netdev.c

grub源码分析文档

	desc_len = sizeof(union e1000_rx_desc_packet_split);

	/* Round up to nearest 4K */
	rx_ring->size = rx_ring->count * desc_len;
	rx_ring->size = ALIGN(rx_ring->size, 4096);

	err = e1000_alloc_ring_dma(adapter, rx_ring);
	if (err)
		goto err_pages;

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

	return 0;

err_pages:
	for (i = 0; i < rx_ring->count; i++) {
		buffer_info = &rx_ring->buffer_info[i];
		kfree(buffer_info->ps_pages);
	}
err:
	vfree(rx_ring->buffer_info);
	e_err("Unable to allocate memory for the transmit descriptor ring\n");
	return err;
}

/**
 * e1000_clean_tx_ring - Free Tx Buffers
 * @adapter: board private structure
 **/
static void e1000_clean_tx_ring(struct e1000_adapter *adapter)
{
	struct e1000_ring *tx_ring = adapter->tx_ring;
	struct e1000_buffer *buffer_info;
	unsigned long size;
	unsigned int i;

	for (i = 0; i < tx_ring->count; i++) {
		buffer_info = &tx_ring->buffer_info[i];
		e1000_put_txbuf(adapter, buffer_info);
	}

	size = sizeof(struct e1000_buffer) * tx_ring->count;
	memset(tx_ring->buffer_info, 0, size);

	memset(tx_ring->desc, 0, tx_ring->size);

	tx_ring->next_to_use = 0;
	tx_ring->next_to_clean = 0;

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

/**
 * e1000e_free_tx_resources - Free Tx Resources per Queue
 * @adapter: board private structure
 *
 * Free all transmit software resources
 **/
void e1000e_free_tx_resources(struct e1000_adapter *adapter)
{
	struct pci_dev *pdev = adapter->pdev;
	struct e1000_ring *tx_ring = adapter->tx_ring;

	e1000_clean_tx_ring(adapter);

	vfree(tx_ring->buffer_info);
	tx_ring->buffer_info = NULL;

	dma_free_coherent(&pdev->dev, tx_ring->size, tx_ring->desc,
			  tx_ring->dma);
	tx_ring->desc = NULL;
}

/**
 * e1000e_free_rx_resources - Free Rx Resources
 * @adapter: board private structure
 *
 * Free all receive software resources
 **/

void e1000e_free_rx_resources(struct e1000_adapter *adapter)
{
	struct pci_dev *pdev = adapter->pdev;
	struct e1000_ring *rx_ring = adapter->rx_ring;
	int i;

	e1000_clean_rx_ring(adapter);

	for (i = 0; i < rx_ring->count; i++) {
		kfree(rx_ring->buffer_info[i].ps_pages);
	}

	vfree(rx_ring->buffer_info);
	rx_ring->buffer_info = NULL;

	dma_free_coherent(&pdev->dev, rx_ring->size, rx_ring->desc,
			  rx_ring->dma);
	rx_ring->desc = NULL;
}

/**
 * e1000_update_itr - update the dynamic ITR value based on statistics
 * @adapter: pointer to adapter
 * @itr_setting: current adapter->itr
 * @packets: the number of packets during this measurement interval
 * @bytes: the number of bytes during this measurement interval
 *
 *      Stores a new ITR value based on packets and byte
 *      counts during the last interrupt.  The advantage of per interrupt
 *      computation is faster updates and more accurate ITR for the current
 *      traffic pattern.  Constants in this function were computed
 *      based on theoretical maximum wire speed and thresholds were set based
 *      on testing data as well as attempting to minimize response time
 *      while increasing bulk throughput.
 *      this functionality is controlled by the InterruptThrottleRate module
 *      parameter (see e1000_param.c)
 **/
static unsigned int e1000_update_itr(struct e1000_adapter *adapter,
				     u16 itr_setting, int packets,
				     int bytes)
{
	unsigned int retval = itr_setting;

	if (packets == 0)
		goto update_itr_done;

	switch (itr_setting) {
	case lowest_latency:
		/* handle TSO and jumbo frames */
		if (bytes/packets > 8000)
			retval = bulk_latency;
		else if ((packets < 5) && (bytes > 512)) {
			retval = low_latency;
		}
		break;
	case low_latency:  /* 50 usec aka 20000 ints/s */
		if (bytes > 10000) {
			/* this if handles the TSO accounting */
			if (bytes/packets > 8000) {
				retval = bulk_latency;
			} else if ((packets < 10) || ((bytes/packets) > 1200)) {
				retval = bulk_latency;
			} else if ((packets > 35)) {
				retval = lowest_latency;
			}
		} else if (bytes/packets > 2000) {
			retval = bulk_latency;
		} else if (packets <= 2 && bytes < 512) {
			retval = lowest_latency;
		}
		break;
	case bulk_latency: /* 250 usec aka 4000 ints/s */
		if (bytes > 25000) {
			if (packets > 35) {
				retval = low_latency;
			}
		} else if (bytes < 6000) {
			retval = low_latency;
		}
		break;
	}

update_itr_done:
	return retval;
}

static void e1000_set_itr(struct e1000_adapter *adapter)
{
	struct e1000_hw *hw = &adapter->hw;
	u16 current_itr;
	u32 new_itr = adapter->itr;

	/* for non-gigabit speeds, just fix the interrupt rate at 4000 */
	if (adapter->link_speed != SPEED_1000) {
		current_itr = 0;
		new_itr = 4000;
		goto set_itr_now;
	}

	adapter->tx_itr = e1000_update_itr(adapter,
				    adapter->tx_itr,
				    adapter->total_tx_packets,
				    adapter->total_tx_bytes);
	/* conservative mode (itr 3) eliminates the lowest_latency setting */
	if (adapter->itr_setting == 3 && adapter->tx_itr == lowest_latency)
		adapter->tx_itr = low_latency;

	adapter->rx_itr = e1000_update_itr(adapter,
				    adapter->rx_itr,
				    adapter->total_rx_packets,
				    adapter->total_rx_bytes);
	/* conservative mode (itr 3) eliminates the lowest_latency setting */
	if (adapter->itr_setting == 3 && adapter->rx_itr == lowest_latency)
		adapter->rx_itr = low_latency;

	current_itr = max(adapter->rx_itr, adapter->tx_itr);

	switch (current_itr) {
	/* counts and packets in update_itr are dependent on these numbers */
	case lowest_latency:
		new_itr = 70000;
		break;
	case low_latency:
		new_itr = 20000; /* aka hwitr = ~200 */
		break;
	case bulk_latency:
		new_itr = 4000;
		break;
	default:
		break;
	}

set_itr_now:
	if (new_itr != adapter->itr) {
		/*
		 * this attempts to bias the interrupt rate towards Bulk
		 * by adding intermediate steps when interrupt rate is
		 * increasing
		 */
		new_itr = new_itr > adapter->itr ?
			     min(adapter->itr + (new_itr >> 2), new_itr) :
			     new_itr;
		adapter->itr = new_itr;
		ew32(ITR, 1000000000 / (new_itr * 256));
	}
}

/**
 * e1000_poll - NAPI Rx polling callback
 * @napi: struct associated with this polling callback
 * @budget: amount of packets driver is allowed to process this poll
 **/
static int e1000_poll(struct napi_struct *napi, int budget)
{
	struct e1000_adapter *adapter = container_of(napi, struct e1000_adapter,
						     napi);
	struct net_device *netdev = adapter->netdev;
	int tx_clean_complete = 1, work_done = 0;

	/*
	 * e1000_poll is called per-cpu.  This lock protects
	 * tx_ring from being cleaned by multiple cpus
	 * simultaneously.  A failure obtaining the lock means
	 * tx_ring is currently being cleaned anyway.
	 */
	if (spin_trylock(&adapter->tx_queue_lock)) {
		tx_clean_complete &= e1000_clean_tx_irq(adapter);
		spin_unlock(&adapter->tx_queue_lock);
	}

	adapter->clean_rx(adapter, &work_done, budget);

	/* If no Tx and not enough Rx work done, exit the polling mode */
	if ((tx_clean_complete && (work_done == 0)) || !netif_running(netdev)) {
		netif_rx_complete(netdev, napi);
		if (adapter->itr_setting & 3)
			e1000_set_itr(adapter);
		if (!test_bit(__E1000_DOWN, &adapter->state))
			e1000_irq_enable(adapter);
		return 0;
	}

	if (!tx_clean_complete)
		work_done = budget;

	return work_done;
}

static void e1000_vlan_rx_add_vid(struct net_device *netdev, u16 vid)
{
	struct e1000_adapter *adapter = netdev_priv(netdev);
	struct e1000_hw *hw = &adapter->hw;
	u32 vfta, index;
	struct net_device *v_netdev;

	/* don't update vlan cookie if already programmed */
	if ((adapter->hw.mng_cookie.status &
	     E1000_MNG_DHCP_COOKIE_STATUS_VLAN) &&
	    (vid == adapter->mng_vlan_id))
		return;
	/* add VID to filter table */
	index = (vid >> 5) & 0x7F;
	vfta = E1000_READ_REG_ARRAY(hw, E1000_VFTA, index);
	vfta |= (1 << (vid & 0x1F));
	e1000e_write_vfta(hw, index, vfta);
	/*
	 * Copy feature flags from netdev to the vlan netdev for this vid.
	 * This allows things like TSO to bubble down to our vlan device.
	 */
	v_netdev = vlan_group_get_device(adapter->vlgrp, vid);
	v_netdev->features |= adapter->netdev->features;
	vlan_group_set_device(adapter->vlgrp, vid, v_netdev);
}

static void e1000_vlan_rx_kill_vid(struct net_device *netdev, u16 vid)
{
	struct e1000_adapter *adapter = netdev_priv(netdev);
	struct e1000_hw *hw = &adapter->hw;
	u32 vfta, index;

	if (!test_bit(__E1000_DOWN, &adapter->state))
		e1000_irq_disable(adapter);
	vlan_group_set_device(adapter->vlgrp, vid, NULL);
	if (!test_bit(__E1000_DOWN, &adapter->state))
		e1000_irq_enable(adapter);

	if ((adapter->hw.mng_cookie.status &
	     E1000_MNG_DHCP_COOKIE_STATUS_VLAN) &&
	    (vid == adapter->mng_vlan_id)) {
		/* release control to f/w */
		e1000_release_hw_control(adapter);
		return;
	}

	/* remove VID from filter table */
	index = (vid >> 5) & 0x7F;
	vfta = E1000_READ_REG_ARRAY(hw, E1000_VFTA, index);
	vfta &= ~(1 << (vid & 0x1F));
	e1000e_write_vfta(hw, index, vfta);
}

static void e1000_update_mng_vlan(struct e1000_adapter *adapter)
{
	struct net_device *netdev = adapter->netdev;
	u16 vid = adapter->hw.mng_cookie.vlan_id;
	u16 old_vid = adapter->mng_vlan_id;

	if (!adapter->vlgrp)
		return;

	if (!vlan_group_get_device(adapter->vlgrp, vid)) {
		adapter->mng_vlan_id = E1000_MNG_VLAN_NONE;
		if (adapter->hw.mng_cookie.status &
			E1000_MNG_DHCP_COOKIE_STATUS_VLAN) {
			e1000_vlan_rx_add_vid(netdev, vid);
			adapter->mng_vlan_id = vid;
		}

		if ((old_vid != (u16)E1000_MNG_VLAN_NONE) &&
				(vid != old_vid) &&
		    !vlan_group_get_device(adapter->vlgrp, old_vid))
			e1000_vlan_rx_kill_vid(netdev, old_vid);
	} else {
		adapter->mng_vlan_id = vid;
	}
}


static void e1000_vlan_rx_register(struct net_device *netdev,
				   struct vlan_group *grp)
{
	struct e1000_adapter *adapter = netdev_priv(netdev);
	struct e1000_hw *hw = &adapter->hw;
	u32 ctrl, rctl;

	if (!test_bit(__E1000_DOWN, &adapter->state))
		e1000_irq_disable(adapter);
	adapter->vlgrp = grp;

	if (grp) {
		/* enable VLAN tag insert/strip */
		ctrl = er32(CTRL);
		ctrl |= E1000_CTRL_VME;
		ew32(CTRL, ctrl);

		if (adapter->flags & FLAG_HAS_HW_VLAN_FILTER) {
			/* enable VLAN receive filtering */
			rctl = er32(RCTL);
			rctl |= E1000_RCTL_VFE;
			rctl &= ~E1000_RCTL_CFIEN;
			ew32(RCTL, rctl);
			e1000_update_mng_vlan(adapter);
		}
	} else {
		/* disable VLAN tag insert/strip */
		ctrl = er32(CTRL);
		ctrl &= ~E1000_CTRL_VME;
		ew32(CTRL, ctrl);

		if (adapter->flags & FLAG_HAS_HW_VLAN_FILTER) {
			/* disable VLAN filtering */
			rctl = er32(RCTL);
			rctl &= ~E1000_RCTL_VFE;
			ew32(RCTL, rctl);
			if (adapter->mng_vlan_id !=
			    (u16)E1000_MNG_VLAN_NONE) {
				e1000_vlan_rx_kill_vid(netdev,
						       adapter->mng_vlan_id);
				adapter->mng_vlan_id = E1000_MNG_VLAN_NONE;
			}
		}
	}

	if (!test_bit(__E1000_DOWN, &adapter->state))
		e1000_irq_enable(adapter);
}

static void e1000_restore_vlan(struct e1000_adapter *adapter)
{
	u16 vid;

	e1000_vlan_rx_register(adapter->netdev, adapter->vlgrp);

	if (!adapter->vlgrp)
		return;

	for (vid = 0; vid < VLAN_GROUP_ARRAY_LEN; vid++) {
		if (!vlan_group_get_device(adapter->vlgrp, vid))
			continue;
		e1000_vlan_rx_add_vid(adapter->netdev, vid);
	}
}

static void e1000_init_manageability(struct e1000_adapter *adapter)
{
	struct e1000_hw *hw = &adapter->hw;
	u32 manc, manc2h;

	if (!(adapter->flags & FLAG_MNG_PT_ENABLED))
		return;

	manc = er32(MANC);

	/*
	 * enable receiving management packets to the host. this will probably
	 * generate destination unreachable messages from the host OS, but
	 * the packets will be handled on SMBUS
	 */
	manc |= E1000_MANC_EN_MNG2HOST;
	manc2h = er32(MANC2H);
#define E1000_MNG2HOST_PORT_623 (1 << 5)
#define E1000_MNG2HOST_PORT_664 (1 << 6)
	manc2h |= E1000_MNG2HOST_PORT_623;
	manc2h |= E1000_MNG2HOST_PORT_664;
	ew32(MANC2H, manc2h);
	ew32(MANC, manc);
}

/**
 * e1000_configure_tx - Configure 8254x Transmit Unit after Reset
 * @adapter: board private structure
 *
 * Configure the Tx unit of the MAC after a reset.
 **/
static void e1000_configure_tx(struct e1000_adapter *adapter)
{
	struct e1000_hw *hw = &adapter->hw;
	struct e1000_ring *tx_ring = adapter->tx_ring;
	u64 tdba;
	u32 tdlen, tctl, tipg, tarc;
	u32 ipgr1, ipgr2;

	/* Setup the HW Tx Head and Tail descriptor pointers */
	tdba = tx_ring->dma;
	tdlen = tx_ring->count * sizeof(struct e1000_tx_desc);
	ew32(TDBAL, (tdba & DMA_32BIT_MASK));
	ew32(TDBAH, (tdba >> 32));
	ew32(TDLEN, tdlen);
	ew32(TDH, 0);
	ew32(TDT, 0);
	tx_ring->head = E1000_TDH;
	tx_ring->tail = E1000_TDT;

	/* Set the default values for the Tx Inter Packet Gap timer */
	tipg = DEFAULT_82543_TIPG_IPGT_COPPER;          /*  8  */
	ipgr1 = DEFAULT_82543_TIPG_IPGR1;               /*  8  */
	ipgr2 = DEFAULT_82543_TIPG_IPGR2;               /*  6  */

	if (adapter->flags & FLAG_TIPG_MEDIUM_FOR_80003ESLAN)
		ipgr2 = DEFAULT_80003ES2LAN_TIPG_IPGR2; /*  7  */

	tipg |= ipgr1 << E1000_TIPG_IPGR1_SHIFT;
	tipg |= ipgr2 << E1000_TIPG_IPGR2_SHIFT;
	ew32(TIPG, tipg);