sfc: Handle serious errors in exactly one interrupt handler

'Fatal' errors set an interrupt flag associated with a specific event
queue; only read the syndrome vector if we see that queue's flag set
(legacy interrupts) or in the interrupt handler for that queue (MSI).

Do not ignore an interrupt if the fatal error flag is set but specific
error flags are all zero.  Even if we don't schedule a reset, we must
respect the queue mask and rearm the appropriate event queues.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 16 deletions

diff --git a/drivers/net/sfc/nic.c b/drivers/net/sfc/nic.c
index 664fd6ceed55..23738f80835b 100644
--- a/drivers/net/sfc/nic.c
+++ b/drivers/net/sfc/nic.c
@@ -1229,15 +1229,9 @@ static inline void efx_nic_interrupts(struct efx_nic *efx,
 				      bool enabled, bool force)
 {
 	efx_oword_t int_en_reg_ker;
-	unsigned int level = 0;
-
-	if (EFX_WORKAROUND_17213(efx) && !EFX_INT_MODE_USE_MSI(efx))
-		/* Set the level always even if we're generating a test
-		 * interrupt, because our legacy interrupt handler is safe */
-		level = 0x1f;
 
 	EFX_POPULATE_OWORD_3(int_en_reg_ker,
-			     FRF_AZ_KER_INT_LEVE_SEL, level,
+			     FRF_AZ_KER_INT_LEVE_SEL, efx->fatal_irq_level,
 			     FRF_AZ_KER_INT_KER, force,
 			     FRF_AZ_DRV_INT_EN_KER, enabled);
 	efx_writeo(efx, &int_en_reg_ker, FR_AZ_INT_EN_KER);
@@ -1291,8 +1285,6 @@ irqreturn_t efx_nic_fatal_interrupt(struct efx_nic *efx)
 		EFX_OWORD_FMT ": %s\n", EFX_OWORD_VAL(*int_ker),
 		EFX_OWORD_VAL(fatal_intr),
 		error ? "disabling bus mastering" : "no recognised error");
-	if (error == 0)
-		goto out;
 
 	/* If this is a memory parity error dump which blocks are offending */
 	mem_perr = EFX_OWORD_FIELD(fatal_intr, FRF_AZ_MEM_PERR_INT_KER);
@@ -1324,7 +1316,7 @@ irqreturn_t efx_nic_fatal_interrupt(struct efx_nic *efx)
 			"NIC will be disabled\n");
 		efx_schedule_reset(efx, RESET_TYPE_DISABLE);
 	}
-out:
+
 	return IRQ_HANDLED;
 }
 
@@ -1346,9 +1338,11 @@ static irqreturn_t efx_legacy_interrupt(int irq, void *dev_id)
 	queues = EFX_EXTRACT_DWORD(reg, 0, 31);
 
 	/* Check to see if we have a serious error condition */
-	syserr = EFX_OWORD_FIELD(*int_ker, FSF_AZ_NET_IVEC_FATAL_INT);
-	if (unlikely(syserr))
-		return efx_nic_fatal_interrupt(efx);
+	if (queues & (1U << efx->fatal_irq_level)) {
+		syserr = EFX_OWORD_FIELD(*int_ker, FSF_AZ_NET_IVEC_FATAL_INT);
+		if (unlikely(syserr))
+			return efx_nic_fatal_interrupt(efx);
+	}
 
 	if (queues != 0) {
 		if (EFX_WORKAROUND_15783(efx))
@@ -1413,9 +1407,11 @@ static irqreturn_t efx_msi_interrupt(int irq, void *dev_id)
 		  irq, raw_smp_processor_id(), EFX_OWORD_VAL(*int_ker));
 
 	/* Check to see if we have a serious error condition */
-	syserr = EFX_OWORD_FIELD(*int_ker, FSF_AZ_NET_IVEC_FATAL_INT);
-	if (unlikely(syserr))
-		return efx_nic_fatal_interrupt(efx);
+	if (channel->channel == efx->fatal_irq_level) {
+		syserr = EFX_OWORD_FIELD(*int_ker, FSF_AZ_NET_IVEC_FATAL_INT);
+		if (unlikely(syserr))
+			return efx_nic_fatal_interrupt(efx);
+	}
 
 	/* Schedule processing of the channel */
 	efx_schedule_channel(channel);
@@ -1553,6 +1549,13 @@ void efx_nic_init_common(struct efx_nic *efx)
 			     FRF_AZ_INT_ADR_KER, efx->irq_status.dma_addr);
 	efx_writeo(efx, &temp, FR_AZ_INT_ADR_KER);
 
+	if (EFX_WORKAROUND_17213(efx) && !EFX_INT_MODE_USE_MSI(efx))
+		/* Use an interrupt level unused by event queues */
+		efx->fatal_irq_level = 0x1f;
+	else
+		/* Use a valid MSI-X vector */
+		efx->fatal_irq_level = 0;
+
 	/* Enable all the genuinely fatal interrupts.  (They are still
 	 * masked by the overall interrupt mask, controlled by
 	 * falcon_interrupts()).