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sfc: Extend the legacy interrupt workarounds

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Siena has two problems with legacy interrupts:
  1. There is no synchronisation between the ISR read completion,
     and the interrupt deassert message.
  2. A downstream read at the "wrong" moment can return 0, and
     suppress generating the next interrupt.

Falcon should suffer from both of these, and it appears it does.
Enable EFX_WORKAROUND_15783 on Falcon as well.

Also, when we see queues == 0, ensure we always schedule or rearm
every event queue.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Steve Hodgson 2010-04-28 09:28:27 +00:00 committed by David S. Miller
parent b7b40eeb0f
commit 41b7e4c326
2 changed files with 10 additions and 15 deletions
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23
drivers/net/sfc/nic.c
View file

@ -1356,33 +1356,28 @@ static irqreturn_t efx_legacy_interrupt(int irq, void *dev_id)
}
result = IRQ_HANDLED;
} else if (EFX_WORKAROUND_15783(efx) &&
efx->irq_zero_count++ == 0) {
} else if (EFX_WORKAROUND_15783(efx)) {
efx_qword_t *event;
/* Ensure we rearm all event queues */
/* We can't return IRQ_HANDLED more than once on seeing ISR=0
* because this might be a shared interrupt. */
if (efx->irq_zero_count++ == 0)
result = IRQ_HANDLED;
/* Ensure we schedule or rearm all event queues */
efx_for_each_channel(channel, efx) {
event = efx_event(channel, channel->eventq_read_ptr);
if (efx_event_present(event))
efx_schedule_channel(channel);
else
efx_nic_eventq_read_ack(channel);
}
result = IRQ_HANDLED;
}
if (result == IRQ_HANDLED) {
efx->last_irq_cpu = raw_smp_processor_id();
EFX_TRACE(efx, "IRQ %d on CPU %d status " EFX_DWORD_FMT "\n",
irq, raw_smp_processor_id(), EFX_DWORD_VAL(reg));
} else if (EFX_WORKAROUND_15783(efx)) {
/* We can't return IRQ_HANDLED more than once on seeing ISR0=0
* because this might be a shared interrupt, but we do need to
* check the channel every time and preemptively rearm it if
* it's idle. */
efx_for_each_channel(channel, efx) {
if (!channel->work_pending)
efx_nic_eventq_read_ack(channel);
}
}
return result;

2
drivers/net/sfc/workarounds.h
View file

@ -37,7 +37,7 @@
/* Truncated IPv4 packets can confuse the TX packet parser */
#define EFX_WORKAROUND_15592 EFX_WORKAROUND_FALCON_AB
/* Legacy ISR read can return zero once */
#define EFX_WORKAROUND_15783 EFX_WORKAROUND_SIENA
#define EFX_WORKAROUND_15783 EFX_WORKAROUND_ALWAYS
/* Legacy interrupt storm when interrupt fifo fills */
#define EFX_WORKAROUND_17213 EFX_WORKAROUND_SIENA