[PATCH 3/4] net: sfp: assume that LOS is not implemented if both LOS normal and inverted is set

Pali Rohár
2020-12-30T15:49:14Z

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.

Co-developed-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Pali Rohár <pali@kernel.org>
---
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 73f3ecf15260..d47485ed239c 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -1475,15 +1475,19 @@ 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);
@@ -1493,18 +1497,22 @@ 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