target/linux/generic/patches-3.18/077-05-bgmac-leave-interrupts-disabled-as-long-as-there-is-.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Sun, 12 Apr 2015 10:08:04 +0200
   3 Subject: [PATCH] bgmac: leave interrupts disabled as long as there is work
   4  to do
   5
   6 Always poll rx and tx during NAPI poll instead of relying on the status
   7 of the first interrupt. This prevents bgmac_poll from leaving unfinished
   8 work around until the next IRQ.
   9 In my tests this makes bridging/routing throughput under heavy load more
  10 stable and ensures that no new IRQs arrive as long as bgmac_poll uses up
  11 the entire budget.
  12
  13 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  14 ---
  15
  16 --- a/drivers/net/ethernet/broadcom/bgmac.c
  17 +++ b/drivers/net/ethernet/broadcom/bgmac.c
  18 @@ -1109,8 +1109,6 @@ static void bgmac_chip_reset(struct bgma
  19         bgmac_phy_init(bgmac);
  20
  21         netdev_reset_queue(bgmac->net_dev);
  22 -
  23 -       bgmac->int_status = 0;
  24  }
  25
  26  static void bgmac_chip_intrs_on(struct bgmac *bgmac)
  27 @@ -1225,14 +1223,13 @@ static irqreturn_t bgmac_interrupt(int i
  28         if (!int_status)
  29                 return IRQ_NONE;
  30
  31 -       /* Ack */
  32 -       bgmac_write(bgmac, BGMAC_INT_STATUS, int_status);
  33 +       int_status &= ~(BGMAC_IS_TX0 | BGMAC_IS_RX);
  34 +       if (int_status)
  35 +               bgmac_err(bgmac, "Unknown IRQs: 0x%08X\n", int_status);
  36
  37         /* Disable new interrupts until handling existing ones */
  38         bgmac_chip_intrs_off(bgmac);
  39
  40 -       bgmac->int_status = int_status;
  41 -
  42         napi_schedule(&bgmac->napi);
  43
  44         return IRQ_HANDLED;
  45 @@ -1241,25 +1238,17 @@ static irqreturn_t bgmac_interrupt(int i
  46  static int bgmac_poll(struct napi_struct *napi, int weight)
  47  {
  48         struct bgmac *bgmac = container_of(napi, struct bgmac, napi);
  49 -       struct bgmac_dma_ring *ring;
  50         int handled = 0;
  51
  52 -       if (bgmac->int_status & BGMAC_IS_TX0) {
  53 -               ring = &bgmac->tx_ring[0];
  54 -               bgmac_dma_tx_free(bgmac, ring);
  55 -               bgmac->int_status &= ~BGMAC_IS_TX0;
  56 -       }
  57 +       /* Ack */
  58 +       bgmac_write(bgmac, BGMAC_INT_STATUS, ~0);
  59
  60 -       if (bgmac->int_status & BGMAC_IS_RX) {
  61 -               ring = &bgmac->rx_ring[0];
  62 -               handled += bgmac_dma_rx_read(bgmac, ring, weight);
  63 -               bgmac->int_status &= ~BGMAC_IS_RX;
  64 -       }
  65 +       bgmac_dma_tx_free(bgmac, &bgmac->tx_ring[0]);
  66 +       handled += bgmac_dma_rx_read(bgmac, &bgmac->rx_ring[0], weight);
  67
  68 -       if (bgmac->int_status) {
  69 -               bgmac_err(bgmac, "Unknown IRQs: 0x%08X\n", bgmac->int_status);
  70 -               bgmac->int_status = 0;
  71 -       }
  72 +       /* Poll again if more events arrived in the meantime */
  73 +       if (bgmac_read(bgmac, BGMAC_INT_STATUS) & (BGMAC_IS_TX0 | BGMAC_IS_RX))
  74 +               return handled;
  75
  76         if (handled < weight) {
  77                 napi_complete(napi);
  78 --- a/drivers/net/ethernet/broadcom/bgmac.h
  79 +++ b/drivers/net/ethernet/broadcom/bgmac.h
  80 @@ -452,7 +452,6 @@ struct bgmac {
  81
  82         /* Int */
  83         u32 int_mask;
  84 -       u32 int_status;
  85
  86         /* Current MAC state */
  87         int mac_speed;