[net-next PATCH 4/5 v4] net: dsa: rtl8366: VLAN 0 as disable tagging

[Linus Walleij <linus.walleij@linaro.org>]

The code in net/8021q/vlan.c, vlan_device_event() sets
VLAN 0 for a VLAN-capable ethernet device when it
comes up.

Since the RTL8366 DSA switches must have a VLAN and
PVID set up for any packets to come through we have
already set up default VLAN for each port as part of
bringing the switch online.

Make sure that setting VLAN 0 has the same effect
and does not try to actually tell the hardware to use
VLAN 0 on the port because that will not work.

Cc: DENG Qingfang <dqfext@gmail.com>
Cc: Mauri Sandberg <sandberg@mailfence.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ChangeLog v3->v4:
- Resend with the rest
ChangeLog v2->v3:
- Collected Andrew's review tag.
ChangeLog v1->v2:
- Rebased on v5.8-rc1 and other changes.
---
 drivers/net/dsa/rtl8366.c | 65 +++++++++++++++++++++++++++++++--------
 1 file changed, 52 insertions(+), 13 deletions(-)

diff --git a/drivers/net/dsa/rtl8366.c b/drivers/net/dsa/rtl8366.c
index b907c0ed9697..a000d458d121 100644
--- a/drivers/net/dsa/rtl8366.c
+++ b/drivers/net/dsa/rtl8366.c
@@ -355,15 +355,25 @@ int rtl8366_vlan_prepare(struct dsa_switch *ds, int port,
 			 const struct switchdev_obj_port_vlan *vlan)
 {
 	struct realtek_smi *smi = ds->priv;
+	u16 vid_begin = vlan->vid_begin;
+	u16 vid_end = vlan->vid_end;
 	u16 vid;
 	int ret;
 
-	for (vid = vlan->vid_begin; vid < vlan->vid_end; vid++)
+	if (vid_begin == 0) {
+		dev_info(smi->dev, "prepare VLAN 0 - ignored\n");
+		if (vid_end == 0)
+			return 0;
+		/* Skip VLAN 0 and start with VLAN 1 */
+		vid_begin = 1;
+	}
+
+	for (vid = vid_begin; vid < vid_end; vid++)
 		if (!smi->ops->is_vlan_valid(smi, vid))
 			return -EINVAL;
 
 	dev_info(smi->dev, "prepare VLANs %04x..%04x\n",
-		 vlan->vid_begin, vlan->vid_end);
+		 vid_begin, vid_end);
 
 	/* Enable VLAN in the hardware
 	 * FIXME: what's with this 4k business?
@@ -383,27 +393,46 @@ void rtl8366_vlan_add(struct dsa_switch *ds, int port,
 	bool untagged = !!(vlan->flags & BRIDGE_VLAN_INFO_UNTAGGED);
 	bool pvid = !!(vlan->flags & BRIDGE_VLAN_INFO_PVID);
 	struct realtek_smi *smi = ds->priv;
+	u16 vid_begin = vlan->vid_begin;
+	u16 vid_end = vlan->vid_end;
 	u32 member = 0;
 	u32 untag = 0;
 	u16 vid;
 	int ret;
 
-	for (vid = vlan->vid_begin; vid < vlan->vid_end; vid++)
-		if (!smi->ops->is_vlan_valid(smi, vid))
+	if (vid_begin == 0) {
+		dev_info(smi->dev, "set VLAN 0 on port %d = default VLAN\n",
+			 port);
+		/* Set up default tagging */
+		ret = rtl8366_set_default_vlan_and_pvid(smi, port);
+		if (ret) {
+			dev_err(smi->dev,
+				"error setting default VLAN on port %d\n",
+				port);
 			return;
+		}
+		if (vid_end == 0)
+			return;
+		/* Skip VLAN 0 and start with VLAN 1 */
+		vid_begin = 1;
+	}
 
-	dev_info(smi->dev, "add VLAN on port %d, %s, %s\n",
-		 port,
-		 untagged ? "untagged" : "tagged",
-		 pvid ? " PVID" : "no PVID");
+	for (vid = vid_begin; vid < vid_end; vid++)
+		if (!smi->ops->is_vlan_valid(smi, vid))
+			return;
 
 	if (dsa_is_dsa_port(ds, port) || dsa_is_cpu_port(ds, port))
 		dev_err(smi->dev, "port is DSA or CPU port\n");
 
-	for (vid = vlan->vid_begin; vid <= vlan->vid_end; ++vid) {
+	for (vid = vid_begin; vid <= vid_end; ++vid) {
 		int pvid_val = 0;
 
-		dev_info(smi->dev, "add VLAN %04x\n", vid);
+		dev_info(smi->dev, "add VLAN %04x to port %d, %s, %s\n",
+			 vid,
+			 port,
+			 untagged ? "untagged" : "tagged",
+			 pvid ? " PVID" : "no PVID");
+
 		member |= BIT(port);
 
 		if (untagged)
@@ -437,15 +466,25 @@ int rtl8366_vlan_del(struct dsa_switch *ds, int port,
 		     const struct switchdev_obj_port_vlan *vlan)
 {
 	struct realtek_smi *smi = ds->priv;
+	u16 vid_begin = vlan->vid_begin;
+	u16 vid_end = vlan->vid_end;
 	u16 vid;
 	int ret;
 
-	dev_info(smi->dev, "del VLAN on port %d\n", port);
+	if (vid_begin == 0) {
+		dev_info(smi->dev, "remove port %d from VLAN 0 (no-op)\n",
+			 port);
+		if (vid_end == 0)
+			return 0;
+		/* Skip VLAN 0 and start with VLAN 1 */
+		vid_begin = 1;
+	}
 
-	for (vid = vlan->vid_begin; vid <= vlan->vid_end; ++vid) {
+	for (vid = vid_begin; vid <= vid_end; ++vid) {
 		int i;
 
-		dev_info(smi->dev, "del VLAN %04x\n", vid);
+		dev_info(smi->dev, "remove VLAN %04x from port %d\n",
+			 vid, port);
 
 		for (i = 0; i < smi->num_vlan_mc; i++) {
 			struct rtl8366_vlan_mc vlanmc;
-- 
2.26.2