em(4)/82571eb: fifo not dma'ed to host memory

Patrick Oeschger paketix at bluewin.ch
Tue Jul 24 11:42:52 UTC 2007


OK - found the problem
the driver in 6.2-RELEASE has different code in em_identify_hardware
my hardware needs the memory access and bus master bits getting set by
the driver
beginning with 6.2-RELEASE this gets only set if PCIM_CMD_BUSMASTEREN is
*not set* and PCIM_CMD_MEMEN is *set* - it seems the 82571EB has both
parameters *not set* after init
is this a bug? feature? typo?

--- /root/em/if_em.c.61    Mon Jul 23 12:17:35 2007
+++ if_em.c.62     Tue Jul 24 13:04:11 2007
   static void
  -em_identify_hardware(struct adapter * adapter)
  +em_identify_hardware(struct adapter *adapter)
  {
          device_t dev = adapter->dev;

          /* Make sure our PCI config space has the necessary stuff set */
          adapter->hw.pci_cmd_word = pci_read_config(dev, PCIR_COMMAND, 2);
  -       if (!((adapter->hw.pci_cmd_word & PCIM_CMD_BUSMASTEREN) &&
  -             (adapter->hw.pci_cmd_word & PCIM_CMD_MEMEN))) {
  -               printf("em%d: Memory Access and/or Bus Master bits were not set!
  \n",     
  -                      adapter->unit);
  +       if ((adapter->hw.pci_cmd_word & PCIM_CMD_BUSMASTEREN) == 0 &&      
  +           (adapter->hw.pci_cmd_word & PCIM_CMD_MEMEN)) {     
  +               device_printf(dev, "Memory Access and/or Bus Master bits "    
  +                   "were not set!\n");
                  adapter->hw.pci_cmd_word |=
                  (PCIM_CMD_BUSMASTEREN | PCIM_CMD_MEMEN);
  -               pci_write_config(dev, PCIR_COMMAND, adapter->hw.pci_cmd_word, 2)
  ;
  +               pci_write_config(dev, PCIR_COMMAND,
  +                   adapter->hw.pci_cmd_word, 2);
          }

> thanks for your feedback jack - i tried the MSI stuff as first task this
> morning
> the interface init'ed without a problem and did not complain about MSI
> what i like most is that no IRQ is assigned now, everything seems to get
> handled in a TASKQ (IRQs were quite weird sometimes when having a bunch of
> interfaces...)
> 
> but now the bad news: even with MSI it is not possible to recv any frames
> what makes me curious is, that the head pointer for receive fifo is *not*
> counting up after receiving a frame (good_packets counter incrementing)
> as far as i understand the 82571EB chipset manual, recv head counter inc
> is done in hardware after receiving a good_packet and having dma'ed it to
> host memory
> from if_em.c/em_process_receive_interrupts:
>  *  This routine executes in interrupt context. It replenishes
>  *  the mbufs in the descriptor and sends data which has been
>  *  dma'ed into host memory to upper layer.
> 
> i did a quick test to check this on 6.1-RELENG by inserting a return
> at the top of em_process_receive_interrupts (see diff)
> register RDH0 is still incrementing for each good_packet received - even
> without receive interrupts being processed at the driver level
> 
>   freebsd61# sysctl dev.em.0.debug_info=1
>   dev.em.0.debug_iemnfo: 0:-1 Adapter hardware address = 0xc4b7c928 
>   em0: CTRL = 0x81c0241 RCTL = 0x8002 
>   em0: RDBAH0 = 0x0 RDBAL0 = 0x3e0ff000 
>   em0: RDLEN0 = 0x1000 RDH0 = 0x3 
>   em0: RDT0 = 0xff RXDCTL = 0x10000
> 
> ...so IMHO this increment (and also dma transfer to host memory) is done
> in hardware - RDH0 is not counting up when running under 7.0-CURRENT...
> 
>   erroneous init of chipset?
>   anyone else running 7.0-CURRENT on a 82571EB pci express chipset?
> 
> TIA for any help on this
> pat
> 
> details for dmesg/if_stats/diff:
> 
>   pcib9: <PCI-PCI bridge> irq 19 at device 11.0 on pci2
>   pcib9:   secondary bus     9
>   pcib9:   subordinate bus   9
>   pcib9:   I/O decode        0x6000-0x6fff
>   pcib9:   memory decode     0xfd700000-0xfd7fffff
>   pcib9:   prefetched decode 0xfce00000-0xfcefffff
>   pci9: <PCI bus> on pcib9
>   pci9: physical bus=9
>   found-> vendor=0x8086, dev=0x105e, revid=0x06
>           bus=9, slot=0, func=0
>           class=02-00-00, hdrtype=0x00, mfdev=1
>           cmdreg=0x0000, statreg=0x0010, cachelnsz=16 (dwords)
>           lattimer=0x00 (0 ns), mingnt=0x00 (0 ns), maxlat=0x00 (0 ns)
>           intpin=a, irq=255
>           powerspec 2  supports D0 D3  current D0
>           MSI supports 1 message, 64 bit
>           map[10]: type Memory, range 32, base 0, size 17, memory disabled
>           map[14]: type Memory, range 32, base 0, size 17, memory disabled
>           map[18]: type I/O Port, range 32, base 0, size  5, port disabled
>   found-> vendor=0x8086, dev=0x105e, revid=0x06
>           bus=9, slot=0, func=1
>           class=02-00-00, hdrtype=0x00, mfdev=1
>           cmdreg=0x0000, statreg=0x0010, cachelnsz=16 (dwords)
>           lattimer=0x00 (0 ns), mingnt=0x00 (0 ns), maxlat=0x00 (0 ns)
>           intpin=b, irq=255
>           powerspec 2  supports D0 D3  current D0
>           MSI supports 1 message, 64 bit
>           map[10]: type Memory, range 32, base 0, size 17, memory disabled
>           map[14]: type Memory, range 32, base 0, size 17, memory disabled
>           map[18]: type I/O Port, range 32, base 0, size  5, port disabled
>   em0: <Intel(R) PRO/1000 Network Connection Version - 6.5.3> at device
>     0.0 on pci9
>   pcib9: em0 requested memory range 0xfd700000-0xfd7fffff: good
>   pcib2: em0 requested memory range 0xfd700000-0xfd7fffff: good
>   pcib1: em0 requested memory range 0xfd700000-0xfd7fffff: good
>   em0: Lazy allocation of 0x20000 bytes rid 0x10 type 3 at 0xfd700000
>   em0: attempting to allocate 1 MSI vectors (1 supported)
>   msi: routing MSI IRQ 256 to vector 49
>   em0: using IRQ 256 for MSI
>   em0: bpf attached
>   em0: Ethernet address: 00:10:f3:0c:5b:2a
>   em0: [FILTER]
>   pci9: <network, ethernet> at device 0.1 (no driver attached)
> 
>   freebsd61# diff -u sys/dev/em/if_em.c.orig sys/dev/em/if_em.c
>   --- sys/dev/em/if_em.c.orig     Wed Jul 18 07:32:53 2007
>   +++ sys/dev/em/if_em.c  Wed Jul 18 07:48:42 2007
>   @@ -277,6 +277,11 @@
>    
>           INIT_DEBUGOUT("em_probe: begin");
>    
>   +        // prevent init of all em(4) devices except pci9/0/0 
>   +        if(pci_get_bus(dev) != 0x09 || pci_get_slot(dev) != 0x00 ||
>   +           pci_get_function(dev) != 0x00)
>   +                return (ENXIO);
>   +
>           pci_vendor_id = pci_get_vendor(dev);
>           if (pci_vendor_id != EM_VENDOR_ID)
>                   return(ENXIO);
>   @@ -2906,6 +2911,8 @@
>           u_int8_t            eop = 0;
>           u_int16_t           len, desc_len, prev_len_adj;
>           int                 i;
>   +
>   +       return;
>    
>           /* Pointer to the receive descriptor being examined. */
>           struct em_rx_desc   *current_desc;
> 
> On Tue, Jul 17, 2007 at 09:17:36AM -0700, Jack Vogel wrote:
> > As an experiment, search in if_em.c for 'msix' look at the logic there.
> > If the adapter is 82575 it will use msix, but the else clause has it
> > use msi ONLY if its '>82571', change that to >=82571 and let's
> > see if maybe using MSI will help you with your problems as I'm
> > pretty confident its interrupt related.
> > 
> > I had intended on making this change shortly anyway, my tests
> > have shown the 571 to work fine this way.
> > 
> > Let me know of the results.
> > 
> > Jack


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