netdev.c

grub源码分析文档

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

/**
 * 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);
			else if (adapter->clean_rx == e1000_clean_jumbo_rx_irq)
				pci_unmap_page(pdev, buffer_info->dma,
				               PAGE_SIZE,
				               PCI_DMA_FROMDEVICE);
			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;
		}
	}

	/* 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;
	}

	/* 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);
}

/**
 * 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;
	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)))
			e1000e_gig_downshift_workaround_ich8lan(hw);

		/*
		 * 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);
	}

	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);
	}

	return IRQ_HANDLED;
}

/**
 * e1000_intr - Interrupt Handler
 * @irq: interrupt number
 * @data: pointer to a network interface device structure
 **/
static irqreturn_t e1000_intr(int irq, void *data)
{
	struct net_device *netdev = data;
	struct e1000_adapter *adapter = netdev_priv(netdev);
	struct e1000_hw *hw = &adapter->hw;

	u32 rctl, icr = er32(ICR);
	if (!icr)
		return IRQ_NONE;  /* Not our interrupt */

	/*
	 * IMS will not auto-mask if INT_ASSERTED is not set, and if it is
	 * not set, then the adapter didn't send an interrupt
	 */
	if (!(icr & E1000_ICR_INT_ASSERTED))
		return IRQ_NONE;

	/*
	 * Interrupt Auto-Mask...upon reading ICR,
	 * interrupts are masked.  No need for the
	 * IMC write
	 */

	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)))
			e1000e_gig_downshift_workaround_ich8lan(hw);

		/*
		 * 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 */
			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);
	}

	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);
	}

	return IRQ_HANDLED;
}

static int e1000_request_irq(struct e1000_adapter *adapter)
{
	struct net_device *netdev = adapter->netdev;
	int irq_flags = IRQF_SHARED;
	int err;

	if (adapter->flags & FLAG_HAS_MSI) {
		err = pci_enable_msi(adapter->pdev);
		if (!err) {
			adapter->flags |= FLAG_MSI_ENABLED;
			irq_flags = 0;
		}
	}

	err = request_irq(adapter->pdev->irq, (adapter->flags & FLAG_HAS_MSI) ?
			  &e1000_intr_msi : &e1000_intr, irq_flags,
			  netdev->name, netdev);
	if (err) {
		if (adapter->flags & FLAG_MSI_ENABLED) {
			pci_disable_msi(adapter->pdev);
			adapter->flags &= ~FLAG_MSI_ENABLED;
		}
		e_err("Unable to allocate interrupt, Error: %d\n", err);
	}

	return err;
}

static void e1000_free_irq(struct e1000_adapter *adapter)
{
	struct net_device *netdev = adapter->netdev;

	free_irq(adapter->pdev->irq, netdev);
	if (adapter->flags & FLAG_MSI_ENABLED) {
		pci_disable_msi(adapter->pdev);
		adapter->flags &= ~FLAG_MSI_ENABLED;
	}
}

/**
 * e1000_irq_disable - Mask off interrupt generation on the NIC
 **/
static void e1000_irq_disable(struct e1000_adapter *adapter)
{
	struct e1000_hw *hw = &adapter->hw;

	ew32(IMC, ~0);
	e1e_flush();
	synchronize_irq(adapter->pdev->irq);
}

/**
 * e1000_irq_enable - Enable default interrupt generation settings
 **/
static void e1000_irq_enable(struct e1000_adapter *adapter)
{
	struct e1000_hw *hw = &adapter->hw;
	ew32(IMS, IMS_ENABLE_MASK);
}

/**
 * e1000_get_hw_control - get control of the h/w from f/w
 * @adapter: address of board private structure
 *
 * e1000_get_hw_control sets {CTRL_EXT|SWSM}:DRV_LOAD bit.
 * For ASF and Pass Through versions of f/w this means that
 * the driver is loaded. For AMT version (only with 82573)
 * of the f/w this means that the network i/f is open.
 **/
static void e1000_get_hw_control(struct e1000_adapter *adapter)
{
	struct e1000_hw *hw = &adapter->hw;
	u32 ctrl_ext;
	u32 swsm;

	/* Let firmware know the driver has taken over */
	if (adapter->flags & FLAG_HAS_SWSM_ON_LOAD) {
		swsm = er32(SWSM);
		ew32(SWSM, swsm | E1000_SWSM_DRV_LOAD);
	} else if (adapter->flags & FLAG_HAS_CTRLEXT_ON_LOAD) {
		ctrl_ext = er32(CTRL_EXT);
		ew32(CTRL_EXT, ctrl_ext | E1000_CTRL_EXT_DRV_LOAD);
	}
}

/**
 * e1000_release_hw_control - release control of the h/w to f/w
 * @adapter: address of board private structure
 *
 * e1000_release_hw_control resets {CTRL_EXT|SWSM}:DRV_LOAD bit.
 * For ASF and Pass Through versions of f/w this means that the
 * driver is no longer loaded. For AMT version (only with 82573) i
 * of the f/w this means that the network i/f is closed.
 *
 **/
static void e1000_release_hw_control(struct e1000_adapter *adapter)
{
	struct e1000_hw *hw = &adapter->hw;
	u32 ctrl_ext;
	u32 swsm;

	/* Let firmware taken over control of h/w */
	if (adapter->flags & FLAG_HAS_SWSM_ON_LOAD) {
		swsm = er32(SWSM);
		ew32(SWSM, swsm & ~E1000_SWSM_DRV_LOAD);
	} else if (adapter->flags & FLAG_HAS_CTRLEXT_ON_LOAD) {
		ctrl_ext = er32(CTRL_EXT);
		ew32(CTRL_EXT, ctrl_ext & ~E1000_CTRL_EXT_DRV_LOAD);
	}
}

/**
 * @e1000_alloc_ring - allocate memory for a ring structure
 **/
static int e1000_alloc_ring_dma(struct e1000_adapter *adapter,
				struct e1000_ring *ring)
{
	struct pci_dev *pdev = adapter->pdev;

	ring->desc = dma_alloc_coherent(&pdev->dev, ring->size, &ring->dma,
					GFP_KERNEL);
	if (!ring->desc)
		return -ENOMEM;

	return 0;
}

/**
 * e1000e_setup_tx_resources - allocate Tx resources (Descriptors)
 * @adapter: board private structure
 *
 * Return 0 on success, negative on failure
 **/
int e1000e_setup_tx_resources(struct e1000_adapter *adapter)
{
	struct e1000_ring *tx_ring = adapter->tx_ring;
	int err = -ENOMEM, size;

	size = sizeof(struct e1000_buffer) * tx_ring->count;
	tx_ring->buffer_info = vmalloc(size);
	if (!tx_ring->buffer_info)
		goto err;
	memset(tx_ring->buffer_info, 0, size);

	/* round up to nearest 4K */
	tx_ring->size = tx_ring->count * sizeof(struct e1000_tx_desc);
	tx_ring->size = ALIGN(tx_ring->size, 4096);

	err = e1000_alloc_ring_dma(adapter, tx_ring);
	if (err)
		goto err;

	tx_ring->next_to_use = 0;
	tx_ring->next_to_clean = 0;
	spin_lock_init(&adapter->tx_queue_lock);

	return 0;
err:
	vfree(tx_ring->buffer_info);
	e_err("Unable to allocate memory for the transmit descriptor ring\n");
	return err;
}

/**
 * e1000e_setup_rx_resources - allocate Rx resources (Descriptors)
 * @adapter: board private structure
 *
 * Returns 0 on success, negative on failure
 **/
int e1000e_setup_rx_resources(struct e1000_adapter *adapter)
{
	struct e1000_ring *rx_ring = adapter->rx_ring;
	struct e1000_buffer *buffer_info;
	int i, size, desc_len, err = -ENOMEM;

	size = sizeof(struct e1000_buffer) * rx_ring->count;
	rx_ring->buffer_info = vmalloc(size);
	if (!rx_ring->buffer_info)
		goto err;
	memset(rx_ring->buffer_info, 0, size);

	for (i = 0; i < rx_ring->count; i++) {
		buffer_info = &rx_ring->buffer_info[i];
		buffer_info->ps_pages = kcalloc(PS_PAGE_BUFFERS,
						sizeof(struct e1000_ps_page),
						GFP_KERNEL);
		if (!buffer_info->ps_pages)
			goto err_pages;
	}