Re: BUG: NULL pointer dereference at 00000000 -- IP: [] :b43:b43_dma_mapping_error+0x16/0x155

Miles Lane
2008-06-10T22:30:25Z

I am not a programmer.

Here is the content of the file. Would you please send back a version
of the file with the necessary changes added?
BTW, I leave tomorrow for a three week vacation, so I hope we can sort
this before I go.

Thanks,

Miles

-----------------------------
/*

Broadcom B43 wireless driver

DMA ringbuffer and descriptor allocation/management

Copyright (c) 2005, 2006 Michael Buesch <mb@bu3sch.de>

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 <asm/div64.h>

/* 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 = (u32) (dmaaddr & ~SSB_DMA_TRANSLATION_MASK);
addrext = (u32) (dmaaddr & SSB_DMA_TRANSLATION_MASK)
>> SSB_DMA_TRANSLATION_SHIFT;
addr |= ssb_dma_translation(ring->dev->dev);
ctl = (bufsize - ring->frameoffset)
& 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 = (u32) (dmaaddr & 0xFFFFFFFF);
addrhi = (((u64) dmaaddr >> 32) & ~SSB_DMA_TRANSLATION_MASK);
addrext = (((u64) dmaaddr >> 32) & SSB_DMA_TRANSLATION_MASK)
>> SSB_DMA_TRANSLATION_SHIFT;
addrhi |= (ssb_dma_translation(ring->dev->dev) << 1);
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 - ring->frameoffset)
& 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) {
dev_kfree_skb_any(meta->skb);
meta->skb = NULL;
}
}

static int alloc_ringmemory(struct b43_dmaring *ring)
{
struct device *dma_dev = ring->dev->dev->dma_dev;
gfp_t flags = GFP_KERNEL;

/* 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. Testing
* has shown that 4K is sufficient for the latter as long as the buffer
* does not cross an 8K boundary.
*
* For unknown reasons - possibly a hardware error - the BCM4311 rev
* 02, which uses 64-bit DMA, needs the ring buffer in very low memory,
* which accounts for the GFP_DMA flag below.
*/
if (ring->type == B43_DMA_64BIT)
flags |= GFP_DMA;
ring->descbase = dma_alloc_coherent(dma_dev, B43_DMA_RINGMEMSIZE,
&(ring->dmabase), flags);
if (!ring->descbase) {
b43err(ring->dev->wl, "DMA ringmemory allocation failed\n");
return -ENOMEM;
}
memset(ring->descbase, 0, B43_DMA_RINGMEMSIZE);

return 0;
}

static void free_ringmemory(struct b43_dmaring *ring)
{
struct device *dma_dev = ring->dev->dev->dma_dev;

dma_free_coherent(dma_dev, B43_DMA_RINGMEMSIZE,
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 1;

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 0;

address_error:
/* We can't support this address. Unmap it again. */
unmap_descbuffer(ring, addr, buffersize, dma_to_device);

return 1;
}

static int setup_rx_descbuffer(struct b43_dmaring *ring,
struct b43_dmadesc_generic *desc,
struct b43_dmadesc_meta *meta, gfp_t gfp_flags)
{
struct b43_rxhdr_fw4 *rxhdr;
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;
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;
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);

rxhdr = (struct b43_rxhdr_fw4 *)(skb->data);
rxhdr->frame_len = 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;
u32 trans = ssb_dma_translation(ring->dev->dev);

if (ring->tx) {
if (ring->type == B43_DMA_64BIT) {
u64 ringbase = (u64) (ring->dmabase);

addrext = ((ringbase >> 32) & SSB_DMA_TRANSLATION_MASK)
>> SSB_DMA_TRANSLATION_SHIFT;
value = B43_DMA64_TXENABLE;
value |= (addrext << B43_DMA64_TXADDREXT_SHIFT)
& B43_DMA64_TXADDREXT_MASK;
b43_dma_write(ring, B43_DMA64_TXCTL, value);
b43_dma_write(ring, B43_DMA64_TXRINGLO,
(ringbase & 0xFFFFFFFF));
b43_dma_write(ring, B43_DMA64_TXRINGHI,
((ringbase >> 32) &
~SSB_DMA_TRANSLATION_MASK)
| (trans << 1));
} else {
u32 ringbase = (u32) (ring->dmabase);

addrext = (ringbase & SSB_DMA_TRANSLATION_MASK)
>> SSB_DMA_TRANSLATION_SHIFT;
value = B43_DMA32_TXENABLE;
value |= (addrext << B43_DMA32_TXADDREXT_SHIFT)
& B43_DMA32_TXADDREXT_MASK;
b43_dma_write(ring, B43_DMA32_TXCTL, value);
b43_dma_write(ring, B43_DMA32_TXRING,
(ringbase & ~SSB_DMA_TRANSLATION_MASK)
| trans);
}
} else {
err = alloc_initial_descbuffers(ring);
if (err)
goto out;
if (ring->type == B43_DMA_64BIT) {
u64 ringbase = (u64) (ring->dmabase);

addrext = ((ringbase >> 32) & SSB_DMA_TRANSLATION_MASK)
>> SSB_DMA_TRANSLATION_SHIFT;
value = (ring->frameoffset << B43_DMA64_RXFROFF_SHIFT);
value |= B43_DMA64_RXENABLE;
value |= (addrext << B43_DMA64_RXADDREXT_SHIFT)
& B43_DMA64_RXADDREXT_MASK;
b43_dma_write(ring, B43_DMA64_RXCTL, value);
b43_dma_write(ring, B43_DMA64_RXRINGLO,
(ringbase & 0xFFFFFFFF));
b43_dma_write(ring, B43_DMA64_RXRINGHI,
((ringbase >> 32) &
~SSB_DMA_TRANSLATION_MASK)
| (trans << 1));
b43_dma_write(ring, B43_DMA64_RXINDEX, ring->nr_slots *
sizeof(struct b43_dmadesc64));
} else {
u32 ringbase = (u32) (ring->dmabase);

addrext = (ringbase & SSB_DMA_TRANSLATION_MASK)
>> SSB_DMA_TRANSLATION_SHIFT;
value = (ring->frameoffset << B43_DMA32_RXFROFF_SHIFT);
value |= B43_DMA32_RXENABLE;
value |= (addrext << B43_DMA32_RXADDREXT_SHIFT)
& B43_DMA32_RXADDREXT_MASK;
b43_dma_write(ring, B43_DMA32_RXCTL, value);
b43_dma_write(ring, B43_DMA32_RXRING,
(ringbase & ~SSB_DMA_TRANSLATION_MASK)
| trans);
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_generic *desc;
struct b43_dmadesc_meta *meta;
int i;

if (!ring->used_slots)
return;
for (i = 0; i < ring->nr_slots; i++) {
desc = ring->ops->idx2desc(ring, i, &meta);

if (!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;

tmp = b43_read32(dev, SSB_TMSHIGH);
if (tmp & SSB_TMSHIGH_DMA64)
return DMA_64BIT_MASK;
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_32BIT_MASK;

return DMA_30BIT_MASK;
}

static enum b43_dmatype dma_mask_to_engine_type(u64 dmamask)
{
if (dmamask == DMA_30BIT_MASK)
return B43_DMA_30BIT;
if (dmamask == DMA_32BIT_MASK)
return B43_DMA_32BIT;
if (dmamask == DMA_64BIT_MASK)
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 err;
int nr_slots;
dma_addr_t dma_test;

ring = kzalloc(sizeof(*ring), GFP_KERNEL);
if (!ring)
goto out;
ring->type = type;

nr_slots = B43_RXRING_SLOTS;
if (for_tx)
nr_slots = B43_TXRING_SLOTS;

ring->meta = kcalloc(nr_slots, sizeof(struct b43_dmadesc_meta),
GFP_KERNEL);
if (!ring->meta)
goto err_kfree_ring;
if (for_tx) {
ring->txhdr_cache = kcalloc(nr_slots,
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(nr_slots,
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);
}

ring->dev = dev;
ring->nr_slots = nr_slots;
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 = 1;
ring->current_slot = -1;
} else {
if (ring->index == 0) {
ring->rx_buffersize = B43_DMA0_RX_BUFFERSIZE;
ring->frameoffset = B43_DMA0_RX_FRAMEOFFSET;
} else if (ring->index == 3) {
ring->rx_buffersize = B43_DMA3_RX_BUFFERSIZE;
ring->frameoffset = B43_DMA3_RX_FRAMEOFFSET;
} else
B43_WARN_ON(1);
}
spin_lock_init(&ring->lock);
#ifdef CONFIG_B43_DEBUG
ring->last_injected_overflow = jiffies;
#endif

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 = 0;
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 = ssb_dma_set_mask(dev->dev, mask);
if (!err)
break;
if (mask == DMA_64BIT_MASK) {
mask = DMA_32BIT_MASK;
fallback = 1;
continue;
}
if (mask == DMA_32BIT_MASK) {
mask = DMA_30BIT_MASK;
fallback = 1;
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;
}

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;

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->id.revision < 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;
default:
B43_WARN_ON(1);
}
*slot = (cookie & 0x0FFF);
B43_WARN_ON(!(ring && *slot >= 0 && *slot < ring->nr_slots));

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);
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;
struct sk_buff *bounce_skb;
u16 cookie;
size_t hdrsize = b43_txhdr_size(ring->dev);

#define SLOTS_PER_PACKET 2

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 * hdrsize]);
cookie = generate_cookie(ring, slot);
err = b43_generate_txhdr(ring->dev, header,
skb->data, skb->len, 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 = 1;

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)) {
bounce_skb = __dev_alloc_skb(skb->len, GFP_ATOMIC | GFP_DMA);
if (!bounce_skb) {
ring->current_slot = old_top_slot;
ring->used_slots = old_used_slots;
err = -ENOMEM;
goto out_unmap_hdr;
}

memcpy(skb_put(bounce_skb, skb->len), skb->data, skb->len);
dev_kfree_skb_any(skb);
skb = bounce_skb;
meta->skb = skb;
meta->dmaaddr = map_descbuffer(ring, skb->data, skb->len, 1);
if (b43_dma_mapping_error(ring, meta->dmaaddr, skb->len, 1)) {
ring->current_slot = old_top_slot;
ring->used_slots = old_used_slots;
err = -EIO;
goto out_free_bounce;
}
}

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_free_bounce:
dev_kfree_skb_any(skb);
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 (b43_modparam_qos) {
/* 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;
unsigned long flags;
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));
}

spin_lock_irqsave(&ring->lock, flags);
B43_WARN_ON(!ring->tx);
if (unlikely(free_slots(ring) < SLOTS_PER_PACKET)) {
b43warn(dev->wl, "DMA queue overflow\n");
err = -ENOSPC;
goto out_unlock;
}
/* Check if the queue was stopped in mac80211,
* but we got called nevertheless.
* That would be a mac80211 bug. */
B43_WARN_ON(ring->stopped);

/* 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. */
dev_kfree_skb_any(skb);
err = 0;
goto out_unlock;
}
if (unlikely(err)) {
b43err(dev->wl, "DMA tx mapping failure\n");
goto out_unlock;
}
ring->nr_tx_packets++;
if ((free_slots(ring) < SLOTS_PER_PACKET) ||
should_inject_overflow(ring)) {
/* This TX ring is full. */
ieee80211_stop_queue(dev->wl->hw, skb_get_queue_mapping(skb));
ring->stopped = 1;
if (b43_debug(dev, B43_DBG_DMAVERBOSE)) {
b43dbg(dev->wl, "Stopped TX ring %d\n", ring->index);
}
}
out_unlock:
spin_unlock_irqrestore(&ring->lock, flags);

return err;
}

/* Called with IRQs disabled. */
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_generic *desc;
struct b43_dmadesc_meta *meta;
int slot;
bool frame_succeed;

ring = parse_cookie(dev, status->cookie, &slot);
if (unlikely(!ring))
return;

spin_lock(&ring->lock); /* IRQs are already disabled. */

B43_WARN_ON(!ring->tx);
ops = ring->ops;
while (1) {
B43_WARN_ON(!(slot >= 0 && slot < ring->nr_slots));
desc = ops->idx2desc(ring, slot, &meta);

if (meta->skb)
unmap_descbuffer(ring, meta->dmaaddr, meta->skb->len,
1);
else
unmap_descbuffer(ring, meta->dmaaddr,
b43_txhdr_size(dev), 1);

if (meta->is_last_fragment) {
struct ieee80211_tx_info *info;

BUG_ON(!meta->skb);

info = IEEE80211_SKB_CB(meta->skb);

memset(&info->status, 0, sizeof(info->status));

/*
* Call back to inform the ieee80211 subsystem about
* the status of the transmission.
*/
frame_succeed = b43_fill_txstatus_report(info, status);
#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_irqsafe(dev->wl->hw, meta->skb);

/* skb is freed by ieee80211_tx_status_irqsafe() */
meta->skb = NULL;
} else {
/* No need to call free_descriptor_buffer here, as
* this is only the txhdr, which is not allocated.
*/
B43_WARN_ON(meta->skb);
}

/* Everything unmapped and free'd. So it's not used anymore. */
ring->used_slots--;

if (meta->is_last_fragment)
break;
slot = next_slot(ring, slot);
}
dev->stats.last_tx = jiffies;
if (ring->stopped) {
B43_WARN_ON(free_slots(ring) < SLOTS_PER_PACKET);
ieee80211_wake_queue(dev->wl->hw, ring->queue_prio);
ring->stopped = 0;
if (b43_debug(dev, B43_DBG_DMAVERBOSE)) {
b43dbg(dev->wl, "Woke up TX ring %d\n", ring->index);
}
}

spin_unlock(&ring->lock);
}

void b43_dma_get_tx_stats(struct b43_wldev *dev,
struct ieee80211_tx_queue_stats *stats)
{
const int nr_queues = dev->wl->hw->queues;
struct b43_dmaring *ring;
unsigned long flags;
int i;

for (i = 0; i < nr_queues; i++) {
ring = select_ring_by_priority(dev, i);

spin_lock_irqsave(&ring->lock, flags);
stats[i].len = ring->used_slots / SLOTS_PER_PACKET;
stats[i].limit = ring->nr_slots / SLOTS_PER_PACKET;
stats[i].count = ring->nr_tx_packets;
spin_unlock_irqrestore(&ring->lock, flags);
}
}

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)) {
/* 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 = ops->idx2desc(ring, *slot, &meta);
/* 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;
}
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");
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);

b43_rx(ring->dev, skb, rxhdr);
drop:
return;
}

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);
}
ops->set_current_rxslot(ring, slot);
ring->current_slot = slot;
}

static void b43_dma_tx_suspend_ring(struct b43_dmaring *ring)
{
unsigned long flags;

spin_lock_irqsave(&ring->lock, flags);
B43_WARN_ON(!ring->tx);
ring->ops->tx_suspend(ring);
spin_unlock_irqrestore(&ring->lock, flags);
}

static void b43_dma_tx_resume_ring(struct b43_dmaring *ring)
{
unsigned long flags;

spin_lock_irqsave(&ring->lock, flags);
B43_WARN_ON(!ring->tx);
ring->ops->tx_resume(ring);
spin_unlock_irqrestore(&ring->lock, flags);
}

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);
}

#ifdef CONFIG_B43_PIO
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);
}
#endif /* CONFIG_B43_PIO */

On Tue, Jun 10, 2008 at 6:15 PM, Michael Buesch <mb@bu3sch.de> wrote:
> On Wednesday 11 June 2008 00:09:27 Miles Lane wrote:
>> I got a slightly different BUG with this patch applied:
>>
>> BUG: unable to handle kernel NULL pointer dereference at 00000000
>> IP: [<f89e3d41>] :b43:b43_dma_mapping_error+0x16/0x97
>
> So can you please debug this? This is trivial. Just add a few printks
> to see which pointer is NULL.
> As I said I don't have this tree and really like to avoid fetching
> and building yet another tree.
>
> --
> Greetings Michael.
>