bnxt_en: add support to enable VF-representors

This patch is a part of a patch-set that introduces support for
VF-reps in the bnxt_en driver. The driver registers eswitch mode
get/set methods with the devlink interface that allow a user to
enable SRIOV switchdev mode. When enabled, the driver registers
a VF-rep netdev object for each VF with the stack. This can
essentially bring the VFs unders the management perview of the
hypervisor and applications such as OVS.

The next patch in the series, adds the RX/TX routines and a slim
netdev implementation for the VF-reps.

Signed-off-by: Sathya Perla <sathya.perla@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 244 insertions, 0 deletions

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c
new file mode 100644
index 000000000000..eab358c2ac97
--- /dev/null
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c
@@ -0,0 +1,244 @@
+/* Broadcom NetXtreme-C/E network driver.
+ *
+ * Copyright (c) 2016-2017 Broadcom Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.
+ */
+#include <linux/pci.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/rtnetlink.h>
+#include <linux/jhash.h>
+
+#include "bnxt_hsi.h"
+#include "bnxt.h"
+#include "bnxt_vfr.h"
+
+#define CFA_HANDLE_INVALID		0xffff
+
+static void __bnxt_vf_reps_destroy(struct bnxt *bp)
+{
+	u16 num_vfs = pci_num_vf(bp->pdev);
+	struct bnxt_vf_rep *vf_rep;
+	int i;
+
+	for (i = 0; i < num_vfs; i++) {
+		vf_rep = bp->vf_reps[i];
+		if (vf_rep) {
+			if (vf_rep->dev) {
+				/* if register_netdev failed, then netdev_ops
+				 * would have been set to NULL
+				 */
+				if (vf_rep->dev->netdev_ops)
+					unregister_netdev(vf_rep->dev);
+				free_netdev(vf_rep->dev);
+			}
+		}
+	}
+
+	kfree(bp->vf_reps);
+	bp->vf_reps = NULL;
+}
+
+void bnxt_vf_reps_destroy(struct bnxt *bp)
+{
+	bool closed = false;
+
+	if (bp->eswitch_mode != DEVLINK_ESWITCH_MODE_SWITCHDEV)
+		return;
+
+	if (!bp->vf_reps)
+		return;
+
+	/* Ensure that parent PF's and VF-reps' RX/TX has been quiesced
+	 * before proceeding with VF-rep cleanup.
+	 */
+	rtnl_lock();
+	if (netif_running(bp->dev)) {
+		bnxt_close_nic(bp, false, false);
+		closed = true;
+	}
+	bp->eswitch_mode = DEVLINK_ESWITCH_MODE_LEGACY;
+
+	if (closed)
+		bnxt_open_nic(bp, false, false);
+	rtnl_unlock();
+
+	/* Need to call vf_reps_destroy() outside of rntl_lock
+	 * as unregister_netdev takes rtnl_lock
+	 */
+	__bnxt_vf_reps_destroy(bp);
+}
+
+/* Use the OUI of the PF's perm addr and report the same mac addr
+ * for the same VF-rep each time
+ */
+static void bnxt_vf_rep_eth_addr_gen(u8 *src_mac, u16 vf_idx, u8 *mac)
+{
+	u32 addr;
+
+	ether_addr_copy(mac, src_mac);
+
+	addr = jhash(src_mac, ETH_ALEN, 0) + vf_idx;
+	mac[3] = (u8)(addr & 0xFF);
+	mac[4] = (u8)((addr >> 8) & 0xFF);
+	mac[5] = (u8)((addr >> 16) & 0xFF);
+}
+
+static void bnxt_vf_rep_netdev_init(struct bnxt *bp, struct bnxt_vf_rep *vf_rep,
+				    struct net_device *dev)
+{
+	struct net_device *pf_dev = bp->dev;
+
+	/* Just inherit all the featues of the parent PF as the VF-R
+	 * uses the RX/TX rings of the parent PF
+	 */
+	dev->hw_features = pf_dev->hw_features;
+	dev->gso_partial_features = pf_dev->gso_partial_features;
+	dev->vlan_features = pf_dev->vlan_features;
+	dev->hw_enc_features = pf_dev->hw_enc_features;
+	dev->features |= pf_dev->features;
+	bnxt_vf_rep_eth_addr_gen(bp->pf.mac_addr, vf_rep->vf_idx,
+				 dev->perm_addr);
+	ether_addr_copy(dev->dev_addr, dev->perm_addr);
+}
+
+static int bnxt_vf_reps_create(struct bnxt *bp)
+{
+	u16 num_vfs = pci_num_vf(bp->pdev);
+	struct bnxt_vf_rep *vf_rep;
+	struct net_device *dev;
+	int rc, i;
+
+	bp->vf_reps = kcalloc(num_vfs, sizeof(vf_rep), GFP_KERNEL);
+	if (!bp->vf_reps)
+		return -ENOMEM;
+
+	for (i = 0; i < num_vfs; i++) {
+		dev = alloc_etherdev(sizeof(*vf_rep));
+		if (!dev) {
+			rc = -ENOMEM;
+			goto err;
+		}
+
+		vf_rep = netdev_priv(dev);
+		bp->vf_reps[i] = vf_rep;
+		vf_rep->dev = dev;
+		vf_rep->bp = bp;
+		vf_rep->vf_idx = i;
+		vf_rep->tx_cfa_action = CFA_HANDLE_INVALID;
+
+		bnxt_vf_rep_netdev_init(bp, vf_rep, dev);
+		rc = register_netdev(dev);
+		if (rc) {
+			/* no need for unregister_netdev in cleanup */
+			dev->netdev_ops = NULL;
+			goto err;
+		}
+	}
+
+	bp->eswitch_mode = DEVLINK_ESWITCH_MODE_SWITCHDEV;
+	return 0;
+
+err:
+	netdev_info(bp->dev, "%s error=%d", __func__, rc);
+	__bnxt_vf_reps_destroy(bp);
+	return rc;
+}
+
+/* Devlink related routines */
+static int bnxt_dl_eswitch_mode_get(struct devlink *devlink, u16 *mode)
+{
+	struct bnxt *bp = bnxt_get_bp_from_dl(devlink);
+
+	*mode = bp->eswitch_mode;
+	return 0;
+}
+
+static int bnxt_dl_eswitch_mode_set(struct devlink *devlink, u16 mode)
+{
+	struct bnxt *bp = bnxt_get_bp_from_dl(devlink);
+	int rc = 0;
+
+	mutex_lock(&bp->sriov_lock);
+	if (bp->eswitch_mode == mode) {
+		netdev_info(bp->dev, "already in %s eswitch mode",
+			    mode == DEVLINK_ESWITCH_MODE_LEGACY ?
+			    "legacy" : "switchdev");
+		rc = -EINVAL;
+		goto done;
+	}
+
+	switch (mode) {
+	case DEVLINK_ESWITCH_MODE_LEGACY:
+		bnxt_vf_reps_destroy(bp);
+		break;
+
+	case DEVLINK_ESWITCH_MODE_SWITCHDEV:
+		if (pci_num_vf(bp->pdev) == 0) {
+			netdev_info(bp->dev,
+				    "Enable VFs before setting swtichdev mode");
+			rc = -EPERM;
+			goto done;
+		}
+		rc = bnxt_vf_reps_create(bp);
+		break;
+
+	default:
+		rc = -EINVAL;
+		goto done;
+	}
+done:
+	mutex_unlock(&bp->sriov_lock);
+	return rc;
+}
+
+static const struct devlink_ops bnxt_dl_ops = {
+	.eswitch_mode_set = bnxt_dl_eswitch_mode_set,
+	.eswitch_mode_get = bnxt_dl_eswitch_mode_get
+};
+
+int bnxt_dl_register(struct bnxt *bp)
+{
+	struct devlink *dl;
+	int rc;
+
+	if (!pci_find_ext_capability(bp->pdev, PCI_EXT_CAP_ID_SRIOV))
+		return 0;
+
+	if (bp->hwrm_spec_code < 0x10800) {
+		netdev_warn(bp->dev, "Firmware does not support SR-IOV E-Switch SWITCHDEV mode.\n");
+		return -ENOTSUPP;
+	}
+
+	dl = devlink_alloc(&bnxt_dl_ops, sizeof(struct bnxt_dl));
+	if (!dl) {
+		netdev_warn(bp->dev, "devlink_alloc failed");
+		return -ENOMEM;
+	}
+
+	bnxt_link_bp_to_dl(dl, bp);
+	bp->eswitch_mode = DEVLINK_ESWITCH_MODE_LEGACY;
+	rc = devlink_register(dl, &bp->pdev->dev);
+	if (rc) {
+		bnxt_link_bp_to_dl(dl, NULL);
+		devlink_free(dl);
+		netdev_warn(bp->dev, "devlink_register failed. rc=%d", rc);
+		return rc;
+	}
+
+	return 0;
+}
+
+void bnxt_dl_unregister(struct bnxt *bp)
+{
+	struct devlink *dl = bp->dl;
+
+	if (!dl)
+		return;
+
+	devlink_unregister(dl);
+	devlink_free(dl);
+}