netdev.c

Intel 82546系列lan driver源码

		/* in the packet split case this is header only */
		prefetch(skb->data - NET_IP_ALIGN);

		i++;
		if (i == rx_ring->count)
			i = 0;
		next_rxd = E1000_RX_DESC_PS(*rx_ring, i);
		prefetch(next_rxd);

		next_buffer = &rx_ring->buffer_info[i];

		cleaned = 1;
		cleaned_count++;
		pci_unmap_single(pdev, buffer_info->dma,
				 adapter->rx_ps_bsize0,
				 PCI_DMA_FROMDEVICE);
		buffer_info->dma = 0;

		if (!(staterr & E1000_RXD_STAT_EOP)) {
			e_dbg("Packet Split buffers didn't pick up the full "
			      "packet\n");
			dev_kfree_skb_irq(skb);
			goto next_desc;
		}

		if (staterr & E1000_RXDEXT_ERR_FRAME_ERR_MASK) {
			dev_kfree_skb_irq(skb);
			goto next_desc;
		}

		length = le16_to_cpu(rx_desc->wb.middle.length0);

		if (!length) {
			e_dbg("Last part of the packet spanning multiple "
			      "descriptors\n");
			dev_kfree_skb_irq(skb);
			goto next_desc;
		}

		/* Good Receive */
		skb_put(skb, length);

#ifdef CONFIG_E1000E_NAPI
		{
		/*
		 * this looks ugly, but it seems compiler issues make it
		 * more efficient than reusing j
		 */
		int l1 = le16_to_cpu(rx_desc->wb.upper.length[0]);

		/*
		 * page alloc/put takes too long and effects small packet
		 * throughput, so unsplit small packets and save the alloc/put
		 * only valid in softirq (napi) context to call kmap_*
		 */
		if (l1 && (l1 <= copybreak) &&
		    ((length + l1) <= adapter->rx_ps_bsize0)) {
			u8 *vaddr;

			ps_page = &buffer_info->ps_pages[0];

			/*
			 * there is no documentation about how to call
			 * kmap_atomic, so we can't hold the mapping
			 * very long
			 */
			pci_dma_sync_single_for_cpu(pdev, ps_page->dma,
				PAGE_SIZE, PCI_DMA_FROMDEVICE);
			vaddr = kmap_atomic(ps_page->page, KM_SKB_DATA_SOFTIRQ);
			memcpy(skb_tail_pointer(skb), vaddr, l1);
			kunmap_atomic(vaddr, KM_SKB_DATA_SOFTIRQ);
			pci_dma_sync_single_for_device(pdev, ps_page->dma,
				PAGE_SIZE, PCI_DMA_FROMDEVICE);

			/* remove the CRC */
			if (!(adapter->flags2 & FLAG2_CRC_STRIPPING))
				l1 -= 4;

			skb_put(skb, l1);
			goto copydone;
		} /* if */
		}
#endif

		for (j = 0; j < PS_PAGE_BUFFERS; j++) {
			length = le16_to_cpu(rx_desc->wb.upper.length[j]);
			if (!length)
				break;

			ps_page = &buffer_info->ps_pages[j];
			pci_unmap_page(pdev, ps_page->dma, PAGE_SIZE,
				       PCI_DMA_FROMDEVICE);
			ps_page->dma = 0;
			skb_fill_page_desc(skb, j, ps_page->page, 0, length);
			ps_page->page = NULL;
			skb->len += length;
			skb->data_len += length;
			skb->truesize += length;
		}

		/* strip the ethernet crc, problem is we're using pages now so
		 * this whole operation can get a little cpu intensive */
		if (!(adapter->flags2 & FLAG2_CRC_STRIPPING))
			pskb_trim(skb, skb->len - 4);

#ifdef CONFIG_E1000E_NAPI
copydone:
#endif
		total_rx_bytes += skb->len;
		total_rx_packets++;

		e1000_rx_checksum(adapter, staterr, le16_to_cpu(
			rx_desc->wb.lower.hi_dword.csum_ip.csum), skb);

		if (rx_desc->wb.upper.header_status &
			   cpu_to_le16(E1000_RXDPS_HDRSTAT_HDRSP))
			adapter->rx_hdr_split++;

		e1000_receive_skb(adapter, netdev, skb,
				  staterr, rx_desc->wb.middle.vlan);

next_desc:
		rx_desc->wb.middle.status_error &= cpu_to_le32(~0xFF);
		buffer_info->skb = NULL;

		/* return some buffers to hardware, one at a time is too slow */
		if (cleaned_count >= E1000_RX_BUFFER_WRITE) {
			adapter->alloc_rx_buf(adapter, cleaned_count);
			cleaned_count = 0;
		}

		/* use prefetched values */
		rx_desc = next_rxd;
		buffer_info = next_buffer;

		staterr = le32_to_cpu(rx_desc->wb.middle.status_error);
	}
	rx_ring->next_to_clean = i;

	cleaned_count = e1000_desc_unused(rx_ring);
	if (cleaned_count)
		adapter->alloc_rx_buf(adapter, cleaned_count);

	adapter->total_rx_bytes += total_rx_bytes;
	adapter->total_rx_packets += total_rx_packets;
	adapter->net_stats.rx_bytes += total_rx_bytes;
	adapter->net_stats.rx_packets += total_rx_packets;
	return cleaned;
}

#ifdef CONFIG_E1000E_NAPI
/**
 * e1000_consume_page - helper function
 **/
static void e1000_consume_page(struct e1000_buffer *bi, struct sk_buff *skb,
                               u16 length)
{
	bi->page = NULL;
	skb->len += length;
	skb->data_len += length;
	skb->truesize += length;
}

/**
 * e1000_clean_jumbo_rx_irq - Send received data up the network stack; legacy
 * @adapter: board private structure
 *
 * the return value indicates whether actual cleaning was done, there
 * is no guarantee that everything was cleaned
 **/

static bool e1000_clean_jumbo_rx_irq(struct e1000_adapter *adapter,
                                     int *work_done, int work_to_do)
{
	struct net_device *netdev = adapter->netdev;
	struct pci_dev *pdev = adapter->pdev;
	struct e1000_ring *rx_ring = adapter->rx_ring;
	struct e1000_rx_desc *rx_desc, *next_rxd;
	struct e1000_buffer *buffer_info, *next_buffer;
	u32 length;
	unsigned int i;
	int cleaned_count = 0;
	bool cleaned = false;
	unsigned int total_rx_bytes=0, total_rx_packets=0;

	i = rx_ring->next_to_clean;
	rx_desc = E1000_RX_DESC(*rx_ring, i);
	buffer_info = &rx_ring->buffer_info[i];

	while (rx_desc->status & E1000_RXD_STAT_DD) {
		struct sk_buff *skb;
		u8 status;

		if (*work_done >= work_to_do)
			break;
		(*work_done)++;

		status = rx_desc->status;
		skb = buffer_info->skb;
		buffer_info->skb = NULL;

		++i;
		if (i == rx_ring->count)
			i = 0;
		next_rxd = E1000_RX_DESC(*rx_ring, i);
		prefetch(next_rxd);

		next_buffer = &rx_ring->buffer_info[i];

		cleaned = true;
		cleaned_count++;
		pci_unmap_page(pdev, buffer_info->dma, PAGE_SIZE,
		               PCI_DMA_FROMDEVICE);
		buffer_info->dma = 0;

		length = le16_to_cpu(rx_desc->length);

		/* errors is only valid for DD + EOP descriptors */
		if (unlikely((status & E1000_RXD_STAT_EOP) &&
		    (rx_desc->errors & E1000_RXD_ERR_FRAME_ERR_MASK))) {
				/* recycle both page and skb */
				buffer_info->skb = skb;
				/* an error means any chain goes out the window
				 * too */
				if (rx_ring->rx_skb_top)
					dev_kfree_skb(rx_ring->rx_skb_top);
				rx_ring->rx_skb_top = NULL;
				goto next_desc;
		}

#define rxtop rx_ring->rx_skb_top
		if (!(status & E1000_RXD_STAT_EOP)) {
			/* this descriptor is only the beginning (or middle) */
			if (!rxtop) {
				/* this is the beginning of a chain */
				rxtop = skb;
				skb_fill_page_desc(rxtop, 0, buffer_info->page,
				                   0, length);
			} else {
				/* this is the middle of a chain */
				skb_fill_page_desc(rxtop,
				    skb_shinfo(rxtop)->nr_frags,
				    buffer_info->page, 0, length);
				/* re-use the skb, only consumed the page */
				buffer_info->skb = skb;
			}
			e1000_consume_page(buffer_info, rxtop, length);
			goto next_desc;
		} else {
			if (rxtop) {
				/* end of the chain */
				skb_fill_page_desc(rxtop,
				    skb_shinfo(rxtop)->nr_frags,
				    buffer_info->page, 0, length);
				/* re-use the current skb, we only consumed the
				 * page */
				buffer_info->skb = skb;
				skb = rxtop;
				rxtop = NULL;
				e1000_consume_page(buffer_info, skb, length);
			} else {
				/* no chain, got EOP, this buf is the packet
				 * copybreak to save the put_page/alloc_page */
				if (length <= copybreak &&
				    skb_tailroom(skb) >= length) {
					u8 *vaddr;
					vaddr = kmap_atomic(buffer_info->page,
					                   KM_SKB_DATA_SOFTIRQ);
					memcpy(skb_tail_pointer(skb), vaddr,
					       length);
					kunmap_atomic(vaddr,
					              KM_SKB_DATA_SOFTIRQ);
					/* re-use the page, so don't erase
					 * buffer_info->page */
					skb_put(skb, length);
				} else {
					skb_fill_page_desc(skb, 0,
					                   buffer_info->page, 0,
				                           length);
					e1000_consume_page(buffer_info, skb,
					                   length);
				}
			}
		}

		/* Receive Checksum Offload XXX recompute due to CRC strip? */
		e1000_rx_checksum(adapter,
		                  (u32)(status) |
		                  ((u32)(rx_desc->errors) << 24),
		                  le16_to_cpu(rx_desc->csum), skb);

		/* probably a little skewed due to removing CRC */
		total_rx_bytes += skb->len;
		total_rx_packets++;

		/* eth type trans needs skb->data to point to something */
		if (!pskb_may_pull(skb, ETH_HLEN)) {
			e_err("pskb_may_pull failed.\n");
			dev_kfree_skb(skb);
			goto next_desc;
		}

		e1000_receive_skb(adapter, netdev, skb, status,
		                  rx_desc->special);

next_desc:
		rx_desc->status = 0;

		/* return some buffers to hardware, one at a time is too slow */
		if (unlikely(cleaned_count >= E1000_RX_BUFFER_WRITE)) {
			adapter->alloc_rx_buf(adapter, cleaned_count);
			cleaned_count = 0;
		}

		/* use prefetched values */
		rx_desc = next_rxd;
		buffer_info = next_buffer;
	}
	rx_ring->next_to_clean = i;

	cleaned_count = e1000_desc_unused(rx_ring);
	if (cleaned_count)
		adapter->alloc_rx_buf(adapter, cleaned_count);

	adapter->total_rx_bytes += total_rx_bytes;
	adapter->total_rx_packets += total_rx_packets;
	adapter->net_stats.rx_bytes += total_rx_bytes;
	adapter->net_stats.rx_packets += total_rx_packets;
	return cleaned;
}

#endif /* CONFIG_E1000E_NAPI */
/**
 * e1000_clean_rx_ring - Free Rx Buffers per Queue
 * @adapter: board private structure
 **/
static void e1000_clean_rx_ring(struct e1000_adapter *adapter)
{
	struct e1000_ring *rx_ring = adapter->rx_ring;
	struct e1000_buffer *buffer_info;
	struct e1000_ps_page *ps_page;
	struct pci_dev *pdev = adapter->pdev;
	unsigned int i, j;

	/* Free all the Rx ring sk_buffs */
	for (i = 0; i < rx_ring->count; i++) {
		buffer_info = &rx_ring->buffer_info[i];
		if (buffer_info->dma) {
			if (adapter->clean_rx == e1000_clean_rx_irq)
				pci_unmap_single(pdev, buffer_info->dma,
						 adapter->rx_buffer_len,
						 PCI_DMA_FROMDEVICE);
#ifdef CONFIG_E1000E_NAPI
			else if (adapter->clean_rx == e1000_clean_jumbo_rx_irq)
				pci_unmap_page(pdev, buffer_info->dma,
				               PAGE_SIZE,
				               PCI_DMA_FROMDEVICE);
#endif
			else if (adapter->clean_rx == e1000_clean_rx_irq_ps)
				pci_unmap_single(pdev, buffer_info->dma,
						 adapter->rx_ps_bsize0,
						 PCI_DMA_FROMDEVICE);
			buffer_info->dma = 0;
		}

		if (buffer_info->page) {
			put_page(buffer_info->page);
			buffer_info->page = NULL;
		}

		if (buffer_info->skb) {
			dev_kfree_skb(buffer_info->skb);
			buffer_info->skb = NULL;
		}

		for (j = 0; j < PS_PAGE_BUFFERS; j++) {
			ps_page = &buffer_info->ps_pages[j];
			if (!ps_page->page)
				break;
			pci_unmap_page(pdev, ps_page->dma, PAGE_SIZE,
				       PCI_DMA_FROMDEVICE);
			ps_page->dma = 0;
			put_page(ps_page->page);
			ps_page->page = NULL;
		}
	}

#ifdef CONFIG_E1000E_NAPI
	/* there also may be some cached data from a chained receive */
	if (rx_ring->rx_skb_top) {
		dev_kfree_skb(rx_ring->rx_skb_top);
		rx_ring->rx_skb_top = NULL;
	}
#endif

	/* Zero out the descriptor ring */
	memset(rx_ring->desc, 0, rx_ring->size);

	rx_ring->next_to_clean = 0;
	rx_ring->next_to_use = 0;

	writel(0, adapter->hw.hw_addr + rx_ring->head);
	writel(0, adapter->hw.hw_addr + rx_ring->tail);
}

static void e1000e_downshift_workaround(struct work_struct *work)
{
	struct e1000_adapter *adapter = container_of(work,
					struct e1000_adapter, downshift_task);

	e1000e_gig_downshift_workaround_ich8lan(&adapter->hw);
}

#ifndef CONFIG_E1000E_NAPI
static void e1000_set_itr(struct e1000_adapter *adapter);
#endif
/**
 * e1000_intr_msi - Interrupt Handler
 * @irq: interrupt number
 * @data: pointer to a network interface device structure
 **/
static irqreturn_t e1000_intr_msi(int irq, void *data)
{
	struct net_device *netdev = data;
	struct e1000_adapter *adapter = netdev_priv(netdev);
	struct e1000_hw *hw = &adapter->hw;
#ifndef CONFIG_E1000E_NAPI
	int i;
#endif
	u32 icr = er32(ICR);

	/*
	 * read ICR disables interrupts using IAM
	 */

	if (icr & (E1000_ICR_RXSEQ | E1000_ICR_LSC)) {
		hw->mac.get_link_status = 1;
		/*
		 * ICH8 workaround-- Call gig speed drop workaround on cable
		 * disconnect (LSC) before accessing any PHY registers
		 */
		if ((adapter->flags & FLAG_LSC_GIG_SPEED_DROP) &&
		    (!(er32(STATUS) & E1000_STATUS_LU)))
			schedule_work(&adapter->downshift_task);

		/*
		 * 80003ES2LAN workaround-- For packet buffer work-around on
		 * link down event; disable receives here in the ISR and reset
		 * adapter in watchdog
		 */
		if (netif_carrier_ok(netdev) &&
		    adapter->flags & FLAG_RX_NEEDS_RESTART) {
			/* disable receives */
			u32 rctl = er32(RCTL);
			ew32(RCTL, rctl & ~E1000_RCTL_EN);
			adapter->flags |= FLAG_RX_RESTART_NOW;
		}
		/* guard against interrupt when we're going down */
		if (!test_bit(__E1000_DOWN, &adapter->state))
			mod_timer(&adapter->watchdog_timer, jiffies + 1);
	}

#ifdef CONFIG_E1000E_NAPI
	if (netif_rx_schedule_prep(netdev, &adapter->napi)) {
		adapter->total_tx_bytes = 0;
		adapter->total_tx_packets = 0;
		adapter->total_rx_bytes = 0;
		adapter->total_rx_packets = 0;
		__netif_rx_schedule(netdev, &adapter->napi);
	}
#else
	adapter->total_tx_bytes = 0;
	adapter->total_rx_bytes = 0;
	adapter->total_tx_packets = 0;
	adapter->total_rx_packets = 0;

	for (i = 0; i < E1000_MAX_INTR; i++) {
		int rx_cleaned = adapter->clean_rx(adapter);
		int tx_cleaned_complete = e1000_clean_tx_irq(adapter);
		if (!rx_cleaned && tx_cleaned_complete)
			break;
	}