[PATCH] b43: use rx desc underrun interrupt
Thommy Jakobsson
thommyj at gmail.com
Mon Apr 22 04:11:41 EDT 2013
On Sun, 21 Apr 2013, Michael B?sch wrote:
> > struct b43_stats {
> > u8 link_noise;
> > + u32 rxdesc_underruns;
>
> Why do we add that? It's not incremented and used anywhere.
>
Sorry, seems like I dont do that of a good joob revewing my own patches.
It slipped in from one of my debug builts. Should I send in this to John
or do you think we have to test it further? It has been running during the
entire night with high load on my device. So that seems to work, but that
is only on one device of course.
//Thommy
Subject:[PATCH] B43: Handle DMA RX descriptor underrun
From: Thommy Jakobsson <thommyj at gmail.com>
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.
Signed-off-by: Thommy Jakobsson <thommyj at gmail.com>
Cc: stable <stable at vger.kernel.org>
---
drivers/net/wireless/b43/dma.c | 19 +++++++++++++++++
drivers/net/wireless/b43/dma.h | 4 +++-
drivers/net/wireless/b43/main.c | 43 ++++++++++++++++-----------------------
3 files changed, 40 insertions(+), 26 deletions(-)
diff --git a/drivers/net/wireless/b43/dma.c b/drivers/net/wireless/b43/dma.c
index 1221469..ee3d640 100644
--- a/drivers/net/wireless/b43/dma.c
+++ b/drivers/net/wireless/b43/dma.c
@@ -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;
diff --git a/drivers/net/wireless/b43/dma.h b/drivers/net/wireless/b43/dma.h
index 9fdd198..df8c8cd 100644
--- a/drivers/net/wireless/b43/dma.h
+++ b/drivers/net/wireless/b43/dma.h
@@ -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,
diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index d377f77..6dd07e2 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -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);
--
1.7.9.5
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