Initial import

1 files changed, 1831 insertions, 0 deletions

diff --git a/drivers/net/wireless/b43/dma.c b/drivers/net/wireless/b43/dma.c
new file mode 100644
index 000000000..683706490
--- /dev/null
+++ b/drivers/net/wireless/b43/dma.c
@@ -0,0 +1,1831 @@
+/*
+
+  Broadcom B43 wireless driver
+
+  DMA ringbuffer and descriptor allocation/management
+
+  Copyright (c) 2005, 2006 Michael Buesch <m@bues.ch>
+
+  Some code in this file is derived from the b44.c driver
+  Copyright (C) 2002 David S. Miller
+  Copyright (C) Pekka Pietikainen
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; see the file COPYING.  If not, write to
+  the Free Software Foundation, Inc., 51 Franklin Steet, Fifth Floor,
+  Boston, MA 02110-1301, USA.
+
+*/
+
+#include "b43.h"
+#include "dma.h"
+#include "main.h"
+#include "debugfs.h"
+#include "xmit.h"
+
+#include <linux/dma-mapping.h>
+#include <linux/pci.h>
+#include <linux/delay.h>
+#include <linux/skbuff.h>
+#include <linux/etherdevice.h>
+#include <linux/slab.h>
+#include <asm/div64.h>
+
+
+/* Required number of TX DMA slots per TX frame.
+ * This currently is 2, because we put the header and the ieee80211 frame
+ * into separate slots. */
+#define TX_SLOTS_PER_FRAME	2
+
+static u32 b43_dma_address(struct b43_dma *dma, dma_addr_t dmaaddr,
+			   enum b43_addrtype addrtype)
+{
+	u32 uninitialized_var(addr);
+
+	switch (addrtype) {
+	case B43_DMA_ADDR_LOW:
+		addr = lower_32_bits(dmaaddr);
+		if (dma->translation_in_low) {
+			addr &= ~SSB_DMA_TRANSLATION_MASK;
+			addr |= dma->translation;
+		}
+		break;
+	case B43_DMA_ADDR_HIGH:
+		addr = upper_32_bits(dmaaddr);
+		if (!dma->translation_in_low) {
+			addr &= ~SSB_DMA_TRANSLATION_MASK;
+			addr |= dma->translation;
+		}
+		break;
+	case B43_DMA_ADDR_EXT:
+		if (dma->translation_in_low)
+			addr = lower_32_bits(dmaaddr);
+		else
+			addr = upper_32_bits(dmaaddr);
+		addr &= SSB_DMA_TRANSLATION_MASK;
+		addr >>= SSB_DMA_TRANSLATION_SHIFT;
+		break;
+	}
+
+	return addr;
+}
+
+/* 32bit DMA ops. */
+static
+struct b43_dmadesc_generic *op32_idx2desc(struct b43_dmaring *ring,
+					  int slot,
+					  struct b43_dmadesc_meta **meta)
+{
+	struct b43_dmadesc32 *desc;
+
+	*meta = &(ring->meta[slot]);
+	desc = ring->descbase;
+	desc = &(desc[slot]);
+
+	return (struct b43_dmadesc_generic *)desc;
+}
+
+static void op32_fill_descriptor(struct b43_dmaring *ring,
+				 struct b43_dmadesc_generic *desc,
+				 dma_addr_t dmaaddr, u16 bufsize,
+				 int start, int end, int irq)
+{
+	struct b43_dmadesc32 *descbase = ring->descbase;
+	int slot;
+	u32 ctl;
+	u32 addr;
+	u32 addrext;
+
+	slot = (int)(&(desc->dma32) - descbase);
+	B43_WARN_ON(!(slot >= 0 && slot < ring->nr_slots));
+
+	addr = b43_dma_address(&ring->dev->dma, dmaaddr, B43_DMA_ADDR_LOW);
+	addrext = b43_dma_address(&ring->dev->dma, dmaaddr, B43_DMA_ADDR_EXT);
+
+	ctl = bufsize & B43_DMA32_DCTL_BYTECNT;
+	if (slot == ring->nr_slots - 1)
+		ctl |= B43_DMA32_DCTL_DTABLEEND;
+	if (start)
+		ctl |= B43_DMA32_DCTL_FRAMESTART;
+	if (end)
+		ctl |= B43_DMA32_DCTL_FRAMEEND;
+	if (irq)
+		ctl |= B43_DMA32_DCTL_IRQ;
+	ctl |= (addrext << B43_DMA32_DCTL_ADDREXT_SHIFT)
+	    & B43_DMA32_DCTL_ADDREXT_MASK;
+
+	desc->dma32.control = cpu_to_le32(ctl);
+	desc->dma32.address = cpu_to_le32(addr);
+}
+
+static void op32_poke_tx(struct b43_dmaring *ring, int slot)
+{
+	b43_dma_write(ring, B43_DMA32_TXINDEX,
+		      (u32) (slot * sizeof(struct b43_dmadesc32)));
+}
+
+static void op32_tx_suspend(struct b43_dmaring *ring)
+{
+	b43_dma_write(ring, B43_DMA32_TXCTL, b43_dma_read(ring, B43_DMA32_TXCTL)
+		      | B43_DMA32_TXSUSPEND);
+}
+
+static void op32_tx_resume(struct b43_dmaring *ring)
+{
+	b43_dma_write(ring, B43_DMA32_TXCTL, b43_dma_read(ring, B43_DMA32_TXCTL)
+		      & ~B43_DMA32_TXSUSPEND);
+}
+
+static int op32_get_current_rxslot(struct b43_dmaring *ring)
+{
+	u32 val;
+
+	val = b43_dma_read(ring, B43_DMA32_RXSTATUS);
+	val &= B43_DMA32_RXDPTR;
+
+	return (val / sizeof(struct b43_dmadesc32));
+}
+
+static void op32_set_current_rxslot(struct b43_dmaring *ring, int slot)
+{
+	b43_dma_write(ring, B43_DMA32_RXINDEX,
+		      (u32) (slot * sizeof(struct b43_dmadesc32)));
+}
+
+static const struct b43_dma_ops dma32_ops = {
+	.idx2desc = op32_idx2desc,
+	.fill_descriptor = op32_fill_descriptor,
+	.poke_tx = op32_poke_tx,
+	.tx_suspend = op32_tx_suspend,
+	.tx_resume = op32_tx_resume,
+	.get_current_rxslot = op32_get_current_rxslot,
+	.set_current_rxslot = op32_set_current_rxslot,
+};
+
+/* 64bit DMA ops. */
+static
+struct b43_dmadesc_generic *op64_idx2desc(struct b43_dmaring *ring,
+					  int slot,
+					  struct b43_dmadesc_meta **meta)
+{
+	struct b43_dmadesc64 *desc;
+
+	*meta = &(ring->meta[slot]);
+	desc = ring->descbase;
+	desc = &(desc[slot]);
+
+	return (struct b43_dmadesc_generic *)desc;
+}
+
+static void op64_fill_descriptor(struct b43_dmaring *ring,
+				 struct b43_dmadesc_generic *desc,
+				 dma_addr_t dmaaddr, u16 bufsize,
+				 int start, int end, int irq)
+{
+	struct b43_dmadesc64 *descbase = ring->descbase;
+	int slot;
+	u32 ctl0 = 0, ctl1 = 0;
+	u32 addrlo, addrhi;
+	u32 addrext;
+
+	slot = (int)(&(desc->dma64) - descbase);
+	B43_WARN_ON(!(slot >= 0 && slot < ring->nr_slots));
+
+	addrlo = b43_dma_address(&ring->dev->dma, dmaaddr, B43_DMA_ADDR_LOW);
+	addrhi = b43_dma_address(&ring->dev->dma, dmaaddr, B43_DMA_ADDR_HIGH);
+	addrext = b43_dma_address(&ring->dev->dma, dmaaddr, B43_DMA_ADDR_EXT);
+
+	if (slot == ring->nr_slots - 1)
+		ctl0 |= B43_DMA64_DCTL0_DTABLEEND;
+	if (start)
+		ctl0 |= B43_DMA64_DCTL0_FRAMESTART;
+	if (end)
+		ctl0 |= B43_DMA64_DCTL0_FRAMEEND;
+	if (irq)
+		ctl0 |= B43_DMA64_DCTL0_IRQ;
+	ctl1 |= bufsize & B43_DMA64_DCTL1_BYTECNT;
+	ctl1 |= (addrext << B43_DMA64_DCTL1_ADDREXT_SHIFT)
+	    & B43_DMA64_DCTL1_ADDREXT_MASK;
+
+	desc->dma64.control0 = cpu_to_le32(ctl0);
+	desc->dma64.control1 = cpu_to_le32(ctl1);
+	desc->dma64.address_low = cpu_to_le32(addrlo);
+	desc->dma64.address_high = cpu_to_le32(addrhi);
+}
+
+static void op64_poke_tx(struct b43_dmaring *ring, int slot)
+{
+	b43_dma_write(ring, B43_DMA64_TXINDEX,
+		      (u32) (slot * sizeof(struct b43_dmadesc64)));
+}
+
+static void op64_tx_suspend(struct b43_dmaring *ring)
+{
+	b43_dma_write(ring, B43_DMA64_TXCTL, b43_dma_read(ring, B43_DMA64_TXCTL)
+		      | B43_DMA64_TXSUSPEND);
+}
+
+static void op64_tx_resume(struct b43_dmaring *ring)
+{
+	b43_dma_write(ring, B43_DMA64_TXCTL, b43_dma_read(ring, B43_DMA64_TXCTL)
+		      & ~B43_DMA64_TXSUSPEND);
+}
+
+static int op64_get_current_rxslot(struct b43_dmaring *ring)
+{
+	u32 val;
+
+	val = b43_dma_read(ring, B43_DMA64_RXSTATUS);
+	val &= B43_DMA64_RXSTATDPTR;
+
+	return (val / sizeof(struct b43_dmadesc64));
+}
+
+static void op64_set_current_rxslot(struct b43_dmaring *ring, int slot)
+{
+	b43_dma_write(ring, B43_DMA64_RXINDEX,
+		      (u32) (slot * sizeof(struct b43_dmadesc64)));
+}
+
+static const struct b43_dma_ops dma64_ops = {
+	.idx2desc = op64_idx2desc,
+	.fill_descriptor = op64_fill_descriptor,
+	.poke_tx = op64_poke_tx,
+	.tx_suspend = op64_tx_suspend,
+	.tx_resume = op64_tx_resume,
+	.get_current_rxslot = op64_get_current_rxslot,
+	.set_current_rxslot = op64_set_current_rxslot,
+};
+
+static inline int free_slots(struct b43_dmaring *ring)
+{
+	return (ring->nr_slots - ring->used_slots);
+}
+
+static inline int next_slot(struct b43_dmaring *ring, int slot)
+{
+	B43_WARN_ON(!(slot >= -1 && slot <= ring->nr_slots - 1));
+	if (slot == ring->nr_slots - 1)
+		return 0;
+	return slot + 1;
+}
+
+static inline int prev_slot(struct b43_dmaring *ring, int slot)
+{
+	B43_WARN_ON(!(slot >= 0 && slot <= ring->nr_slots - 1));
+	if (slot == 0)
+		return ring->nr_slots - 1;
+	return slot - 1;
+}
+
+#ifdef CONFIG_B43_DEBUG
+static void update_max_used_slots(struct b43_dmaring *ring,
+				  int current_used_slots)
+{
+	if (current_used_slots <= ring->max_used_slots)
+		return;
+	ring->max_used_slots = current_used_slots;
+	if (b43_debug(ring->dev, B43_DBG_DMAVERBOSE)) {
+		b43dbg(ring->dev->wl,
+		       "max_used_slots increased to %d on %s ring %d\n",
+		       ring->max_used_slots,
+		       ring->tx ? "TX" : "RX", ring->index);
+	}
+}
+#else
+static inline
+    void update_max_used_slots(struct b43_dmaring *ring, int current_used_slots)
+{
+}
+#endif /* DEBUG */
+
+/* Request a slot for usage. */
+static inline int request_slot(struct b43_dmaring *ring)
+{
+	int slot;
+
+	B43_WARN_ON(!ring->tx);
+	B43_WARN_ON(ring->stopped);
+	B43_WARN_ON(free_slots(ring) == 0);
+
+	slot = next_slot(ring, ring->current_slot);
+	ring->current_slot = slot;
+	ring->used_slots++;
+
+	update_max_used_slots(ring, ring->used_slots);
+
+	return slot;
+}
+
+static u16 b43_dmacontroller_base(enum b43_dmatype type, int controller_idx)
+{
+	static const u16 map64[] = {
+		B43_MMIO_DMA64_BASE0,
+		B43_MMIO_DMA64_BASE1,
+		B43_MMIO_DMA64_BASE2,
+		B43_MMIO_DMA64_BASE3,
+		B43_MMIO_DMA64_BASE4,
+		B43_MMIO_DMA64_BASE5,
+	};
+	static const u16 map32[] = {
+		B43_MMIO_DMA32_BASE0,
+		B43_MMIO_DMA32_BASE1,
+		B43_MMIO_DMA32_BASE2,
+		B43_MMIO_DMA32_BASE3,
+		B43_MMIO_DMA32_BASE4,
+		B43_MMIO_DMA32_BASE5,
+	};
+
+	if (type == B43_DMA_64BIT) {
+		B43_WARN_ON(!(controller_idx >= 0 &&
+			      controller_idx < ARRAY_SIZE(map64)));
+		return map64[controller_idx];
+	}
+	B43_WARN_ON(!(controller_idx >= 0 &&
+		      controller_idx < ARRAY_SIZE(map32)));
+	return map32[controller_idx];
+}
+
+static inline
+    dma_addr_t map_descbuffer(struct b43_dmaring *ring,
+			      unsigned char *buf, size_t len, int tx)
+{
+	dma_addr_t dmaaddr;
+
+	if (tx) {
+		dmaaddr = dma_map_single(ring->dev->dev->dma_dev,
+					 buf, len, DMA_TO_DEVICE);
+	} else {
+		dmaaddr = dma_map_single(ring->dev->dev->dma_dev,
+					 buf, len, DMA_FROM_DEVICE);
+	}
+
+	return dmaaddr;
+}
+
+static inline
+    void unmap_descbuffer(struct b43_dmaring *ring,
+			  dma_addr_t addr, size_t len, int tx)
+{
+	if (tx) {
+		dma_unmap_single(ring->dev->dev->dma_dev,
+				 addr, len, DMA_TO_DEVICE);
+	} else {
+		dma_unmap_single(ring->dev->dev->dma_dev,
+				 addr, len, DMA_FROM_DEVICE);
+	}
+}
+
+static inline
+    void sync_descbuffer_for_cpu(struct b43_dmaring *ring,
+				 dma_addr_t addr, size_t len)
+{
+	B43_WARN_ON(ring->tx);
+	dma_sync_single_for_cpu(ring->dev->dev->dma_dev,
+				    addr, len, DMA_FROM_DEVICE);
+}
+
+static inline
+    void sync_descbuffer_for_device(struct b43_dmaring *ring,
+				    dma_addr_t addr, size_t len)
+{
+	B43_WARN_ON(ring->tx);
+	dma_sync_single_for_device(ring->dev->dev->dma_dev,
+				   addr, len, DMA_FROM_DEVICE);
+}
+
+static inline
+    void free_descriptor_buffer(struct b43_dmaring *ring,
+				struct b43_dmadesc_meta *meta)
+{
+	if (meta->skb) {
+		if (ring->tx)
+			ieee80211_free_txskb(ring->dev->wl->hw, meta->skb);
+		else
+			dev_kfree_skb_any(meta->skb);
+		meta->skb = NULL;
+	}
+}
+
+static int alloc_ringmemory(struct b43_dmaring *ring)
+{
+	/* The specs call for 4K buffers for 30- and 32-bit DMA with 4K
+	 * alignment and 8K buffers for 64-bit DMA with 8K alignment.
+	 * In practice we could use smaller buffers for the latter, but the
+	 * alignment is really important because of the hardware bug. If bit
+	 * 0x00001000 is used in DMA address, some hardware (like BCM4331)
+	 * copies that bit into B43_DMA64_RXSTATUS and we get false values from
+	 * B43_DMA64_RXSTATDPTR. Let's just use 8K buffers even if we don't use
+	 * more than 256 slots for ring.
+	 */
+	u16 ring_mem_size = (ring->type == B43_DMA_64BIT) ?
+				B43_DMA64_RINGMEMSIZE : B43_DMA32_RINGMEMSIZE;
+
+	ring->descbase = dma_zalloc_coherent(ring->dev->dev->dma_dev,
+					     ring_mem_size, &(ring->dmabase),
+					     GFP_KERNEL);
+	if (!ring->descbase)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void free_ringmemory(struct b43_dmaring *ring)
+{
+	u16 ring_mem_size = (ring->type == B43_DMA_64BIT) ?
+				B43_DMA64_RINGMEMSIZE : B43_DMA32_RINGMEMSIZE;
+	dma_free_coherent(ring->dev->dev->dma_dev, ring_mem_size,
+			  ring->descbase, ring->dmabase);
+}
+
+/* Reset the RX DMA channel */
+static int b43_dmacontroller_rx_reset(struct b43_wldev *dev, u16 mmio_base,
+				      enum b43_dmatype type)
+{
+	int i;
+	u32 value;
+	u16 offset;
+
+	might_sleep();
+
+	offset = (type == B43_DMA_64BIT) ? B43_DMA64_RXCTL : B43_DMA32_RXCTL;
+	b43_write32(dev, mmio_base + offset, 0);
+	for (i = 0; i < 10; i++) {
+		offset = (type == B43_DMA_64BIT) ? B43_DMA64_RXSTATUS :
+						   B43_DMA32_RXSTATUS;
+		value = b43_read32(dev, mmio_base + offset);
+		if (type == B43_DMA_64BIT) {
+			value &= B43_DMA64_RXSTAT;
+			if (value == B43_DMA64_RXSTAT_DISABLED) {
+				i = -1;
+				break;
+			}
+		} else {
+			value &= B43_DMA32_RXSTATE;
+			if (value == B43_DMA32_RXSTAT_DISABLED) {
+				i = -1;
+				break;
+			}
+		}
+		msleep(1);
+	}
+	if (i != -1) {
+		b43err(dev->wl, "DMA RX reset timed out\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+/* Reset the TX DMA channel */
+static int b43_dmacontroller_tx_reset(struct b43_wldev *dev, u16 mmio_base,
+				      enum b43_dmatype type)
+{
+	int i;
+	u32 value;
+	u16 offset;
+
+	might_sleep();
+
+	for (i = 0; i < 10; i++) {
+		offset = (type == B43_DMA_64BIT) ? B43_DMA64_TXSTATUS :
+						   B43_DMA32_TXSTATUS;
+		value = b43_read32(dev, mmio_base + offset);
+		if (type == B43_DMA_64BIT) {
+			value &= B43_DMA64_TXSTAT;
+			if (value == B43_DMA64_TXSTAT_DISABLED ||
+			    value == B43_DMA64_TXSTAT_IDLEWAIT ||
+			    value == B43_DMA64_TXSTAT_STOPPED)
+				break;
+		} else {
+			value &= B43_DMA32_TXSTATE;
+			if (value == B43_DMA32_TXSTAT_DISABLED ||
+			    value == B43_DMA32_TXSTAT_IDLEWAIT ||
+			    value == B43_DMA32_TXSTAT_STOPPED)
+				break;
+		}
+		msleep(1);
+	}
+	offset = (type == B43_DMA_64BIT) ? B43_DMA64_TXCTL : B43_DMA32_TXCTL;
+	b43_write32(dev, mmio_base + offset, 0);
+	for (i = 0; i < 10; i++) {
+		offset = (type == B43_DMA_64BIT) ? B43_DMA64_TXSTATUS :
+						   B43_DMA32_TXSTATUS;
+		value = b43_read32(dev, mmio_base + offset);
+		if (type == B43_DMA_64BIT) {
+			value &= B43_DMA64_TXSTAT;
+			if (value == B43_DMA64_TXSTAT_DISABLED) {
+				i = -1;
+				break;
+			}
+		} else {
+			value &= B43_DMA32_TXSTATE;
+			if (value == B43_DMA32_TXSTAT_DISABLED) {
+				i = -1;
+				break;
+			}
+		}
+		msleep(1);
+	}
+	if (i != -1) {
+		b43err(dev->wl, "DMA TX reset timed out\n");
+		return -ENODEV;
+	}
+	/* ensure the reset is completed. */
+	msleep(1);
+
+	return 0;
+}
+
+/* Check if a DMA mapping address is invalid. */
+static bool b43_dma_mapping_error(struct b43_dmaring *ring,
+				  dma_addr_t addr,
+				  size_t buffersize, bool dma_to_device)
+{
+	if (unlikely(dma_mapping_error(ring->dev->dev->dma_dev, addr)))
+		return true;
+
+	switch (ring->type) {
+	case B43_DMA_30BIT:
+		if ((u64)addr + buffersize > (1ULL << 30))
+			goto address_error;
+		break;
+	case B43_DMA_32BIT:
+		if ((u64)addr + buffersize > (1ULL << 32))
+			goto address_error;
+		break;
+	case B43_DMA_64BIT:
+		/* Currently we can't have addresses beyond
+		 * 64bit in the kernel. */
+		break;
+	}
+
+	/* The address is OK. */
+	return false;
+
+address_error:
+	/* We can't support this address. Unmap it again. */
+	unmap_descbuffer(ring, addr, buffersize, dma_to_device);
+
+	return true;
+}
+
+static bool b43_rx_buffer_is_poisoned(struct b43_dmaring *ring, struct sk_buff *skb)
+{
+	unsigned char *f = skb->data + ring->frameoffset;
+
+	return ((f[0] & f[1] & f[2] & f[3] & f[4] & f[5] & f[6] & f[7]) == 0xFF);
+}
+
+static void b43_poison_rx_buffer(struct b43_dmaring *ring, struct sk_buff *skb)
+{
+	struct b43_rxhdr_fw4 *rxhdr;
+	unsigned char *frame;
+
+	/* This poisons the RX buffer to detect DMA failures. */
+
+	rxhdr = (struct b43_rxhdr_fw4 *)(skb->data);
+	rxhdr->frame_len = 0;
+
+	B43_WARN_ON(ring->rx_buffersize < ring->frameoffset + sizeof(struct b43_plcp_hdr6) + 2);
+	frame = skb->data + ring->frameoffset;
+	memset(frame, 0xFF, sizeof(struct b43_plcp_hdr6) + 2 /* padding */);
+}
+
+static int setup_rx_descbuffer(struct b43_dmaring *ring,
+			       struct b43_dmadesc_generic *desc,
+			       struct b43_dmadesc_meta *meta, gfp_t gfp_flags)
+{
+	dma_addr_t dmaaddr;
+	struct sk_buff *skb;
+
+	B43_WARN_ON(ring->tx);
+
+	skb = __dev_alloc_skb(ring->rx_buffersize, gfp_flags);
+	if (unlikely(!skb))
+		return -ENOMEM;
+	b43_poison_rx_buffer(ring, skb);
+	dmaaddr = map_descbuffer(ring, skb->data, ring->rx_buffersize, 0);
+	if (b43_dma_mapping_error(ring, dmaaddr, ring->rx_buffersize, 0)) {
+		/* ugh. try to realloc in zone_dma */
+		gfp_flags |= GFP_DMA;
+
+		dev_kfree_skb_any(skb);
+
+		skb = __dev_alloc_skb(ring->rx_buffersize, gfp_flags);
+		if (unlikely(!skb))
+			return -ENOMEM;
+		b43_poison_rx_buffer(ring, skb);
+		dmaaddr = map_descbuffer(ring, skb->data,
+					 ring->rx_buffersize, 0);
+		if (b43_dma_mapping_error(ring, dmaaddr, ring->rx_buffersize, 0)) {
+			b43err(ring->dev->wl, "RX DMA buffer allocation failed\n");
+			dev_kfree_skb_any(skb);
+			return -EIO;
+		}
+	}
+
+	meta->skb = skb;
+	meta->dmaaddr = dmaaddr;
+	ring->ops->fill_descriptor(ring, desc, dmaaddr,
+				   ring->rx_buffersize, 0, 0, 0);
+
+	return 0;
+}
+
+/* Allocate the initial descbuffers.
+ * This is used for an RX ring only.
+ */
+static int alloc_initial_descbuffers(struct b43_dmaring *ring)
+{
+	int i, err = -ENOMEM;
+	struct b43_dmadesc_generic *desc;
+	struct b43_dmadesc_meta *meta;
+
+	for (i = 0; i < ring->nr_slots; i++) {
+		desc = ring->ops->idx2desc(ring, i, &meta);
+
+		err = setup_rx_descbuffer(ring, desc, meta, GFP_KERNEL);
+		if (err) {
+			b43err(ring->dev->wl,
+			       "Failed to allocate initial descbuffers\n");
+			goto err_unwind;
+		}
+	}
+	mb();
+	ring->used_slots = ring->nr_slots;
+	err = 0;
+      out:
+	return err;
+
+      err_unwind:
+	for (i--; i >= 0; i--) {
+		desc = ring->ops->idx2desc(ring, i, &meta);
+
+		unmap_descbuffer(ring, meta->dmaaddr, ring->rx_buffersize, 0);
+		dev_kfree_skb(meta->skb);
+	}
+	goto out;
+}
+
+/* Do initial setup of the DMA controller.
+ * Reset the controller, write the ring busaddress
+ * and switch the "enable" bit on.
+ */
+static int dmacontroller_setup(struct b43_dmaring *ring)
+{
+	int err = 0;
+	u32 value;
+	u32 addrext;
+	bool parity = ring->dev->dma.parity;
+	u32 addrlo;
+	u32 addrhi;
+
+	if (ring->tx) {
+		if (ring->type == B43_DMA_64BIT) {
+			u64 ringbase = (u64) (ring->dmabase);
+			addrext = b43_dma_address(&ring->dev->dma, ringbase, B43_DMA_ADDR_EXT);
+			addrlo = b43_dma_address(&ring->dev->dma, ringbase, B43_DMA_ADDR_LOW);
+			addrhi = b43_dma_address(&ring->dev->dma, ringbase, B43_DMA_ADDR_HIGH);
+
+			value = B43_DMA64_TXENABLE;
+			value |= (addrext << B43_DMA64_TXADDREXT_SHIFT)
+			    & B43_DMA64_TXADDREXT_MASK;
+			if (!parity)
+				value |= B43_DMA64_TXPARITYDISABLE;
+			b43_dma_write(ring, B43_DMA64_TXCTL, value);
+			b43_dma_write(ring, B43_DMA64_TXRINGLO, addrlo);
+			b43_dma_write(ring, B43_DMA64_TXRINGHI, addrhi);
+		} else {
+			u32 ringbase = (u32) (ring->dmabase);
+			addrext = b43_dma_address(&ring->dev->dma, ringbase, B43_DMA_ADDR_EXT);
+			addrlo = b43_dma_address(&ring->dev->dma, ringbase, B43_DMA_ADDR_LOW);
+
+			value = B43_DMA32_TXENABLE;
+			value |= (addrext << B43_DMA32_TXADDREXT_SHIFT)
+			    & B43_DMA32_TXADDREXT_MASK;
+			if (!parity)
+				value |= B43_DMA32_TXPARITYDISABLE;
+			b43_dma_write(ring, B43_DMA32_TXCTL, value);
+			b43_dma_write(ring, B43_DMA32_TXRING, addrlo);
+		}
+	} else {
+		err = alloc_initial_descbuffers(ring);
+		if (err)
+			goto out;
+		if (ring->type == B43_DMA_64BIT) {
+			u64 ringbase = (u64) (ring->dmabase);
+			addrext = b43_dma_address(&ring->dev->dma, ringbase, B43_DMA_ADDR_EXT);
+			addrlo = b43_dma_address(&ring->dev->dma, ringbase, B43_DMA_ADDR_LOW);
+			addrhi = b43_dma_address(&ring->dev->dma, ringbase, B43_DMA_ADDR_HIGH);
+
+			value = (ring->frameoffset << B43_DMA64_RXFROFF_SHIFT);
+			value |= B43_DMA64_RXENABLE;
+			value |= (addrext << B43_DMA64_RXADDREXT_SHIFT)
+			    & B43_DMA64_RXADDREXT_MASK;
+			if (!parity)
+				value |= B43_DMA64_RXPARITYDISABLE;
+			b43_dma_write(ring, B43_DMA64_RXCTL, value);
+			b43_dma_write(ring, B43_DMA64_RXRINGLO, addrlo);
+			b43_dma_write(ring, B43_DMA64_RXRINGHI, addrhi);
+			b43_dma_write(ring, B43_DMA64_RXINDEX, ring->nr_slots *
+				      sizeof(struct b43_dmadesc64));
+		} else {
+			u32 ringbase = (u32) (ring->dmabase);
+			addrext = b43_dma_address(&ring->dev->dma, ringbase, B43_DMA_ADDR_EXT);
+			addrlo = b43_dma_address(&ring->dev->dma, ringbase, B43_DMA_ADDR_LOW);
+
+			value = (ring->frameoffset << B43_DMA32_RXFROFF_SHIFT);
+			value |= B43_DMA32_RXENABLE;
+			value |= (addrext << B43_DMA32_RXADDREXT_SHIFT)
+			    & B43_DMA32_RXADDREXT_MASK;
+			if (!parity)
+				value |= B43_DMA32_RXPARITYDISABLE;
+			b43_dma_write(ring, B43_DMA32_RXCTL, value);
+			b43_dma_write(ring, B43_DMA32_RXRING, addrlo);
+			b43_dma_write(ring, B43_DMA32_RXINDEX, ring->nr_slots *
+				      sizeof(struct b43_dmadesc32));
+		}
+	}
+
+out:
+	return err;
+}
+
+/* Shutdown the DMA controller. */
+static void dmacontroller_cleanup(struct b43_dmaring *ring)
+{
+	if (ring->tx) {
+		b43_dmacontroller_tx_reset(ring->dev, ring->mmio_base,
+					   ring->type);
+		if (ring->type == B43_DMA_64BIT) {
+			b43_dma_write(ring, B43_DMA64_TXRINGLO, 0);
+			b43_dma_write(ring, B43_DMA64_TXRINGHI, 0);
+		} else
+			b43_dma_write(ring, B43_DMA32_TXRING, 0);
+	} else {
+		b43_dmacontroller_rx_reset(ring->dev, ring->mmio_base,
+					   ring->type);
+		if (ring->type == B43_DMA_64BIT) {
+			b43_dma_write(ring, B43_DMA64_RXRINGLO, 0);
+			b43_dma_write(ring, B43_DMA64_RXRINGHI, 0);
+		} else
+			b43_dma_write(ring, B43_DMA32_RXRING, 0);
+	}
+}
+
+static void free_all_descbuffers(struct b43_dmaring *ring)
+{
+	struct b43_dmadesc_meta *meta;
+	int i;
+
+	if (!ring->used_slots)
+		return;
+	for (i = 0; i < ring->nr_slots; i++) {
+		/* get meta - ignore returned value */
+		ring->ops->idx2desc(ring, i, &meta);
+
+		if (!meta->skb || b43_dma_ptr_is_poisoned(meta->skb)) {
+			B43_WARN_ON(!ring->tx);
+			continue;
+		}
+		if (ring->tx) {
+			unmap_descbuffer(ring, meta->dmaaddr,
+					 meta->skb->len, 1);
+		} else {
+			unmap_descbuffer(ring, meta->dmaaddr,
+					 ring->rx_buffersize, 0);
+		}
+		free_descriptor_buffer(ring, meta);
+	}
+}
+
+static u64 supported_dma_mask(struct b43_wldev *dev)
+{
+	u32 tmp;
+	u16 mmio_base;
+
+	switch (dev->dev->bus_type) {
+#ifdef CONFIG_B43_BCMA
+	case B43_BUS_BCMA:
+		tmp = bcma_aread32(dev->dev->bdev, BCMA_IOST);
+		if (tmp & BCMA_IOST_DMA64)
+			return DMA_BIT_MASK(64);
+		break;
+#endif
+#ifdef CONFIG_B43_SSB
+	case B43_BUS_SSB:
+		tmp = ssb_read32(dev->dev->sdev, SSB_TMSHIGH);
+		if (tmp & SSB_TMSHIGH_DMA64)
+			return DMA_BIT_MASK(64);
+		break;
+#endif
+	}
+
+	mmio_base = b43_dmacontroller_base(0, 0);
+	b43_write32(dev, mmio_base + B43_DMA32_TXCTL, B43_DMA32_TXADDREXT_MASK);
+	tmp = b43_read32(dev, mmio_base + B43_DMA32_TXCTL);
+	if (tmp & B43_DMA32_TXADDREXT_MASK)
+		return DMA_BIT_MASK(32);
+
+	return DMA_BIT_MASK(30);
+}
+
+static enum b43_dmatype dma_mask_to_engine_type(u64 dmamask)
+{
+	if (dmamask == DMA_BIT_MASK(30))
+		return B43_DMA_30BIT;
+	if (dmamask == DMA_BIT_MASK(32))
+		return B43_DMA_32BIT;
+	if (dmamask == DMA_BIT_MASK(64))
+		return B43_DMA_64BIT;
+	B43_WARN_ON(1);
+	return B43_DMA_30BIT;
+}
+
+/* Main initialization function. */
+static
+struct b43_dmaring *b43_setup_dmaring(struct b43_wldev *dev,
+				      int controller_index,
+				      int for_tx,
+				      enum b43_dmatype type)
+{
+	struct b43_dmaring *ring;
+	int i, err;
+	dma_addr_t dma_test;
+
+	ring = kzalloc(sizeof(*ring), GFP_KERNEL);
+	if (!ring)
+		goto out;
+
+	ring->nr_slots = B43_RXRING_SLOTS;
+	if (for_tx)
+		ring->nr_slots = B43_TXRING_SLOTS;
+
+	ring->meta = kcalloc(ring->nr_slots, sizeof(struct b43_dmadesc_meta),
+			     GFP_KERNEL);
+	if (!ring->meta)
+		goto err_kfree_ring;
+	for (i = 0; i < ring->nr_slots; i++)
+		ring->meta->skb = B43_DMA_PTR_POISON;
+
+	ring->type = type;
+	ring->dev = dev;
+	ring->mmio_base = b43_dmacontroller_base(type, controller_index);
+	ring->index = controller_index;
+	if (type == B43_DMA_64BIT)
+		ring->ops = &dma64_ops;
+	else
+		ring->ops = &dma32_ops;
+	if (for_tx) {
+		ring->tx = true;
+		ring->current_slot = -1;
+	} else {
+		if (ring->index == 0) {
+			switch (dev->fw.hdr_format) {
+			case B43_FW_HDR_598:
+				ring->rx_buffersize = B43_DMA0_RX_FW598_BUFSIZE;
+				ring->frameoffset = B43_DMA0_RX_FW598_FO;
+				break;
+			case B43_FW_HDR_410:
+			case B43_FW_HDR_351:
+				ring->rx_buffersize = B43_DMA0_RX_FW351_BUFSIZE;
+				ring->frameoffset = B43_DMA0_RX_FW351_FO;
+				break;
+			}
+		} else
+			B43_WARN_ON(1);
+	}
+#ifdef CONFIG_B43_DEBUG
+	ring->last_injected_overflow = jiffies;
+#endif
+
+	if (for_tx) {
+		/* Assumption: B43_TXRING_SLOTS can be divided by TX_SLOTS_PER_FRAME */
+		BUILD_BUG_ON(B43_TXRING_SLOTS % TX_SLOTS_PER_FRAME != 0);
+
+		ring->txhdr_cache = kcalloc(ring->nr_slots / TX_SLOTS_PER_FRAME,
+					    b43_txhdr_size(dev),
+					    GFP_KERNEL);
+		if (!ring->txhdr_cache)
+			goto err_kfree_meta;
+
+		/* test for ability to dma to txhdr_cache */
+		dma_test = dma_map_single(dev->dev->dma_dev,
+					  ring->txhdr_cache,
+					  b43_txhdr_size(dev),
+					  DMA_TO_DEVICE);
+
+		if (b43_dma_mapping_error(ring, dma_test,
+					  b43_txhdr_size(dev), 1)) {
+			/* ugh realloc */
+			kfree(ring->txhdr_cache);
+			ring->txhdr_cache = kcalloc(ring->nr_slots / TX_SLOTS_PER_FRAME,
+						    b43_txhdr_size(dev),
+						    GFP_KERNEL | GFP_DMA);
+			if (!ring->txhdr_cache)
+				goto err_kfree_meta;
+
+			dma_test = dma_map_single(dev->dev->dma_dev,
+						  ring->txhdr_cache,
+						  b43_txhdr_size(dev),
+						  DMA_TO_DEVICE);
+
+			if (b43_dma_mapping_error(ring, dma_test,
+						  b43_txhdr_size(dev), 1)) {
+
+				b43err(dev->wl,
+				       "TXHDR DMA allocation failed\n");
+				goto err_kfree_txhdr_cache;
+			}
+		}
+
+		dma_unmap_single(dev->dev->dma_dev,
+				 dma_test, b43_txhdr_size(dev),
+				 DMA_TO_DEVICE);
+	}
+
+	err = alloc_ringmemory(ring);
+	if (err)
+		goto err_kfree_txhdr_cache;
+	err = dmacontroller_setup(ring);
+	if (err)
+		goto err_free_ringmemory;
+
+      out:
+	return ring;
+
+      err_free_ringmemory:
+	free_ringmemory(ring);
+      err_kfree_txhdr_cache:
+	kfree(ring->txhdr_cache);
+      err_kfree_meta:
+	kfree(ring->meta);
+      err_kfree_ring:
+	kfree(ring);
+	ring = NULL;
+	goto out;
+}
+
+#define divide(a, b)	({	\
+	typeof(a) __a = a;	\
+	do_div(__a, b);		\
+	__a;			\
+  })
+
+#define modulo(a, b)	({	\
+	typeof(a) __a = a;	\
+	do_div(__a, b);		\
+  })
+
+/* Main cleanup function. */
+static void b43_destroy_dmaring(struct b43_dmaring *ring,
+				const char *ringname)
+{
+	if (!ring)
+		return;
+
+#ifdef CONFIG_B43_DEBUG
+	{
+		/* Print some statistics. */
+		u64 failed_packets = ring->nr_failed_tx_packets;
+		u64 succeed_packets = ring->nr_succeed_tx_packets;
+		u64 nr_packets = failed_packets + succeed_packets;
+		u64 permille_failed = 0, average_tries = 0;
+
+		if (nr_packets)
+			permille_failed = divide(failed_packets * 1000, nr_packets);
+		if (nr_packets)
+			average_tries = divide(ring->nr_total_packet_tries * 100, nr_packets);
+
+		b43dbg(ring->dev->wl, "DMA-%u %s: "
+		       "Used slots %d/%d, Failed frames %llu/%llu = %llu.%01llu%%, "
+		       "Average tries %llu.%02llu\n",
+		       (unsigned int)(ring->type), ringname,
+		       ring->max_used_slots,
+		       ring->nr_slots,
+		       (unsigned long long)failed_packets,
+		       (unsigned long long)nr_packets,
+		       (unsigned long long)divide(permille_failed, 10),
+		       (unsigned long long)modulo(permille_failed, 10),
+		       (unsigned long long)divide(average_tries, 100),
+		       (unsigned long long)modulo(average_tries, 100));
+	}
+#endif /* DEBUG */
+
+	/* 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->txhdr_cache);
+	kfree(ring->meta);
+	kfree(ring);
+}
+
+#define destroy_ring(dma, ring) do {				\
+	b43_destroy_dmaring((dma)->ring, __stringify(ring));	\
+	(dma)->ring = NULL;					\
+    } while (0)
+
+void b43_dma_free(struct b43_wldev *dev)
+{
+	struct b43_dma *dma;
+
+	if (b43_using_pio_transfers(dev))
+		return;
+	dma = &dev->dma;
+
+	destroy_ring(dma, rx_ring);
+	destroy_ring(dma, tx_ring_AC_BK);
+	destroy_ring(dma, tx_ring_AC_BE);
+	destroy_ring(dma, tx_ring_AC_VI);
+	destroy_ring(dma, tx_ring_AC_VO);
+	destroy_ring(dma, tx_ring_mcast);
+}
+
+static int b43_dma_set_mask(struct b43_wldev *dev, u64 mask)
+{
+	u64 orig_mask = mask;
+	bool fallback = false;
+	int err;
+
+	/* Try to set the DMA mask. If it fails, try falling back to a
+	 * lower mask, as we can always also support a lower one. */
+	while (1) {
+		err = dma_set_mask_and_coherent(dev->dev->dma_dev, mask);
+		if (!err)
+			break;
+		if (mask == DMA_BIT_MASK(64)) {
+			mask = DMA_BIT_MASK(32);
+			fallback = true;
+			continue;
+		}
+		if (mask == DMA_BIT_MASK(32)) {
+			mask = DMA_BIT_MASK(30);
+			fallback = true;
+			continue;
+		}
+		b43err(dev->wl, "The machine/kernel does not support "
+		       "the required %u-bit DMA mask\n",
+		       (unsigned int)dma_mask_to_engine_type(orig_mask));
+		return -EOPNOTSUPP;
+	}
+	if (fallback) {
+		b43info(dev->wl, "DMA mask fallback from %u-bit to %u-bit\n",
+			(unsigned int)dma_mask_to_engine_type(orig_mask),
+			(unsigned int)dma_mask_to_engine_type(mask));
+	}
+
+	return 0;
+}
+
+/* Some hardware with 64-bit DMA seems to be bugged and looks for translation
+ * bit in low address word instead of high one.
+ */
+static bool b43_dma_translation_in_low_word(struct b43_wldev *dev,
+					    enum b43_dmatype type)
+{
+	if (type != B43_DMA_64BIT)
+		return true;
+
+#ifdef CONFIG_B43_SSB
+	if (dev->dev->bus_type == B43_BUS_SSB &&
+	    dev->dev->sdev->bus->bustype == SSB_BUSTYPE_PCI &&
+	    !(pci_is_pcie(dev->dev->sdev->bus->host_pci) &&
+	      ssb_read32(dev->dev->sdev, SSB_TMSHIGH) & SSB_TMSHIGH_DMA64))
+			return true;
+#endif
+	return false;
+}
+
+int b43_dma_init(struct b43_wldev *dev)
+{
+	struct b43_dma *dma = &dev->dma;
+	int err;
+	u64 dmamask;
+	enum b43_dmatype type;
+
+	dmamask = supported_dma_mask(dev);
+	type = dma_mask_to_engine_type(dmamask);
+	err = b43_dma_set_mask(dev, dmamask);
+	if (err)
+		return err;
+
+	switch (dev->dev->bus_type) {
+#ifdef CONFIG_B43_BCMA
+	case B43_BUS_BCMA:
+		dma->translation = bcma_core_dma_translation(dev->dev->bdev);
+		break;
+#endif
+#ifdef CONFIG_B43_SSB
+	case B43_BUS_SSB:
+		dma->translation = ssb_dma_translation(dev->dev->sdev);
+		break;
+#endif
+	}
+	dma->translation_in_low = b43_dma_translation_in_low_word(dev, type);
+
+	dma->parity = true;
+#ifdef CONFIG_B43_BCMA
+	/* TODO: find out which SSB devices need disabling parity */
+	if (dev->dev->bus_type == B43_BUS_BCMA)
+		dma->parity = false;
+#endif
+
+	err = -ENOMEM;
+	/* setup TX DMA channels. */
+	dma->tx_ring_AC_BK = b43_setup_dmaring(dev, 0, 1, type);
+	if (!dma->tx_ring_AC_BK)
+		goto out;
+
+	dma->tx_ring_AC_BE = b43_setup_dmaring(dev, 1, 1, type);
+	if (!dma->tx_ring_AC_BE)
+		goto err_destroy_bk;
+
+	dma->tx_ring_AC_VI = b43_setup_dmaring(dev, 2, 1, type);
+	if (!dma->tx_ring_AC_VI)
+		goto err_destroy_be;
+
+	dma->tx_ring_AC_VO = b43_setup_dmaring(dev, 3, 1, type);
+	if (!dma->tx_ring_AC_VO)
+		goto err_destroy_vi;
+
+	dma->tx_ring_mcast = b43_setup_dmaring(dev, 4, 1, type);
+	if (!dma->tx_ring_mcast)
+		goto err_destroy_vo;
+
+	/* setup RX DMA channel. */
+	dma->rx_ring = b43_setup_dmaring(dev, 0, 0, type);
+	if (!dma->rx_ring)
+		goto err_destroy_mcast;
+
+	/* No support for the TX status DMA ring. */
+	B43_WARN_ON(dev->dev->core_rev < 5);
+
+	b43dbg(dev->wl, "%u-bit DMA initialized\n",
+	       (unsigned int)type);
+	err = 0;
+out:
+	return err;
+
+err_destroy_mcast:
+	destroy_ring(dma, tx_ring_mcast);
+err_destroy_vo:
+	destroy_ring(dma, tx_ring_AC_VO);
+err_destroy_vi:
+	destroy_ring(dma, tx_ring_AC_VI);
+err_destroy_be:
+	destroy_ring(dma, tx_ring_AC_BE);
+err_destroy_bk:
+	destroy_ring(dma, tx_ring_AC_BK);
+	return err;
+}
+
+/* Generate a cookie for the TX header. */
+static u16 generate_cookie(struct b43_dmaring *ring, int slot)
+{
+	u16 cookie;
+
+	/* Use the upper 4 bits of the cookie as
+	 * DMA controller ID and store the slot number
+	 * in the lower 12 bits.
+	 * Note that the cookie must never be 0, as this
+	 * is a special value used in RX path.
+	 * It can also not be 0xFFFF because that is special
+	 * for multicast frames.
+	 */
+	cookie = (((u16)ring->index + 1) << 12);
+	B43_WARN_ON(slot & ~0x0FFF);
+	cookie |= (u16)slot;
+
+	return cookie;
+}
+
+/* Inspect a cookie and find out to which controller/slot it belongs. */
+static
+struct b43_dmaring *parse_cookie(struct b43_wldev *dev, u16 cookie, int *slot)
+{
+	struct b43_dma *dma = &dev->dma;
+	struct b43_dmaring *ring = NULL;
+
+	switch (cookie & 0xF000) {
+	case 0x1000:
+		ring = dma->tx_ring_AC_BK;
+		break;
+	case 0x2000:
+		ring = dma->tx_ring_AC_BE;
+		break;
+	case 0x3000:
+		ring = dma->tx_ring_AC_VI;
+		break;
+	case 0x4000:
+		ring = dma->tx_ring_AC_VO;
+		break;
+	case 0x5000:
+		ring = dma->tx_ring_mcast;
+		break;
+	}
+	*slot = (cookie & 0x0FFF);
+	if (unlikely(!ring || *slot < 0 || *slot >= ring->nr_slots)) {
+		b43dbg(dev->wl, "TX-status contains "
+		       "invalid cookie: 0x%04X\n", cookie);
+		return NULL;
+	}
+
+	return ring;
+}
+
+static int dma_tx_fragment(struct b43_dmaring *ring,
+			   struct sk_buff *skb)
+{
+	const struct b43_dma_ops *ops = ring->ops;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	struct b43_private_tx_info *priv_info = b43_get_priv_tx_info(info);
+	u8 *header;
+	int slot, old_top_slot, old_used_slots;
+	int err;
+	struct b43_dmadesc_generic *desc;
+	struct b43_dmadesc_meta *meta;
+	struct b43_dmadesc_meta *meta_hdr;
+	u16 cookie;
+	size_t hdrsize = b43_txhdr_size(ring->dev);
+
+	/* Important note: If the number of used DMA slots per TX frame
+	 * is changed here, the TX_SLOTS_PER_FRAME definition at the top of
+	 * the file has to be updated, too!
+	 */
+
+	old_top_slot = ring->current_slot;
+	old_used_slots = ring->used_slots;
+
+	/* Get a slot for the header. */
+	slot = request_slot(ring);
+	desc = ops->idx2desc(ring, slot, &meta_hdr);
+	memset(meta_hdr, 0, sizeof(*meta_hdr));
+
+	header = &(ring->txhdr_cache[(slot / TX_SLOTS_PER_FRAME) * hdrsize]);
+	cookie = generate_cookie(ring, slot);
+	err = b43_generate_txhdr(ring->dev, header,
+				 skb, info, cookie);
+	if (unlikely(err)) {
+		ring->current_slot = old_top_slot;
+		ring->used_slots = old_used_slots;
+		return err;
+	}
+
+	meta_hdr->dmaaddr = map_descbuffer(ring, (unsigned char *)header,
+					   hdrsize, 1);
+	if (b43_dma_mapping_error(ring, meta_hdr->dmaaddr, hdrsize, 1)) {
+		ring->current_slot = old_top_slot;
+		ring->used_slots = old_used_slots;
+		return -EIO;
+	}
+	ops->fill_descriptor(ring, desc, meta_hdr->dmaaddr,
+			     hdrsize, 1, 0, 0);
+
+	/* Get a slot for the payload. */
+	slot = request_slot(ring);
+	desc = ops->idx2desc(ring, slot, &meta);
+	memset(meta, 0, sizeof(*meta));
+
+	meta->skb = skb;
+	meta->is_last_fragment = true;
+	priv_info->bouncebuffer = NULL;
+
+	meta->dmaaddr = map_descbuffer(ring, skb->data, skb->len, 1);
+	/* create a bounce buffer in zone_dma on mapping failure. */
+	if (b43_dma_mapping_error(ring, meta->dmaaddr, skb->len, 1)) {
+		priv_info->bouncebuffer = kmemdup(skb->data, skb->len,
+						  GFP_ATOMIC | GFP_DMA);
+		if (!priv_info->bouncebuffer) {
+			ring->current_slot = old_top_slot;
+			ring->used_slots = old_used_slots;
+			err = -ENOMEM;
+			goto out_unmap_hdr;
+		}
+
+		meta->dmaaddr = map_descbuffer(ring, priv_info->bouncebuffer, skb->len, 1);
+		if (b43_dma_mapping_error(ring, meta->dmaaddr, skb->len, 1)) {
+			kfree(priv_info->bouncebuffer);
+			priv_info->bouncebuffer = NULL;
+			ring->current_slot = old_top_slot;
+			ring->used_slots = old_used_slots;
+			err = -EIO;
+			goto out_unmap_hdr;
+		}
+	}
+
+	ops->fill_descriptor(ring, desc, meta->dmaaddr, skb->len, 0, 1, 1);
+
+	if (info->flags & IEEE80211_TX_CTL_SEND_AFTER_DTIM) {
+		/* Tell the firmware about the cookie of the last
+		 * mcast frame, so it can clear the more-data bit in it. */
+		b43_shm_write16(ring->dev, B43_SHM_SHARED,
+				B43_SHM_SH_MCASTCOOKIE, cookie);
+	}
+	/* Now transfer the whole frame. */
+	wmb();
+	ops->poke_tx(ring, next_slot(ring, slot));
+	return 0;
+
+out_unmap_hdr:
+	unmap_descbuffer(ring, meta_hdr->dmaaddr,
+			 hdrsize, 1);
+	return err;
+}
+
+static inline int should_inject_overflow(struct b43_dmaring *ring)
+{
+#ifdef CONFIG_B43_DEBUG
+	if (unlikely(b43_debug(ring->dev, B43_DBG_DMAOVERFLOW))) {
+		/* Check if we should inject another ringbuffer overflow
+		 * to test handling of this situation in the stack. */
+		unsigned long next_overflow;
+
+		next_overflow = ring->last_injected_overflow + HZ;
+		if (time_after(jiffies, next_overflow)) {
+			ring->last_injected_overflow = jiffies;
+			b43dbg(ring->dev->wl,
+			       "Injecting TX ring overflow on "
+			       "DMA controller %d\n", ring->index);
+			return 1;
+		}
+	}
+#endif /* CONFIG_B43_DEBUG */
+	return 0;
+}
+
+/* Static mapping of mac80211's queues (priorities) to b43 DMA rings. */
+static struct b43_dmaring *select_ring_by_priority(struct b43_wldev *dev,
+						   u8 queue_prio)
+{
+	struct b43_dmaring *ring;
+
+	if (dev->qos_enabled) {
+		/* 0 = highest priority */
+		switch (queue_prio) {
+		default:
+			B43_WARN_ON(1);
+			/* fallthrough */
+		case 0:
+			ring = dev->dma.tx_ring_AC_VO;
+			break;
+		case 1:
+			ring = dev->dma.tx_ring_AC_VI;
+			break;
+		case 2:
+			ring = dev->dma.tx_ring_AC_BE;
+			break;
+		case 3:
+			ring = dev->dma.tx_ring_AC_BK;
+			break;
+		}
+	} else
+		ring = dev->dma.tx_ring_AC_BE;
+
+	return ring;
+}
+
+int b43_dma_tx(struct b43_wldev *dev, struct sk_buff *skb)
+{
+	struct b43_dmaring *ring;
+	struct ieee80211_hdr *hdr;
+	int err = 0;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+
+	hdr = (struct ieee80211_hdr *)skb->data;
+	if (info->flags & IEEE80211_TX_CTL_SEND_AFTER_DTIM) {
+		/* The multicast ring will be sent after the DTIM */
+		ring = dev->dma.tx_ring_mcast;
+		/* Set the more-data bit. Ucode will clear it on
+		 * the last frame for us. */
+		hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_MOREDATA);
+	} else {
+		/* Decide by priority where to put this frame. */
+		ring = select_ring_by_priority(
+			dev, skb_get_queue_mapping(skb));
+	}
+
+	B43_WARN_ON(!ring->tx);
+
+	if (unlikely(ring->stopped)) {
+		/* We get here only because of a bug in mac80211.
+		 * Because of a race, one packet may be queued after
+		 * the queue is stopped, thus we got called when we shouldn't.
+		 * For now, just refuse the transmit. */
+		if (b43_debug(dev, B43_DBG_DMAVERBOSE))
+			b43err(dev->wl, "Packet after queue stopped\n");
+		err = -ENOSPC;
+		goto out;
+	}
+
+	if (unlikely(WARN_ON(free_slots(ring) < TX_SLOTS_PER_FRAME))) {
+		/* If we get here, we have a real error with the queue
+		 * full, but queues not stopped. */
+		b43err(dev->wl, "DMA queue overflow\n");
+		err = -ENOSPC;
+		goto out;
+	}
+
+	/* Assign the queue number to the ring (if not already done before)
+	 * so TX status handling can use it. The queue to ring mapping is
+	 * static, so we don't need to store it per frame. */
+	ring->queue_prio = skb_get_queue_mapping(skb);
+
+	err = dma_tx_fragment(ring, skb);
+	if (unlikely(err == -ENOKEY)) {
+		/* Drop this packet, as we don't have the encryption key
+		 * anymore and must not transmit it unencrypted. */
+		ieee80211_free_txskb(dev->wl->hw, skb);
+		err = 0;
+		goto out;
+	}
+	if (unlikely(err)) {
+		b43err(dev->wl, "DMA tx mapping failure\n");
+		goto out;
+	}
+	if ((free_slots(ring) < TX_SLOTS_PER_FRAME) ||
+	    should_inject_overflow(ring)) {
+		/* This TX ring is full. */
+		unsigned int skb_mapping = skb_get_queue_mapping(skb);
+		ieee80211_stop_queue(dev->wl->hw, skb_mapping);
+		dev->wl->tx_queue_stopped[skb_mapping] = 1;
+		ring->stopped = true;
+		if (b43_debug(dev, B43_DBG_DMAVERBOSE)) {
+			b43dbg(dev->wl, "Stopped TX ring %d\n", ring->index);
+		}
+	}
+out:
+
+	return err;
+}
+
+void b43_dma_handle_txstatus(struct b43_wldev *dev,
+			     const struct b43_txstatus *status)
+{
+	const struct b43_dma_ops *ops;
+	struct b43_dmaring *ring;
+	struct b43_dmadesc_meta *meta;
+	static const struct b43_txstatus fake; /* filled with 0 */
+	const struct b43_txstatus *txstat;
+	int slot, firstused;
+	bool frame_succeed;
+	int skip;
+	static u8 err_out1, err_out2;
+
+	ring = parse_cookie(dev, status->cookie, &slot);
+	if (unlikely(!ring))
+		return;
+	B43_WARN_ON(!ring->tx);
+
+	/* Sanity check: TX packets are processed in-order on one ring.
+	 * Check if the slot deduced from the cookie really is the first
+	 * used slot. */
+	firstused = ring->current_slot - ring->used_slots + 1;
+	if (firstused < 0)
+		firstused = ring->nr_slots + firstused;
+
+	skip = 0;
+	if (unlikely(slot != firstused)) {
+		/* This possibly is a firmware bug and will result in
+		 * malfunction, memory leaks and/or stall of DMA functionality.
+		 */
+		if (slot == next_slot(ring, next_slot(ring, firstused))) {
+			/* If a single header/data pair was missed, skip over
+			 * the first two slots in an attempt to recover.
+			 */
+			slot = firstused;
+			skip = 2;
+			if (!err_out1) {
+				/* Report the error once. */
+				b43dbg(dev->wl,
+				       "Skip on DMA ring %d slot %d.\n",
+				       ring->index, slot);
+				err_out1 = 1;
+			}
+		} else {
+			/* More than a single header/data pair were missed.
+			 * Report this error once.
+			 */
+			if (!err_out2)
+				b43dbg(dev->wl,
+				       "Out of order TX status report on DMA ring %d. Expected %d, but got %d\n",
+				       ring->index, firstused, slot);
+			err_out2 = 1;
+			return;
+		}
+	}
+
+	ops = ring->ops;
+	while (1) {
+		B43_WARN_ON(slot < 0 || slot >= ring->nr_slots);
+		/* get meta - ignore returned value */
+		ops->idx2desc(ring, slot, &meta);
+
+		if (b43_dma_ptr_is_poisoned(meta->skb)) {
+			b43dbg(dev->wl, "Poisoned TX slot %d (first=%d) "
+			       "on ring %d\n",
+			       slot, firstused, ring->index);
+			break;
+		}
+
+		if (meta->skb) {
+			struct b43_private_tx_info *priv_info =
+			     b43_get_priv_tx_info(IEEE80211_SKB_CB(meta->skb));
+
+			unmap_descbuffer(ring, meta->dmaaddr,
+					 meta->skb->len, 1);
+			kfree(priv_info->bouncebuffer);
+			priv_info->bouncebuffer = NULL;
+		} else {
+			unmap_descbuffer(ring, meta->dmaaddr,
+					 b43_txhdr_size(dev), 1);
+		}
+
+		if (meta->is_last_fragment) {
+			struct ieee80211_tx_info *info;
+
+			if (unlikely(!meta->skb)) {
+				/* This is a scatter-gather fragment of a frame,
+				 * so the skb pointer must not be NULL.
+				 */
+				b43dbg(dev->wl, "TX status unexpected NULL skb "
+				       "at slot %d (first=%d) on ring %d\n",
+				       slot, firstused, ring->index);
+				break;
+			}
+
+			info = IEEE80211_SKB_CB(meta->skb);
+
+			/*
+			 * Call back to inform the ieee80211 subsystem about
+			 * the status of the transmission. When skipping over
+			 * a missed TX status report, use a status structure
+			 * filled with zeros to indicate that the frame was not
+			 * sent (frame_count 0) and not acknowledged
+			 */
+			if (unlikely(skip))
+				txstat = &fake;
+			else
+				txstat = status;
+
+			frame_succeed = b43_fill_txstatus_report(dev, info,
+								 txstat);
+#ifdef CONFIG_B43_DEBUG
+			if (frame_succeed)
+				ring->nr_succeed_tx_packets++;
+			else
+				ring->nr_failed_tx_packets++;
+			ring->nr_total_packet_tries += status->frame_count;
+#endif /* DEBUG */
+			ieee80211_tx_status(dev->wl->hw, meta->skb);
+
+			/* skb will be freed by ieee80211_tx_status().
+			 * Poison our pointer. */
+			meta->skb = B43_DMA_PTR_POISON;
+		} else {
+			/* No need to call free_descriptor_buffer here, as
+			 * this is only the txhdr, which is not allocated.
+			 */
+			if (unlikely(meta->skb)) {
+				b43dbg(dev->wl, "TX status unexpected non-NULL skb "
+				       "at slot %d (first=%d) on ring %d\n",
+				       slot, firstused, ring->index);
+				break;
+			}
+		}
+
+		/* Everything unmapped and free'd. So it's not used anymore. */
+		ring->used_slots--;
+
+		if (meta->is_last_fragment && !skip) {
+			/* This is the last scatter-gather
+			 * fragment of the frame. We are done. */
+			break;
+		}
+		slot = next_slot(ring, slot);
+		if (skip > 0)
+			--skip;
+	}
+	if (ring->stopped) {
+		B43_WARN_ON(free_slots(ring) < TX_SLOTS_PER_FRAME);
+		ring->stopped = false;
+	}
+
+	if (dev->wl->tx_queue_stopped[ring->queue_prio]) {
+		dev->wl->tx_queue_stopped[ring->queue_prio] = 0;
+	} else {
+		/* If the driver queue is running wake the corresponding
+		 * mac80211 queue. */
+		ieee80211_wake_queue(dev->wl->hw, ring->queue_prio);
+		if (b43_debug(dev, B43_DBG_DMAVERBOSE)) {
+			b43dbg(dev->wl, "Woke up TX ring %d\n", ring->index);
+		}
+	}
+	/* Add work to the queue. */
+	ieee80211_queue_work(dev->wl->hw, &dev->wl->tx_work);
+}
+
+static void dma_rx(struct b43_dmaring *ring, int *slot)
+{
+	const struct b43_dma_ops *ops = ring->ops;
+	struct b43_dmadesc_generic *desc;
+	struct b43_dmadesc_meta *meta;
+	struct b43_rxhdr_fw4 *rxhdr;
+	struct sk_buff *skb;
+	u16 len;
+	int err;
+	dma_addr_t dmaaddr;
+
+	desc = ops->idx2desc(ring, *slot, &meta);
+
+	sync_descbuffer_for_cpu(ring, meta->dmaaddr, ring->rx_buffersize);
+	skb = meta->skb;
+
+	rxhdr = (struct b43_rxhdr_fw4 *)skb->data;
+	len = le16_to_cpu(rxhdr->frame_len);
+	if (len == 0) {
+		int i = 0;
+
+		do {
+			udelay(2);
+			barrier();
+			len = le16_to_cpu(rxhdr->frame_len);
+		} while (len == 0 && i++ < 5);
+		if (unlikely(len == 0)) {
+			dmaaddr = meta->dmaaddr;
+			goto drop_recycle_buffer;
+		}
+	}
+	if (unlikely(b43_rx_buffer_is_poisoned(ring, skb))) {
+		/* Something went wrong with the DMA.
+		 * The device did not touch the buffer and did not overwrite the poison. */
+		b43dbg(ring->dev->wl, "DMA RX: Dropping poisoned buffer.\n");
+		dmaaddr = meta->dmaaddr;
+		goto drop_recycle_buffer;
+	}
+	if (unlikely(len + ring->frameoffset > 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 = ops->idx2desc(ring, *slot, &meta);
+			/* recycle the descriptor buffer. */
+			b43_poison_rx_buffer(ring, meta->skb);
+			sync_descbuffer_for_device(ring, meta->dmaaddr,
+						   ring->rx_buffersize);
+			*slot = next_slot(ring, *slot);
+			cnt++;
+			tmp -= ring->rx_buffersize;
+			if (tmp <= 0)
+				break;
+		}
+		b43err(ring->dev->wl, "DMA RX buffer too small "
+		       "(len: %u, buffer: %u, nr-dropped: %d)\n",
+		       len, ring->rx_buffersize, cnt);
+		goto drop;
+	}
+
+	dmaaddr = meta->dmaaddr;
+	err = setup_rx_descbuffer(ring, desc, meta, GFP_ATOMIC);
+	if (unlikely(err)) {
+		b43dbg(ring->dev->wl, "DMA RX: setup_rx_descbuffer() failed\n");
+		goto drop_recycle_buffer;
+	}
+
+	unmap_descbuffer(ring, dmaaddr, ring->rx_buffersize, 0);
+	skb_put(skb, len + ring->frameoffset);
+	skb_pull(skb, ring->frameoffset);
+
+	b43_rx(ring->dev, skb, rxhdr);
+drop:
+	return;
+
+drop_recycle_buffer:
+	/* Poison and recycle the RX buffer. */
+	b43_poison_rx_buffer(ring, skb);
+	sync_descbuffer_for_device(ring, dmaaddr, ring->rx_buffersize);
+}
+
+void b43_dma_handle_rx_overflow(struct b43_dmaring *ring)
+{
+	int current_slot, previous_slot;
+
+	B43_WARN_ON(ring->tx);
+
+	/* Device has filled all buffers, drop all packets and let TCP
+	 * decrease speed.
+	 * Decrement RX index by one will let the device to see all slots
+	 * as free again
+	 */
+	/*
+	*TODO: How to increase rx_drop in mac80211?
+	*/
+	current_slot = ring->ops->get_current_rxslot(ring);
+	previous_slot = prev_slot(ring, current_slot);
+	ring->ops->set_current_rxslot(ring, previous_slot);
+}
+
+void b43_dma_rx(struct b43_dmaring *ring)
+{
+	const struct b43_dma_ops *ops = ring->ops;
+	int slot, current_slot;
+	int used_slots = 0;
+
+	B43_WARN_ON(ring->tx);
+	current_slot = ops->get_current_rxslot(ring);
+	B43_WARN_ON(!(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);
+		update_max_used_slots(ring, ++used_slots);
+	}
+	wmb();
+	ops->set_current_rxslot(ring, slot);
+	ring->current_slot = slot;
+}
+
+static void b43_dma_tx_suspend_ring(struct b43_dmaring *ring)
+{
+	B43_WARN_ON(!ring->tx);
+	ring->ops->tx_suspend(ring);
+}
+
+static void b43_dma_tx_resume_ring(struct b43_dmaring *ring)
+{
+	B43_WARN_ON(!ring->tx);
+	ring->ops->tx_resume(ring);
+}
+
+void b43_dma_tx_suspend(struct b43_wldev *dev)
+{
+	b43_power_saving_ctl_bits(dev, B43_PS_AWAKE);
+	b43_dma_tx_suspend_ring(dev->dma.tx_ring_AC_BK);
+	b43_dma_tx_suspend_ring(dev->dma.tx_ring_AC_BE);
+	b43_dma_tx_suspend_ring(dev->dma.tx_ring_AC_VI);
+	b43_dma_tx_suspend_ring(dev->dma.tx_ring_AC_VO);
+	b43_dma_tx_suspend_ring(dev->dma.tx_ring_mcast);
+}
+
+void b43_dma_tx_resume(struct b43_wldev *dev)
+{
+	b43_dma_tx_resume_ring(dev->dma.tx_ring_mcast);
+	b43_dma_tx_resume_ring(dev->dma.tx_ring_AC_VO);
+	b43_dma_tx_resume_ring(dev->dma.tx_ring_AC_VI);
+	b43_dma_tx_resume_ring(dev->dma.tx_ring_AC_BE);
+	b43_dma_tx_resume_ring(dev->dma.tx_ring_AC_BK);
+	b43_power_saving_ctl_bits(dev, 0);
+}
+
+static void direct_fifo_rx(struct b43_wldev *dev, enum b43_dmatype type,
+			   u16 mmio_base, bool enable)
+{
+	u32 ctl;
+
+	if (type == B43_DMA_64BIT) {
+		ctl = b43_read32(dev, mmio_base + B43_DMA64_RXCTL);
+		ctl &= ~B43_DMA64_RXDIRECTFIFO;
+		if (enable)
+			ctl |= B43_DMA64_RXDIRECTFIFO;
+		b43_write32(dev, mmio_base + B43_DMA64_RXCTL, ctl);
+	} else {
+		ctl = b43_read32(dev, mmio_base + B43_DMA32_RXCTL);
+		ctl &= ~B43_DMA32_RXDIRECTFIFO;
+		if (enable)
+			ctl |= B43_DMA32_RXDIRECTFIFO;
+		b43_write32(dev, mmio_base + B43_DMA32_RXCTL, ctl);
+	}
+}
+
+/* Enable/Disable Direct FIFO Receive Mode (PIO) on a RX engine.
+ * This is called from PIO code, so DMA structures are not available. */
+void b43_dma_direct_fifo_rx(struct b43_wldev *dev,
+			    unsigned int engine_index, bool enable)
+{
+	enum b43_dmatype type;
+	u16 mmio_base;
+
+	type = dma_mask_to_engine_type(supported_dma_mask(dev));
+
+	mmio_base = b43_dmacontroller_base(type, engine_index);
+	direct_fifo_rx(dev, type, mmio_base, enable);
+}