--- /dev/null
+From 5921f167baf30255ebc079c6e751a7ed31cd986d Mon Sep 17 00:00:00 2001
+From: Thommy Jakobsson <thommyj@gmail.com>
+Date: Tue, 23 Apr 2013 21:45:11 +0200
+Subject: [PATCH 2/3] B43: Handle DMA RX descriptor underrun
+
+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>
+---
+ 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(-)
+
+--- 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;
+--- 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,
+--- a/drivers/net/wireless/b43/main.c
++++ b/drivers/net/wireless/b43/main.c
+@@ -1907,32 +1907,20 @@ static void b43_do_interrupt_thread(stru
+ }
+ }
+
+- 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]);
++ 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]);
+ #ifdef CONFIG_B43_PIO
+- b43err(dev->wl, "This device does not support DMA "
++ 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;
++ /* Fall back to PIO transfers if we get fatal DMA errors! */
++ dev->use_pio = true;
+ #endif
+- 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]);
+- }
++ b43_controller_restart(dev, "DMA error");
++ return;
+ }
+
+ if (unlikely(reason & B43_IRQ_UCODE_DEBUG))
+@@ -1951,6 +1939,11 @@ static void b43_do_interrupt_thread(stru
+ 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);
+@@ -2008,7 +2001,7 @@ static irqreturn_t b43_do_interrupt(stru
+ 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)
+@@ -3137,7 +3130,7 @@ static int b43_chip_init(struct b43_wlde
+ 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);
projects / openwrt / staging / chunkeey.git / commitdiff