bcm43xx_dma.c

博通的bcm43xx系列Minipci接口无线网卡驱动

	ring->mmio_base = dma_controller_base;
	if (tx) {
		ring->tx = 1;
		ring->current_slot = -1;
	} else {
		switch (dma_controller_base) {
		case BCM43xx_MMIO_DMA1_BASE:
			ring->rx_buffersize = BCM43xx_DMA1_RXBUFFERSIZE;
			ring->frameoffset = BCM43xx_DMA1_RX_FRAMEOFFSET;
			break;
		case BCM43xx_MMIO_DMA4_BASE:
			ring->rx_buffersize = BCM43xx_DMA4_RXBUFFERSIZE;
			ring->frameoffset = BCM43xx_DMA4_RX_FRAMEOFFSET;
			break;
		default:
			assert(0);
		}
	}

	err = alloc_ringmemory(ring);
	if (err)
		goto err_kfree_meta;
	err = dmacontroller_setup(ring);
	if (err)
		goto err_free_ringmemory;

out:
	return ring;

err_free_ringmemory:
	free_ringmemory(ring);
err_kfree_meta:
	kfree(ring->meta);
err_kfree_ring:
	kfree(ring);
	ring = NULL;
	goto out;
}

/* Main cleanup function. */
static void bcm43xx_destroy_dmaring(struct bcm43xx_dmaring *ring)
{
	if (!ring)
		return;

	dprintk(KERN_INFO PFX "DMA 0x%04x (%s) max used slots: %d/%d\n",
		ring->mmio_base,
		(ring->tx) ? "TX" : "RX",
		ring->max_used_slots, ring->nr_slots);
	/* Device IRQs are disabled prior entering this function,
	 * so no need to take care of concurrency with rx handler stuff.
	 */
	dmacontroller_cleanup(ring);
	free_all_descbuffers(ring);
	free_ringmemory(ring);

	kfree(ring->meta);
	kfree(ring);
}

void bcm43xx_dma_free(struct bcm43xx_private *bcm)
{
	struct bcm43xx_dma *dma = bcm->current_core->dma;

	bcm43xx_destroy_dmaring(dma->rx_ring1);
	dma->rx_ring1 = NULL;
	bcm43xx_destroy_dmaring(dma->rx_ring0);
	dma->rx_ring0 = NULL;
	bcm43xx_destroy_dmaring(dma->tx_ring3);
	dma->tx_ring3 = NULL;
	bcm43xx_destroy_dmaring(dma->tx_ring2);
	dma->tx_ring2 = NULL;
	bcm43xx_destroy_dmaring(dma->tx_ring1);
	dma->tx_ring1 = NULL;
	bcm43xx_destroy_dmaring(dma->tx_ring0);
	dma->tx_ring0 = NULL;
}

int bcm43xx_dma_init(struct bcm43xx_private *bcm)
{
	struct bcm43xx_dma *dma = bcm->current_core->dma;
	struct bcm43xx_dmaring *ring;
	int err = -ENOMEM;

	/* setup TX DMA channels. */
	ring = bcm43xx_setup_dmaring(bcm, BCM43xx_MMIO_DMA1_BASE,
				     BCM43xx_TXRING_SLOTS, 1);
	if (!ring)
		goto out;
	dma->tx_ring0 = ring;

	ring = bcm43xx_setup_dmaring(bcm, BCM43xx_MMIO_DMA2_BASE,
				     BCM43xx_TXRING_SLOTS, 1);
	if (!ring)
		goto err_destroy_tx0;
	dma->tx_ring1 = ring;

	ring = bcm43xx_setup_dmaring(bcm, BCM43xx_MMIO_DMA3_BASE,
				     BCM43xx_TXRING_SLOTS, 1);
	if (!ring)
		goto err_destroy_tx1;
	dma->tx_ring2 = ring;

	ring = bcm43xx_setup_dmaring(bcm, BCM43xx_MMIO_DMA4_BASE,
				     BCM43xx_TXRING_SLOTS, 1);
	if (!ring)
		goto err_destroy_tx2;
	dma->tx_ring3 = ring;

	/* setup RX DMA channels. */
	ring = bcm43xx_setup_dmaring(bcm, BCM43xx_MMIO_DMA1_BASE,
				     BCM43xx_RXRING_SLOTS, 0);
	if (!ring)
		goto err_destroy_tx3;
	dma->rx_ring0 = ring;

	if (bcm->current_core->rev < 5) {
		ring = bcm43xx_setup_dmaring(bcm, BCM43xx_MMIO_DMA4_BASE,
					     BCM43xx_RXRING_SLOTS, 0);
		if (!ring)
			goto err_destroy_rx0;
		dma->rx_ring1 = ring;
	}

	dprintk(KERN_INFO PFX "DMA initialized\n");
	err = 0;
out:
	return err;

err_destroy_rx0:
	bcm43xx_destroy_dmaring(dma->rx_ring0);
	dma->rx_ring0 = NULL;
err_destroy_tx3:
	bcm43xx_destroy_dmaring(dma->tx_ring3);
	dma->tx_ring3 = NULL;
err_destroy_tx2:
	bcm43xx_destroy_dmaring(dma->tx_ring2);
	dma->tx_ring2 = NULL;
err_destroy_tx1:
	bcm43xx_destroy_dmaring(dma->tx_ring1);
	dma->tx_ring1 = NULL;
err_destroy_tx0:
	bcm43xx_destroy_dmaring(dma->tx_ring0);
	dma->tx_ring0 = NULL;
	goto out;
}

/* Generate a cookie for the TX header. */
static u16 generate_cookie(struct bcm43xx_dmaring *ring,
			   int slot)
{
	u16 cookie = 0x0000;

	/* Use the upper 4 bits of the cookie as
	 * DMA controller ID and store the slot number
	 * in the lower 12 bits
	 */
	switch (ring->mmio_base) {
	default:
		assert(0);
	case BCM43xx_MMIO_DMA1_BASE:
		break;
	case BCM43xx_MMIO_DMA2_BASE:
		cookie = 0x1000;
		break;
	case BCM43xx_MMIO_DMA3_BASE:
		cookie = 0x2000;
		break;
	case BCM43xx_MMIO_DMA4_BASE:
		cookie = 0x3000;
		break;
	}
	assert(((u16)slot & 0xF000) == 0x0000);
	cookie |= (u16)slot;

	return cookie;
}

/* Inspect a cookie and find out to which controller/slot it belongs. */
static
struct bcm43xx_dmaring * parse_cookie(struct bcm43xx_private *bcm,
				      u16 cookie, int *slot)
{
	struct bcm43xx_dma *dma = bcm->current_core->dma;
	struct bcm43xx_dmaring *ring = NULL;

	switch (cookie & 0xF000) {
	case 0x0000:
		ring = dma->tx_ring0;
		break;
	case 0x1000:
		ring = dma->tx_ring1;
		break;
	case 0x2000:
		ring = dma->tx_ring2;
		break;
	case 0x3000:
		ring = dma->tx_ring3;
		break;
	default:
		assert(0);
	}
	*slot = (cookie & 0x0FFF);
	assert(*slot >= 0 && *slot < ring->nr_slots);

	return ring;
}

static void dmacontroller_poke_tx(struct bcm43xx_dmaring *ring,
				  int slot)
{
	/* Everything is ready to start. Buffers are DMA mapped and
	 * associated with slots.
	 * "slot" is the last slot of the new frame we want to transmit.
	 * Close your seat belts now, please.
	 */
	wmb();
	slot = next_slot(ring, slot);
	bcm43xx_write32(ring->bcm,
			ring->mmio_base + BCM43xx_DMA_TX_DESC_INDEX,
			(u32)(slot * sizeof(struct bcm43xx_dmadesc)));
}

static int dma_tx_fragment(struct bcm43xx_dmaring *ring,
			   struct sk_buff *skb,
			   u8 cur_frag)
{
	int slot;
	struct bcm43xx_dmadesc *desc;
	struct bcm43xx_dmadesc_meta *meta;
	u32 desc_ctl;
	u32 desc_addr;

	assert(skb_shinfo(skb)->nr_frags == 0);

	slot = request_slot(ring);
	desc = ring->vbase + slot;
	meta = ring->meta + slot;

	/* Add a device specific TX header. */
	assert(skb_headroom(skb) >= sizeof(struct bcm43xx_txhdr));
	/* Reserve enough headroom for the device tx header. */
	__skb_push(skb, sizeof(struct bcm43xx_txhdr));
	/* Now calculate and add the tx header.
	 * The tx header includes the PLCP header.
	 */
	bcm43xx_generate_txhdr(ring->bcm,
			       (struct bcm43xx_txhdr *)skb->data,
			       skb->data + sizeof(struct bcm43xx_txhdr),
			       skb->len - sizeof(struct bcm43xx_txhdr),
			       (cur_frag == 0),
			       generate_cookie(ring, slot));

	meta->skb = skb;
	meta->dmaaddr = map_descbuffer(ring, skb->data, skb->len, 1);
	if (unlikely(meta->dmaaddr + skb->len > BCM43xx_DMA_BUSADDRMAX)) {
		return_slot(ring, slot);
		printk(KERN_ERR PFX ">>>FATAL ERROR<<<  DMA TX SKB >1G "
				    "(0x%08x, len: %u)\n",
		       meta->dmaaddr, skb->len);
		return -ENOMEM;
	}

	desc_addr = (u32)(meta->dmaaddr + ring->memoffset);
	desc_ctl = BCM43xx_DMADTOR_FRAMESTART | BCM43xx_DMADTOR_FRAMEEND;
	desc_ctl |= BCM43xx_DMADTOR_COMPIRQ;
	desc_ctl |= (BCM43xx_DMADTOR_BYTECNT_MASK &
		     (u32)(meta->skb->len - ring->frameoffset));
	if (slot == ring->nr_slots - 1)
		desc_ctl |= BCM43xx_DMADTOR_DTABLEEND;

	set_desc_ctl(desc, desc_ctl);
	set_desc_addr(desc, desc_addr);
	/* Now transfer the whole frame. */
	dmacontroller_poke_tx(ring, slot);

	return 0;
}

int bcm43xx_dma_tx(struct bcm43xx_private *bcm,
		   struct ieee80211_txb *txb)
{
	/* We just received a packet from the kernel network subsystem.
	 * Add headers and DMA map the memory. Poke
	 * the device to send the stuff.
	 * Note that this is called from atomic context.
	 */
	struct bcm43xx_dmaring *ring = bcm->current_core->dma->tx_ring1;
	u8 i;
	struct sk_buff *skb;

	assert(ring->tx);
	if (unlikely(free_slots(ring) < txb->nr_frags)) {
		/* The queue should be stopped,
		 * if we are low on free slots.
		 * If this ever triggers, we have to lower the suspend_mark.
		 */
		dprintkl(KERN_ERR PFX "Out of DMA descriptor slots!\n");
		return -ENOMEM;
	}

	for (i = 0; i < txb->nr_frags; i++) {
		skb = txb->fragments[i];
		/* Take skb from ieee80211_txb_free */
		txb->fragments[i] = NULL;
		dma_tx_fragment(ring, skb, i);
		//TODO: handle failure of dma_tx_fragment
	}
	ieee80211_txb_free(txb);

	return 0;
}

void bcm43xx_dma_handle_xmitstatus(struct bcm43xx_private *bcm,
				   struct bcm43xx_xmitstatus *status)
{
	struct bcm43xx_dmaring *ring;
	struct bcm43xx_dmadesc *desc;
	struct bcm43xx_dmadesc_meta *meta;
	int is_last_fragment;
	int slot;

	ring = parse_cookie(bcm, status->cookie, &slot);
	assert(ring);
	assert(ring->tx);
	assert(get_desc_ctl(ring->vbase + slot) & BCM43xx_DMADTOR_FRAMESTART);
	while (1) {
		assert(slot >= 0 && slot < ring->nr_slots);
		desc = ring->vbase + slot;
		meta = ring->meta + slot;

		is_last_fragment = !!(get_desc_ctl(desc) & BCM43xx_DMADTOR_FRAMEEND);
		unmap_descbuffer(ring, meta->dmaaddr, meta->skb->len, 1);
		free_descriptor_buffer(ring, desc, meta, 1);
		/* Everything belonging to the slot is unmapped
		 * and freed, so we can return it.
		 */
		return_slot(ring, slot);

		if (is_last_fragment)
			break;
		slot = next_slot(ring, slot);
	}
	bcm->stats.last_tx = jiffies;
}

static void dma_rx(struct bcm43xx_dmaring *ring,
		   int *slot)
{
	struct bcm43xx_dmadesc *desc;
	struct bcm43xx_dmadesc_meta *meta;
	struct bcm43xx_rxhdr *rxhdr;
	struct sk_buff *skb;
	u16 len;
	int err;
	dma_addr_t dmaaddr;

	desc = ring->vbase + *slot;
	meta = ring->meta + *slot;

	sync_descbuffer_for_cpu(ring, meta->dmaaddr, ring->rx_buffersize);
	skb = meta->skb;

	if (ring->mmio_base == BCM43xx_MMIO_DMA4_BASE) {
		/* We received an xmit status. */
		struct bcm43xx_hwxmitstatus *hw = (struct bcm43xx_hwxmitstatus *)skb->data;
		struct bcm43xx_xmitstatus stat;

		stat.cookie = le16_to_cpu(hw->cookie);
		stat.flags = hw->flags;
		stat.cnt1 = hw->cnt1;
		stat.cnt2 = hw->cnt2;
		stat.seq = le16_to_cpu(hw->seq);
		stat.unknown = le16_to_cpu(hw->unknown);

		bcm43xx_debugfs_log_txstat(ring->bcm, &stat);
		bcm43xx_dma_handle_xmitstatus(ring->bcm, &stat);
		/* recycle the descriptor buffer. */
		sync_descbuffer_for_device(ring, meta->dmaaddr, ring->rx_buffersize);

		return;
	}
	rxhdr = (struct bcm43xx_rxhdr *)skb->data;
	len = le16_to_cpu(rxhdr->frame_length);
	if (len == 0) {
		int i = 0;

		do {
			udelay(2);
			barrier();
			len = le16_to_cpu(rxhdr->frame_length);
		} while (len == 0 && i++ < 5);
		if (unlikely(len == 0)) {
			/* recycle the descriptor buffer. */
			sync_descbuffer_for_device(ring, meta->dmaaddr,
						   ring->rx_buffersize);
			goto drop;
		}
	}
	if (unlikely(len > ring->rx_buffersize)) {
		/* The data did not fit into one descriptor buffer
		 * and is split over multiple buffers.
		 * This should never happen, as we try to allocate buffers
		 * big enough. So simply ignore this packet.
		 */
		int cnt = 0;
		s32 tmp = len;

		while (1) {
			desc = ring->vbase + *slot;
			meta = ring->meta + *slot;
			/* recycle the descriptor buffer. */
			sync_descbuffer_for_device(ring, meta->dmaaddr,
						   ring->rx_buffersize);
			*slot = next_slot(ring, *slot);
			cnt++;
			tmp -= ring->rx_buffersize;
			if (tmp <= 0)
				break;
		}
		printkl(KERN_ERR PFX "DMA RX buffer too small "
				     "(len: %u, buffer: %u, nr-dropped: %d)\n",
		        len, ring->rx_buffersize, cnt);
		goto drop;
	}
	len -= IEEE80211_FCS_LEN;

	dmaaddr = meta->dmaaddr;
	err = setup_rx_descbuffer(ring, desc, meta, GFP_ATOMIC);
	if (unlikely(err)) {
		dprintkl(KERN_ERR PFX "DMA RX: setup_rx_descbuffer() failed\n");
		sync_descbuffer_for_device(ring, dmaaddr,
					   ring->rx_buffersize);
		goto drop;
	}

	unmap_descbuffer(ring, dmaaddr, ring->rx_buffersize, 0);
	skb_put(skb, len + ring->frameoffset);
	skb_pull(skb, ring->frameoffset);

	err = bcm43xx_rx(ring->bcm, skb, rxhdr);
	if (err) {
		dev_kfree_skb_irq(skb);
		goto drop;
	}

drop:
	return;
}

void bcm43xx_dma_rx(struct bcm43xx_dmaring *ring)
{
	u32 status;
	u16 descptr;
	int slot, current_slot;
#ifdef CONFIG_BCM43XX_DEBUG
	int used_slots = 0;
#endif

	assert(!ring->tx);
	status = bcm43xx_read32(ring->bcm, ring->mmio_base + BCM43xx_DMA_RX_STATUS);
	descptr = (status & BCM43xx_DMA_RXSTAT_DPTR_MASK);
	current_slot = descptr / sizeof(struct bcm43xx_dmadesc);
	assert(current_slot >= 0 && current_slot < ring->nr_slots);

	slot = ring->current_slot;
	for ( ; slot != current_slot; slot = next_slot(ring, slot)) {
		dma_rx(ring, &slot);
#ifdef CONFIG_BCM43XX_DEBUG
		if (++used_slots > ring->max_used_slots)
			ring->max_used_slots = used_slots;
#endif
	}
	bcm43xx_write32(ring->bcm,
			ring->mmio_base + BCM43xx_DMA_RX_DESC_INDEX,
			(u32)(slot * sizeof(struct bcm43xx_dmadesc)));
	ring->current_slot = slot;
}

/* vim: set ts=8 sw=8 sts=8: */