bnxt_en: Deprecate support for legacy INTX mode

Firmware has deprecated support for legacy INTX in 2022 (since v2.27)
and INTX hasn't been tested for many years before that.  INTX was
only used as a fallback mechansim in case MSIX wasn't available.  MSIX
is always supported by all firmware.  If MSIX capability in PCI config
space is not found during probe, abort.
Reviewed-by: Hongguang Gao <hongguang.gao@broadcom.com>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20240828183235.128948-5-michael.chan@broadcom.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -10770,7 +10770,7 @@ static int bnxt_get_num_msix(struct bnxt *bp)
 	return bnxt_nq_rings_in_use(bp);
 }
 
-static int bnxt_init_msix(struct bnxt *bp)
+static int bnxt_init_int_mode(struct bnxt *bp)
 {
 	int i, total_vecs, max, rc = 0, min = 1, ulp_msix, tx_cp;
 	struct msix_entry *msix_ent;
@@ -10828,7 +10828,7 @@ static int bnxt_init_msix(struct bnxt *bp)
 	return 0;
 
 msix_setup_exit:
-	netdev_err(bp->dev, "bnxt_init_msix err: %x\n", rc);
+	netdev_err(bp->dev, "bnxt_init_int_mode err: %x\n", rc);
 	kfree(bp->irq_tbl);
 	bp->irq_tbl = NULL;
 	pci_disable_msix(bp->pdev);
@@ -10836,35 +10836,6 @@ static int bnxt_init_msix(struct bnxt *bp)
 	return rc;
 }
 
-static int bnxt_init_inta(struct bnxt *bp)
-{
-	bp->irq_tbl = kzalloc(sizeof(struct bnxt_irq), GFP_KERNEL);
-	if (!bp->irq_tbl)
-		return -ENOMEM;
-
-	bp->total_irqs = 1;
-	bp->rx_nr_rings = 1;
-	bp->tx_nr_rings = 1;
-	bp->cp_nr_rings = 1;
-	bp->flags |= BNXT_FLAG_SHARED_RINGS;
-	bp->irq_tbl[0].vector = bp->pdev->irq;
-	return 0;
-}
-
-static int bnxt_init_int_mode(struct bnxt *bp)
-{
-	int rc = -ENODEV;
-
-	if (bp->flags & BNXT_FLAG_MSIX_CAP)
-		rc = bnxt_init_msix(bp);
-
-	if (!(bp->flags & BNXT_FLAG_USING_MSIX) && BNXT_PF(bp)) {
-		/* fallback to INTA */
-		rc = bnxt_init_inta(bp);
-	}
-	return rc;
-}
-
 static void bnxt_clear_int_mode(struct bnxt *bp)
 {
 	if (bp->flags & BNXT_FLAG_USING_MSIX)
@@ -12910,7 +12881,7 @@ bool bnxt_rfs_capable(struct bnxt *bp, bool new_rss_ctx)
 	    !BNXT_SUPPORTS_NTUPLE_VNIC(bp))
 		return bnxt_rfs_supported(bp);
 
-	if (!(bp->flags & BNXT_FLAG_MSIX_CAP) || !bnxt_can_reserve_rings(bp) || !bp->rx_nr_rings)
+	if (!bnxt_can_reserve_rings(bp) || !bp->rx_nr_rings)
 		return false;
 
 	hwr.grp = bp->rx_nr_rings;
@@ -15772,6 +15743,11 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (pci_is_bridge(pdev))
 		return -ENODEV;
 
+	if (!pdev->msix_cap) {
+		dev_err(&pdev->dev, "MSIX capability not found, aborting\n");
+		return -ENODEV;
+	}
+
 	/* Clear any pending DMA transactions from crash kernel
 	 * while loading driver in capture kernel.
 	 */
@@ -15798,9 +15774,6 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (BNXT_PF(bp))
 		SET_NETDEV_DEVLINK_PORT(dev, &bp->dl_port);
 
-	if (pdev->msix_cap)
-		bp->flags |= BNXT_FLAG_MSIX_CAP;
-
 	rc = bnxt_init_board(pdev, dev);
 	if (rc < 0)
 		goto init_err_free;

drivers/net/ethernet/broadcom/bnxt/bnxt.h

@@ -2200,7 +2200,6 @@ struct bnxt {
 	#define BNXT_FLAG_AGG_RINGS	(BNXT_FLAG_JUMBO | BNXT_FLAG_GRO | \
 					 BNXT_FLAG_LRO)
 	#define BNXT_FLAG_USING_MSIX	0x40
-	#define BNXT_FLAG_MSIX_CAP	0x80
 	#define BNXT_FLAG_RFS		0x100
 	#define BNXT_FLAG_SHARED_RINGS	0x200
 	#define BNXT_FLAG_PORT_STATS	0x400