4 files changed, 24 insertions, 5 deletions

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index 761ccc64eee9..b29a819f721d 100644
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -6456,6 +6456,7 @@ const struct efx_nic_type efx_hunt_a0_vf_nic_type = {
 	.rx_ts_offset = ES_DZ_RX_PREFIX_TSTAMP_OFST,
 	.can_rx_scatter = true,
 	.always_rx_scatter = true,
+	.min_interrupt_mode = EFX_INT_MODE_MSIX,
 	.max_interrupt_mode = EFX_INT_MODE_MSIX,
 	.timer_period_max = 1 << ERF_DD_EVQ_IND_TIMER_VAL_WIDTH,
 	.offload_features = EF10_OFFLOAD_FEATURES,
@@ -6588,6 +6589,7 @@ const struct efx_nic_type efx_hunt_a0_nic_type = {
 	.can_rx_scatter = true,
 	.always_rx_scatter = true,
 	.option_descriptors = true,
+	.min_interrupt_mode = EFX_INT_MODE_LEGACY,
 	.max_interrupt_mode = EFX_INT_MODE_MSIX,
 	.timer_period_max = 1 << ERF_DD_EVQ_IND_TIMER_VAL_WIDTH,
 	.offload_features = EF10_OFFLOAD_FEATURES,
diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index cb8e2c3f806a..8c4c273643dc 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -1420,9 +1420,12 @@ static int efx_probe_interrupts(struct efx_nic *efx)
 					   xentries, 1, n_channels);
 		if (rc < 0) {
 			/* Fall back to single channel MSI */
-			efx->interrupt_mode = EFX_INT_MODE_MSI;
 			netif_err(efx, drv, efx->net_dev,
 				  "could not enable MSI-X\n");
+			if (efx->type->min_interrupt_mode >= EFX_INT_MODE_MSI)
+				efx->interrupt_mode = EFX_INT_MODE_MSI;
+			else
+				return rc;
 		} else if (rc < n_channels) {
 			netif_err(efx, drv, efx->net_dev,
 				  "WARNING: Insufficient MSI-X vectors"
@@ -1465,7 +1468,10 @@ static int efx_probe_interrupts(struct efx_nic *efx)
 		} else {
 			netif_err(efx, drv, efx->net_dev,
 				  "could not enable MSI\n");
-			efx->interrupt_mode = EFX_INT_MODE_LEGACY;
+			if (efx->type->min_interrupt_mode >= EFX_INT_MODE_LEGACY)
+				efx->interrupt_mode = EFX_INT_MODE_LEGACY;
+			else
+				return rc;
 		}
 	}
 
@@ -2935,7 +2941,7 @@ static const struct efx_phy_operations efx_dummy_phy_operations = {
 static int efx_init_struct(struct efx_nic *efx,
 			   struct pci_dev *pci_dev, struct net_device *net_dev)
 {
-	int i;
+	int rc = -ENOMEM, i;
 
 	/* Initialise common structures */
 	INIT_LIST_HEAD(&efx->node);
@@ -2976,8 +2982,15 @@ static int efx_init_struct(struct efx_nic *efx,
 	}
 
 	/* Higher numbered interrupt modes are less capable! */
+	if (WARN_ON_ONCE(efx->type->max_interrupt_mode >
+			 efx->type->min_interrupt_mode)) {
+		rc = -EIO;
+		goto fail;
+	}
 	efx->interrupt_mode = max(efx->type->max_interrupt_mode,
 				  interrupt_mode);
+	efx->interrupt_mode = min(efx->type->min_interrupt_mode,
+				  interrupt_mode);
 
 	/* Would be good to use the net_dev name, but we're too early */
 	snprintf(efx->workqueue_name, sizeof(efx->workqueue_name), "sfc%s",
@@ -2990,7 +3003,7 @@ static int efx_init_struct(struct efx_nic *efx,
 
 fail:
 	efx_fini_struct(efx);
-	return -ENOMEM;
+	return rc;
 }
 
 static void efx_fini_struct(struct efx_nic *efx)
diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index 5cb8112b1cf3..c0537ea06c9a 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -1142,8 +1142,10 @@ struct efx_udp_tunnel {
  * @can_rx_scatter: NIC is able to scatter packets to multiple buffers
  * @always_rx_scatter: NIC will always scatter packets to multiple buffers
  * @option_descriptors: NIC supports TX option descriptors
+ * @min_interrupt_mode: Lowest capability interrupt mode supported
+ *	from &enum efx_int_mode.
  * @max_interrupt_mode: Highest capability interrupt mode supported
- *	from &enum efx_init_mode.
+ *	from &enum efx_int_mode.
  * @timer_period_max: Maximum period of interrupt timer (in ticks)
  * @offload_features: net_device feature flags for protocol offload
  *	features implemented in hardware
@@ -1306,6 +1308,7 @@ struct efx_nic_type {
 	bool can_rx_scatter;
 	bool always_rx_scatter;
 	bool option_descriptors;
+	unsigned int min_interrupt_mode;
 	unsigned int max_interrupt_mode;
 	unsigned int timer_period_max;
 	netdev_features_t offload_features;
diff --git a/drivers/net/ethernet/sfc/siena.c b/drivers/net/ethernet/sfc/siena.c
index b1d36df71ecb..a617f657eae3 100644
--- a/drivers/net/ethernet/sfc/siena.c
+++ b/drivers/net/ethernet/sfc/siena.c
@@ -1069,6 +1069,7 @@ const struct efx_nic_type siena_a0_nic_type = {
 	.rx_buffer_padding = 0,
 	.can_rx_scatter = true,
 	.option_descriptors = false,
+	.min_interrupt_mode = EFX_INT_MODE_LEGACY,
 	.max_interrupt_mode = EFX_INT_MODE_MSIX,
 	.timer_period_max = 1 << FRF_CZ_TC_TIMER_VAL_WIDTH,
 	.offload_features = (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |