c2.c

linux内核源码

static void c2_rx_error(struct c2_port *c2_port, struct c2_element *elem)
{
	struct c2_rx_desc *rx_desc = elem->ht_desc;
	struct c2_rxp_hdr *rxp_hdr = (struct c2_rxp_hdr *) elem->skb->data;

	if (rxp_hdr->status != RXP_HRXD_OK ||
	    rxp_hdr->len > (rx_desc->len - sizeof(*rxp_hdr))) {
		pr_debug("BAD RXP_HRXD\n");
		pr_debug("  rx_desc : %p\n", rx_desc);
		pr_debug("    index : %Zu\n",
			elem - c2_port->rx_ring.start);
		pr_debug("    len   : %u\n", rx_desc->len);
		pr_debug("  rxp_hdr : %p [PA %p]\n", rxp_hdr,
			(void *) __pa((unsigned long) rxp_hdr));
		pr_debug("    flags : 0x%x\n", rxp_hdr->flags);
		pr_debug("    status: 0x%x\n", rxp_hdr->status);
		pr_debug("    len   : %u\n", rxp_hdr->len);
		pr_debug("    rsvd  : 0x%x\n", rxp_hdr->rsvd);
	}

	/* Setup the skb for reuse since we're dropping this pkt */
	elem->skb->data = elem->skb->head;
	skb_reset_tail_pointer(elem->skb);

	/* Zero out the rxp hdr in the sk_buff */
	memset(elem->skb->data, 0, sizeof(*rxp_hdr));

	/* Write the descriptor to the adapter's rx ring */
	__raw_writew(0, elem->hw_desc + C2_RXP_STATUS);
	__raw_writew(0, elem->hw_desc + C2_RXP_COUNT);
	__raw_writew(cpu_to_be16((u16) elem->maplen - sizeof(*rxp_hdr)),
		     elem->hw_desc + C2_RXP_LEN);
	__raw_writeq(cpu_to_be64(elem->mapaddr), elem->hw_desc + C2_RXP_ADDR);
	__raw_writew(cpu_to_be16(RXP_HRXD_READY), elem->hw_desc + C2_RXP_FLAGS);

	pr_debug("packet dropped\n");
	c2_port->netstats.rx_dropped++;
}

static void c2_rx_interrupt(struct net_device *netdev)
{
	struct c2_port *c2_port = netdev_priv(netdev);
	struct c2_dev *c2dev = c2_port->c2dev;
	struct c2_ring *rx_ring = &c2_port->rx_ring;
	struct c2_element *elem;
	struct c2_rx_desc *rx_desc;
	struct c2_rxp_hdr *rxp_hdr;
	struct sk_buff *skb;
	dma_addr_t mapaddr;
	u32 maplen, buflen;
	unsigned long flags;

	spin_lock_irqsave(&c2dev->lock, flags);

	/* Begin where we left off */
	rx_ring->to_clean = rx_ring->start + c2dev->cur_rx;

	for (elem = rx_ring->to_clean; elem->next != rx_ring->to_clean;
	     elem = elem->next) {
		rx_desc = elem->ht_desc;
		mapaddr = elem->mapaddr;
		maplen = elem->maplen;
		skb = elem->skb;
		rxp_hdr = (struct c2_rxp_hdr *) skb->data;

		if (rxp_hdr->flags != RXP_HRXD_DONE)
			break;
		buflen = rxp_hdr->len;

		/* Sanity check the RXP header */
		if (rxp_hdr->status != RXP_HRXD_OK ||
		    buflen > (rx_desc->len - sizeof(*rxp_hdr))) {
			c2_rx_error(c2_port, elem);
			continue;
		}

		/*
		 * Allocate and map a new skb for replenishing the host
		 * RX desc
		 */
		if (c2_rx_alloc(c2_port, elem)) {
			c2_rx_error(c2_port, elem);
			continue;
		}

		/* Unmap the old skb */
		pci_unmap_single(c2dev->pcidev, mapaddr, maplen,
				 PCI_DMA_FROMDEVICE);

		prefetch(skb->data);

		/*
		 * Skip past the leading 8 bytes comprising of the
		 * "struct c2_rxp_hdr", prepended by the adapter
		 * to the usual Ethernet header ("struct ethhdr"),
		 * to the start of the raw Ethernet packet.
		 *
		 * Fix up the various fields in the sk_buff before
		 * passing it up to netif_rx(). The transfer size
		 * (in bytes) specified by the adapter len field of
		 * the "struct rxp_hdr_t" does NOT include the
		 * "sizeof(struct c2_rxp_hdr)".
		 */
		skb->data += sizeof(*rxp_hdr);
		skb_set_tail_pointer(skb, buflen);
		skb->len = buflen;
		skb->protocol = eth_type_trans(skb, netdev);

		netif_rx(skb);

		netdev->last_rx = jiffies;
		c2_port->netstats.rx_packets++;
		c2_port->netstats.rx_bytes += buflen;
	}

	/* Save where we left off */
	rx_ring->to_clean = elem;
	c2dev->cur_rx = elem - rx_ring->start;
	C2_SET_CUR_RX(c2dev, c2dev->cur_rx);

	spin_unlock_irqrestore(&c2dev->lock, flags);
}

/*
 * Handle netisr0 TX & RX interrupts.
 */
static irqreturn_t c2_interrupt(int irq, void *dev_id)
{
	unsigned int netisr0, dmaisr;
	int handled = 0;
	struct c2_dev *c2dev = (struct c2_dev *) dev_id;

	/* Process CCILNET interrupts */
	netisr0 = readl(c2dev->regs + C2_NISR0);
	if (netisr0) {

		/*
		 * There is an issue with the firmware that always
		 * provides the status of RX for both TX & RX
		 * interrupts.  So process both queues here.
		 */
		c2_rx_interrupt(c2dev->netdev);
		c2_tx_interrupt(c2dev->netdev);

		/* Clear the interrupt */
		writel(netisr0, c2dev->regs + C2_NISR0);
		handled++;
	}

	/* Process RNIC interrupts */
	dmaisr = readl(c2dev->regs + C2_DISR);
	if (dmaisr) {
		writel(dmaisr, c2dev->regs + C2_DISR);
		c2_rnic_interrupt(c2dev);
		handled++;
	}

	if (handled) {
		return IRQ_HANDLED;
	} else {
		return IRQ_NONE;
	}
}

static int c2_up(struct net_device *netdev)
{
	struct c2_port *c2_port = netdev_priv(netdev);
	struct c2_dev *c2dev = c2_port->c2dev;
	struct c2_element *elem;
	struct c2_rxp_hdr *rxp_hdr;
	struct in_device *in_dev;
	size_t rx_size, tx_size;
	int ret, i;
	unsigned int netimr0;

	if (netif_msg_ifup(c2_port))
		pr_debug("%s: enabling interface\n", netdev->name);

	/* Set the Rx buffer size based on MTU */
	c2_set_rxbufsize(c2_port);

	/* Allocate DMA'able memory for Tx/Rx host descriptor rings */
	rx_size = c2_port->rx_ring.count * sizeof(struct c2_rx_desc);
	tx_size = c2_port->tx_ring.count * sizeof(struct c2_tx_desc);

	c2_port->mem_size = tx_size + rx_size;
	c2_port->mem = pci_alloc_consistent(c2dev->pcidev, c2_port->mem_size,
					    &c2_port->dma);
	if (c2_port->mem == NULL) {
		pr_debug("Unable to allocate memory for "
			"host descriptor rings\n");
		return -ENOMEM;
	}

	memset(c2_port->mem, 0, c2_port->mem_size);

	/* Create the Rx host descriptor ring */
	if ((ret =
	     c2_rx_ring_alloc(&c2_port->rx_ring, c2_port->mem, c2_port->dma,
			      c2dev->mmio_rxp_ring))) {
		pr_debug("Unable to create RX ring\n");
		goto bail0;
	}

	/* Allocate Rx buffers for the host descriptor ring */
	if (c2_rx_fill(c2_port)) {
		pr_debug("Unable to fill RX ring\n");
		goto bail1;
	}

	/* Create the Tx host descriptor ring */
	if ((ret = c2_tx_ring_alloc(&c2_port->tx_ring, c2_port->mem + rx_size,
				    c2_port->dma + rx_size,
				    c2dev->mmio_txp_ring))) {
		pr_debug("Unable to create TX ring\n");
		goto bail1;
	}

	/* Set the TX pointer to where we left off */
	c2_port->tx_avail = c2_port->tx_ring.count - 1;
	c2_port->tx_ring.to_use = c2_port->tx_ring.to_clean =
	    c2_port->tx_ring.start + c2dev->cur_tx;

	/* missing: Initialize MAC */

	BUG_ON(c2_port->tx_ring.to_use != c2_port->tx_ring.to_clean);

	/* Reset the adapter, ensures the driver is in sync with the RXP */
	c2_reset(c2_port);

	/* Reset the READY bit in the sk_buff RXP headers & adapter HRXDQ */
	for (i = 0, elem = c2_port->rx_ring.start; i < c2_port->rx_ring.count;
	     i++, elem++) {
		rxp_hdr = (struct c2_rxp_hdr *) elem->skb->data;
		rxp_hdr->flags = 0;
		__raw_writew(cpu_to_be16(RXP_HRXD_READY),
			     elem->hw_desc + C2_RXP_FLAGS);
	}

	/* Enable network packets */
	netif_start_queue(netdev);

	/* Enable IRQ */
	writel(0, c2dev->regs + C2_IDIS);
	netimr0 = readl(c2dev->regs + C2_NIMR0);
	netimr0 &= ~(C2_PCI_HTX_INT | C2_PCI_HRX_INT);
	writel(netimr0, c2dev->regs + C2_NIMR0);

	/* Tell the stack to ignore arp requests for ipaddrs bound to
	 * other interfaces.  This is needed to prevent the host stack
	 * from responding to arp requests to the ipaddr bound on the
	 * rdma interface.
	 */
	in_dev = in_dev_get(netdev);
	IN_DEV_CONF_SET(in_dev, ARP_IGNORE, 1);
	in_dev_put(in_dev);

	return 0;

      bail1:
	c2_rx_clean(c2_port);
	kfree(c2_port->rx_ring.start);

      bail0:
	pci_free_consistent(c2dev->pcidev, c2_port->mem_size, c2_port->mem,
			    c2_port->dma);

	return ret;
}

static int c2_down(struct net_device *netdev)
{
	struct c2_port *c2_port = netdev_priv(netdev);
	struct c2_dev *c2dev = c2_port->c2dev;

	if (netif_msg_ifdown(c2_port))
		pr_debug("%s: disabling interface\n",
			netdev->name);

	/* Wait for all the queued packets to get sent */
	c2_tx_interrupt(netdev);

	/* Disable network packets */
	netif_stop_queue(netdev);

	/* Disable IRQs by clearing the interrupt mask */
	writel(1, c2dev->regs + C2_IDIS);
	writel(0, c2dev->regs + C2_NIMR0);

	/* missing: Stop transmitter */

	/* missing: Stop receiver */

	/* Reset the adapter, ensures the driver is in sync with the RXP */
	c2_reset(c2_port);

	/* missing: Turn off LEDs here */

	/* Free all buffers in the host descriptor rings */
	c2_tx_clean(c2_port);
	c2_rx_clean(c2_port);

	/* Free the host descriptor rings */
	kfree(c2_port->rx_ring.start);
	kfree(c2_port->tx_ring.start);
	pci_free_consistent(c2dev->pcidev, c2_port->mem_size, c2_port->mem,
			    c2_port->dma);

	return 0;
}

static void c2_reset(struct c2_port *c2_port)
{
	struct c2_dev *c2dev = c2_port->c2dev;
	unsigned int cur_rx = c2dev->cur_rx;

	/* Tell the hardware to quiesce */
	C2_SET_CUR_RX(c2dev, cur_rx | C2_PCI_HRX_QUI);

	/*
	 * The hardware will reset the C2_PCI_HRX_QUI bit once
	 * the RXP is quiesced.  Wait 2 seconds for this.
	 */
	ssleep(2);

	cur_rx = C2_GET_CUR_RX(c2dev);

	if (cur_rx & C2_PCI_HRX_QUI)
		pr_debug("c2_reset: failed to quiesce the hardware!\n");

	cur_rx &= ~C2_PCI_HRX_QUI;

	c2dev->cur_rx = cur_rx;

	pr_debug("Current RX: %u\n", c2dev->cur_rx);
}

static int c2_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
{
	struct c2_port *c2_port = netdev_priv(netdev);
	struct c2_dev *c2dev = c2_port->c2dev;
	struct c2_ring *tx_ring = &c2_port->tx_ring;
	struct c2_element *elem;
	dma_addr_t mapaddr;
	u32 maplen;
	unsigned long flags;
	unsigned int i;

	spin_lock_irqsave(&c2_port->tx_lock, flags);

	if (unlikely(c2_port->tx_avail < (skb_shinfo(skb)->nr_frags + 1))) {
		netif_stop_queue(netdev);
		spin_unlock_irqrestore(&c2_port->tx_lock, flags);

		pr_debug("%s: Tx ring full when queue awake!\n",
			netdev->name);
		return NETDEV_TX_BUSY;
	}

	maplen = skb_headlen(skb);
	mapaddr =
	    pci_map_single(c2dev->pcidev, skb->data, maplen, PCI_DMA_TODEVICE);

	elem = tx_ring->to_use;
	elem->skb = skb;
	elem->mapaddr = mapaddr;
	elem->maplen = maplen;

	/* Tell HW to xmit */
	__raw_writeq(cpu_to_be64(mapaddr), elem->hw_desc + C2_TXP_ADDR);
	__raw_writew(cpu_to_be16(maplen), elem->hw_desc + C2_TXP_LEN);
	__raw_writew(cpu_to_be16(TXP_HTXD_READY), elem->hw_desc + C2_TXP_FLAGS);

	c2_port->netstats.tx_packets++;
	c2_port->netstats.tx_bytes += maplen;

	/* Loop thru additional data fragments and queue them */
	if (skb_shinfo(skb)->nr_frags) {
		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
			maplen = frag->size;
			mapaddr =
			    pci_map_page(c2dev->pcidev, frag->page,
					 frag->page_offset, maplen,
					 PCI_DMA_TODEVICE);

			elem = elem->next;
			elem->skb = NULL;
			elem->mapaddr = mapaddr;
			elem->maplen = maplen;

			/* Tell HW to xmit */
			__raw_writeq(cpu_to_be64(mapaddr),
				     elem->hw_desc + C2_TXP_ADDR);
			__raw_writew(cpu_to_be16(maplen),
				     elem->hw_desc + C2_TXP_LEN);
			__raw_writew(cpu_to_be16(TXP_HTXD_READY),
				     elem->hw_desc + C2_TXP_FLAGS);

			c2_port->netstats.tx_packets++;
			c2_port->netstats.tx_bytes += maplen;
		}
	}

	tx_ring->to_use = elem->next;
	c2_port->tx_avail -= (skb_shinfo(skb)->nr_frags + 1);

	if (c2_port->tx_avail <= MAX_SKB_FRAGS + 1) {
		netif_stop_queue(netdev);
		if (netif_msg_tx_queued(c2_port))
			pr_debug("%s: transmit queue full\n",
				netdev->name);
	}

	spin_unlock_irqrestore(&c2_port->tx_lock, flags);

	netdev->trans_start = jiffies;