bnxt_en: Implement ethtool -X to set indirection table.

With the new infrastructure in place, we can now support the setting of
the indirection table from ethtool.

When changing channels, in a rare case that firmware cannot reserve the
rings that were promised, we will still try to keep the RSS map and only
revert to default when absolutely necessary.

v4: Revert RSS map to default during ring change only when absolutely
    necessary.

v3: Add warning messages when firmware cannot reserve the requested RX
    rings, and when the RSS table entries have to change to default.

v2: When changing channels, if the RSS table size changes and RSS map
    is non-default, return error.
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -4869,6 +4869,19 @@ static void bnxt_set_dflt_rss_indir_tbl(struct bnxt *bp)
 		memset(&bp->rss_indir_tbl[i], 0, pad * sizeof(u16));
 }
 
+static u16 bnxt_get_max_rss_ring(struct bnxt *bp)
+{
+	u16 i, tbl_size, max_ring = 0;
+
+	if (!bp->rss_indir_tbl)
+		return 0;
+
+	tbl_size = bnxt_get_rxfh_indir_size(bp->dev);
+	for (i = 0; i < tbl_size; i++)
+		max_ring = max(max_ring, bp->rss_indir_tbl[i]);
+	return max_ring;
+}
+
 int bnxt_get_nr_rss_ctxs(struct bnxt *bp, int rx_rings)
 {
 	if (bp->flags & BNXT_FLAG_CHIP_P5)
@@ -6058,6 +6071,21 @@ static int __bnxt_reserve_rings(struct bnxt *bp)
 		rx = rx_rings << 1;
 	cp = sh ? max_t(int, tx, rx_rings) : tx + rx_rings;
 	bp->tx_nr_rings = tx;
+
+	/* If we cannot reserve all the RX rings, reset the RSS map only
+	 * if absolutely necessary
+	 */
+	if (rx_rings != bp->rx_nr_rings) {
+		netdev_warn(bp->dev, "Able to reserve only %d out of %d requested RX rings\n",
+			    rx_rings, bp->rx_nr_rings);
+		if ((bp->dev->priv_flags & IFF_RXFH_CONFIGURED) &&
+		    (bnxt_get_nr_rss_ctxs(bp, bp->rx_nr_rings) !=
+		     bnxt_get_nr_rss_ctxs(bp, rx_rings) ||
+		     bnxt_get_max_rss_ring(bp) >= rx_rings)) {
+			netdev_warn(bp->dev, "RSS table entries reverting to default\n");
+			bp->dev->priv_flags &= ~IFF_RXFH_CONFIGURED;
+		}
+	}
 	bp->rx_nr_rings = rx_rings;
 	bp->cp_nr_rings = cp;
 
@@ -8262,7 +8290,8 @@ int bnxt_reserve_rings(struct bnxt *bp, bool irq_re_init)
 			rc = bnxt_init_int_mode(bp);
 		bnxt_ulp_irq_restart(bp, rc);
 	}
-	bnxt_set_dflt_rss_indir_tbl(bp);
+	if (!netif_is_rxfh_configured(bp->dev))
+		bnxt_set_dflt_rss_indir_tbl(bp);
 
 	if (rc) {
 		netdev_err(bp->dev, "ring reservation/IRQ init failure rc: %d\n", rc);

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

@@ -926,6 +926,13 @@ static int bnxt_set_channels(struct net_device *dev,
 		return rc;
 	}
 
+	if (bnxt_get_nr_rss_ctxs(bp, req_rx_rings) !=
+	    bnxt_get_nr_rss_ctxs(bp, bp->rx_nr_rings) &&
+	    (dev->priv_flags & IFF_RXFH_CONFIGURED)) {
+		netdev_warn(dev, "RSS table size change required, RSS table entries must be default to proceed\n");
+		return -EINVAL;
+	}
+
 	if (netif_running(dev)) {
 		if (BNXT_PF(bp)) {
 			/* TODO CHIMP_FW: Send message to all VF's
@@ -1313,6 +1320,35 @@ static int bnxt_get_rxfh(struct net_device *dev, u32 *indir, u8 *key,
 	return 0;
 }
 
+static int bnxt_set_rxfh(struct net_device *dev, const u32 *indir,
+			 const u8 *key, const u8 hfunc)
+{
+	struct bnxt *bp = netdev_priv(dev);
+	int rc = 0;
+
+	if (hfunc && hfunc != ETH_RSS_HASH_TOP)
+		return -EOPNOTSUPP;
+
+	if (key)
+		return -EOPNOTSUPP;
+
+	if (indir) {
+		u32 i, pad, tbl_size = bnxt_get_rxfh_indir_size(dev);
+
+		for (i = 0; i < tbl_size; i++)
+			bp->rss_indir_tbl[i] = indir[i];
+		pad = bp->rss_indir_tbl_entries - tbl_size;
+		if (pad)
+			memset(&bp->rss_indir_tbl[i], 0, pad * sizeof(u16));
+	}
+
+	if (netif_running(bp->dev)) {
+		bnxt_close_nic(bp, false, false);
+		rc = bnxt_open_nic(bp, false, false);
+	}
+	return rc;
+}
+
 static void bnxt_get_drvinfo(struct net_device *dev,
 			     struct ethtool_drvinfo *info)
 {
@@ -3619,6 +3655,7 @@ const struct ethtool_ops bnxt_ethtool_ops = {
 	.get_rxfh_indir_size    = bnxt_get_rxfh_indir_size,
 	.get_rxfh_key_size      = bnxt_get_rxfh_key_size,
 	.get_rxfh               = bnxt_get_rxfh,
+	.set_rxfh		= bnxt_set_rxfh,
 	.flash_device		= bnxt_flash_device,
 	.get_eeprom_len         = bnxt_get_eeprom_len,
 	.get_eeprom             = bnxt_get_eeprom,