qemu/docs/specs/rocker.txt
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   1Rocker Network Switch Register Programming Guide
   2Copyright (c) Scott Feldman <sfeldma@gmail.com>
   3Copyright (c) Neil Horman <nhorman@tuxdriver.com>
   4Version 0.11, 12/29/2014
   5
   6LICENSE
   7=======
   8
   9This program is free software; you can redistribute it and/or modify
  10it under the terms of the GNU General Public License as published by
  11the Free Software Foundation; either version 2 of the License, or
  12(at your option) any later version.
  13
  14This program is distributed in the hope that it will be useful,
  15but WITHOUT ANY WARRANTY; without even the implied warranty of
  16MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17GNU General Public License for more details.
  18
  19SECTION 1: Introduction
  20=======================
  21
  22Overview
  23--------
  24
  25This document describes the hardware/software interface for the Rocker switch
  26device.  The intended audience is authors of OS drivers and device emulation
  27software.
  28
  29Notations and Conventions
  30-------------------------
  31
  32o In register descriptions, [n:m] indicates a range from bit n to bit m,
  33inclusive.
  34o Use of leading 0x indicates a hexadecimal number.
  35o Use of leading 0b indicates a binary number.
  36o The use of RSVD or Reserved indicates that a bit or field is reserved for
  37future use.
  38o Field width is in bytes, unless otherwise noted.
  39o Register are (R) read-only, (R/W) read/write, (W) write-only, or (COR) clear
  40on read
  41o TLV values in network-byte-order are designated with (N).
  42
  43
  44SECTION 2: PCI Configuration Registers
  45======================================
  46
  47PCI Configuration Space
  48-----------------------
  49
  50Each switch instance registers as a PCI device with PCI configuration space:
  51
  52        offset  width   description             value
  53        ---------------------------------------------
  54        0x0     2       Vendor ID               0x1b36
  55        0x2     2       Device ID               0x0006
  56        0x4     4       Command/Status
  57        0x8     1       Revision ID             0x01
  58        0x9     3       Class code              0x2800
  59        0xC     1       Cache line size
  60        0xD     1       Latency timer
  61        0xE     1       Header type
  62        0xF     1       Built-in self test
  63        0x10    4       Base address low
  64        0x14    4       Base address high
  65        0x18-28         Reserved
  66        0x2C    2       Subsystem vendor ID     *
  67        0x2E    2       Subsystem ID            *
  68        0x30-38         Reserved
  69        0x3C    1       Interrupt line
  70        0x3D    1       Interrupt pin           0x00
  71        0x3E    1       Min grant               0x00
  72        0x3D    1       Max latency             0x00
  73        0x40    1       TRDY timeout
  74        0x41    1       Retry count
  75        0x42    2       Reserved
  76
  77
  78* Assigned by sub-system implementation
  79
  80SECTION 3: Memory-Mapped Register Space
  81=======================================
  82
  83There are two memory-mapped BARs.  BAR0 maps device register space and is
  840x2000 in size.  BAR1 maps MSI-X vector and PBA tables and is also 0x2000 in
  85size, allowing for 256 MSI-X vectors.
  86
  87All registers are 4 or 8 bytes long.  It is assumed host software will access 4
  88byte registers with one 4-byte access, and 8 byte registers with either two
  894-byte accesses or a single 8-byte access.  In the case of two 4-byte accesses,
  90access must be lower and then upper 4-bytes, in that order.
  91
  92BAR0 device register space is organized as follows:
  93
  94        offset          description
  95        ------------------------------------------------------
  96        0x0000-0x000f   Bogus registers to catch misbehaving
  97                        drivers.  Writes do nothing.  Reads
  98                        back as 0xDEADBABE.
  99        0x0010-0x00ff   Test registers
 100        0x0300-0x03ff   General purpose registers
 101        0x1000-0x1fff   Descriptor control
 102
 103Holes in register space are reserved.  Writes to reserved registers do nothing.
 104Reads to reserved registers read back as 0.
 105
 106No fancy stuff like write-combining is enabled on any of the registers.
 107
 108BAR1 MSI-X register space is organized as follows:
 109
 110        offset          description
 111        ------------------------------------------------------
 112        0x0000-0x0fff   MSI-X vector table (256 vectors total)
 113        0x1000-0x1fff   MSI-X PBA table
 114
 115
 116SECTION 4: Interrupts, DMA, and Endianness
 117==========================================
 118
 119PCI Interrupts
 120--------------
 121
 122The device supports only MSI-X interrupts.  BAR1 memory-mapped region contains
 123the MSI-X vector and PBA tables, with support for up to 256 MSI-X vectors.
 124
 125The vector assignment is:
 126
 127        vector          description
 128        -----------------------------------------------------
 129        0               Command descriptor ring completion
 130        1               Event descriptor ring completion
 131        2               Test operation completion
 132        3               RSVD
 133        4-255           Tx and Rx descriptor ring completion
 134                          Tx vector is even
 135                          Rx vector is odd
 136
 137A MSI-X vector table entry is 16 bytes:
 138
 139        field           offset  width   description
 140        -------------------------------------------------------------
 141        lower_addr      0x0     4       [31:2] message address[31:2]
 142                                        [1:0] Rsvd (4 byte alignment
 143                                                    required)
 144        upper_addr      0x4     4       [31:19] Rsvd
 145                                        [14:0] message address[46:32]
 146        data            0x8     4       message data[31:0]
 147        control         0xc     4       [31:1] Rsvd
 148                                        [0] mask (0 = enable,
 149                                                  1 = masked)
 150
 151Software should install the Interrupt Service Routine (ISR) before any ports
 152are enabled or any commands are issued on the command ring.
 153
 154DMA Operations
 155--------------
 156
 157DMA operations are used for packet DMA to/from the CPU, command and event
 158processing.  Command processing includes statistical counters and table dumps,
 159table insertion/deletion, and more.  Event processing provides an async
 160notification method for device-originating events.  Each DMA operation has a
 161set of control registers to manage a descriptor ring.  The descriptor rings are
 162allocated from contiguous host DMA-able memory and registers specify the rings
 163base address, size and current head and tail indices.  Software always writes
 164the head, and hardware always writes the tail.
 165
 166The higher-order bit of DMA_DESC_COMP_ERR is used to mark hardware completion
 167of a descriptor.  Software will clear this bit when posting a descriptor to the
 168ring, and hardware will set this bit when the descriptor is complete.
 169
 170Descriptor ring sizes must be a power of 2 and range from 2 to 64K entries.
 171Descriptor rings' base address must be 8-byte aligned.  Descriptors must be
 172packed within ring.  Each descriptor in each ring must also be aligned on an 8
 173byte boundary.  Each descriptor ring will have these registers:
 174
 175        DMA_DESC_xxx_BASE_ADDR, offset 0x1000 + (x * 32), 64-bit, (R/W)
 176        DMA_DESC_xxx_SIZE, offset 0x1008 + (x * 32), 32-bit, (R/W)
 177        DMA_DESC_xxx_HEAD, offset 0x100c + (x * 32), 32-bit, (R/W)
 178        DMA_DESC_xxx_TAIL, offset 0x1010 + (x * 32), 32-bit, (R)
 179        DMA_DESC_xxx_CTRL, offset 0x1014 + (x * 32), 32-bit, (W)
 180        DMA_DESC_xxx_CREDITS, offset 0x1018 + (x * 32), 32-bit, (R/W)
 181        DMA_DESC_xxx_RSVD1, offset 0x101c + (x * 32), 32-bit, (R/W)
 182
 183Where x is descriptor ring index:
 184
 185        index           ring
 186        --------------------
 187        0               CMD
 188        1               EVENT
 189        2               TX (port 0)
 190        3               RX (port 0)
 191        4               TX (port 1)
 192        5               RX (port 1)
 193        .
 194        .
 195        .
 196        124             TX (port 61)
 197        125             RX (port 61)
 198        126             Resv
 199        127             Resv
 200
 201Writing BASE_ADDR or SIZE will reset HEAD and TAIL to zero.  HEAD cannot be
 202written past TAIL.  To do so would wrap the ring.  An empty ring is when HEAD
 203== TAIL.  A full ring is when HEAD is one position behind TAIL.  Both HEAD and
 204TAIL increment and modulo wrap at the ring size.
 205
 206CTRL register bits:
 207
 208        bit     name            description
 209        ------------------------------------------------------------------------
 210        [0]     CTRL_RESET      Reset the descriptor ring
 211        [1:31]  Reserved
 212
 213All descriptor types share some common fields:
 214
 215        field                   width   description
 216        -------------------------------------------------------------------
 217        DMA_DESC_BUF_ADDR       8       Phys addr of desc payload, 8-byte
 218                                        aligned
 219        DMA_DESC_COOKIE         8       Desc cookie for completion matching,
 220                                        upper-most bit is reserved
 221        DMA_DESC_BUF_SIZE       2       Desc payload size in bytes
 222        DMA_DESC_TLV_SIZE       2       Desc payload total size in bytes
 223                                        used for TLVs.  Must be <=
 224                                        DMA_DESC_BUF_SIZE.
 225        DMA_DESC_COMP_ERR       2       Completion status of associated
 226                                        desc payload.  High order bit is
 227                                        clear on new descs, toggled by
 228                                        hw for completed items.
 229
 230To support forward- and backward-compatibility, descriptor and completion
 231payloads are specified in TLV format.  Fields are packed with Type=field name,
 232Length=field length, and Value=field value.  Software will ignore unknown fields
 233filled in by the switch.  Likewise, the switch will ignore unknown fields
 234filled in by software.
 235
 236Descriptor payload buffer is 8-byte aligned and TLVs are 8-byte aligned.  The
 237value within a TLV is also 8-byte aligned.  The (packed, 8 byte) TLV header is:
 238
 239        field   width   description
 240        -----------------------------
 241        type    4       TLV type
 242        len     2       TLV value length
 243        pad     2       Reserved
 244
 245The alignment requirements for descriptors and TLVs are to avoid unaligned
 246access exceptions in software.  Note that the payload for each TLV is also
 2478 byte aligned.
 248
 249Figure 1 shows an example descriptor buffer with two TLVs.
 250
 251                  <------- 8 bytes ------->
 252
 253  8-byte  +––––+  +–––––––––––+–––––+–––––+                     +–+
 254  align           |   type    | len | pad |    TLV#1 hdr          |
 255                  +–––––––––––+–––––+–––––+    (len=22)           |
 256                  |                       |                       |
 257                  |  value                |    TVL#1 value        |
 258                  |                       |    (padded to 8-byte  |
 259                  |                 +–––––+     alignment)        |
 260                  |                 |/////|                       |
 261   8-byte +––––+  +–––––––––––+–––––––––––+                       |
 262   align          |   type    | len | pad |    TLV#2 hdr    DESC_BUF_SIZE
 263                  +–––––+–––––+–––––+–––––+    (len=2)            |
 264                  |value|/////////////////|    TLV#2 value        |
 265                  +–––––+/////////////////|                       |
 266                  |///////////////////////|                       |
 267                  |///////////////////////|                       |
 268                  |///////////////////////|                       |
 269                  |////////unused/////////|                       |
 270                  |////////space//////////|                       |
 271                  |///////////////////////|                       |
 272                  |///////////////////////|                       |
 273                  |///////////////////////|                       |
 274                  +–––––––––––––––––––––––+                     +–+
 275
 276                                fig. 1
 277
 278TLVs can be nested within the NEST TLV type.
 279
 280Interrupt credits
 281^^^^^^^^^^^^^^^^^
 282
 283MSI-X vectors used for descriptor ring completions use a credit mechanism for
 284efficient device, PCIe bus, OS and driver operations.  Each descriptor ring has
 285a credit count which represents the number of outstanding descriptors to be
 286processed by the driver.  As the device marks descriptors complete, the credit
 287count is incremented.  As the driver processes those outstanding descriptors,
 288it returns credits back to the device.  This way, the device knows the driver's
 289progress and can make decisions about when to fire the next interrupt or not.
 290When the credit count is zero, and the first descriptors are posted for the
 291driver, a single interrupt is fired.  Once the interrupt is fired, the
 292interrupt is disabled (auto-masked*).  In response to the interrupt, the driver
 293will process descriptors and PIO write a returned credit value for that
 294descriptor ring.  If the driver returns all credits (the driver caught up with
 295the device and there is no outstanding work), then the interrupt is unmasked,
 296but not fired.  If only partial credits are returned, the interrupt remains
 297masked but the device generates an interrupt, signaling the driver that more
 298outstanding work is available.
 299
 300(* this masking is unrelated to the MSI-X interrupt mask register)
 301
 302Endianness
 303----------
 304
 305Device registers are hard-coded to little-endian (LE).  The driver should
 306convert to/from host endianness to LE for device register accesses.
 307
 308Descriptors are LE.  Descriptor buffer TLVs will have LE type and length
 309fields, but the value field can either be LE or network-byte-order, depending
 310on context.  TLV values containing network packet data will be in network-byte
 311order.  A TLV value containing a field or mask used to compare against network
 312packet data is network-byte order.  For example, flow match fields (and masks)
 313are network-byte-order since they're matched directly, byte-by-byte, against
 314network packet data.  All non-network-packet TLV multi-byte values will be LE.
 315
 316TLV values in network-byte-order are designated with (N).
 317
 318
 319SECTION 5: Test Registers
 320=========================
 321
 322Rocker has several test registers to support troubleshooting register access,
 323interrupt generation, and DMA operations:
 324
 325        TEST_REG, offset 0x0010, 32-bit (R/W)
 326        TEST_REG64, offset 0x0018, 64-bit (R/W)
 327        TEST_IRQ, offset 0x0020, 32-bit (R/W)
 328        TEST_DMA_ADDR, offset 0x0028, 64-bit (R/W)
 329        TEST_DMA_SIZE, offset 0x0030, 32-bit (R/W)
 330        TEST_DMA_CTRL, offset 0x0034, 32-bit (R/W)
 331
 332Reads to TEST_REG and TEST_REG64 will read a value equal to twice the last
 333value written to the register.  The 32-bit and 64-bit versions are for testing
 33432-bit and 64-bit host accesses.
 335
 336A vector can be written to TEST_IRQ and the device will generate an interrupt
 337for that vector.
 338
 339To test basic DMA operations, allocate a DMA-able host buffer and put the
 340buffer address into TEST_DMA_ADDR and size into TEST_DMA_SIZE.  Then, write to
 341TEST_DMA_CTRL to manipulate the buffer contents.  TEST_DMA_CTRL operations are:
 342
 343        operation               value   description
 344        -----------------------------------------------------------
 345        TEST_DMA_CTRL_CLEAR     1       clear buffer
 346        TEST_DMA_CTRL_FILL      2       fill buffer bytes with 0x96
 347        TEST_DMA_CTRL_INVERT    4       invert bytes in buffer
 348
 349Various buffer address and sizes should be tested to verify no address boundary
 350issue exists.  In particular, buffers that start on odd-8-byte boundary and/or
 351span multiple PAGE sizes should be tested.
 352
 353
 354SECTION 6: Ports
 355================
 356
 357Physical and Logical Ports
 358------------------------------------
 359
 360The switch supports up to 62 physical (front-panel) ports.  Register
 361PORT_PHYS_COUNT returns the actual number of physical ports available:
 362
 363        PORT_PHYS_COUNT, offset 0x0304, 32-bit, (R)
 364
 365In addition to front-panel ports, the switch supports logical ports for
 366tunnels.
 367
 368Front-panel ports and logical tunnel ports are mapped into a single 32-bit port
 369space.  A special CPU port is assigned port 0.  The front-panel ports are
 370mapped to ports 1-62.  A special loopback port is assigned port 63.  Logical
 371tunnel ports are assigned ports 0x0001000-0x0001ffff.
 372To summarize the port assignments:
 373
 374        port                    mapping
 375        -------------------------------------------------------
 376        0                       CPU port (for packets to/from host CPU)
 377        1-62                    front-panel physical ports
 378        63                      loopback port
 379        64-0x0000ffff           RSVD
 380        0x00010000-0x0001ffff   logical tunnel ports
 381        0x00020000-0xffffffff   RSVD
 382
 383Physical Port Mode
 384------------------
 385
 386Switch front-panel ports operate in a mode.  Currently, the only mode is
 387OF-DPA.  OF-DPA[1] mode is based on OpenFlow Data Plane Abstraction (OF-DPA)
 388Abstract Switch Specification, Version 1.0, from Broadcom Corporation.  To
 389set/get the mode for front-panel ports, see port settings, below.
 390
 391Port Settings
 392-------------
 393
 394Link status for all front-panel ports is available via PORT_PHYS_LINK_STATUS:
 395
 396        PORT_PHYS_LINK_STATUS, offset 0x0310, 64-bit, (R)
 397
 398        Value is port bitmap.  Bits 0 and 63 always read 0.  Bits 1-62
 399        read 1 for link UP and 0 for link DOWN for respective front-panel ports.
 400
 401Other properties for front-panel ports are available via DMA CMD descriptors:
 402
 403        Get PORT_SETTINGS descriptor:
 404
 405                field           width   description
 406                ----------------------------------------------
 407                PORT_SETTINGS   2       CMD_GET
 408                PPORT           4       Physical port #
 409
 410        Get PORT_SETTINGS completion:
 411
 412                field           width   description
 413                ----------------------------------------------
 414                PPORT           4       Physical port #
 415                SPEED           4       Current port interface speed, in Mbps
 416                DUPLEX          1       1 = Full, 0 = Half
 417                AUTONEG         1       1 = enabled, 0 = disabled
 418                MACADDR         6       Port MAC address
 419                MODE            1       0 = OF-DPA
 420                LEARNING        1       MAC address learning on port
 421                                                1 = enabled
 422                                                0 = disabled
 423                PHYS_NAME       <var>   Physical port name (string)
 424
 425        Set PORT_SETTINGS descriptor:
 426
 427                field           width   description
 428                ----------------------------------------------
 429                PORT_SETTINGS   2       CMD_SET
 430                PPORT           4       Physical port #
 431                SPEED           4       Port interface speed, in Mbps
 432                DUPLEX          1       1 = Full, 0 = Half
 433                AUTONEG         1       1 = enabled, 0 = disabled
 434                MACADDR         6       Port MAC address
 435                MODE            1       0 = OF-DPA
 436
 437Port Enable
 438-----------
 439
 440Front-panel ports are initially disabled, which means port ingress and egress
 441packets will be dropped.  To enable or disable a port, use PORT_PHYS_ENABLE:
 442
 443        PORT_PHYS_ENABLE: offset 0x0318, 64-bit, (R/W)
 444
 445        Value is bitmap of first 64 ports.  Bits 0 and 63 are ignored
 446        and always read as 0.  Write 1 to enable port; write 0 to disable it.
 447        Default is 0.
 448
 449
 450SECTION 7: Switch Control
 451=========================
 452
 453This section covers switch-wide register settings.
 454
 455Control
 456-------
 457
 458This register is used for low level control of the switch.
 459
 460        CONTROL: offset 0x0300, 32-bit, (W)
 461
 462        bit     name            description
 463        ------------------------------------------------------------------------
 464        [0]     CONTROL_RESET   If set, device will perform reset
 465        [1:31]  Reserved
 466
 467Switch ID
 468---------
 469
 470The switch has a SWITCH_ID to be used by software to uniquely identify the
 471switch:
 472
 473        SWITCH_ID: offset 0x0320, 64-bit, (R)
 474
 475        Value is opaque to switch software and no special encoding is implied.
 476
 477
 478SECTION 8: Events
 479=================
 480
 481Non-I/O asynchronous events from the device are notified to the host using the
 482event ring.  The TLV structure for events is:
 483
 484        field           width   description
 485        ---------------------------------------------------
 486        TYPE            4       Event type, one of:
 487                                        1: LINK_CHANGED
 488                                        2: MAC_VLAN_SEEN
 489        INFO            <nest>  Event info (details below)
 490
 491Link Changed Event
 492------------------
 493
 494When link status changes on a physical port, this event is generated.
 495
 496        field           width   description
 497        ---------------------------------------------------
 498        INFO            <nest>
 499          PPORT         4       Physical port
 500          LINKUP        1       Link status:
 501                                        0: down
 502                                        1: up
 503
 504MAC VLAN Seen Event
 505-------------------
 506
 507When a packet ingresses on a port and the source MAC/VLAN isn't known to the
 508device, the device will generate this event.  In response to the event, the
 509driver should install to the device the MAC/VLAN on the port into the bridge
 510table.  Once installed, the MAC/VLAN is known on the port and this event will
 511no longer be generated.
 512
 513        field           width   description
 514        ---------------------------------------------------
 515        INFO            <nest>
 516          PPORT         4       Physical port
 517          MAC           6       MAC address
 518          VLAN          2       VLAN ID
 519
 520
 521SECTION 9: CPU Packet Processing
 522================================
 523
 524Ingress packets directed to the host CPU for further processing are delivered
 525in the DMA RX ring.  Likewise, host CPU originating packets destined to egress
 526on switch ports are scheduled by software using the DMA TX ring.
 527
 528Tx Packet Processing
 529--------------------
 530
 531Software schedules packets for egress on switch ports using the DMA TX ring.  A
 532TX descriptor buffer describes the packet location and size in host DMA-able
 533memory, the destination port, and any hardware-offload functions (such as L3
 534payload checksum offload).  Software then bumps the descriptor head to signal
 535hardware of new Tx work.  In response, hardware will DMA read Tx descriptors up
 536to head, DMA read descriptor buffer and packet data, perform offloading
 537functions, and finally frame packet on wire (network).  Once packet processing
 538is complete, hardware will writeback status to descriptor(s) to signal to
 539software that Tx is complete and software resources (e.g. skb) backing packet
 540can be released.
 541
 542Figure 2 shows an example 3-fragment packet queued with one Tx descriptor.  A
 543TLV is used for each packet fragment.
 544
 545                                                   pkt frag 1
 546                                                   +–––––––+  +–+
 547                                               +–––+       |    |
 548                                 desc buf      |   |       |    |
 549                                +––––––––+     |   |       |    |
 550                Tx ring     +–––+        +–––––+   |       |    |
 551              +–––––––––+   |   |  TLVs  |         +–––––––+    |
 552              |         +–––+   +––––––––+         pkt frag 2   |
 553              | desc 0  |       |        +–––––+   +–––––––+    |
 554              +–––––––––+       |  TLVs  |     +–––+       |    |
 555        head+–+         |       +––––––––+         |       |    |
 556              | desc 1  |       |        +–––––+   +–––––––+    |pkt
 557              +–––––––––+       |  TLVs  |     |                |
 558              |         |       +––––––––+     |   pkt frag 3   |
 559              |         |                      |   +–––––––+    |
 560              +–––––––––+                      +–––+       |    |
 561              |         |                          |       |    |
 562              |         |                          |       |    |
 563              +–––––––––+                          |       |    |
 564              |         |                          |       |    |
 565              |         |                          |       |    |
 566              +–––––––––+                          |       |    |
 567              |         |                          +–––––––+  +–+
 568              |         |
 569              +–––––––––+
 570
 571                                fig 2.
 572
 573The TLVs for Tx descriptor buffer are:
 574
 575        field                   width   description
 576        ---------------------------------------------------------------------
 577        PPORT                   4       Destination physical port #
 578        TX_OFFLOAD              1       Hardware offload modes:
 579                                          0: no offload
 580                                          1: insert IP csum (ipv4 only)
 581                                          2: insert TCP/UDP csum
 582                                          3: L3 csum calc and insert
 583                                             into csum offset (TX_L3_CSUM_OFF)
 584                                            16-bit 1's complement csum value.
 585                                             IPv4 pseudo-header and IP
 586                                             already calculated by OS
 587                                           and inserted.
 588                                          4: TSO (TCP Segmentation Offload)
 589        TX_L3_CSUM_OFF          2       For L3 csum offload mode, the offset,
 590                                        from the beginning of the packet,
 591                                        of the csum field in the L3 header
 592        TX_TSO_MSS              2       For TSO offload mode, the
 593                                        Maximum Segment Size in bytes
 594        TX_TSO_HDR_LEN          2       For TSO offload mode, the
 595                                        length of ethernet, IP, and
 596                                        TCP/UDP headers, including IP
 597                                        and TCP options.
 598        TX_FRAGS                <array> Packet fragments
 599          TX_FRAG               <nest>  Packet fragment
 600            TX_FRAG_ADDR        8       DMA address of packet fragment
 601            TX_FRAG_LEN         2       Packet fragment length
 602
 603Possible status return codes in descriptor on completion are:
 604
 605        DESC_COMP_ERR   reason
 606        --------------------------------------------------------------------
 607        0               OK
 608        -ROCKER_ENXIO   address or data read err on desc buf or packet
 609                        fragment
 610        -ROCKER_EINVAL  bad pport or TSO or csum offloading error
 611        -ROCKER_ENOMEM  no memory for internal staging tx fragment
 612
 613Rx Packet Processing
 614--------------------
 615
 616For packets ingressing on switch ports that are not forwarded by the switch but
 617rather directed to the host CPU for further processing are delivered in the DMA
 618RX ring.  Rx descriptor buffers are allocated by software and placed on the
 619ring.  Hardware will fill Rx descriptor buffers with packet data, write the
 620completion, and signal to software that a new packet is ready.  Since Rx packet
 621size is not known a-priori, the Rx descriptor buffer must be allocated for
 622worst-case packet size.  A single Rx descriptor will contain the entire Rx
 623packet data in one RX_FRAG.  Other Rx TLVs describe and hardware offloads
 624performed on the packet, such as checksum validation.
 625
 626The TLVs for Rx descriptor buffer are:
 627
 628        field           width   description
 629        ---------------------------------------------------
 630        PPORT           4       Source physical port #
 631        RX_FLAGS        2       Packet parsing flags:
 632                                  (1 << 0): IPv4 packet
 633                                  (1 << 1): IPv6 packet
 634                                  (1 << 2): csum calculated
 635                                  (1 << 3): IPv4 csum good
 636                                  (1 << 4): IP fragment
 637                                  (1 << 5): TCP packet
 638                                  (1 << 6): UDP packet
 639                                  (1 << 7): TCP/UDP csum good
 640                                  (1 << 8): Offload forward
 641        RX_CSUM         2       IP calculated checksum:
 642                                  IPv4: IP payload csum
 643                                  IPv6: header and payload csum
 644                                (Only valid is RX_FLAGS:csum calc is set)
 645        RX_FRAG_ADDR    8       DMA address of packet fragment
 646        RX_FRAG_MAX_LEN 2       Packet maximum fragment length
 647        RX_FRAG_LEN     2       Actual packet fragment length after receive
 648
 649Offload forward RX_FLAG indicates the device has already forwarded the packet
 650so the host CPU should not also forward the packet.
 651
 652Possible status return codes in descriptor on completion are:
 653
 654        DESC_COMP_ERR   reason
 655        --------------------------------------------------------------------
 656        0               OK
 657        -ROCKER_ENXIO   address or data read err on desc buf
 658        -ROCKER_ENOMEM  no memory for internal staging desc buf
 659        -ROCKER_EMSGSIZE Rx descriptor buffer wasn't big enough to contain
 660                        packet data TLV and other TLVs.
 661
 662
 663SECTION 10: OF-DPA Mode
 664======================
 665
 666OF-DPA mode allows the switch to offload flow packet processing functions to
 667hardware.  An OpenFlow controller would communicate with an OpenFlow agent
 668installed on the switch.  The OpenFlow agent would (directly or indirectly)
 669communicate with the Rocker switch driver, which in turn would program switch
 670hardware with flow functionality, as defined in OF-DPA.  The block diagram is:
 671
 672                +–––––––––––––––----–––+
 673                |        OF            |
 674                |  Remote Controller   |
 675                +––––––––+––----–––––––+
 676                         |
 677                         |
 678                +––––––––+–––––––––+
 679                |       OF         |
 680                |   Local Agent    |
 681                +––––––––––––––––––+
 682                |                  |
 683                |   Rocker Driver  |
 684                +––––––––––––––––––+
 685                    <this spec>
 686                +––––––––––––––––––+
 687                |                  |
 688                |   Rocker Switch  |
 689                +––––––––––––––––––+
 690
 691To participate in flow functions, ports must be configure for OF-DPA mode
 692during switch initialization.
 693
 694OF-DPA Flow Table Interface
 695---------------------------
 696
 697There are commands to add, modify, delete, and get stats of flow table entries.
 698The commands are issued using the DMA CMD descriptor ring.  The following
 699commands are defined:
 700
 701        CMD_ADD:                add an entry to flow table
 702        CMD_MOD:                modify an entry in flow table
 703        CMD_DEL:                delete an entry from flow table
 704        CMD_GET_STATS:          get stats for flow entry
 705
 706TLVs for add and modify commands are:
 707
 708        field                   width   description
 709        ----------------------------------------------------
 710        OF_DPA_CMD              2       CMD_[ADD|MOD]
 711        OF_DPA_TBL              2       Flow table ID
 712                                          0: ingress port
 713                                          10: vlan
 714                                          20: termination mac
 715                                          30: unicast routing
 716                                          40: multicast routing
 717                                          50: bridging
 718                                          60: ACL policy
 719        OF_DPA_PRIORITY         4       Flow priority
 720        OF_DPA_HARDTIME         4       Hard timeout for flow
 721        OF_DPA_IDLETIME         4       Idle timeout for flow
 722        OF_DPA_COOKIE           8       Cookie
 723
 724Additional TLVs based on flow table ID:
 725
 726Table ID 0: ingress port
 727
 728        field                   width   description
 729        ----------------------------------------------------
 730        OF_DPA_IN_PPORT         4       ingress physical port number
 731        OF_DPA_GOTO_TBL         2       goto table ID; zero to drop
 732
 733Table ID 10: vlan
 734
 735        field                   width   description
 736        ----------------------------------------------------
 737        OF_DPA_IN_PPORT         4       ingress physical port number
 738        OF_DPA_VLAN_ID          2 (N)   vlan ID
 739        OF_DPA_VLAN_ID_MASK     2 (N)   vlan ID mask
 740        OF_DPA_GOTO_TBL         2       goto table ID; zero to drop
 741        OF_DPA_NEW_VLAN_ID      2 (N)   new vlan ID
 742
 743Table ID 20: termination mac
 744
 745        field                   width   description
 746        ----------------------------------------------------
 747        OF_DPA_IN_PPORT         4       ingress physical port number
 748        OF_DPA_IN_PPORT_MASK    4       ingress physical port number mask
 749        OF_DPA_ETHERTYPE        2 (N)   must be either 0x0800 or 0x86dd
 750        OF_DPA_DST_MAC          6 (N)   destination MAC
 751        OF_DPA_DST_MAC_MASK     6 (N)   destination MAC mask
 752        OF_DPA_VLAN_ID          2 (N)   vlan ID
 753        OF_DPA_VLAN_ID_MASK     2 (N)   vlan ID mask
 754        OF_DPA_GOTO_TBL         2       only acceptable values are
 755                                        unicast or multicast routing
 756                                        table IDs
 757        OF_DPA_OUT_PPORT        2       if specified, must be
 758                                        controller, set zero otherwise
 759
 760Table ID 30: unicast routing
 761
 762        field                   width   description
 763        ----------------------------------------------------
 764        OF_DPA_ETHERTYPE        2 (N)   must be either 0x0800 or 0x86dd
 765        OF_DPA_DST_IP           4 (N)   destination IPv4 address.
 766                                        Must be unicast address
 767        OF_DPA_DST_IP_MASK      4 (N)   IP mask.  Must be prefix mask
 768        OF_DPA_DST_IPV6         16 (N)  destination IPv6 address.
 769                                        Must be unicast address
 770        OF_DPA_DST_IPV6_MASK    16 (N)  IPv6 mask. Must be prefix mask
 771        OF_DPA_GOTO_TBL         2       goto table ID; zero to drop
 772        OF_DPA_GROUP_ID         4       data for GROUP action must
 773                                        be an L3 Unicast group entry
 774
 775Table ID 40: multicast routing
 776
 777        field                   width   description
 778        ----------------------------------------------------
 779        OF_DPA_ETHERTYPE        2 (N)   must be either 0x0800 or 0x86dd
 780        OF_DPA_VLAN_ID          2 (N)   vlan ID
 781        OF_DPA_SRC_IP           4 (N)   source IPv4. Optional,
 782                                        can contain IPv4 address,
 783                                        must be completely masked
 784                                        if not used
 785        OF_DPA_SRC_IP_MASK      4 (N)   IP Mask
 786        OF_DPA_DST_IP           4 (N)   destination IPv4 address.
 787                                        Must be multicast address
 788        OF_DPA_SRC_IPV6         16 (N)  source IPv6 Address. Optional.
 789                                        Can contain IPv6 address,
 790                                        must be completely masked
 791                                        if not used
 792        OF_DPA_SRC_IPV6_MASK    16 (N)  IPv6 mask.
 793        OF_DPA_DST_IPV6         16 (N)  destination IPv6 Address. Must
 794                                        be multicast address
 795                                        Must be multicast address
 796        OF_DPA_GOTO_TBL         2       goto table ID; zero to drop
 797        OF_DPA_GROUP_ID         4       data for GROUP action must
 798                                        be an L3 multicast group entry
 799
 800Table ID 50: bridging
 801
 802        field                   width   description
 803        ----------------------------------------------------
 804        OF_DPA_VLAN_ID          2 (N)   vlan ID
 805        OF_DPA_TUNNEL_ID        4       tunnel ID
 806        OF_DPA_DST_MAC          6 (N)   destination MAC
 807        OF_DPA_DST_MAC_MASK     6 (N)   destination MAC mask
 808        OF_DPA_GOTO_TBL         2       goto table ID; zero to drop
 809        OF_DPA_GROUP_ID         4       data for GROUP action must
 810                                        be a L2 Interface, L2
 811                                        Multicast, L2 Flood,
 812                                        or L2 Overlay group entry
 813                                        as appropriate
 814        OF_DPA_TUNNEL_LPORT     4       unicast Tenant Bridging
 815                                        flows specify a tunnel
 816                                        logical port ID
 817        OF_DPA_OUT_PPORT        2       data for OUTPUT action,
 818                                        restricted to CONTROLLER,
 819                                        set to 0 otherwise
 820
 821Table ID 60: acl policy
 822
 823        field                   width   description
 824        ----------------------------------------------------
 825        OF_DPA_IN_PPORT         4       ingress physical port number
 826        OF_DPA_IN_PPORT_MASK    4       ingress physical port number mask
 827        OF_DPA_ETHERTYPE        2 (N)   ethertype
 828        OF_DPA_VLAN_ID          2 (N)   vlan ID
 829        OF_DPA_VLAN_ID_MASK     2 (N)   vlan ID mask
 830        OF_DPA_VLAN_PCP         2 (N)   vlan Priority Code Point
 831        OF_DPA_VLAN_PCP_MASK    2 (N)   vlan Priority Code Point mask
 832        OF_DPA_SRC_MAC          6 (N)   source MAC
 833        OF_DPA_SRC_MAC_MASK     6 (N)   source MAC mask
 834        OF_DPA_DST_MAC          6 (N)   destination MAC
 835        OF_DPA_DST_MAC_MASK     6 (N)   destination MAC mask
 836        OF_DPA_TUNNEL_ID        4       tunnel ID
 837        OF_DPA_SRC_IP           4 (N)   source IPv4. Optional,
 838                                        can contain IPv4 address,
 839                                        must be completely masked
 840                                        if not used
 841        OF_DPA_SRC_IP_MASK      4 (N)   IP Mask
 842        OF_DPA_DST_IP           4 (N)   destination IPv4 address.
 843                                        Must be multicast address
 844        OF_DPA_DST_IP_MASK      4 (N)   IP Mask
 845        OF_DPA_SRC_IPV6         16 (N)  source IPv6 Address. Optional.
 846                                        Can contain IPv6 address,
 847                                        must be completely masked
 848                                        if not used
 849        OF_DPA_SRC_IPV6_MASK    16 (N)  IPv6 mask
 850        OF_DPA_DST_IPV6         16 (N)  destination IPv6 Address. Must
 851                                        be multicast address.
 852        OF_DPA_DST_IPV6_MASK    16 (N)  IPv6 mask
 853        OF_DPA_SRC_ARP_IP       4 (N)   source IPv4 address in the ARP
 854                                        payload.  Only used if ethertype
 855                                        == 0x0806.
 856        OF_DPA_SRC_ARP_IP_MASK  4 (N)   IP Mask
 857        OF_DPA_IP_PROTO         1       IP protocol
 858        OF_DPA_IP_PROTO_MASK    1       IP protocol mask
 859        OF_DPA_IP_DSCP          1       DSCP
 860        OF_DPA_IP_DSCP_MASK     1       DSCP mask
 861        OF_DPA_IP_ECN           1       ECN
 862        OF_DPA_IP_ECN_MASK              1       ECN mask
 863        OF_DPA_L4_SRC_PORT      2 (N)   L4 source port, only for
 864                                        TCP, UDP, or SCTP
 865        OF_DPA_L4_SRC_PORT_MASK 2 (N)   L4 source port mask
 866        OF_DPA_L4_DST_PORT      2 (N)   L4 source port, only for
 867                                        TCP, UDP, or SCTP
 868        OF_DPA_L4_DST_PORT_MASK 2 (N)   L4 source port mask
 869        OF_DPA_ICMP_TYPE        1       ICMP type, only if IP
 870                                        protocol is 1
 871        OF_DPA_ICMP_TYPE_MASK   1       ICMP type mask
 872        OF_DPA_ICMP_CODE        1       ICMP code
 873        OF_DPA_ICMP_CODE_MASK   1       ICMP code mask
 874        OF_DPA_IPV6_LABEL       4 (N)   IPv6 flow label
 875        OF_DPA_IPV6_LABEL_MASK  4 (N)   IPv6 flow label mask
 876        OF_DPA_GROUP_ID         4       data for GROUP action
 877        OF_DPA_QUEUE_ID_ACTION  1       write the queue ID
 878        OF_DPA_NEW_QUEUE_ID     1       queue ID
 879        OF_DPA_VLAN_PCP_ACTION  1       write the VLAN priority
 880        OF_DPA_NEW_VLAN_PCP     1       VLAN priority
 881        OF_DPA_IP_DSCP_ACTION   1       write the DSCP
 882        OF_DPA_NEW_IP_DSCP      1       new DSCP
 883        OF_DPA_TUNNEL_LPORT     4       restrct to valid tunnel
 884                                        logical port, set to 0
 885                                        otherwise.
 886        OF_DPA_OUT_PPORT        2       data for OUTPUT action,
 887                                        restricted to CONTROLLER,
 888                                        set to 0 otherwise
 889        OF_DPA_CLEAR_ACTIONS    4       if 1 packets matching flow are
 890                                        dropped (all other instructions
 891                                        ignored)
 892
 893TLVs for flow delete and get stats command are:
 894
 895        field                   width   description
 896        ---------------------------------------------------
 897        OF_DPA_CMD              2       CMD_[DEL|GET_STATS]
 898        OF_DPA_COOKIE           8       Cookie
 899
 900On completion of get stats command, the descriptor buffer is written back with
 901the following TLVs:
 902
 903        field                   width   description
 904        ---------------------------------------------------
 905        OF_DPA_STAT_DURATION    4       Flow duration
 906        OF_DPA_STAT_RX_PKTS     8       Received packets
 907        OF_DPA_STAT_TX_PKTS     8       Transmit packets
 908
 909Possible status return codes in descriptor on completion are:
 910
 911        DESC_COMP_ERR   command                 reason
 912        --------------------------------------------------------------------
 913        0               all                     OK
 914        -ROCKER_EFAULT  all                     head or tail index outside
 915                                                of ring
 916        -ROCKER_ENXIO   all                     address or data read err on
 917                                                desc buf
 918        -ROCKER_EMSGSIZE GET_STATS              cmd descriptor buffer wasn't
 919                                                big enough to contain write-back
 920                                                TLVs
 921        -ROCKER_EINVAL  all                     invalid parameters passed in
 922        -ROCKER_EEXIST  ADD                     entry already exists
 923        -ROCKER_ENOSPC  ADD                     no space left in flow table
 924        -ROCKER_ENOENT  MOD|DEL|GET_STATS       cookie invalid
 925
 926Group Table Interface
 927---------------------
 928
 929There are commands to add, modify, delete, and get stats of group table
 930entries.  The commands are issued using the DMA CMD descriptor ring.  The
 931following commands are defined:
 932
 933        CMD_ADD:                add an entry to group table
 934        CMD_MOD:                modify an entry in group table
 935        CMD_DEL:                delete an entry from group table
 936        CMD_GET_STATS:          get stats for group entry
 937
 938TLVs for add and modify commands are:
 939
 940        field                   width   description
 941        -----------------------------------------------------------
 942        FLOW_GROUP_CMD          2       CMD_[ADD|MOD]
 943        FLOW_GROUP_ID           2       Flow group ID
 944        FLOW_GROUP_TYPE         1       Group type:
 945                                          0: L2 interface
 946                                          1: L2 rewrite
 947                                          2: L3 unicast
 948                                          3: L2 multicast
 949                                          4: L2 flood
 950                                          5: L3 interface
 951                                          6: L3 multicast
 952                                          7: L3 ECMP
 953                                          8: L2 overlay
 954        FLOW_VLAN_ID            2       Vlan ID (types 0, 3, 4, 6)
 955        FLOW_L2_PORT            2       Port (types 0)
 956        FLOW_INDEX              4       Index (all types but 0)
 957        FLOW_OVERLAY_TYPE       1       Overlay sub-type (type 8):
 958                                          0: Flood unicast tunnel
 959                                          1: Flood multicast tunnel
 960                                          2: Multicast unicast tunnel
 961                                          3: Multicast multicast tunnel
 962        FLOW_GROUP_ACTION               nest
 963          FLOW_GROUP_ID         2       next group ID in chain (all
 964                                        types except 0)
 965          FLOW_OUT_PORT         4       egress port (types 0, 8)
 966          FLOW_POP_VLAN_TAG     1       strip outer VLAN tag (type 1
 967                                        only)
 968          FLOW_VLAN_ID          2       (types 1, 5)
 969          FLOW_SRC_MAC          6       (types 1, 2, 5)
 970          FLOW_DST_MAC          6       (types 1, 2)
 971
 972TLVs for flow delete and get stats command are:
 973
 974        field                   width   description
 975        -----------------------------------------------------------
 976        FLOW_GROUP_CMD          2       CMD_[DEL|GET_STATS]
 977        FLOW_GROUP_ID           2       Flow group ID
 978
 979On completion of get stats command, the descriptor buffer is written back with
 980the following TLVs:
 981
 982        field                   width   description
 983        ---------------------------------------------------
 984        FLOW_GROUP_ID           2       Flow group ID
 985        FLOW_STAT_DURATION      4       Flow duration
 986        FLOW_STAT_REF_COUNT     4       Flow reference count
 987        FLOW_STAT_BUCKET_COUNT  4       Flow bucket count
 988
 989Possible status return codes in descriptor on completion are:
 990
 991        DESC_COMP_ERR   command                 reason
 992        --------------------------------------------------------------------
 993        0               all                     OK
 994        -ROCKER_EFAULT  all                     head or tail index outside
 995                                                of ring
 996        -ROCKER_ENXIO   all                     address or data read err on
 997                                                desc buf
 998        -ROCKER_ENOSPC  GET_STATS               cmd descriptor buffer wasn't
 999                                                big enough to contain write-back
1000                                                TLVs
1001        -ROCKER_EINVAL  ADD|MOD                 invalid parameters passed in
1002        -ROCKER_EEXIST  ADD                     entry already exists
1003        -ROCKER_ENOSPC  ADD                     no space left in flow table
1004        -ROCKER_ENOENT  MOD|DEL|GET_STATS       group ID invalid
1005        -ROCKER_EBUSY   DEL                     group reference count non-zero
1006        -ROCKER_ENODEV  ADD                     next group ID doesn't exist
1007
1008
1009
1010References
1011==========
1012
1013[1] OpenFlow Data Plane Abstraction (OF-DPA) Abstract Switch Specification,
1014Version 1.0, from Broadcom Corporation, February 21, 2014.
1015