ambassador.c

来自「linux 内核源代码」· C语言 代码 · 共 2,334 行 · 第 1/5 页

static inline void tx_complete (amb_dev * dev, tx_out * tx) {
  tx_simple * tx_descr = bus_to_virt (tx->handle);
  struct sk_buff * skb = tx_descr->skb;
  
  PRINTD (DBG_FLOW|DBG_TX, "tx_complete %p %p", dev, tx);
  
  // VC layer stats
  atomic_inc(&ATM_SKB(skb)->vcc->stats->tx);
  
  // free the descriptor
  kfree (tx_descr);
  
  // free the skb
  amb_kfree_skb (skb);
  
  dev->stats.tx_ok++;
  return;
}

/********** RX completion **********/

static void rx_complete (amb_dev * dev, rx_out * rx) {
  struct sk_buff * skb = bus_to_virt (rx->handle);
  u16 vc = be16_to_cpu (rx->vc);
  // unused: u16 lec_id = be16_to_cpu (rx->lec_id);
  u16 status = be16_to_cpu (rx->status);
  u16 rx_len = be16_to_cpu (rx->length);
  
  PRINTD (DBG_FLOW|DBG_RX, "rx_complete %p %p (len=%hu)", dev, rx, rx_len);
  
  // XXX move this in and add to VC stats ???
  if (!status) {
    struct atm_vcc * atm_vcc = dev->rxer[vc];
    dev->stats.rx.ok++;
    
    if (atm_vcc) {
      
      if (rx_len <= atm_vcc->qos.rxtp.max_sdu) {
	
	if (atm_charge (atm_vcc, skb->truesize)) {
	  
	  // prepare socket buffer
	  ATM_SKB(skb)->vcc = atm_vcc;
	  skb_put (skb, rx_len);
	  
	  dump_skb ("<<<", vc, skb);
	  
	  // VC layer stats
	  atomic_inc(&atm_vcc->stats->rx);
	  __net_timestamp(skb);
	  // end of our responsability
	  atm_vcc->push (atm_vcc, skb);
	  return;
	  
	} else {
	  // someone fix this (message), please!
	  PRINTD (DBG_INFO|DBG_RX, "dropped thanks to atm_charge (vc %hu, truesize %u)", vc, skb->truesize);
	  // drop stats incremented in atm_charge
	}
	
      } else {
      	PRINTK (KERN_INFO, "dropped over-size frame");
	// should we count this?
	atomic_inc(&atm_vcc->stats->rx_drop);
      }
      
    } else {
      PRINTD (DBG_WARN|DBG_RX, "got frame but RX closed for channel %hu", vc);
      // this is an adapter bug, only in new version of microcode
    }
    
  } else {
    dev->stats.rx.error++;
    if (status & CRC_ERR)
      dev->stats.rx.badcrc++;
    if (status & LEN_ERR)
      dev->stats.rx.toolong++;
    if (status & ABORT_ERR)
      dev->stats.rx.aborted++;
    if (status & UNUSED_ERR)
      dev->stats.rx.unused++;
  }
  
  dev_kfree_skb_any (skb);
  return;
}

/*
  
  Note on queue handling.
  
  Here "give" and "take" refer to queue entries and a queue (pair)
  rather than frames to or from the host or adapter. Empty frame
  buffers are given to the RX queue pair and returned unused or
  containing RX frames. TX frames (well, pointers to TX fragment
  lists) are given to the TX queue pair, completions are returned.
  
*/

/********** command queue **********/

// I really don't like this, but it's the best I can do at the moment

// also, the callers are responsible for byte order as the microcode
// sometimes does 16-bit accesses (yuk yuk yuk)

static int command_do (amb_dev * dev, command * cmd) {
  amb_cq * cq = &dev->cq;
  volatile amb_cq_ptrs * ptrs = &cq->ptrs;
  command * my_slot;
  
  PRINTD (DBG_FLOW|DBG_CMD, "command_do %p", dev);
  
  if (test_bit (dead, &dev->flags))
    return 0;
  
  spin_lock (&cq->lock);
  
  // if not full...
  if (cq->pending < cq->maximum) {
    // remember my slot for later
    my_slot = ptrs->in;
    PRINTD (DBG_CMD, "command in slot %p", my_slot);
    
    dump_command (cmd);
    
    // copy command in
    *ptrs->in = *cmd;
    cq->pending++;
    ptrs->in = NEXTQ (ptrs->in, ptrs->start, ptrs->limit);
    
    // mail the command
    wr_mem (dev, offsetof(amb_mem, mb.adapter.cmd_address), virt_to_bus (ptrs->in));
    
    if (cq->pending > cq->high)
      cq->high = cq->pending;
    spin_unlock (&cq->lock);
    
    // these comments were in a while-loop before, msleep removes the loop
    // go to sleep
    // PRINTD (DBG_CMD, "wait: sleeping %lu for command", timeout);
    msleep(cq->pending);
    
    // wait for my slot to be reached (all waiters are here or above, until...)
    while (ptrs->out != my_slot) {
      PRINTD (DBG_CMD, "wait: command slot (now at %p)", ptrs->out);
      set_current_state(TASK_UNINTERRUPTIBLE);
      schedule();
    }
    
    // wait on my slot (... one gets to its slot, and... )
    while (ptrs->out->request != cpu_to_be32 (SRB_COMPLETE)) {
      PRINTD (DBG_CMD, "wait: command slot completion");
      set_current_state(TASK_UNINTERRUPTIBLE);
      schedule();
    }
    
    PRINTD (DBG_CMD, "command complete");
    // update queue (... moves the queue along to the next slot)
    spin_lock (&cq->lock);
    cq->pending--;
    // copy command out
    *cmd = *ptrs->out;
    ptrs->out = NEXTQ (ptrs->out, ptrs->start, ptrs->limit);
    spin_unlock (&cq->lock);
    
    return 0;
  } else {
    cq->filled++;
    spin_unlock (&cq->lock);
    return -EAGAIN;
  }
  
}

/********** TX queue pair **********/

static inline int tx_give (amb_dev * dev, tx_in * tx) {
  amb_txq * txq = &dev->txq;
  unsigned long flags;
  
  PRINTD (DBG_FLOW|DBG_TX, "tx_give %p", dev);

  if (test_bit (dead, &dev->flags))
    return 0;
  
  spin_lock_irqsave (&txq->lock, flags);
  
  if (txq->pending < txq->maximum) {
    PRINTD (DBG_TX, "TX in slot %p", txq->in.ptr);

    *txq->in.ptr = *tx;
    txq->pending++;
    txq->in.ptr = NEXTQ (txq->in.ptr, txq->in.start, txq->in.limit);
    // hand over the TX and ring the bell
    wr_mem (dev, offsetof(amb_mem, mb.adapter.tx_address), virt_to_bus (txq->in.ptr));
    wr_mem (dev, offsetof(amb_mem, doorbell), TX_FRAME);
    
    if (txq->pending > txq->high)
      txq->high = txq->pending;
    spin_unlock_irqrestore (&txq->lock, flags);
    return 0;
  } else {
    txq->filled++;
    spin_unlock_irqrestore (&txq->lock, flags);
    return -EAGAIN;
  }
}

static inline int tx_take (amb_dev * dev) {
  amb_txq * txq = &dev->txq;
  unsigned long flags;
  
  PRINTD (DBG_FLOW|DBG_TX, "tx_take %p", dev);
  
  spin_lock_irqsave (&txq->lock, flags);
  
  if (txq->pending && txq->out.ptr->handle) {
    // deal with TX completion
    tx_complete (dev, txq->out.ptr);
    // mark unused again
    txq->out.ptr->handle = 0;
    // remove item
    txq->pending--;
    txq->out.ptr = NEXTQ (txq->out.ptr, txq->out.start, txq->out.limit);
    
    spin_unlock_irqrestore (&txq->lock, flags);
    return 0;
  } else {
    
    spin_unlock_irqrestore (&txq->lock, flags);
    return -1;
  }
}

/********** RX queue pairs **********/

static inline int rx_give (amb_dev * dev, rx_in * rx, unsigned char pool) {
  amb_rxq * rxq = &dev->rxq[pool];
  unsigned long flags;
  
  PRINTD (DBG_FLOW|DBG_RX, "rx_give %p[%hu]", dev, pool);
  
  spin_lock_irqsave (&rxq->lock, flags);
  
  if (rxq->pending < rxq->maximum) {
    PRINTD (DBG_RX, "RX in slot %p", rxq->in.ptr);

    *rxq->in.ptr = *rx;
    rxq->pending++;
    rxq->in.ptr = NEXTQ (rxq->in.ptr, rxq->in.start, rxq->in.limit);
    // hand over the RX buffer
    wr_mem (dev, offsetof(amb_mem, mb.adapter.rx_address[pool]), virt_to_bus (rxq->in.ptr));
    
    spin_unlock_irqrestore (&rxq->lock, flags);
    return 0;
  } else {
    spin_unlock_irqrestore (&rxq->lock, flags);
    return -1;
  }
}

static inline int rx_take (amb_dev * dev, unsigned char pool) {
  amb_rxq * rxq = &dev->rxq[pool];
  unsigned long flags;
  
  PRINTD (DBG_FLOW|DBG_RX, "rx_take %p[%hu]", dev, pool);
  
  spin_lock_irqsave (&rxq->lock, flags);
  
  if (rxq->pending && (rxq->out.ptr->status || rxq->out.ptr->length)) {
    // deal with RX completion
    rx_complete (dev, rxq->out.ptr);
    // mark unused again
    rxq->out.ptr->status = 0;
    rxq->out.ptr->length = 0;
    // remove item
    rxq->pending--;
    rxq->out.ptr = NEXTQ (rxq->out.ptr, rxq->out.start, rxq->out.limit);
    
    if (rxq->pending < rxq->low)
      rxq->low = rxq->pending;
    spin_unlock_irqrestore (&rxq->lock, flags);
    return 0;
  } else {
    if (!rxq->pending && rxq->buffers_wanted)
      rxq->emptied++;
    spin_unlock_irqrestore (&rxq->lock, flags);
    return -1;
  }
}

/********** RX Pool handling **********/

/* pre: buffers_wanted = 0, post: pending = 0 */
static inline void drain_rx_pool (amb_dev * dev, unsigned char pool) {
  amb_rxq * rxq = &dev->rxq[pool];
  
  PRINTD (DBG_FLOW|DBG_POOL, "drain_rx_pool %p %hu", dev, pool);
  
  if (test_bit (dead, &dev->flags))
    return;
  
  /* we are not quite like the fill pool routines as we cannot just
     remove one buffer, we have to remove all of them, but we might as
     well pretend... */
  if (rxq->pending > rxq->buffers_wanted) {
    command cmd;
    cmd.request = cpu_to_be32 (SRB_FLUSH_BUFFER_Q);
    cmd.args.flush.flags = cpu_to_be32 (pool << SRB_POOL_SHIFT);
    while (command_do (dev, &cmd))
      schedule();
    /* the pool may also be emptied via the interrupt handler */
    while (rxq->pending > rxq->buffers_wanted)
      if (rx_take (dev, pool))
	schedule();
  }
  
  return;
}

static void drain_rx_pools (amb_dev * dev) {
  unsigned char pool;
  
  PRINTD (DBG_FLOW|DBG_POOL, "drain_rx_pools %p", dev);
  
  for (pool = 0; pool < NUM_RX_POOLS; ++pool)
    drain_rx_pool (dev, pool);
}

static inline void fill_rx_pool (amb_dev * dev, unsigned char pool,
                                 gfp_t priority)
{
  rx_in rx;
  amb_rxq * rxq;
  
  PRINTD (DBG_FLOW|DBG_POOL, "fill_rx_pool %p %hu %x", dev, pool, priority);
  
  if (test_bit (dead, &dev->flags))
    return;
  
  rxq = &dev->rxq[pool];
  while (rxq->pending < rxq->maximum && rxq->pending < rxq->buffers_wanted) {
    
    struct sk_buff * skb = alloc_skb (rxq->buffer_size, priority);
    if (!skb) {
      PRINTD (DBG_SKB|DBG_POOL, "failed to allocate skb for RX pool %hu", pool);
      return;
    }
    if (check_area (skb->data, skb->truesize)) {
      dev_kfree_skb_any (skb);
      return;
    }
    // cast needed as there is no %? for pointer differences
    PRINTD (DBG_SKB, "allocated skb at %p, head %p, area %li",
	    skb, skb->head, (long) (skb_end_pointer(skb) - skb->head));
    rx.handle = virt_to_bus (skb);
    rx.host_address = cpu_to_be32 (virt_to_bus (skb->data));
    if (rx_give (dev, &rx, pool))
      dev_kfree_skb_any (skb);
    
  }
  
  return;
}

// top up all RX pools (can also be called as a bottom half)
static void fill_rx_pools (amb_dev * dev) {
  unsigned char pool;
  
  PRINTD (DBG_FLOW|DBG_POOL, "fill_rx_pools %p", dev);
  
  for (pool = 0; pool < NUM_RX_POOLS; ++pool)
    fill_rx_pool (dev, pool, GFP_ATOMIC);
  
  return;
}

/********** enable host interrupts **********/

static inline void interrupts_on (amb_dev * dev) {
  wr_plain (dev, offsetof(amb_mem, interrupt_control),
	    rd_plain (dev, offsetof(amb_mem, interrupt_control))
	    | AMB_INTERRUPT_BITS);
}

/********** disable host interrupts **********/

static inline void interrupts_off (amb_dev * dev) {
  wr_plain (dev, offsetof(amb_mem, interrupt_control),
	    rd_plain (dev, offsetof(amb_mem, interrupt_control))
	    &~ AMB_INTERRUPT_BITS);
}

/********** interrupt handling **********/

static irqreturn_t interrupt_handler(int irq, void *dev_id) {
  amb_dev * dev = dev_id;
  
  PRINTD (DBG_IRQ|DBG_FLOW, "interrupt_handler: %p", dev_id);
  
  {
    u32 interrupt = rd_plain (dev, offsetof(amb_mem, interrupt));
  
    // for us or someone else sharing the same interrupt
    if (!interrupt) {
      PRINTD (DBG_IRQ, "irq not for me: %d", irq);
      return IRQ_NONE;
    }
    
    // definitely for us
    PRINTD (DBG_IRQ, "FYI: interrupt was %08x", interrupt);
    wr_plain (dev, offsetof(amb_mem, interrupt), -1);
  }
  
  {
    unsigned int irq_work = 0;
    unsigned char pool;
    for (pool = 0; pool < NUM_RX_POOLS; ++pool)
      while (!rx_take (dev, pool))
	++irq_work;
    while (!tx_take (dev))
      ++irq_work;
  
    if (irq_work) {
#ifdef FILL_RX_POOLS_IN_BH
      schedule_work (&dev->bh);
#else
      fill_rx_pools (dev);
#endif

      PRINTD (DBG_IRQ, "work done: %u", irq_work);
    } else {
      PRINTD (DBG_IRQ|DBG_WARN, "no work done");
    }
  }
  
  PRINTD (DBG_IRQ|DBG_FLOW, "interrupt_handler done: %p", dev_id);
  return IRQ_HANDLED;
}

/********** make rate (not quite as much fun as Horizon) **********/

static int make_rate (unsigned int rate, rounding r,
		      u16 * bits, unsigned int * actual) {
  unsigned char exp = -1; // hush gcc
  unsigned int man = -1;  // hush gcc
  
  PRINTD (DBG_FLOW|DBG_QOS, "make_rate %u", rate);
  
  // rates in cells per second, ITU format (nasty 16-bit floating-point)
  // given 5-bit e and 9-bit m:
  // rate = EITHER (1+m/2^9)*2^e    OR 0
  // bits = EITHER 1<<14 | e<<9 | m OR 0
  // (bit 15 is "reserved", bit 14 "non-zero")
  // smallest rate is 0 (special representation)
  // largest rate is (1+511/512)*2^31 = 4290772992 (< 2^32-1)
  // smallest non-zero rate is (1+0/512)*2^0 = 1 (> 0)
  // simple algorithm:
  // find position of top bit, this gives e
  // remove top bit and shift (rounding if feeling clever) by 9-e
  
  // ucode bug: please don't set bit 14! so 0 rate not representable
  
  if (rate > 0xffc00000U) {
    // larger than largest representable rate