net: sfp: re-attempt probing for phy

Some 1000BASE-T PHY modules take a while for the PHY to wake up.
Retry the probe a number of times before deciding that the module has
no PHY.

Tested with:
 Sourcephotonics SPGBTXCNFC - PHY takes less than 50ms to respond.
 Champion One 1000SFPT - PHY takes about 200ms to respond.
 Mikrotik S-RJ01 - no PHY

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 76fa95e5454261c2ac75e0b80338c0dfbe84fa79..e54aef92103877ba7640737c154dc5d60dc898fa 100644 (file)
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -62,6 +62,7 @@ enum {
        SFP_S_FAIL,
        SFP_S_WAIT,
        SFP_S_INIT,
+       SFP_S_INIT_PHY,
        SFP_S_INIT_TX_FAULT,
        SFP_S_WAIT_LOS,
        SFP_S_LINK_UP,
@@ -126,6 +127,7 @@ static const char * const sm_state_strings[] = {
        [SFP_S_FAIL] = "fail",
        [SFP_S_WAIT] = "wait",
        [SFP_S_INIT] = "init",
+       [SFP_S_INIT_PHY] = "init_phy",
        [SFP_S_INIT_TX_FAULT] = "init_tx_fault",
        [SFP_S_WAIT_LOS] = "wait_los",
        [SFP_S_LINK_UP] = "link_up",
@@ -180,6 +182,12 @@ static const enum gpiod_flags gpio_flags[] = {
 #define N_FAULT_INIT           5
 #define N_FAULT                        5
 
+/* T_PHY_RETRY is the time interval between attempts to probe the PHY.
+ * R_PHY_RETRY is the number of attempts.
+ */
+#define T_PHY_RETRY            msecs_to_jiffies(50)
+#define R_PHY_RETRY            12
+
 /* 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
  * connect before the I2C bus on MOD DEF 1/2.
@@ -235,6 +243,7 @@ struct sfp {
        unsigned char sm_dev_state;
        unsigned short sm_state;
        unsigned char sm_fault_retries;
+       unsigned char sm_phy_retries;
 
        struct sfp_eeprom_id id;
        unsigned int module_power_mW;
@@ -1416,10 +1425,8 @@ static int sfp_sm_probe_phy(struct sfp *sfp, bool is_c45)
        int err;
 
        phy = get_phy_device(sfp->i2c_mii, SFP_PHY_ADDR, is_c45);
-       if (phy == ERR_PTR(-ENODEV)) {
-               dev_info(sfp->dev, "no PHY detected\n");
-               return 0;
-       }
+       if (phy == ERR_PTR(-ENODEV))
+               return PTR_ERR(phy);
        if (IS_ERR(phy)) {
                dev_err(sfp->dev, "mdiobus scan returned %ld\n", PTR_ERR(phy));
                return PTR_ERR(phy);
@@ -1867,6 +1874,7 @@ static void sfp_sm_module(struct sfp *sfp, unsigned int event)
 static void sfp_sm_main(struct sfp *sfp, unsigned int event)
 {
        unsigned long timeout;
+       int ret;
 
        /* Some events are global */
        if (sfp->sm_state != SFP_S_DOWN &&
@@ -1940,22 +1948,39 @@ static void sfp_sm_main(struct sfp *sfp, unsigned int event)
                        sfp_sm_fault(sfp, SFP_S_INIT_TX_FAULT,
                                     sfp->sm_fault_retries == N_FAULT_INIT);
                } else if (event == SFP_E_TIMEOUT || event == SFP_E_TX_CLEAR) {
-       init_done:      /* TX_FAULT deasserted or we timed out with TX_FAULT
-                        * clear.  Probe for the PHY and check the LOS state.
-                        */
-                       if (sfp_sm_probe_for_phy(sfp)) {
-                               sfp_sm_next(sfp, SFP_S_FAIL, 0);
-                               break;
-                       }
-                       if (sfp_module_start(sfp->sfp_bus)) {
-                               sfp_sm_next(sfp, SFP_S_FAIL, 0);
+       init_done:
+                       sfp->sm_phy_retries = R_PHY_RETRY;
+                       goto phy_probe;
+               }
+               break;
+
+       case SFP_S_INIT_PHY:
+               if (event != SFP_E_TIMEOUT)
+                       break;
+       phy_probe:
+               /* TX_FAULT deasserted or we timed out with TX_FAULT
+                * clear.  Probe for the PHY and check the LOS state.
+                */
+               ret = sfp_sm_probe_for_phy(sfp);
+               if (ret == -ENODEV) {
+                       if (--sfp->sm_phy_retries) {
+                               sfp_sm_next(sfp, SFP_S_INIT_PHY, T_PHY_RETRY);
                                break;
+                       } else {
+                               dev_info(sfp->dev, "no PHY detected\n");
                        }
-                       sfp_sm_link_check_los(sfp);
-
-                       /* Reset the fault retry count */
-                       sfp->sm_fault_retries = N_FAULT;
+               } else if (ret) {
+                       sfp_sm_next(sfp, SFP_S_FAIL, 0);
+                       break;
                }
+               if (sfp_module_start(sfp->sfp_bus)) {
+                       sfp_sm_next(sfp, SFP_S_FAIL, 0);
+                       break;
+               }
+               sfp_sm_link_check_los(sfp);
+
+               /* Reset the fault retry count */
+               sfp->sm_fault_retries = N_FAULT;
                break;
 
        case SFP_S_INIT_TX_FAULT: