package/mac80211/patches/840-b43-Handle-DMA-RX-descriptor-underrun.patch

   1 From 5921f167baf30255ebc079c6e751a7ed31cd986d Mon Sep 17 00:00:00 2001
   2 From: Thommy Jakobsson <thommyj@gmail.com>
   3 Date: Tue, 23 Apr 2013 21:45:11 +0200
   4 Subject: [PATCH 2/3] B43: Handle DMA RX descriptor underrun
   5
   6 Add handling of rx descriptor underflow. This fixes a fault that could
   7 happen on slow machines, where data is received faster than the CPU can
   8 handle. In such a case the device will use up all rx descriptors and
   9 refuse to send any more data before confirming that it is ok. This
  10 patch enables necessary interrupt to discover such a situation and will
  11 handle them by dropping everything in the ring buffer.
  12
  13 Reviewed-by: Michael Buesch <m@bues.ch>
  14 Signed-off-by: Thommy Jakobsson <thommyj@gmail.com>
  15 Cc: stable <stable@vger.kernel.org>
  16 ---
  17  drivers/net/wireless/b43/dma.c  |   19 +++++++++++++++++
  18  drivers/net/wireless/b43/dma.h  |    4 +++-
  19  drivers/net/wireless/b43/main.c |   43 ++++++++++++++++-----------------------
  20  3 files changed, 40 insertions(+), 26 deletions(-)
  21
  22 --- a/drivers/net/wireless/b43/dma.c
  23 +++ b/drivers/net/wireless/b43/dma.c
  24 @@ -1733,6 +1733,25 @@ drop_recycle_buffer:
  25         sync_descbuffer_for_device(ring, dmaaddr, ring->rx_buffersize);
  26  }
  27
  28 +void b43_dma_handle_rx_overflow(struct b43_dmaring *ring)
  29 +{
  30 +       int current_slot, previous_slot;
  31 +
  32 +       B43_WARN_ON(ring->tx);
  33 +
  34 +       /* Device has filled all buffers, drop all packets and let TCP
  35 +        * decrease speed.
  36 +        * Decrement RX index by one will let the device to see all slots
  37 +        * as free again
  38 +        */
  39 +       /*
  40 +       *TODO: How to increase rx_drop in mac80211?
  41 +       */
  42 +       current_slot = ring->ops->get_current_rxslot(ring);
  43 +       previous_slot = prev_slot(ring, current_slot);
  44 +       ring->ops->set_current_rxslot(ring, previous_slot);
  45 +}
  46 +
  47  void b43_dma_rx(struct b43_dmaring *ring)
  48  {
  49         const struct b43_dma_ops *ops = ring->ops;
  50 --- a/drivers/net/wireless/b43/dma.h
  51 +++ b/drivers/net/wireless/b43/dma.h
  52 @@ -9,7 +9,7 @@
  53  /* DMA-Interrupt reasons. */
  54  #define B43_DMAIRQ_FATALMASK   ((1 << 10) | (1 << 11) | (1 << 12) \
  55                                          | (1 << 14) | (1 << 15))
  56 -#define B43_DMAIRQ_NONFATALMASK        (1 << 13)
  57 +#define B43_DMAIRQ_RDESC_UFLOW         (1 << 13)
  58  #define B43_DMAIRQ_RX_DONE             (1 << 16)
  59
  60  /*** 32-bit DMA Engine. ***/
  61 @@ -295,6 +295,8 @@ int b43_dma_tx(struct b43_wldev *dev,
  62  void b43_dma_handle_txstatus(struct b43_wldev *dev,
  63                              const struct b43_txstatus *status);
  64
  65 +void b43_dma_handle_rx_overflow(struct b43_dmaring *ring);
  66 +
  67  void b43_dma_rx(struct b43_dmaring *ring);
  68
  69  void b43_dma_direct_fifo_rx(struct b43_wldev *dev,
  70 --- a/drivers/net/wireless/b43/main.c
  71 +++ b/drivers/net/wireless/b43/main.c
  72 @@ -1907,32 +1907,20 @@ static void b43_do_interrupt_thread(stru
  73                 }
  74         }
  75
  76 -       if (unlikely(merged_dma_reason & (B43_DMAIRQ_FATALMASK |
  77 -                                         B43_DMAIRQ_NONFATALMASK))) {
  78 -               if (merged_dma_reason & B43_DMAIRQ_FATALMASK) {
  79 -                       b43err(dev->wl, "Fatal DMA error: "
  80 -                              "0x%08X, 0x%08X, 0x%08X, "
  81 -                              "0x%08X, 0x%08X, 0x%08X\n",
  82 -                              dma_reason[0], dma_reason[1],
  83 -                              dma_reason[2], dma_reason[3],
  84 -                              dma_reason[4], dma_reason[5]);
  85 +       if (unlikely(merged_dma_reason & (B43_DMAIRQ_FATALMASK))) {
  86 +               b43err(dev->wl,
  87 +                       "Fatal DMA error: 0x%08X, 0x%08X, 0x%08X, 0x%08X, 0x%08X, 0x%08X\n",
  88 +                       dma_reason[0], dma_reason[1],
  89 +                       dma_reason[2], dma_reason[3],
  90 +                       dma_reason[4], dma_reason[5]);
  91  #ifdef CONFIG_B43_PIO
  92 -                       b43err(dev->wl, "This device does not support DMA "
  93 +               b43err(dev->wl, "This device does not support DMA "
  94                                "on your system. It will now be switched to PIO.\n");
  95 -                       /* Fall back to PIO transfers if we get fatal DMA errors! */
  96 -                       dev->use_pio = true;
  97 +               /* Fall back to PIO transfers if we get fatal DMA errors! */
  98 +               dev->use_pio = true;
  99  #endif
 100 -                       b43_controller_restart(dev, "DMA error");
 101 -                       return;
 102 -               }
 103 -               if (merged_dma_reason & B43_DMAIRQ_NONFATALMASK) {
 104 -                       b43err(dev->wl, "DMA error: "
 105 -                              "0x%08X, 0x%08X, 0x%08X, "
 106 -                              "0x%08X, 0x%08X, 0x%08X\n",
 107 -                              dma_reason[0], dma_reason[1],
 108 -                              dma_reason[2], dma_reason[3],
 109 -                              dma_reason[4], dma_reason[5]);
 110 -               }
 111 +               b43_controller_restart(dev, "DMA error");
 112 +               return;
 113         }
 114
 115         if (unlikely(reason & B43_IRQ_UCODE_DEBUG))
 116 @@ -1951,6 +1939,11 @@ static void b43_do_interrupt_thread(stru
 117                 handle_irq_noise(dev);
 118
 119         /* Check the DMA reason registers for received data. */
 120 +       if (dma_reason[0] & B43_DMAIRQ_RDESC_UFLOW) {
 121 +               if (B43_DEBUG)
 122 +                       b43warn(dev->wl, "RX descriptor underrun\n");
 123 +               b43_dma_handle_rx_overflow(dev->dma.rx_ring);
 124 +       }
 125         if (dma_reason[0] & B43_DMAIRQ_RX_DONE) {
 126                 if (b43_using_pio_transfers(dev))
 127                         b43_pio_rx(dev->pio.rx_queue);
 128 @@ -2008,7 +2001,7 @@ static irqreturn_t b43_do_interrupt(stru
 129                 return IRQ_NONE;
 130
 131         dev->dma_reason[0] = b43_read32(dev, B43_MMIO_DMA0_REASON)
 132 -           & 0x0001DC00;
 133 +           & 0x0001FC00;
 134         dev->dma_reason[1] = b43_read32(dev, B43_MMIO_DMA1_REASON)
 135             & 0x0000DC00;
 136         dev->dma_reason[2] = b43_read32(dev, B43_MMIO_DMA2_REASON)
 137 @@ -3137,7 +3130,7 @@ static int b43_chip_init(struct b43_wlde
 138                 b43_write32(dev, 0x018C, 0x02000000);
 139         }
 140         b43_write32(dev, B43_MMIO_GEN_IRQ_REASON, 0x00004000);
 141 -       b43_write32(dev, B43_MMIO_DMA0_IRQ_MASK, 0x0001DC00);
 142 +       b43_write32(dev, B43_MMIO_DMA0_IRQ_MASK, 0x0001FC00);
 143         b43_write32(dev, B43_MMIO_DMA1_IRQ_MASK, 0x0000DC00);
 144         b43_write32(dev, B43_MMIO_DMA2_IRQ_MASK, 0x0000DC00);
 145         b43_write32(dev, B43_MMIO_DMA3_IRQ_MASK, 0x0001DC00);