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net/ps3: Fix gelic RX DMA restart

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Fix the condition where PS3 network RX hangs when no network
TX is occurring 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 <geoff@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Geoff Levand 2011-07-14 16:03:29 -07:00 committed by David S. Miller
parent 6383c0b35b
commit ecae42d370
2 changed files with 8 additions and 14 deletions
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21
drivers/net/ps3_gelic_net.c
View file

@ -993,10 +993,6 @@ static int gelic_card_decode_one_descr(struct gelic_card *card)
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;
@ -1059,6 +1055,11 @@ static int gelic_card_decode_one_descr(struct gelic_card *card)
/* 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
@ -1087,10 +1088,9 @@ 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;
}
@ -1156,11 +1156,6 @@ static irqreturn_t gelic_card_interrupt(int irq, void *ptr)
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);

1
drivers/net/ps3_gelic_net.h
View file

@ -289,7 +289,6 @@ struct gelic_card {
struct gelic_descr_chain tx_chain;
struct gelic_descr_chain rx_chain;
int rx_dma_restart_required;
/*
* tx_lock guards tx descriptor list and
* tx_dma_progress.