target/linux/ps3/patches-2.6.28/0016-ps3-gelic-fix-rxdmac.patch

   1 Subject: net/ps3_gelic: Fix RX DMA restart
   2
   3 Fix the condition where PS3 network RX hangs when no network
   4 TX is occuring by calling gelic_card_enable_rxdmac() during
   5 RX_DMA_CHAIN_END event processing.
   6
   7 The gelic hardware automatically clears its RX_DMA_EN flag when
   8 it detects an RX_DMA_CHAIN_END event.  In its processing of
   9 RX_DMA_CHAIN_END the gelic driver is required to set RX_DMA_EN
  10 (with a call to gelic_card_enable_rxdmac()) to restart RX DMA
  11 transfers.  The existing gelic driver code does not set
  12 RX_DMA_EN directly in its processing of the RX_DMA_CHAIN_END
  13 event, but uses a flag variable card->rx_dma_restart_required
  14 to schedule the setting of RX_DMA_EN until next inside the
  15 interrupt handler.
  16
  17 It seems this delayed setting of RX_DMA_EN causes the hang since
  18 the next RX interrupt after the RX_DMA_CHAIN_END event where
  19 RX_DMA_EN is scheduled to be set will not occur since RX_DMA_EN
  20 was not set.  In the case were network TX is occuring, RX_DMA_EN
  21 is set in the next TX interrupt and RX processing continues.
  22
  23 Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
  24 ---
  25  drivers/net/ps3_gelic_net.c |   21 ++++++++-------------
  26  drivers/net/ps3_gelic_net.h |    1 -
  27  2 files changed, 8 insertions(+), 14 deletions(-)
  28
  29 --- a/drivers/net/ps3_gelic_net.c
  30 +++ b/drivers/net/ps3_gelic_net.c
  31 @@ -970,10 +970,6 @@ static int gelic_card_decode_one_descr(s
  32         int dmac_chain_ended;
  33
  34         status = gelic_descr_get_status(descr);
  35 -       /* is this descriptor terminated with next_descr == NULL? */
  36 -       dmac_chain_ended =
  37 -               be32_to_cpu(descr->dmac_cmd_status) &
  38 -               GELIC_DESCR_RX_DMA_CHAIN_END;
  39
  40         if (status == GELIC_DESCR_DMA_CARDOWNED)
  41                 return 0;
  42 @@ -1036,6 +1032,11 @@ static int gelic_card_decode_one_descr(s
  43         /* ok, we've got a packet in descr */
  44         gelic_net_pass_skb_up(descr, card, netdev);
  45  refill:
  46 +
  47 +       /* is the current descriptor terminated with next_descr == NULL? */
  48 +       dmac_chain_ended =
  49 +               be32_to_cpu(descr->dmac_cmd_status) &
  50 +               GELIC_DESCR_RX_DMA_CHAIN_END;
  51         /*
  52          * So that always DMAC can see the end
  53          * of the descriptor chain to avoid
  54 @@ -1064,10 +1065,9 @@ refill:
  55          * If dmac chain was met, DMAC stopped.
  56          * thus re-enable it
  57          */
  58 -       if (dmac_chain_ended) {
  59 -               card->rx_dma_restart_required = 1;
  60 -               dev_dbg(ctodev(card), "reenable rx dma scheduled\n");
  61 -       }
  62 +
  63 +       if (dmac_chain_ended)
  64 +               gelic_card_enable_rxdmac(card);
  65
  66         return 1;
  67  }
  68 @@ -1133,11 +1133,6 @@ static irqreturn_t gelic_card_interrupt(
  69
  70         status &= card->irq_mask;
  71
  72 -       if (card->rx_dma_restart_required) {
  73 -               card->rx_dma_restart_required = 0;
  74 -               gelic_card_enable_rxdmac(card);
  75 -       }
  76 -
  77         if (status & GELIC_CARD_RXINT) {
  78                 gelic_card_rx_irq_off(card);
  79                 napi_schedule(&card->napi);
  80 --- a/drivers/net/ps3_gelic_net.h
  81 +++ b/drivers/net/ps3_gelic_net.h
  82 @@ -284,7 +284,6 @@ struct gelic_card {
  83
  84         struct gelic_descr_chain tx_chain;
  85         struct gelic_descr_chain rx_chain;
  86 -       int rx_dma_restart_required;
  87         int rx_csum;
  88         /*
  89          * tx_lock guards tx descriptor list and