PS3: Fix gelic network RX hang

SVN-Revision: 16759

diff --git a/target/linux/ps3/patches-2.6.28/0016-ps3-gelic-fix-rxdmac.patch b/target/linux/ps3/patches-2.6.28/0016-ps3-gelic-fix-rxdmac.patch
new file mode 100644 (file)
index 0000000..00204e3
--- /dev/null
+++ b/target/linux/ps3/patches-2.6.28/0016-ps3-gelic-fix-rxdmac.patch
@@ -0,0 +1,89 @@
+Subject: net/ps3_gelic: Fix RX DMA restart
+
+Fix the condition where PS3 network RX hangs when no network
+TX is occuring by calling gelic_card_enable_rxdmac() during
+RX_DMA_CHAIN_END event processing.
+
+The gelic hardware automatically clears its RX_DMA_EN flag when
+it detects an RX_DMA_CHAIN_END event.  In its processing of
+RX_DMA_CHAIN_END the gelic driver is required to set RX_DMA_EN
+(with a call to gelic_card_enable_rxdmac()) to restart RX DMA
+transfers.  The existing gelic driver code does not set
+RX_DMA_EN directly in its processing of the RX_DMA_CHAIN_END
+event, but uses a flag variable card->rx_dma_restart_required
+to schedule the setting of RX_DMA_EN until next inside the
+interrupt handler.
+
+It seems this delayed setting of RX_DMA_EN causes the hang since
+the next RX interrupt after the RX_DMA_CHAIN_END event where
+RX_DMA_EN is scheduled to be set will not occur since RX_DMA_EN
+was not set.  In the case were network TX is occuring, RX_DMA_EN
+is set in the next TX interrupt and RX processing continues.
+
+Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
+---
+ drivers/net/ps3_gelic_net.c |   21 ++++++++-------------
+ drivers/net/ps3_gelic_net.h |    1 -
+ 2 files changed, 8 insertions(+), 14 deletions(-)
+
+--- a/drivers/net/ps3_gelic_net.c
++++ b/drivers/net/ps3_gelic_net.c
+@@ -970,10 +970,6 @@ static int gelic_card_decode_one_descr(s
+       int dmac_chain_ended;
+ 
+       status = gelic_descr_get_status(descr);
+-      /* is this descriptor terminated with next_descr == NULL? */
+-      dmac_chain_ended =
+-              be32_to_cpu(descr->dmac_cmd_status) &
+-              GELIC_DESCR_RX_DMA_CHAIN_END;
+ 
+       if (status == GELIC_DESCR_DMA_CARDOWNED)
+               return 0;
+@@ -1036,6 +1032,11 @@ static int gelic_card_decode_one_descr(s
+       /* ok, we've got a packet in descr */
+       gelic_net_pass_skb_up(descr, card, netdev);
+ refill:
++
++      /* is the current descriptor terminated with next_descr == NULL? */
++      dmac_chain_ended =
++              be32_to_cpu(descr->dmac_cmd_status) &
++              GELIC_DESCR_RX_DMA_CHAIN_END;
+       /*
+        * So that always DMAC can see the end
+        * of the descriptor chain to avoid
+@@ -1064,10 +1065,9 @@ refill:
+        * If dmac chain was met, DMAC stopped.
+        * thus re-enable it
+        */
+-      if (dmac_chain_ended) {
+-              card->rx_dma_restart_required = 1;
+-              dev_dbg(ctodev(card), "reenable rx dma scheduled\n");
+-      }
++
++      if (dmac_chain_ended)
++              gelic_card_enable_rxdmac(card);
+ 
+       return 1;
+ }
+@@ -1133,11 +1133,6 @@ static irqreturn_t gelic_card_interrupt(
+ 
+       status &= card->irq_mask;
+ 
+-      if (card->rx_dma_restart_required) {
+-              card->rx_dma_restart_required = 0;
+-              gelic_card_enable_rxdmac(card);
+-      }
+-
+       if (status & GELIC_CARD_RXINT) {
+               gelic_card_rx_irq_off(card);
+               napi_schedule(&card->napi);
+--- a/drivers/net/ps3_gelic_net.h
++++ b/drivers/net/ps3_gelic_net.h
+@@ -284,7 +284,6 @@ struct gelic_card {
+ 
+       struct gelic_descr_chain tx_chain;
+       struct gelic_descr_chain rx_chain;
+-      int rx_dma_restart_required;
+       int rx_csum;
+       /*
+        * tx_lock guards tx descriptor list and