From: Thommy Jakobsson <thommyj@xxxxxxxxx> 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@xxxxxxx> Signed-off-by: Thommy Jakobsson <thommyj@xxxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> --- Hi John, patch for fixing problems seen on slow hardware and b43. Discussed at b43 mailinglist and openwrt ticket system (https://dev.openwrt.org/ticket/7552) BR, Thommy Jakobsson --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
