[PATCH net v2 1/2] net: dsa: mv88e6xxx: write the ATU FID register on 88E6141/88E6341

From: Luke Howard <hidden>
Date: 2026-07-09 23:29:54
Also in: lkml
Subsystem: marvell 88e6xxx ethernet switch fabric driver, networking drivers, networking [dsa], the rest · Maintainers: Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Vladimir Oltean, Linus Torvalds

The driver decided whether a device has a dedicated ATU FID register
from its database count, taking the register path only when there were
more than 256 databases. The 88E6141/88E6341 have 256 databases but do
have the register, so they fell back to the legacy path and the FID
register was never written. Every FDB entry was then loaded into FID 0,
breaking VLAN aware bridging.

The number of databases does not imply whether the register is present.
Add an explicit atu_fid_reg flag, set it on every device that has the
register (all that previously matched the >256 heuristic, plus the
88E6141/88E6341), and key the register access off the flag instead of
the database count.

Fixes: a75961d0ebfd ("net: dsa: mv88e6xxx: Add support for ethernet switch 88E6341")
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Luke Howard <redacted>
---
 drivers/net/dsa/mv88e6xxx/chip.c        | 27 +++++++++++++++++++++++++++
 drivers/net/dsa/mv88e6xxx/chip.h        | 10 +++++++---
 drivers/net/dsa/mv88e6xxx/global1_atu.c |  4 ++--
 3 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 80b877c74513d..7938e50900ca8 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c

@@ -5747,6 +5747,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6097,
 		.name = "Marvell 88E6085",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 8192,
 		.num_ports = 10,
 		.num_internal_phys = 5,

@@ -5792,6 +5793,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6097,
 		.name = "Marvell 88E6097/88E6097F",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 8192,
 		.num_ports = 11,
 		.num_internal_phys = 8,

@@ -5817,6 +5819,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6165,
 		.name = "Marvell 88E6123",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 1024,
 		.num_ports = 3,
 		.num_internal_phys = 5,

@@ -5863,6 +5866,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6341,
 		.name = "Marvell 88E6141",
 		.num_databases = 256,
+		.atu_fid_reg = true,
 		.num_macs = 2048,
 		.num_ports = 6,
 		.num_internal_phys = 5,

@@ -5889,6 +5893,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6165,
 		.name = "Marvell 88E6161",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 1024,
 		.num_ports = 6,
 		.num_internal_phys = 5,

@@ -5915,6 +5920,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6165,
 		.name = "Marvell 88E6165",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 8192,
 		.num_ports = 6,
 		.num_internal_phys = 0,

@@ -5940,6 +5946,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6351,
 		.name = "Marvell 88E6171",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 8192,
 		.num_ports = 7,
 		.num_internal_phys = 5,

@@ -5965,6 +5972,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6352,
 		.name = "Marvell 88E6172",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 8192,
 		.num_ports = 7,
 		.num_internal_phys = 5,

@@ -5991,6 +5999,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6351,
 		.name = "Marvell 88E6175",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 8192,
 		.num_ports = 7,
 		.num_internal_phys = 5,

@@ -6016,6 +6025,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6352,
 		.name = "Marvell 88E6176",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 8192,
 		.num_ports = 7,
 		.num_internal_phys = 5,

@@ -6064,6 +6074,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6390,
 		.name = "Marvell 88E6190",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 16384,
 		.num_ports = 11,	/* 10 + Z80 */
 		.num_internal_phys = 9,

@@ -6089,6 +6100,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6390,
 		.name = "Marvell 88E6190X",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 16384,
 		.num_ports = 11,	/* 10 + Z80 */
 		.num_internal_phys = 9,

@@ -6114,6 +6126,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6390,
 		.name = "Marvell 88E6191",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 16384,
 		.num_ports = 11,	/* 10 + Z80 */
 		.num_internal_phys = 9,

@@ -6139,6 +6152,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6393,
 		.name = "Marvell 88E6191X",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_ports = 11,	/* 10 + Z80 */
 		.num_internal_phys = 8,
 		.internal_phys_offset = 1,

@@ -6164,6 +6178,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6393,
 		.name = "Marvell 88E6193X",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_ports = 11,	/* 10 + Z80 */
 		.num_internal_phys = 8,
 		.num_tcam_entries = 256,

@@ -6218,6 +6233,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6352,
 		.name = "Marvell 88E6240",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 8192,
 		.num_ports = 7,
 		.num_internal_phys = 5,

@@ -6267,6 +6283,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6390,
 		.name = "Marvell 88E6290",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_ports = 11,	/* 10 + Z80 */
 		.num_internal_phys = 9,
 		.num_gpio = 16,

@@ -6294,6 +6311,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6320,
 		.name = "Marvell 88E6320",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 8192,
 		.num_ports = 7,
 		.num_internal_phys = 2,

@@ -6322,6 +6340,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6320,
 		.name = "Marvell 88E6321",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 8192,
 		.num_ports = 7,
 		.num_internal_phys = 2,

@@ -6350,6 +6369,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6341,
 		.name = "Marvell 88E6341",
 		.num_databases = 256,
+		.atu_fid_reg = true,
 		.num_macs = 2048,
 		.num_internal_phys = 5,
 		.num_ports = 6,

@@ -6377,6 +6397,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6351,
 		.name = "Marvell 88E6350",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 8192,
 		.num_ports = 7,
 		.num_internal_phys = 5,

@@ -6402,6 +6423,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6351,
 		.name = "Marvell 88E6351",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 8192,
 		.num_ports = 7,
 		.num_internal_phys = 5,

@@ -6427,6 +6449,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6352,
 		.name = "Marvell 88E6352",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 8192,
 		.num_ports = 7,
 		.num_internal_phys = 5,

@@ -6453,6 +6476,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6393,
 		.name = "Marvell 88E6361",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 16384,
 		.num_ports = 11,
 		/* Ports 1, 2 and 8 are not routed */

@@ -6480,6 +6504,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6390,
 		.name = "Marvell 88E6390",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 16384,
 		.num_ports = 11,	/* 10 + Z80 */
 		.num_internal_phys = 9,

@@ -6508,6 +6533,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6390,
 		.name = "Marvell 88E6390X",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_macs = 16384,
 		.num_ports = 11,	/* 10 + Z80 */
 		.num_internal_phys = 9,

@@ -6535,6 +6561,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.family = MV88E6XXX_FAMILY_6393,
 		.name = "Marvell 88E6393X",
 		.num_databases = 4096,
+		.atu_fid_reg = true,
 		.num_ports = 11,	/* 10 + Z80 */
 		.num_internal_phys = 8,
 		.num_tcam_entries = 256,

diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index e966e7c4cc5de..aca64fd4cb95c 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h

@@ -165,16 +165,20 @@ struct mv88e6xxx_info {
 	 */
 	bool dual_chip;
 
+	/* Has a dedicated ATU FID register. */
+	bool atu_fid_reg;
+
+	/* Supports PTP */
+	bool ptp_support;
+
 	enum mv88e6xxx_edsa_support edsa_support;
 
 	/* Mask for FromPort and ToPort value of PortVec used in ATU Move
 	 * operation. 0 means that the ATU Move operation is not supported.
 	 */
 	u8 atu_move_port_mask;
-	const struct mv88e6xxx_ops *ops;
 
-	/* Supports PTP */
-	bool ptp_support;
+	const struct mv88e6xxx_ops *ops;
 
 	/* Internal PHY start index. 0 means that internal PHYs range starts at
 	 * port 0, 1 means internal PHYs range starts at port 1, etc

diff --git a/drivers/net/dsa/mv88e6xxx/global1_atu.c b/drivers/net/dsa/mv88e6xxx/global1_atu.c
index c47f068f56b32..522978f638e2f 100644
--- a/drivers/net/dsa/mv88e6xxx/global1_atu.c
+++ b/drivers/net/dsa/mv88e6xxx/global1_atu.c

@@ -135,7 +135,7 @@ static int mv88e6xxx_g1_atu_op(struct mv88e6xxx_chip *chip, u16 fid, u16 op)
 	int err;
 
 	/* FID bits are dispatched all around gradually as more are supported */
-	if (mv88e6xxx_num_databases(chip) > 256) {
+	if (chip->info->atu_fid_reg) {
 		err = mv88e6xxx_g1_atu_fid_write(chip, fid);
 		if (err)
 			return err;

@@ -179,7 +179,7 @@ static int mv88e6xxx_g1_atu_fid_read(struct mv88e6xxx_chip *chip, u16 *fid)
 	u16 val = 0, upper = 0, op = 0;
 	int err = -EOPNOTSUPP;
 
-	if (mv88e6xxx_num_databases(chip) > 256) {
+	if (chip->info->atu_fid_reg) {
 		err = mv88e6xxx_g1_read(chip, MV88E6352_G1_ATU_FID, &val);
 		val &= 0xfff;
 		if (err)

-- 
2.43.0

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