netdev - [PATCH net-next] net: dsa: mv88e6xxx: 6352: parse VTU data before loading STU data

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Date:   Sun,  8 Nov 2020 23:38:10 +0100
From:   Tobias Waldekranz <tobias@...dekranz.com>
To:     davem@...emloft.net, kuba@...nel.org
Cc:     andrew@...n.ch, vivien.didelot@...il.com, netdev@...r.kernel.org
Subject: [PATCH net-next] net: dsa: mv88e6xxx: 6352: parse VTU data before loading STU data

On the 6352, doing a VTU GetNext op, followed by an STU GetNext op
will leave you with both the member- and state- data in the VTU/STU
data registers. But on the 6097 (which uses the same implementation),
the STU GetNext will override the information gathered from the VTU
GetNext.

Separate the two stages, parsing the result of the VTU GetNext before
doing the STU GetNext.

We opt to update the existing implementation for all applicable chips,
as opposed to creating a separate callback for 6097. Though the
previous implementation did work for (at least) 6352, the datasheet
does not mention the masking behavior.

Signed-off-by: Tobias Waldekranz <tobias@...dekranz.com>
---

I was not sure if I should have created a separate callback, but I
have not found any documentation that suggests that you can expect the
STU GetNext op to mask the bits that are used to store VTU membership
information in the way that 6352 does. So depending on undocumented
behavior felt like something we would want to get rid of anyway.

Tested on 6097F and 6352.

drivers/net/dsa/mv88e6xxx/global1_vtu.c | 55 ++++++++++++++++++++-----
 1 file changed, 45 insertions(+), 10 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/global1_vtu.c b/drivers/net/dsa/mv88e6xxx/global1_vtu.c
index 48390b7b18ad..2f146645a723 100644
--- a/drivers/net/dsa/mv88e6xxx/global1_vtu.c
+++ b/drivers/net/dsa/mv88e6xxx/global1_vtu.c
@@ -125,11 +125,9 @@ static int mv88e6xxx_g1_vtu_vid_write(struct mv88e6xxx_chip *chip,
  * Offset 0x08: VTU/STU Data Register 2
  * Offset 0x09: VTU/STU Data Register 3
  */
-
-static int mv88e6185_g1_vtu_data_read(struct mv88e6xxx_chip *chip,
-				      struct mv88e6xxx_vtu_entry *entry)
+static int mv88e6185_g1_vtu_stu_data_read(struct mv88e6xxx_chip *chip,
+					  u16 *regs)
 {
-	u16 regs[3];
 	int i;
 
 	/* Read all 3 VTU/STU Data registers */
@@ -142,12 +140,45 @@ static int mv88e6185_g1_vtu_data_read(struct mv88e6xxx_chip *chip,
 			return err;
 	}
 
-	/* Extract MemberTag and PortState data */
+	return 0;
+}
+
+static int mv88e6185_g1_vtu_data_read(struct mv88e6xxx_chip *chip,
+				      struct mv88e6xxx_vtu_entry *entry)
+{
+	u16 regs[3];
+	int err;
+	int i;
+
+	err = mv88e6185_g1_vtu_stu_data_read(chip, regs);
+	if (err)
+		return err;
+
+	/* Extract MemberTag data */
 	for (i = 0; i < mv88e6xxx_num_ports(chip); ++i) {
 		unsigned int member_offset = (i % 4) * 4;
-		unsigned int state_offset = member_offset + 2;
 
 		entry->member[i] = (regs[i / 4] >> member_offset) & 0x3;
+	}
+
+	return 0;
+}
+
+static int mv88e6185_g1_stu_data_read(struct mv88e6xxx_chip *chip,
+				      struct mv88e6xxx_vtu_entry *entry)
+{
+	u16 regs[3];
+	int err;
+	int i;
+
+	err = mv88e6185_g1_vtu_stu_data_read(chip, regs);
+	if (err)
+		return err;
+
+	/* Extract PortState data */
+	for (i = 0; i < mv88e6xxx_num_ports(chip); ++i) {
+		unsigned int state_offset = (i % 4) * 4 + 2;
+
 		entry->state[i] = (regs[i / 4] >> state_offset) & 0x3;
 	}
 
@@ -374,16 +405,20 @@ int mv88e6352_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
 		return err;
 
 	if (entry->valid) {
-		/* Fetch (and mask) VLAN PortState data from the STU */
-		err = mv88e6xxx_g1_vtu_stu_get(chip, entry);
+		err = mv88e6185_g1_vtu_data_read(chip, entry);
 		if (err)
 			return err;
 
-		err = mv88e6185_g1_vtu_data_read(chip, entry);
+		err = mv88e6xxx_g1_vtu_fid_read(chip, entry);
 		if (err)
 			return err;
 
-		err = mv88e6xxx_g1_vtu_fid_read(chip, entry);
+		/* Fetch VLAN PortState data from the STU */
+		err = mv88e6xxx_g1_vtu_stu_get(chip, entry);
+		if (err)
+			return err;
+
+		err = mv88e6185_g1_stu_data_read(chip, entry);
 		if (err)
 			return err;
 	}
-- 
2.17.1