Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org>
To:     Russell King - ARM Linux admin <linux@armlinux.org.uk>,
        Andrew Lunn <andrew@lunn.ch>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>
Cc:     Thomas Schreiber <tschreibe@gmail.com>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        =?UTF-8?q?Marek=20Beh=C3=BAn?= <kabel@kernel.org>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/3] net: sfp: assume that LOS is not implemented if both LOS normal and inverted is set
Date:   Wed,  6 Jan 2021 16:37:48 +0100
Message-Id: <20210106153749.6748-3-pali@kernel.org>
In-Reply-To: <20210106153749.6748-1-pali@kernel.org>
References: <20201230154755.14746-1-pali@kernel.org>
 <20210106153749.6748-1-pali@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Russell King <rmk+kernel@armlinux.org.uk>

Some GPON SFP modules (e.g. Ubiquiti U-Fiber Instant) have set both
SFP_OPTIONS_LOS_INVERTED and SFP_OPTIONS_LOS_NORMAL bits in their EEPROM.

Such combination of bits is meaningless so assume that LOS signal is not
implemented.

This patch fixes link carrier for GPON SFP module Ubiquiti U-Fiber Instant.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Pali Rohár <pali@kernel.org>

---
Changes in v2:
* Fix author/signed-off-by lines
---
 drivers/net/phy/sfp.c | 36 ++++++++++++++++++++++--------------
 1 file changed, 22 insertions(+), 14 deletions(-)

diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index c0a891cdcd73..15fb8f7dfe5b 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -1488,15 +1488,19 @@ static void sfp_sm_link_down(struct sfp *sfp)
 
 static void sfp_sm_link_check_los(struct sfp *sfp)
 {
-	unsigned int los = sfp->state & SFP_F_LOS;
+	const __be16 los_inverted = cpu_to_be16(SFP_OPTIONS_LOS_INVERTED);
+	const __be16 los_normal = cpu_to_be16(SFP_OPTIONS_LOS_NORMAL);
+	__be16 los_options = sfp->id.ext.options & (los_inverted | los_normal);
+	bool los = false;
 
 	/* If neither SFP_OPTIONS_LOS_INVERTED nor SFP_OPTIONS_LOS_NORMAL
-	 * are set, we assume that no LOS signal is available.
+	 * are set, we assume that no LOS signal is available. If both are
+	 * set, we assume LOS is not implemented (and is meaningless.)
 	 */
-	if (sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_LOS_INVERTED))
-		los ^= SFP_F_LOS;
-	else if (!(sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_LOS_NORMAL)))
-		los = 0;
+	if (los_options == los_inverted)
+		los = !(sfp->state & SFP_F_LOS);
+	else if (los_options == los_normal)
+		los = !!(sfp->state & SFP_F_LOS);
 
 	if (los)
 		sfp_sm_next(sfp, SFP_S_WAIT_LOS, 0);
@@ -1506,18 +1510,22 @@ static void sfp_sm_link_check_los(struct sfp *sfp)
 
 static bool sfp_los_event_active(struct sfp *sfp, unsigned int event)
 {
-	return (sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_LOS_INVERTED) &&
-		event == SFP_E_LOS_LOW) ||
-	       (sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_LOS_NORMAL) &&
-		event == SFP_E_LOS_HIGH);
+	const __be16 los_inverted = cpu_to_be16(SFP_OPTIONS_LOS_INVERTED);
+	const __be16 los_normal = cpu_to_be16(SFP_OPTIONS_LOS_NORMAL);
+	__be16 los_options = sfp->id.ext.options & (los_inverted | los_normal);
+
+	return (los_options == los_inverted && event == SFP_E_LOS_LOW) ||
+	       (los_options == los_normal && event == SFP_E_LOS_HIGH);
 }
 
 static bool sfp_los_event_inactive(struct sfp *sfp, unsigned int event)
 {
-	return (sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_LOS_INVERTED) &&
-		event == SFP_E_LOS_HIGH) ||
-	       (sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_LOS_NORMAL) &&
-		event == SFP_E_LOS_LOW);
+	const __be16 los_inverted = cpu_to_be16(SFP_OPTIONS_LOS_INVERTED);
+	const __be16 los_normal = cpu_to_be16(SFP_OPTIONS_LOS_NORMAL);
+	__be16 los_options = sfp->id.ext.options & (los_inverted | los_normal);
+
+	return (los_options == los_inverted && event == SFP_E_LOS_HIGH) ||
+	       (los_options == los_normal && event == SFP_E_LOS_LOW);
 }
 
 static void sfp_sm_fault(struct sfp *sfp, unsigned int next_state, bool warn)
-- 
2.20.1