[net-next PATCH 0/2] net: dsa: tag_rtl8_4: fixes doc and set keep

[net-next PATCH 0/2] net: dsa: tag_rtl8_4: fixes doc and set keep

[Luiz Angelo Daros de Luca]

This small series addresses two points in the rtl8_4 tagger used by the
realtel rtl8365mb driver.

The first patch updates the documentation of the tag format while the
second patch sets the KEEP flag bit, ensuring that the switch
respects the frame's VLAN format as provided by the kernel.

These patches were previously part of a larger series but are being 
submitted independently as they are self-contained and already 
received review.

Changes in v1:
- Resubmitted as a standalone series from the previous larger set.
- Kept Reviewed-by tags from Linus Walleij.

Link: https://patch.msgid.link/CAD++jLmX31KfhGXA6SMAPXb14dHSC1t4JQZ=PQvjh-3hUcnzJA@mail.gmail.com
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
---
Alvin Šipraga (1):
      net: dsa: tag_rtl8_4: update format description

Luiz Angelo Daros de Luca (1):
      net: dsa: tag_rtl8_4: set KEEP flag

 net/dsa/tag_rtl8_4.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)
---
base-commit: 1a8dd88469bf742fd5eda91cd8e0f720a983ec5a
change-id: 20260407-realtek_fixes-e1a81e477cbb

Best regards,
--  
Luiz Angelo Daros de Luca <luizluca@gmail.com>

[net-next PATCH 1/2] net: dsa: tag_rtl8_4: update format description

[Luiz Angelo Daros de Luca]

From: Alvin Šipraga <alsi@bang-olufsen.dk>

Document the updated tag layout fields (EFID, VSEL/VIDX) and clarify
which bits are set/cleared when emitting tags.

Co-developed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
---
 net/dsa/tag_rtl8_4.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/net/dsa/tag_rtl8_4.c b/net/dsa/tag_rtl8_4.c
index 2464545da4d2..b7ed39c5419f 100644
--- a/net/dsa/tag_rtl8_4.c
+++ b/net/dsa/tag_rtl8_4.c
@@ -17,8 +17,8 @@
  *  |              (8-bit)              |              (8-bit)              |
  *  |          Protocol [0x04]          |              REASON               | b
  *  |-----------------------------------+-----------------------------------| y
- *  |   (1)  | (1) | (2) |   (1)  | (3) | (1)  | (1) |    (1)    |   (5)    | t
- *  | FID_EN |  X  | FID | PRI_EN | PRI | KEEP |  X  | LEARN_DIS |    X     | e
+ *  |   (1)   |   (3)  |   (1)  |  (3)  | (1)  | (1)  |    (1)     |  (5)   | t
+ *  | EFID_EN |  EFID  | PRI_EN |  PRI  | KEEP | VSEL | LEARN_DIS  |  VIDX  | e
  *  |-----------------------------------+-----------------------------------| s
  *  |   (1)  |                       (15-bit)                               | |
  *  |  ALLOW |                        TX/RX                                 | v
@@ -32,19 +32,22 @@
  *     EtherType |         note that Realtek uses the same EtherType for
  *               |         other incompatible tag formats (e.g. tag_rtl4_a.c)
  *    Protocol   | 0x04: indicates that this tag conforms to this format
- *    X          | reserved
  *   ------------+-------------
  *    REASON     | reason for forwarding packet to CPU
  *               | 0: packet was forwarded or flooded to CPU
  *               | 80: packet was trapped to CPU
- *    FID_EN     | 1: packet has an FID
- *               | 0: no FID
- *    FID        | FID of packet (if FID_EN=1)
+ *    EFID_EN    | 1: packet has an EFID
+ *               | 0: no EFID
+ *    EFID       | Extended filter ID (EFID) of packet (if EFID_EN=1)
  *    PRI_EN     | 1: force priority of packet
  *               | 0: don't force priority
  *    PRI        | priority of packet (if PRI_EN=1)
  *    KEEP       | preserve packet VLAN tag format
+ *    VSEL       | 0: switch should classify packet according to VLAN tag
+ *               | 1: switch should classify packet according to VLAN membership
+ *               |    configuration with index VIDX
  *    LEARN_DIS  | don't learn the source MAC address of the packet
+ *    VIDX       | index of a VLAN membership configuration to use with VSEL
  *    ALLOW      | 1: treat TX/RX field as an allowance port mask, meaning the
  *               |    packet may only be forwarded to ports specified in the
  *               |    mask
@@ -111,7 +114,7 @@ static void rtl8_4_write_tag(struct sk_buff *skb, struct net_device *dev,
 	/* Set Protocol; zero REASON */
 	tag16[1] = htons(FIELD_PREP(RTL8_4_PROTOCOL, RTL8_4_PROTOCOL_RTL8365MB));
 
-	/* Zero FID_EN, FID, PRI_EN, PRI, KEEP; set LEARN_DIS */
+	/* Zero EFID_EN, EFID, PRI_EN, PRI, VSEL, VIDX, KEEP; set LEARN_DIS */
 	tag16[2] = htons(FIELD_PREP(RTL8_4_LEARN_DIS, 1));
 
 	/* Zero ALLOW; set RX (CPU->switch) forwarding port mask */

-- 
2.53.0

[net-next PATCH 2/2] net: dsa: tag_rtl8_4: set KEEP flag

[Luiz Angelo Daros de Luca]

KEEP=1 is needed because we should respect the format of the packet as
the kernel sends it to us. Unless tx forward offloading is used, the
kernel is giving us the packet exactly as it should leave the specified
port on the wire. Until now this was not needed because the ports were
always functioning in a standalone mode in a VLAN-unaware way, so the
switch would not tag or untag frames anyway. But arguably it should have
been KEEP=1 all along.

Co-developed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
---
 net/dsa/tag_rtl8_4.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/dsa/tag_rtl8_4.c b/net/dsa/tag_rtl8_4.c
index b7ed39c5419f..852c6b88079a 100644
--- a/net/dsa/tag_rtl8_4.c
+++ b/net/dsa/tag_rtl8_4.c
@@ -99,6 +99,7 @@
 #define   RTL8_4_REASON_TRAP		80
 
 #define RTL8_4_LEARN_DIS		BIT(5)
+#define RTL8_4_KEEP			BIT(7)
 
 #define RTL8_4_TX			GENMASK(3, 0)
 #define RTL8_4_RX			GENMASK(10, 0)
@@ -114,8 +115,9 @@ static void rtl8_4_write_tag(struct sk_buff *skb, struct net_device *dev,
 	/* Set Protocol; zero REASON */
 	tag16[1] = htons(FIELD_PREP(RTL8_4_PROTOCOL, RTL8_4_PROTOCOL_RTL8365MB));
 
-	/* Zero EFID_EN, EFID, PRI_EN, PRI, VSEL, VIDX, KEEP; set LEARN_DIS */
-	tag16[2] = htons(FIELD_PREP(RTL8_4_LEARN_DIS, 1));
+	/* Zero EFID_EN, EFID, PRI_EN, PRI, VSEL, VIDX; set KEEP, LEARN_DIS */
+	tag16[2] = htons(FIELD_PREP(RTL8_4_LEARN_DIS, 1) |
+			 FIELD_PREP(RTL8_4_KEEP, 1));
 
 	/* Zero ALLOW; set RX (CPU->switch) forwarding port mask */
 	tag16[3] = htons(FIELD_PREP(RTL8_4_RX, dsa_xmit_port_mask(skb, dev)));

-- 
2.53.0