[PATCH net v3] net: phy: dp83869: fix status reporting for 1000base-x autonegotiation

[PATCH net v3] net: phy: dp83869: fix status reporting for 1000base-x autonegotiation

[Romain Gantois]

The DP83869 PHY transceiver supports converting from RGMII to 1000base-x.
In this operation mode, autonegotiation can be performed, as described in
IEEE802.3.

The DP83869 has a set of fiber-specific registers located at offset 0xc00.
When the transceiver is configured in RGMII-to-1000base-x mode, these
registers are mapped onto offset 0, which should make reading the
autonegotiation status transparent.

However, the fiber registers at offset 0xc04 and 0xc05 follow the bit
layout specified in Clause 37, and genphy_read_status() assumes a Clause 22
layout. Thus, genphy_read_status() doesn't properly read the capabilities
advertised by the link partner, resulting in incorrect link parameters.

Similarly, genphy_config_aneg() doesn't properly write advertised
capabilities.

Fix the 1000base-x autonegotiation procedure by replacing
genphy_read_status() and genphy_config_aneg() with their Clause 37
equivalents.

Fixes: a29de52ba2a1 ("net: dp83869: Add ability to advertise Fiber connection")
Cc: stable@vger.kernel.org
Signed-off-by: Romain Gantois <romain.gantois@bootlin.com>
---
Changes in v3:
- Used the genphy_c37 helpers instead of custom logic
- Link to v2: https://lore.kernel.org/r/20241104-dp83869-1000base-x-v2-1-f97e39a778bf@bootlin.com

Changes in v2:
- Fixed an uninitialized use.
- Link to v1: https://lore.kernel.org/r/20241029-dp83869-1000base-x-v1-1-fcafe360bd98@bootlin.com
---
 drivers/net/phy/dp83869.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/net/phy/dp83869.c b/drivers/net/phy/dp83869.c
index 5f056d7db83eed23f1cab42365fdc566a0d8e47f..b6b38caf9c0ed0b3ae12a2af7e56754e3ece642f 100644
--- a/drivers/net/phy/dp83869.c
+++ b/drivers/net/phy/dp83869.c
@@ -153,19 +153,32 @@ struct dp83869_private {
 	int mode;
 };
 
+static int dp83869_config_aneg(struct phy_device *phydev)
+{
+	struct dp83869_private *dp83869 = phydev->priv;
+
+	if (dp83869->mode != DP83869_RGMII_1000_BASE)
+		return genphy_config_aneg(phydev);
+
+	return genphy_c37_config_aneg(phydev);
+}
+
 static int dp83869_read_status(struct phy_device *phydev)
 {
 	struct dp83869_private *dp83869 = phydev->priv;
+	bool changed;
 	int ret;
 
+	if (dp83869->mode == DP83869_RGMII_1000_BASE)
+		return genphy_c37_read_status(phydev, &changed);
+
 	ret = genphy_read_status(phydev);
 	if (ret)
 		return ret;
 
-	if (linkmode_test_bit(ETHTOOL_LINK_MODE_FIBRE_BIT, phydev->supported)) {
+	if (dp83869->mode == DP83869_RGMII_100_BASE) {
 		if (phydev->link) {
-			if (dp83869->mode == DP83869_RGMII_100_BASE)
-				phydev->speed = SPEED_100;
+			phydev->speed = SPEED_100;
 		} else {
 			phydev->speed = SPEED_UNKNOWN;
 			phydev->duplex = DUPLEX_UNKNOWN;
@@ -898,6 +911,7 @@ static int dp83869_phy_reset(struct phy_device *phydev)
 	.soft_reset	= dp83869_phy_reset,			\
 	.config_intr	= dp83869_config_intr,			\
 	.handle_interrupt = dp83869_handle_interrupt,		\
+	.config_aneg    = dp83869_config_aneg,                  \
 	.read_status	= dp83869_read_status,			\
 	.get_tunable	= dp83869_get_tunable,			\
 	.set_tunable	= dp83869_set_tunable,			\

---
base-commit: 20bbe5b802494444791beaf2c6b9597fcc67ff49
change-id: 20241025-dp83869-1000base-x-0f0a61725784

Best regards,
-- 
Romain Gantois <romain.gantois@bootlin.com>

Re: [PATCH net v3] net: phy: dp83869: fix status reporting for 1000base-x autonegotiation

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 12 Nov 2024 15:06:08 +0100 you wrote:
> The DP83869 PHY transceiver supports converting from RGMII to 1000base-x.
> In this operation mode, autonegotiation can be performed, as described in
> IEEE802.3.
> 
> The DP83869 has a set of fiber-specific registers located at offset 0xc00.
> When the transceiver is configured in RGMII-to-1000base-x mode, these
> registers are mapped onto offset 0, which should make reading the
> autonegotiation status transparent.
> 
> [...]

Here is the summary with links:
  - [net,v3] net: phy: dp83869: fix status reporting for 1000base-x autonegotiation
    https://git.kernel.org/netdev/net/c/378e8feea9a7

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html