| 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 | @@ -969,10 +969,6 @@ 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 | @@ -1035,6 +1031,11 @@ 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 | @@ -1063,10 +1064,9 @@ 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 | @@ -1132,11 +1132,6 @@ 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 |
| 90 | |
