: vlan
+					  20: termination mac
+					  30: unicast routing
+					  40: multicast routing
+					  50: bridging
+					  60: ACL policy
+	OF_DPA_PRIORITY		4	Flow priority
+	OF_DPA_HARDTIME		4	Hard timeout for flow
+	OF_DPA_IDLETIME		4	Idle timeout for flow
+	OF_DPA_COOKIE		8	Cookie
+
+Additional TLVs based on flow table ID:
+
+Table ID 0: ingress port
+
+	field			width	description
+	----------------------------------------------------
+	OF_DPA_IN_PPORT		4	ingress physical port number
+	OF_DPA_GOTO_TBL		2	goto table ID; zero to drop
+
+Table ID 10: vlan
+
+	field			width	description
+	----------------------------------------------------
+	OF_DPA_IN_PPORT		4	ingress physical port number
+	OF_DPA_VLAN_ID		2 (N)	vlan ID
+	OF_DPA_VLAN_ID_MASK	2 (N)	vlan ID mask
+	OF_DPA_GOTO_TBL		2	goto table ID; zero to drop
+	OF_DPA_NEW_VLAN_ID	2 (N)	new vlan ID
+
+Table ID 20: termination mac
+
+	field			width	description
+	----------------------------------------------------
+	OF_DPA_IN_PPORT		4	ingress physical port number
+	OF_DPA_IN_PPORT_MASK	4	ingress physical port number mask
+	OF_DPA_ETHERTYPE	2 (N)	must be either 0x0800 or 0x86dd
+	OF_DPA_DST_MAC		6 (N)	destination MAC
+	OF_DPA_DST_MAC_MASK	6 (N)	destination MAC mask
+	OF_DPA_VLAN_ID		2 (N)	vlan ID
+	OF_DPA_VLAN_ID_MASK	2 (N)	vlan ID mask
+	OF_DPA_GOTO_TBL		2	only acceptable values are
+					unicast or multicast routing
+					table IDs
+	OF_DPA_OUT_PPORT	2	if specified, must be
+					controller, set zero otherwise
+
+Table ID 30: unicast routing
+
+	field			width	description
+	----------------------------------------------------
+	OF_DPA_ETHERTYPE	2 (N)	must be either 0x0800 or 0x86dd
+	OF_DPA_DST_IP		4 (N)	destination IPv4 address.
+					Must be unicast address
+	OF_DPA_DST_IP_MASK	4 (N)	IP mask.  Must be prefix mask
+	OF_DPA_DST_IPV6		16 (N)	destination IPv6 address.
+					Must be unicast address
+	OF_DPA_DST_IPV6_MASK	16 (N)	IPv6 mask. Must be prefix mask
+	OF_DPA_GOTO_TBL		2	goto table ID; zero to drop
+	OF_DPA_GROUP_ID		4	data for GROUP action must
+					be an L3 Unicast group entry
+
+Table ID 40: multicast routing
+
+	field			width	description
+	----------------------------------------------------
+	OF_DPA_ETHERTYPE	2 (N)	must be either 0x0800 or 0x86dd
+	OF_DPA_VLAN_ID		2 (N)	vlan ID
+	OF_DPA_SRC_IP		4 (N)	source IPv4. Optional,
+					can contain IPv4 address,
+					must be completely masked
+					if not used
+	OF_DPA_SRC_IP_MASK	4 (N)	IP Mask
+	OF_DPA_DST_IP		4 (N)	destination IPv4 address.
+					Must be multicast address
+	OF_DPA_SRC_IPV6		16 (N)	source IPv6 Address. Optional.
+					Can contain IPv6 address,
+					must be completely masked
+					if not used
+	OF_DPA_SRC_IPV6_MASK	16 (N)	IPv6 mask.
+	OF_DPA_DST_IPV6		16 (N)	destination IPv6 Address. Must
+					be multicast address
+					Must be multicast address
+	OF_DPA_GOTO_TBL		2	goto table ID; zero to drop
+	OF_DPA_GROUP_ID		4	data for GROUP action must
+					be an L3 multicast group entry
+
+Table ID 50: bridging
+
+	field			width	description
+	----------------------------------------------------
+	OF_DPA_VLAN_ID		2 (N)	vlan ID
+	OF_DPA_TUNNEL_ID	4	tunnel ID
+	OF_DPA_DST_MAC		6 (N)	destination MAC
+	OF_DPA_DST_MAC_MASK	6 (N)	destination MAC mask
+	OF_DPA_GOTO_TBL		2	goto table ID; zero to drop
+	OF_DPA_GROUP_ID		4	data for GROUP action must
+					be a L2 Interface, L2
+					Multicast, L2 Flood,
+					or L2 Overlay group entry
+					as appropriate
+	OF_DPA_TUNNEL_LPORT	4	unicast Tenant Bridging
+					flows specify a tunnel
+					logical port ID
+	OF_DPA_OUT_PPORT	2	data for OUTPUT action,
+					restricted to CONTROLLER,
+					set to 0 otherwise
+
+Table ID 60: acl policy
+
+	field			width	description
+	----------------------------------------------------
+	OF_DPA_IN_PPORT		4	ingress physical port number
+	OF_DPA_IN_PPORT_MASK	4	ingress physical port number mask
+	OF_DPA_ETHERTYPE	2 (N)	ethertype
+	OF_DPA_VLAN_ID		2 (N)	vlan ID
+	OF_DPA_VLAN_ID_MASK	2 (N)	vlan ID mask
+	OF_DPA_VLAN_PCP		2 (N)	vlan Priority Code Point
+	OF_DPA_VLAN_PCP_MASK	2 (N)	vlan Priority Code Point mask
+	OF_DPA_SRC_MAC		6 (N)	source MAC
+	OF_DPA_SRC_MAC_MASK	6 (N)	source MAC mask
+	OF_DPA_DST_MAC		6 (N)	destination MAC
+	OF_DPA_DST_MAC_MASK	6 (N)	destination MAC mask
+	OF_DPA_TUNNEL_ID	4	tunnel ID
+	OF_DPA_SRC_IP		4 (N)	source IPv4. Optional,
+					can contain IPv4 address,
+					must be completely masked
+					if not used
+	OF_DPA_SRC_IP_MASK	4 (N)	IP Mask
+	OF_DPA_DST_IP		4 (N)	destination IPv4 address.
+					Must be multicast address
+	OF_DPA_DST_IP_MASK	4 (N)	IP Mask
+	OF_DPA_SRC_IPV6		16 (N)	source IPv6 Address. Optional.
+					Can contain IPv6 address,
+					must be completely masked
+					if not used
+	OF_DPA_SRC_IPV6_MASK	16 (N)	IPv6 mask
+	OF_DPA_DST_IPV6		16 (N)	destination IPv6 Address. Must
+					be multicast address.
+	OF_DPA_DST_IPV6_MASK	16 (N)	IPv6 mask
+	OF_DPA_SRC_ARP_IP	4 (N)	source IPv4 address in the ARP
+					payload.  Only used if ethertype
+					== 0x0806.
+	OF_DPA_SRC_ARP_IP_MASK	4 (N)	IP Mask
+	OF_DPA_IP_PROTO		1	IP protocol
+	OF_DPA_IP_PROTO_MASK	1	IP protocol mask
+	OF_DPA_IP_DSCP		1	DSCP
+	OF_DPA_IP_DSCP_MASK	1	DSCP mask
+	OF_DPA_IP_ECN		1	ECN
+	OF_DPA_IP_ECN_MASK		1	ECN mask
+	OF_DPA_L4_SRC_PORT	2 (N)	L4 source port, only for
+					TCP, UDP, or SCTP
+	OF_DPA_L4_SRC_PORT_MASK	2 (N)	L4 source port mask
+	OF_DPA_L4_DST_PORT	2 (N)	L4 source port, only for
+					TCP, UDP, or SCTP
+	OF_DPA_L4_DST_PORT_MASK	2 (N)	L4 source port mask
+	OF_DPA_ICMP_TYPE	1	ICMP type, only if IP
+					protocol is 1
+	OF_DPA_ICMP_TYPE_MASK	1	ICMP type mask
+	OF_DPA_ICMP_CODE	1	ICMP code
+	OF_DPA_ICMP_CODE_MASK	1	ICMP code mask
+	OF_DPA_IPV6_LABEL	4 (N)	IPv6 flow label
+	OF_DPA_IPV6_LABEL_MASK	4 (N)	IPv6 flow label mask
+	OF_DPA_GROUP_ID		4	data for GROUP action
+	OF_DPA_QUEUE_ID_ACTION	1	write the queue ID
+	OF_DPA_NEW_QUEUE_ID	1	queue ID
+	OF_DPA_VLAN_PCP_ACTION	1	write the VLAN priority
+	OF_DPA_NEW_VLAN_PCP	1	VLAN priority
+	OF_DPA_IP_DSCP_ACTION	1	write the DSCP
+	OF_DPA_NEW_IP_DSCP	1	new DSCP
+	OF_DPA_TUNNEL_LPORT	4	restrct to valid tunnel
+					logical port, set to 0
+					otherwise.
+	OF_DPA_OUT_PPORT	2	data for OUTPUT action,
+					restricted to CONTROLLER,
+					set to 0 otherwise
+	OF_DPA_CLEAR_ACTIONS	4	if 1 packets matching flow are
+					dropped (all other instructions
+					ignored)
+
+TLVs for flow delete and get stats command are:
+
+	field			width	description
+	---------------------------------------------------
+	OF_DPA_CMD		2	CMD_[DEL|GET_STATS]
+	OF_DPA_COOKIE		8	Cookie
+
+On completion of get stats command, the descriptor buffer is written back with
+the following TLVs:
+
+	field			width	description
+	---------------------------------------------------
+	OF_DPA_STAT_DURATION	4	Flow duration
+	OF_DPA_STAT_RX_PKTS	8	Received packets
+	OF_DPA_STAT_TX_PKTS	8	Transmit packets
+
+Possible status return codes in descriptor on completion are:
+
+	DESC_COMP_ERR	command			reason
+	--------------------------------------------------------------------
+	0		all			OK
+	-ROCKER_EFAULT	all			head or tail index outside
+						of ring
+	-ROCKER_ENXIO	all			address or data read err on
+						desc buf
+	-ROCKER_EMSGSIZE GET_STATS		cmd descriptor buffer wasn't
+						big enough to contain write-back
+						TLVs
+	-ROCKER_EINVAL	all			invalid parameters passed in
+	-ROCKER_EEXIST	ADD			entry already exists
+	-ROCKER_ENOSPC	ADD			no space left in flow table
+	-ROCKER_ENOENT	MOD|DEL|GET_STATS	cookie invalid
+
+Group Table Interface
+---------------------
+
+There are commands to add, modify, delete, and get stats of group table
+entries.  The commands are issued using the DMA CMD descriptor ring.  The
+following commands are defined:
+
+	CMD_ADD:		add an entry to group table
+	CMD_MOD:		modify an entry in group table
+	CMD_DEL:		delete an entry from group table
+	CMD_GET_STATS:		get stats for group entry
+
+TLVs for add and modify commands are:
+
+	field			width	description
+	-----------------------------------------------------------
+	FLOW_GROUP_CMD		2	CMD_[ADD|MOD]
+	FLOW_GROUP_ID		2	Flow group ID
+	FLOW_GROUP_TYPE		1	Group type:
+					  0: L2 interface
+					  1: L2 rewrite
+					  2: L3 unicast
+					  3: L2 multicast
+					  4: L2 flood
+					  5: L3 interface
+					  6: L3 multicast
+					  7: L3 ECMP
+					  8: L2 overlay
+	FLOW_VLAN_ID		2	Vlan ID (types 0, 3, 4, 6)
+	FLOW_L2_PORT		2	Port (types 0)
+	FLOW_INDEX		4	Index (all types but 0)
+	FLOW_OVERLAY_TYPE	1	Overlay sub-type (type 8):
+					  0: Flood unicast tunnel
+					  1: Flood multicast tunnel
+					  2: Multicast unicast tunnel
+					  3: Multicast multicast tunnel
+	FLOW_GROUP_ACTION		nest
+	  FLOW_GROUP_ID		2	next group ID in chain (all
+					types except 0)
+	  FLOW_OUT_PORT		4	egress port (types 0, 8)
+	  FLOW_POP_VLAN_TAG	1	strip outer VLAN tag (type 1
+					only)
+	  FLOW_VLAN_ID		2	(types 1, 5)
+	  FLOW_SRC_MAC		6	(types 1, 2, 5)
+	  FLOW_DST_MAC		6	(types 1, 2)
+
+TLVs for flow delete and get stats command are:
+
+	field			width	description
+	-----------------------------------------------------------
+	FLOW_GROUP_CMD		2	CMD_[DEL|GET_STATS]
+	FLOW_GROUP_ID		2	Flow group ID
+
+On completion of get stats command, the descriptor buffer is written back with
+the following TLVs:
+
+	field			width	description
+	---------------------------------------------------
+	FLOW_GROUP_ID		2	Flow group ID
+	FLOW_STAT_DURATION	4	Flow duration
+	FLOW_STAT_REF_COUNT	4	Flow reference count
+	FLOW_STAT_BUCKET_COUNT	4	Flow bucket count
+
+Possible status return codes in descriptor on completion are:
+
+	DESC_COMP_ERR	command			reason
+	--------------------------------------------------------------------
+	0		all			OK
+	-ROCKER_EFAULT	all			head or tail index outside
+						of ring
+	-ROCKER_ENXIO	all			address or data read err on
+						desc buf
+	-ROCKER_ENOSPC	GET_STATS		cmd descriptor buffer wasn't
+						big enough to contain write-back
+						TLVs
+	-ROCKER_EINVAL	ADD|MOD			invalid parameters passed in
+	-ROCKER_EEXIST	ADD			entry already exists
+	-ROCKER_ENOSPC	ADD			no space left in flow table
+	-ROCKER_ENOENT	MOD|DEL|GET_STATS	group ID invalid
+	-ROCKER_EBUSY	DEL			group reference count non-zero
+	-ROCKER_ENODEV	ADD			next group ID doesn't exist
+
+
+
+References
+==========
+
+[1] OpenFlow Data Plane Abstraction (OF-DPA) Abstract Switch Specification,
+Version 1.0, from Broadcom Corporation, February 21, 2014.