b44.c

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static void b44_timer(unsigned long __opaque)
{
	struct b44 *bp = (struct b44 *) __opaque;

	spin_lock_irq(&bp->lock);

	b44_check_phy(bp);

	b44_stats_update(bp);

	spin_unlock_irq(&bp->lock);

	mod_timer(&bp->timer, round_jiffies(jiffies + HZ));
}

static void b44_tx(struct b44 *bp)
{
	u32 cur, cons;

	cur  = br32(bp, B44_DMATX_STAT) & DMATX_STAT_CDMASK;
	cur /= sizeof(struct dma_desc);

	/* XXX needs updating when NETIF_F_SG is supported */
	for (cons = bp->tx_cons; cons != cur; cons = NEXT_TX(cons)) {
		struct ring_info *rp = &bp->tx_buffers[cons];
		struct sk_buff *skb = rp->skb;

		BUG_ON(skb == NULL);

		dma_unmap_single(bp->sdev->dev,
				 rp->mapping,
				 skb->len,
				 DMA_TO_DEVICE);
		rp->skb = NULL;
		dev_kfree_skb_irq(skb);
	}

	bp->tx_cons = cons;
	if (netif_queue_stopped(bp->dev) &&
	    TX_BUFFS_AVAIL(bp) > B44_TX_WAKEUP_THRESH)
		netif_wake_queue(bp->dev);

	bw32(bp, B44_GPTIMER, 0);
}

/* Works like this.  This chip writes a 'struct rx_header" 30 bytes
 * before the DMA address you give it.  So we allocate 30 more bytes
 * for the RX buffer, DMA map all of it, skb_reserve the 30 bytes, then
 * point the chip at 30 bytes past where the rx_header will go.
 */
static int b44_alloc_rx_skb(struct b44 *bp, int src_idx, u32 dest_idx_unmasked)
{
	struct dma_desc *dp;
	struct ring_info *src_map, *map;
	struct rx_header *rh;
	struct sk_buff *skb;
	dma_addr_t mapping;
	int dest_idx;
	u32 ctrl;

	src_map = NULL;
	if (src_idx >= 0)
		src_map = &bp->rx_buffers[src_idx];
	dest_idx = dest_idx_unmasked & (B44_RX_RING_SIZE - 1);
	map = &bp->rx_buffers[dest_idx];
	skb = netdev_alloc_skb(bp->dev, RX_PKT_BUF_SZ);
	if (skb == NULL)
		return -ENOMEM;

	mapping = dma_map_single(bp->sdev->dev, skb->data,
				 RX_PKT_BUF_SZ,
				 DMA_FROM_DEVICE);

	/* Hardware bug work-around, the chip is unable to do PCI DMA
	   to/from anything above 1GB :-( */
	if (dma_mapping_error(mapping) ||
		mapping + RX_PKT_BUF_SZ > DMA_30BIT_MASK) {
		/* Sigh... */
		if (!dma_mapping_error(mapping))
			dma_unmap_single(bp->sdev->dev, mapping,
					RX_PKT_BUF_SZ, DMA_FROM_DEVICE);
		dev_kfree_skb_any(skb);
		skb = __netdev_alloc_skb(bp->dev, RX_PKT_BUF_SZ, GFP_ATOMIC|GFP_DMA);
		if (skb == NULL)
			return -ENOMEM;
		mapping = dma_map_single(bp->sdev->dev, skb->data,
					 RX_PKT_BUF_SZ,
					 DMA_FROM_DEVICE);
		if (dma_mapping_error(mapping) ||
			mapping + RX_PKT_BUF_SZ > DMA_30BIT_MASK) {
			if (!dma_mapping_error(mapping))
				dma_unmap_single(bp->sdev->dev, mapping, RX_PKT_BUF_SZ,DMA_FROM_DEVICE);
			dev_kfree_skb_any(skb);
			return -ENOMEM;
		}
	}

	rh = (struct rx_header *) skb->data;
	skb_reserve(skb, RX_PKT_OFFSET);

	rh->len = 0;
	rh->flags = 0;

	map->skb = skb;
	map->mapping = mapping;

	if (src_map != NULL)
		src_map->skb = NULL;

	ctrl  = (DESC_CTRL_LEN & (RX_PKT_BUF_SZ - RX_PKT_OFFSET));
	if (dest_idx == (B44_RX_RING_SIZE - 1))
		ctrl |= DESC_CTRL_EOT;

	dp = &bp->rx_ring[dest_idx];
	dp->ctrl = cpu_to_le32(ctrl);
	dp->addr = cpu_to_le32((u32) mapping + RX_PKT_OFFSET + bp->dma_offset);

	if (bp->flags & B44_FLAG_RX_RING_HACK)
		b44_sync_dma_desc_for_device(bp->sdev, bp->rx_ring_dma,
			                    dest_idx * sizeof(dp),
			                    DMA_BIDIRECTIONAL);

	return RX_PKT_BUF_SZ;
}

static void b44_recycle_rx(struct b44 *bp, int src_idx, u32 dest_idx_unmasked)
{
	struct dma_desc *src_desc, *dest_desc;
	struct ring_info *src_map, *dest_map;
	struct rx_header *rh;
	int dest_idx;
	__le32 ctrl;

	dest_idx = dest_idx_unmasked & (B44_RX_RING_SIZE - 1);
	dest_desc = &bp->rx_ring[dest_idx];
	dest_map = &bp->rx_buffers[dest_idx];
	src_desc = &bp->rx_ring[src_idx];
	src_map = &bp->rx_buffers[src_idx];

	dest_map->skb = src_map->skb;
	rh = (struct rx_header *) src_map->skb->data;
	rh->len = 0;
	rh->flags = 0;
	dest_map->mapping = src_map->mapping;

	if (bp->flags & B44_FLAG_RX_RING_HACK)
		b44_sync_dma_desc_for_cpu(bp->sdev, bp->rx_ring_dma,
			                 src_idx * sizeof(src_desc),
			                 DMA_BIDIRECTIONAL);

	ctrl = src_desc->ctrl;
	if (dest_idx == (B44_RX_RING_SIZE - 1))
		ctrl |= cpu_to_le32(DESC_CTRL_EOT);
	else
		ctrl &= cpu_to_le32(~DESC_CTRL_EOT);

	dest_desc->ctrl = ctrl;
	dest_desc->addr = src_desc->addr;

	src_map->skb = NULL;

	if (bp->flags & B44_FLAG_RX_RING_HACK)
		b44_sync_dma_desc_for_device(bp->sdev, bp->rx_ring_dma,
					     dest_idx * sizeof(dest_desc),
					     DMA_BIDIRECTIONAL);

	dma_sync_single_for_device(bp->sdev->dev, le32_to_cpu(src_desc->addr),
				   RX_PKT_BUF_SZ,
				   DMA_FROM_DEVICE);
}

static int b44_rx(struct b44 *bp, int budget)
{
	int received;
	u32 cons, prod;

	received = 0;
	prod  = br32(bp, B44_DMARX_STAT) & DMARX_STAT_CDMASK;
	prod /= sizeof(struct dma_desc);
	cons = bp->rx_cons;

	while (cons != prod && budget > 0) {
		struct ring_info *rp = &bp->rx_buffers[cons];
		struct sk_buff *skb = rp->skb;
		dma_addr_t map = rp->mapping;
		struct rx_header *rh;
		u16 len;

		dma_sync_single_for_cpu(bp->sdev->dev, map,
					    RX_PKT_BUF_SZ,
					    DMA_FROM_DEVICE);
		rh = (struct rx_header *) skb->data;
		len = le16_to_cpu(rh->len);
		if ((len > (RX_PKT_BUF_SZ - RX_PKT_OFFSET)) ||
		    (rh->flags & cpu_to_le16(RX_FLAG_ERRORS))) {
		drop_it:
			b44_recycle_rx(bp, cons, bp->rx_prod);
		drop_it_no_recycle:
			bp->stats.rx_dropped++;
			goto next_pkt;
		}

		if (len == 0) {
			int i = 0;

			do {
				udelay(2);
				barrier();
				len = le16_to_cpu(rh->len);
			} while (len == 0 && i++ < 5);
			if (len == 0)
				goto drop_it;
		}

		/* Omit CRC. */
		len -= 4;

		if (len > RX_COPY_THRESHOLD) {
			int skb_size;
			skb_size = b44_alloc_rx_skb(bp, cons, bp->rx_prod);
			if (skb_size < 0)
				goto drop_it;
			dma_unmap_single(bp->sdev->dev, map,
					 skb_size, DMA_FROM_DEVICE);
			/* Leave out rx_header */
                	skb_put(skb, len + RX_PKT_OFFSET);
            	        skb_pull(skb, RX_PKT_OFFSET);
		} else {
			struct sk_buff *copy_skb;

			b44_recycle_rx(bp, cons, bp->rx_prod);
			copy_skb = dev_alloc_skb(len + 2);
			if (copy_skb == NULL)
				goto drop_it_no_recycle;

			skb_reserve(copy_skb, 2);
			skb_put(copy_skb, len);
			/* DMA sync done above, copy just the actual packet */
			skb_copy_from_linear_data_offset(skb, RX_PKT_OFFSET,
							 copy_skb->data, len);
			skb = copy_skb;
		}
		skb->ip_summed = CHECKSUM_NONE;
		skb->protocol = eth_type_trans(skb, bp->dev);
		netif_receive_skb(skb);
		bp->dev->last_rx = jiffies;
		received++;
		budget--;
	next_pkt:
		bp->rx_prod = (bp->rx_prod + 1) &
			(B44_RX_RING_SIZE - 1);
		cons = (cons + 1) & (B44_RX_RING_SIZE - 1);
	}

	bp->rx_cons = cons;
	bw32(bp, B44_DMARX_PTR, cons * sizeof(struct dma_desc));

	return received;
}

static int b44_poll(struct napi_struct *napi, int budget)
{
	struct b44 *bp = container_of(napi, struct b44, napi);
	struct net_device *netdev = bp->dev;
	int work_done;

	spin_lock_irq(&bp->lock);

	if (bp->istat & (ISTAT_TX | ISTAT_TO)) {
		/* spin_lock(&bp->tx_lock); */
		b44_tx(bp);
		/* spin_unlock(&bp->tx_lock); */
	}
	spin_unlock_irq(&bp->lock);

	work_done = 0;
	if (bp->istat & ISTAT_RX)
		work_done += b44_rx(bp, budget);

	if (bp->istat & ISTAT_ERRORS) {
		unsigned long flags;

		spin_lock_irqsave(&bp->lock, flags);
		b44_halt(bp);
		b44_init_rings(bp);
		b44_init_hw(bp, B44_FULL_RESET_SKIP_PHY);
		netif_wake_queue(bp->dev);
		spin_unlock_irqrestore(&bp->lock, flags);
		work_done = 0;
	}

	if (work_done < budget) {
		netif_rx_complete(netdev, napi);
		b44_enable_ints(bp);
	}

	return work_done;
}

static irqreturn_t b44_interrupt(int irq, void *dev_id)
{
	struct net_device *dev = dev_id;
	struct b44 *bp = netdev_priv(dev);
	u32 istat, imask;
	int handled = 0;

	spin_lock(&bp->lock);

	istat = br32(bp, B44_ISTAT);
	imask = br32(bp, B44_IMASK);

	/* The interrupt mask register controls which interrupt bits
	 * will actually raise an interrupt to the CPU when set by hw/firmware,
	 * but doesn't mask off the bits.
	 */
	istat &= imask;
	if (istat) {
		handled = 1;

		if (unlikely(!netif_running(dev))) {
			printk(KERN_INFO "%s: late interrupt.\n", dev->name);
			goto irq_ack;
		}

		if (netif_rx_schedule_prep(dev, &bp->napi)) {
			/* NOTE: These writes are posted by the readback of
			 *       the ISTAT register below.
			 */
			bp->istat = istat;
			__b44_disable_ints(bp);
			__netif_rx_schedule(dev, &bp->napi);
		} else {
			printk(KERN_ERR PFX "%s: Error, poll already scheduled\n",
			       dev->name);
		}

irq_ack:
		bw32(bp, B44_ISTAT, istat);
		br32(bp, B44_ISTAT);
	}
	spin_unlock(&bp->lock);
	return IRQ_RETVAL(handled);
}

static void b44_tx_timeout(struct net_device *dev)
{
	struct b44 *bp = netdev_priv(dev);

	printk(KERN_ERR PFX "%s: transmit timed out, resetting\n",
	       dev->name);

	spin_lock_irq(&bp->lock);

	b44_halt(bp);
	b44_init_rings(bp);
	b44_init_hw(bp, B44_FULL_RESET);

	spin_unlock_irq(&bp->lock);

	b44_enable_ints(bp);

	netif_wake_queue(dev);
}

static int b44_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct b44 *bp = netdev_priv(dev);
	int rc = NETDEV_TX_OK;
	dma_addr_t mapping;
	u32 len, entry, ctrl;

	len = skb->len;
	spin_lock_irq(&bp->lock);

	/* This is a hard error, log it. */
	if (unlikely(TX_BUFFS_AVAIL(bp) < 1)) {
		netif_stop_queue(dev);
		printk(KERN_ERR PFX "%s: BUG! Tx Ring full when queue awake!\n",
		       dev->name);
		goto err_out;
	}

	mapping = dma_map_single(bp->sdev->dev, skb->data, len, DMA_TO_DEVICE);
	if (dma_mapping_error(mapping) || mapping + len > DMA_30BIT_MASK) {
		struct sk_buff *bounce_skb;

		/* Chip can't handle DMA to/from >1GB, use bounce buffer */
		if (!dma_mapping_error(mapping))
			dma_unmap_single(bp->sdev->dev, mapping, len,
					DMA_TO_DEVICE);

		bounce_skb = __dev_alloc_skb(len, GFP_ATOMIC | GFP_DMA);
		if (!bounce_skb)
			goto err_out;

		mapping = dma_map_single(bp->sdev->dev, bounce_skb->data,
					 len, DMA_TO_DEVICE);
		if (dma_mapping_error(mapping) || mapping + len > DMA_30BIT_MASK) {
			if (!dma_mapping_error(mapping))
				dma_unmap_single(bp->sdev->dev, mapping,
					 len, DMA_TO_DEVICE);
			dev_kfree_skb_any(bounce_skb);
			goto err_out;
		}

		skb_copy_from_linear_data(skb, skb_put(bounce_skb, len), len);
		dev_kfree_skb_any(skb);
		skb = bounce_skb;
	}

	entry = bp->tx_prod;
	bp->tx_buffers[entry].skb = skb;
	bp->tx_buffers[entry].mapping = mapping;

	ctrl  = (len & DESC_CTRL_LEN);
	ctrl |= DESC_CTRL_IOC | DESC_CTRL_SOF | DESC_CTRL_EOF;
	if (entry == (B44_TX_RING_SIZE - 1))
		ctrl |= DESC_CTRL_EOT;

	bp->tx_ring[entry].ctrl = cpu_to_le32(ctrl);
	bp->tx_ring[entry].addr = cpu_to_le32((u32) mapping+bp->dma_offset);

	if (bp->flags & B44_FLAG_TX_RING_HACK)
		b44_sync_dma_desc_for_device(bp->sdev, bp->tx_ring_dma,
			                    entry * sizeof(bp->tx_ring[0]),
			                    DMA_TO_DEVICE);

	entry = NEXT_TX(entry);

	bp->tx_prod = entry;

	wmb();

	bw32(bp, B44_DMATX_PTR, entry * sizeof(struct dma_desc));
	if (bp->flags & B44_FLAG_BUGGY_TXPTR)
		bw32(bp, B44_DMATX_PTR, entry * sizeof(struct dma_desc));
	if (bp->flags & B44_FLAG_REORDER_BUG)
		br32(bp, B44_DMATX_PTR);

	if (TX_BUFFS_AVAIL(bp) < 1)
		netif_stop_queue(dev);

	dev->trans_start = jiffies;

out_unlock:
	spin_unlock_irq(&bp->lock);

	return rc;

err_out:
	rc = NETDEV_TX_BUSY;
	goto out_unlock;
}

static int b44_change_mtu(struct net_device *dev, int new_mtu)
{
	struct b44 *bp = netdev_priv(dev);

	if (new_mtu < B44_MIN_MTU || new_mtu > B44_MAX_MTU)
		return -EINVAL;

	if (!netif_running(dev)) {
		/* We'll just catch it later when the
		 * device is up'd.
		 */
		dev->mtu = new_mtu;
		return 0;
	}

	spin_lock_irq(&bp->lock);
	b44_halt(bp);
	dev->mtu = new_mtu;
	b44_init_rings(bp);
	b44_init_hw(bp, B44_FULL_RESET);
	spin_unlock_irq(&bp->lock);

	b44_enable_ints(bp);

	return 0;
}

/* Free up pending packets in all rx/tx rings.
 *
 * The chip has been shut down and the driver detached from
 * the networking, so no interrupts or new tx packets will
 * end up in the driver.  bp->lock is not held and we are not
 * in an interrupt context and thus may sleep.
 */
static void b44_free_rings(struct b44 *bp)
{
	struct ring_info *rp;
	int i;

	for (i = 0; i < B44_RX_RING_SIZE; i++) {
		rp = &bp->rx_buffers[i];

		if (rp->skb == NULL)
			continue;
		dma_unmap_single(bp->sdev->dev, rp->mapping, RX_PKT_BUF_SZ,
					DMA_FROM_DEVICE);
		dev_kfree_skb_any(rp->skb);
		rp->skb = NULL;
	}

	/* XXX needs changes once NETIF_F_SG is set... */
	for (i = 0; i < B44_TX_RING_SIZE; i++) {
		rp = &bp->tx_buffers[i];

		if (rp->skb == NULL)
			continue;
		dma_unmap_single(bp->sdev->dev, rp->mapping, rp->skb->len,
					DMA_TO_DEVICE);
		dev_kfree_skb_any(rp->skb);
		rp->skb = NULL;
	}
}

/* Initialize tx/rx rings for packet processing.
 *
 * The chip has been shut down and the driver detached from
 * the networking, so no interrupts or new tx packets will
 * end up in the driver.
 */
static void b44_init_rings(struct b44 *bp)
{
	int i;

	b44_free_rings(bp);

	memset(bp->rx_ring, 0, B44_RX_RING_BYTES);
	memset(bp->tx_ring, 0, B44_TX_RING_BYTES);

	if (bp->flags & B44_FLAG_RX_RING_HACK)
		dma_sync_single_for_device(bp->sdev->dev, bp->rx_ring_dma,
			                  DMA_TABLE_BYTES,
			                  DMA_BIDIRECTIONAL);

	if (bp->flags & B44_FLAG_TX_RING_HACK)
		dma_sync_single_for_device(bp->sdev->dev, bp->tx_ring_dma,
			                  DMA_TABLE_BYTES,
			                  DMA_TO_DEVICE);

	for (i = 0; i < bp->rx_pending; i++) {
		if (b44_alloc_rx_skb(bp, -1, i) < 0)
			break;
	}
}

/*
 * Must not be invoked with interrupt sources disabled and
 * the hardware shutdown down.
 */
static void b44_free_consistent(struct b44 *bp)
{
	kfree(bp->rx_buffers);
	bp->rx_buffers = NULL;
	kfree(bp->tx_buffers);
	bp->tx_buffers = NULL;
	if (bp->rx_ring) {
		if (bp->flags & B44_FLAG_RX_RING_HACK) {
			dma_unmap_single(bp->sdev->dev, bp->rx_ring_dma,
					DMA_TABLE_BYTES,
					DMA_BIDIRECTIONAL);
			kfree(bp->rx_ring);
		} else
			dma_free_coherent(bp->sdev->dev, DMA_TABLE_BYTES,
					    bp->rx_ring, bp->rx_ring_dma);
		bp->rx_ring = NULL;
		bp->flags &= ~B44_FLAG_RX_RING_HACK;
	}
	if (bp->tx_ring) {
		if (bp->flags & B44_FLAG_TX_RING_HACK) {
			dma_unmap_single(bp->sdev->dev, bp->tx_ring_dma,
					DMA_TABLE_BYTES,
					DMA_TO_DEVICE);
			kfree(bp->tx_ring);
		} else
			dma_free_coherent(bp->sdev->dev, DMA_TABLE_BYTES,
					    bp->tx_ring, bp->tx_ring_dma);
		bp->tx_ring = NULL;
		bp->flags &= ~B44_FLAG_TX_RING_HACK;
	}
}