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Revert "b43: Enforce DMA descriptor memory constraints"
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This reverts commit 9bd568a.

That commit is shown to cause allocation failures during initialization
on some machines.

http://bugzilla.kernel.org/show_bug.cgi?id=14844

Signed-off-by: John W. Linville <linville@tuxdriver.com>
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John W. Linville committed Dec 29, 2009
1 parent 6c853da commit 55afc80
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Showing 2 changed files with 46 additions and 158 deletions.
197 changes: 45 additions & 152 deletions drivers/net/wireless/b43/dma.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -383,160 +383,44 @@ static inline
}
}

/* Check if a DMA region fits the device constraints.
* Returns true, if the region is OK for usage with this device. */
static inline bool b43_dma_address_ok(struct b43_dmaring *ring,
dma_addr_t addr, size_t size)
{
switch (ring->type) {
case B43_DMA_30BIT:
if ((u64)addr + size > (1ULL << 30))
return 0;
break;
case B43_DMA_32BIT:
if ((u64)addr + size > (1ULL << 32))
return 0;
break;
case B43_DMA_64BIT:
/* Currently we can't have addresses beyond
* 64bit in the kernel. */
break;
}
return 1;
}

#define is_4k_aligned(addr) (((u64)(addr) & 0x0FFFull) == 0)
#define is_8k_aligned(addr) (((u64)(addr) & 0x1FFFull) == 0)

static void b43_unmap_and_free_ringmem(struct b43_dmaring *ring, void *base,
dma_addr_t dmaaddr, size_t size)
{
ssb_dma_unmap_single(ring->dev->dev, dmaaddr, size, DMA_TO_DEVICE);
free_pages((unsigned long)base, get_order(size));
}

static void * __b43_get_and_map_ringmem(struct b43_dmaring *ring,
dma_addr_t *dmaaddr, size_t size,
gfp_t gfp_flags)
{
void *base;

base = (void *)__get_free_pages(gfp_flags, get_order(size));
if (!base)
return NULL;
memset(base, 0, size);
*dmaaddr = ssb_dma_map_single(ring->dev->dev, base, size,
DMA_TO_DEVICE);
if (ssb_dma_mapping_error(ring->dev->dev, *dmaaddr)) {
free_pages((unsigned long)base, get_order(size));
return NULL;
}

return base;
}

static void * b43_get_and_map_ringmem(struct b43_dmaring *ring,
dma_addr_t *dmaaddr, size_t size)
{
void *base;

base = __b43_get_and_map_ringmem(ring, dmaaddr, size,
GFP_KERNEL);
if (!base) {
b43err(ring->dev->wl, "Failed to allocate or map pages "
"for DMA ringmemory\n");
return NULL;
}
if (!b43_dma_address_ok(ring, *dmaaddr, size)) {
/* The memory does not fit our device constraints.
* Retry with GFP_DMA set to get lower memory. */
b43_unmap_and_free_ringmem(ring, base, *dmaaddr, size);
base = __b43_get_and_map_ringmem(ring, dmaaddr, size,
GFP_KERNEL | GFP_DMA);
if (!base) {
b43err(ring->dev->wl, "Failed to allocate or map pages "
"in the GFP_DMA region for DMA ringmemory\n");
return NULL;
}
if (!b43_dma_address_ok(ring, *dmaaddr, size)) {
b43_unmap_and_free_ringmem(ring, base, *dmaaddr, size);
b43err(ring->dev->wl, "Failed to allocate DMA "
"ringmemory that fits device constraints\n");
return NULL;
}
}
/* We expect the memory to be 4k aligned, at least. */
if (B43_WARN_ON(!is_4k_aligned(*dmaaddr))) {
b43_unmap_and_free_ringmem(ring, base, *dmaaddr, size);
return NULL;
}

return base;
}

static int alloc_ringmemory(struct b43_dmaring *ring)
{
unsigned int required;
void *base;
dma_addr_t dmaaddr;

/* There are several requirements to the descriptor ring memory:
* - The memory region needs to fit the address constraints for the
* device (same as for frame buffers).
* - For 30/32bit DMA devices, the descriptor ring must be 4k aligned.
* - For 64bit DMA devices, the descriptor ring must be 8k aligned.
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.
*
* The flags here must match the flags in free_ringmemory below!
*/

if (ring->type == B43_DMA_64BIT)
required = ring->nr_slots * sizeof(struct b43_dmadesc64);
else
required = ring->nr_slots * sizeof(struct b43_dmadesc32);
if (B43_WARN_ON(required > 0x1000))
flags |= GFP_DMA;
ring->descbase = ssb_dma_alloc_consistent(ring->dev->dev,
B43_DMA_RINGMEMSIZE,
&(ring->dmabase), flags);
if (!ring->descbase) {
b43err(ring->dev->wl, "DMA ringmemory allocation failed\n");
return -ENOMEM;

ring->alloc_descsize = 0x1000;
base = b43_get_and_map_ringmem(ring, &dmaaddr, ring->alloc_descsize);
if (!base)
return -ENOMEM;
ring->alloc_descbase = base;
ring->alloc_dmabase = dmaaddr;

if ((ring->type != B43_DMA_64BIT) || is_8k_aligned(dmaaddr)) {
/* We're on <=32bit DMA, or we already got 8k aligned memory.
* That's all we need, so we're fine. */
ring->descbase = base;
ring->dmabase = dmaaddr;
return 0;
}
b43_unmap_and_free_ringmem(ring, base, dmaaddr, ring->alloc_descsize);

/* Ok, we failed at the 8k alignment requirement.
* Try to force-align the memory region now. */
ring->alloc_descsize = 0x2000;
base = b43_get_and_map_ringmem(ring, &dmaaddr, ring->alloc_descsize);
if (!base)
return -ENOMEM;
ring->alloc_descbase = base;
ring->alloc_dmabase = dmaaddr;

if (is_8k_aligned(dmaaddr)) {
/* We're already 8k aligned. That Ok, too. */
ring->descbase = base;
ring->dmabase = dmaaddr;
return 0;
}
/* Force-align it to 8k */
ring->descbase = (void *)((u8 *)base + 0x1000);
ring->dmabase = dmaaddr + 0x1000;
B43_WARN_ON(!is_8k_aligned(ring->dmabase));
memset(ring->descbase, 0, B43_DMA_RINGMEMSIZE);

return 0;
}

static void free_ringmemory(struct b43_dmaring *ring)
{
b43_unmap_and_free_ringmem(ring, ring->alloc_descbase,
ring->alloc_dmabase, ring->alloc_descsize);
gfp_t flags = GFP_KERNEL;

if (ring->type == B43_DMA_64BIT)
flags |= GFP_DMA;

ssb_dma_free_consistent(ring->dev->dev, B43_DMA_RINGMEMSIZE,
ring->descbase, ring->dmabase, flags);
}

/* Reset the RX DMA channel */
Expand Down Expand Up @@ -646,14 +530,29 @@ static bool b43_dma_mapping_error(struct b43_dmaring *ring,
if (unlikely(ssb_dma_mapping_error(ring->dev->dev, addr)))
return 1;

if (!b43_dma_address_ok(ring, addr, buffersize)) {
/* We can't support this address. Unmap it again. */
unmap_descbuffer(ring, addr, buffersize, dma_to_device);
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 bool b43_rx_buffer_is_poisoned(struct b43_dmaring *ring, struct sk_buff *skb)
Expand Down Expand Up @@ -715,9 +614,6 @@ static int setup_rx_descbuffer(struct b43_dmaring *ring,
meta->dmaaddr = dmaaddr;
ring->ops->fill_descriptor(ring, desc, dmaaddr,
ring->rx_buffersize, 0, 0, 0);
ssb_dma_sync_single_for_device(ring->dev->dev,
ring->alloc_dmabase,
ring->alloc_descsize, DMA_TO_DEVICE);

return 0;
}
Expand Down Expand Up @@ -1354,9 +1250,6 @@ static int dma_tx_fragment(struct b43_dmaring *ring,
}
/* Now transfer the whole frame. */
wmb();
ssb_dma_sync_single_for_device(ring->dev->dev,
ring->alloc_dmabase,
ring->alloc_descsize, DMA_TO_DEVICE);
ops->poke_tx(ring, next_slot(ring, slot));
return 0;

Expand Down
7 changes: 1 addition & 6 deletions drivers/net/wireless/b43/dma.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -157,6 +157,7 @@ struct b43_dmadesc_generic {
} __attribute__ ((__packed__));

/* Misc DMA constants */
#define B43_DMA_RINGMEMSIZE PAGE_SIZE
#define B43_DMA0_RX_FRAMEOFFSET 30

/* DMA engine tuning knobs */
Expand Down Expand Up @@ -246,12 +247,6 @@ struct b43_dmaring {
/* The QOS priority assigned to this ring. Only used for TX rings.
* This is the mac80211 "queue" value. */
u8 queue_prio;
/* Pointers and size of the originally allocated and mapped memory
* region for the descriptor ring. */
void *alloc_descbase;
dma_addr_t alloc_dmabase;
unsigned int alloc_descsize;
/* Pointer to our wireless device. */
struct b43_wldev *dev;
#ifdef CONFIG_B43_DEBUG
/* Maximum number of used slots. */
Expand Down

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