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B43: Handle DMA RX descriptor underrun

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Add handling of rx descriptor underflow. This fixes a fault that could
happen on slow machines, where data is received faster than the CPU can
handle. In such a case the device will use up all rx descriptors and
refuse to send any more data before confirming that it is ok. This
patch enables necessary interrupt to discover such a situation and will
handle them by dropping everything in the ring buffer.

Reviewed-by: Michael Buesch <m@bues.ch>
Signed-off-by: Thommy Jakobsson <thommyj@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Thommy Jakobsson 2013-04-23 21:45:11 +02:00 committed by John W. Linville
parent db17834043
commit 73b82bf0bf
3 changed files with 40 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/net/wireless/b43/dma.c
View File

@ -1733,6 +1733,25 @@ drop_recycle_buffer:
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;

4
drivers/net/wireless/b43/dma.h
View File

@ -9,7 +9,7 @@
/* DMA-Interrupt reasons. */
#define B43_DMAIRQ_FATALMASK ((1 << 10) | (1 << 11) | (1 << 12) \
| (1 << 14) | (1 << 15))
#define B43_DMAIRQ_NONFATALMASK (1 << 13)
#define B43_DMAIRQ_RDESC_UFLOW (1 << 13)
#define B43_DMAIRQ_RX_DONE (1 << 16)
/*** 32-bit DMA Engine. ***/
@ -295,6 +295,8 @@ int b43_dma_tx(struct b43_wldev *dev,
void b43_dma_handle_txstatus(struct b43_wldev *dev,
const struct b43_txstatus *status);
void b43_dma_handle_rx_overflow(struct b43_dmaring *ring);
void b43_dma_rx(struct b43_dmaring *ring);
void b43_dma_direct_fifo_rx(struct b43_wldev *dev,

43
drivers/net/wireless/b43/main.c
View File

@ -1902,30 +1902,18 @@ static void b43_do_interrupt_thread(struct b43_wldev *dev)
}
}
if (unlikely(merged_dma_reason & (B43_DMAIRQ_FATALMASK |
B43_DMAIRQ_NONFATALMASK))) {
if (merged_dma_reason & B43_DMAIRQ_FATALMASK) {
b43err(dev->wl, "Fatal DMA error: "
"0x%08X, 0x%08X, 0x%08X, "
"0x%08X, 0x%08X, 0x%08X\n",
dma_reason[0], dma_reason[1],
dma_reason[2], dma_reason[3],
dma_reason[4], dma_reason[5]);
b43err(dev->wl, "This device does not support DMA "
if (unlikely(merged_dma_reason & (B43_DMAIRQ_FATALMASK))) {
b43err(dev->wl,
"Fatal DMA error: 0x%08X, 0x%08X, 0x%08X, 0x%08X, 0x%08X, 0x%08X\n",
dma_reason[0], dma_reason[1],
dma_reason[2], dma_reason[3],
dma_reason[4], dma_reason[5]);
b43err(dev->wl, "This device does not support DMA "
"on your system. It will now be switched to PIO.\n");
/* Fall back to PIO transfers if we get fatal DMA errors! */
dev->use_pio = true;
b43_controller_restart(dev, "DMA error");
return;
}
if (merged_dma_reason & B43_DMAIRQ_NONFATALMASK) {
b43err(dev->wl, "DMA error: "
"0x%08X, 0x%08X, 0x%08X, "
"0x%08X, 0x%08X, 0x%08X\n",
dma_reason[0], dma_reason[1],
dma_reason[2], dma_reason[3],
dma_reason[4], dma_reason[5]);
}
/* Fall back to PIO transfers if we get fatal DMA errors! */
dev->use_pio = true;
b43_controller_restart(dev, "DMA error");
return;
}
if (unlikely(reason & B43_IRQ_UCODE_DEBUG))
@ -1944,6 +1932,11 @@ static void b43_do_interrupt_thread(struct b43_wldev *dev)
handle_irq_noise(dev);
/* Check the DMA reason registers for received data. */
if (dma_reason[0] & B43_DMAIRQ_RDESC_UFLOW) {
if (B43_DEBUG)
b43warn(dev->wl, "RX descriptor underrun\n");
b43_dma_handle_rx_overflow(dev->dma.rx_ring);
}
if (dma_reason[0] & B43_DMAIRQ_RX_DONE) {
if (b43_using_pio_transfers(dev))
b43_pio_rx(dev->pio.rx_queue);
@ -2001,7 +1994,7 @@ static irqreturn_t b43_do_interrupt(struct b43_wldev *dev)
return IRQ_NONE;
dev->dma_reason[0] = b43_read32(dev, B43_MMIO_DMA0_REASON)
& 0x0001DC00;
& 0x0001FC00;
dev->dma_reason[1] = b43_read32(dev, B43_MMIO_DMA1_REASON)
& 0x0000DC00;
dev->dma_reason[2] = b43_read32(dev, B43_MMIO_DMA2_REASON)
@ -3130,7 +3123,7 @@ static int b43_chip_init(struct b43_wldev *dev)
b43_write32(dev, 0x018C, 0x02000000);
}
b43_write32(dev, B43_MMIO_GEN_IRQ_REASON, 0x00004000);
b43_write32(dev, B43_MMIO_DMA0_IRQ_MASK, 0x0001DC00);
b43_write32(dev, B43_MMIO_DMA0_IRQ_MASK, 0x0001FC00);
b43_write32(dev, B43_MMIO_DMA1_IRQ_MASK, 0x0000DC00);
b43_write32(dev, B43_MMIO_DMA2_IRQ_MASK, 0x0000DC00);
b43_write32(dev, B43_MMIO_DMA3_IRQ_MASK, 0x0001DC00);