cvs commit: src/sys/dev/re if_re.c src/sys/pci if_rlreg.h

[Pyun YongHyeon]

yongari     2008-04-22 05:41:29 UTC

  FreeBSD src repository

  Modified files:        (Branch: RELENG_7)
    sys/dev/re           if_re.c 
    sys/pci              if_rlreg.h 
  Log:
  MFC if_re.c 1.101, if_re.c 1.102, if_rlreg.h 1.70 to RELENG_7.
    Overhaul re(4).
    o Increased number of Rx/Tx descriptors to 256 for 8169 GigEs
      because it's hard to push the hardware to the limit with default
      64 descriptors.
      TSO requires large number of Tx descriptors to pass a full sized
      TCP segment(65535 bytes IP packet) to hardware. Previously it
      consumed 32 Tx descriptors, assuming MCLBYTES DMA segment size,
      to send the TCP segment which means re(4) couldn't queue more
      than two full sized IP packets.
      For 8139C+ it still uses 64 Rx/Tx descriptors due to its hardware
      limitations. With this changes there are (very) small waste of
      memory for 8139C+ users but I don't think it would affect 8139C+
      users for most cases.
    o Various bus_dma(9) fixes.
       - The hardware supports DAC so allow 64bit DMA operations.
       - Removed BUS_DMA_ALLOC_NOW flag.
       - Increased DMA segment size to 4096 from MCLBYTES because TSO
         consumes too many descriptors with MCLBYTES DMA segment size.
       - Tx/Rx side bus_dmamap_load_mbuf_sg(9) support. With these
         changes the code is more readable than previous one and got a
         (slightly) better performance as it doesn't need to pass/
         decode arguments to/from callback function.
       - Removed unnecessary callback function re_dmamap_desc() and
         nuked rl_dmaload_arg structure which was used in the callback.
       - Additional protection for DMA map load failure. In case of
         failure reuse current map instead of returning a bogus DMA
         map.
      -  Deferred DMA map unloading/sync operation for maximum
         performance until we really need to load new DMA map. If we
         happen to reuse current map(e.g. input error) there is no need
         to sync/unload/load again.
      -  The number of allowable Tx DMA segments for a mbuf chains are
         now 32 instead of magic nseg value. If the number of available
         Tx descriptors are short enough to send highly fragmented mbuf
         chains an optimized re_defrag() is called to collapse mbuf
         chains which is supposed to be much faster than m_defrag(9).
         re_defrag() was borrowed from ath(4).
       - Separated Rx/Tx DMA tag from a common DMA tag such that Rx DMA
         tag correctly uses DMA maps that were created with DMA alignment
         restriction(8bytes alignments). Tx DMA tag does not have such
         alignment limitation.
       - Added additional sanity checks for DMA ring map load failure.
       - Added additional spare Rx DMA map for graceful handling of Rx
         DMA map load failure.
       - Fixed misused bus_dmamap_sync(9) and added missing
         bus_dmamap_sync(9) in re_encap()/re_txeof()/re_rxeof().
    o Enabled TSO again as re(4) have reasonable number of Tx
      descriptors.
    o Don't touch DMA address of a Tx descriptor in re_txeof(). It's
      not needed.
    o Fix incorrect update of if_ierrors counter. For Rx buffer
      shortage it should update if_qdrops as the buffer is reused.
    o Added checks for unsupported H/W revisions and return ENXIO for
      these hardwares. This is required to remove resource allocation
      code in re_probe as other drivers do in device probe routine.
    o Modified descriptor index manipulation macros as it's now possible
      to have different number of descriptors for Rx/Tx.
    o In re_start, to save a lock operation, use IFQ_DRV_IS_EMPTY before
      trying to invoke IFQ_DRV_DEQUEUE. Also don't blindly call re_encap
      since we already know the number of available Tx descriptors in
      advance.
    o Removed RL_TX_DESC_THLD which was used to reserve RL_TX_DESC_THLD
      descriptors in Tx path. There is no such a limitation mentioned in
      8139C+/8169/8110/8168/8101/8111 datasheet and it seems to work ok
      without reserving RL_TX_DESC_THLD descriptors.
    o Fix a comment for RL_GTXSTART. The register is 8bits register.
    o Added comments for 8169/8139C+ hardware restrictions on descriptors.
    o Removed forward declaration for "struct rl_softc", it's not needed.
    o Added a new structure rl_txdesc for Tx descriptor managements and
      a structure rl_rxdesc for Rx descriptor managements.
    o Removed unused member variable rl_intlock in driver softc. There are
      still several unused member variables which are supposed to be used
      to access hardware statistics counters. But it seems that accessing
      hardware counters were not implemented yet.
  
  Revision  Changes    Path
  1.95.2.6  +483 -359  src/sys/dev/re/if_re.c
  1.67.2.3  +37 -23    src/sys/pci/if_rlreg.h