net: sfp: avoid tx-fault with Nokia GPON module

The Nokia GPON module can hold tx-fault active while it is initialising
which can take up to 60s. Avoid this causing the module to be declared
faulty after the SFP MSA defined non-cooled module timeout.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index c0b9a8e4e65a9ba5f4d6f90a036efbb15d8aa21b..27360d1840b23c4ec794caad282d5f7c3fd726ac 100644 (file)
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -155,10 +155,20 @@ static const enum gpiod_flags gpio_flags[] = {
        GPIOD_ASIS,
 };
 
-#define T_WAIT         msecs_to_jiffies(50)
-#define T_INIT_JIFFIES msecs_to_jiffies(300)
-#define T_RESET_US     10
-#define T_FAULT_RECOVER        msecs_to_jiffies(1000)
+/* t_start_up (SFF-8431) or t_init (SFF-8472) is the time required for a
+ * non-cooled module to initialise its laser safety circuitry. We wait
+ * an initial T_WAIT period before we check the tx fault to give any PHY
+ * on board (for a copper SFP) time to initialise.
+ */
+#define T_WAIT                 msecs_to_jiffies(50)
+#define T_START_UP             msecs_to_jiffies(300)
+#define T_START_UP_BAD_GPON    msecs_to_jiffies(60000)
+
+/* t_reset is the time required to assert the TX_DISABLE signal to reset
+ * an indicated TX_FAULT.
+ */
+#define T_RESET_US             10
+#define T_FAULT_RECOVER                msecs_to_jiffies(1000)
 
 /* SFP module presence detection is poor: the three MOD DEF signals are
  * the same length on the PCB, which means it's possible for MOD DEF 0 to
@@ -218,6 +228,7 @@ struct sfp {
 
        struct sfp_eeprom_id id;
        unsigned int module_power_mW;
+       unsigned int module_t_start_up;
 
 #if IS_ENABLED(CONFIG_HWMON)
        struct sfp_diag diag;
@@ -1655,6 +1666,12 @@ static int sfp_sm_mod_probe(struct sfp *sfp, bool report)
        if (ret < 0)
                return ret;
 
+       if (!memcmp(id.base.vendor_name, "ALCATELLUCENT   ", 16) &&
+           !memcmp(id.base.vendor_pn, "3FE46541AA      ", 16))
+               sfp->module_t_start_up = T_START_UP_BAD_GPON;
+       else
+               sfp->module_t_start_up = T_START_UP;
+
        return 0;
 }
 
@@ -1855,11 +1872,12 @@ static void sfp_sm_main(struct sfp *sfp, unsigned int event)
                        break;
 
                if (sfp->state & SFP_F_TX_FAULT) {
-                       /* Wait t_init before indicating that the link is up,
-                        * provided the current state indicates no TX_FAULT. If
-                        * TX_FAULT clears before this time, that's fine too.
+                       /* Wait up to t_init (SFF-8472) or t_start_up (SFF-8431)
+                        * from the TX_DISABLE deassertion for the module to
+                        * initialise, which is indicated by TX_FAULT
+                        * deasserting.
                         */
-                       timeout = T_INIT_JIFFIES;
+                       timeout = sfp->module_t_start_up;
                        if (timeout > T_WAIT)
                                timeout -= T_WAIT;
                        else
@@ -1876,8 +1894,8 @@ static void sfp_sm_main(struct sfp *sfp, unsigned int event)
 
        case SFP_S_INIT:
                if (event == SFP_E_TIMEOUT && sfp->state & SFP_F_TX_FAULT) {
-                       /* TX_FAULT is still asserted after t_init, so assume
-                        * there is a fault.
+                       /* TX_FAULT is still asserted after t_init or
+                        * or t_start_up, so assume there is a fault.
                         */
                        sfp_sm_fault(sfp, SFP_S_INIT_TX_FAULT,
                                     sfp->sm_retries == 5);
@@ -1896,7 +1914,7 @@ static void sfp_sm_main(struct sfp *sfp, unsigned int event)
        case SFP_S_INIT_TX_FAULT:
                if (event == SFP_E_TIMEOUT) {
                        sfp_module_tx_fault_reset(sfp);
-                       sfp_sm_next(sfp, SFP_S_INIT, T_INIT_JIFFIES);
+                       sfp_sm_next(sfp, SFP_S_INIT, sfp->module_t_start_up);
                }
                break;
 
@@ -1920,7 +1938,7 @@ static void sfp_sm_main(struct sfp *sfp, unsigned int event)
        case SFP_S_TX_FAULT:
                if (event == SFP_E_TIMEOUT) {
                        sfp_module_tx_fault_reset(sfp);
-                       sfp_sm_next(sfp, SFP_S_REINIT, T_INIT_JIFFIES);
+                       sfp_sm_next(sfp, SFP_S_REINIT, sfp->module_t_start_up);
                }
                break;