target/linux/generic/backport-5.4/735-v5.5-net-sfp-allow-sfp-to-probe-slow-to-initialise-GPON-m.patch

   1 From fb56cd08880aff8fb030e684fa4311bef712a499 Mon Sep 17 00:00:00 2001
   2 From: Russell King <rmk+kernel@armlinux.org.uk>
   3 Date: Tue, 5 Nov 2019 13:02:30 +0000
   4 Subject: [PATCH 633/660] net: sfp: allow sfp to probe slow to initialise GPON
   5  modules
   6
   7 Some GPON modules (e.g. Huawei MA5671A) take a significant amount of
   8 time to start responding on the I2C bus, contary to the SFF
   9 specifications.
  10
  11 Work around this by implementing a two-level timeout strategy, where
  12 we initially quickly retry for the module, and then use a slower retry
  13 after we exceed a maximum number of quick attempts.
  14
  15 Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
  16 ---
  17  drivers/net/phy/sfp.c | 38 ++++++++++++++++++++++++++++----------
  18  1 file changed, 28 insertions(+), 10 deletions(-)
  19
  20 --- a/drivers/net/phy/sfp.c
  21 +++ b/drivers/net/phy/sfp.c
  22 @@ -167,9 +167,12 @@ static const enum gpiod_flags gpio_flags
  23   * The SFF-8472 specifies t_serial ("Time from power on until module is
  24   * ready for data transmission over the two wire serial bus.") as 300ms.
  25   */
  26 -#define T_SERIAL       msecs_to_jiffies(300)
  27 -#define T_HPOWER_LEVEL msecs_to_jiffies(300)
  28 -#define T_PROBE_RETRY  msecs_to_jiffies(100)
  29 +#define T_SERIAL               msecs_to_jiffies(300)
  30 +#define T_HPOWER_LEVEL         msecs_to_jiffies(300)
  31 +#define T_PROBE_RETRY_INIT     msecs_to_jiffies(100)
  32 +#define R_PROBE_RETRY_INIT     10
  33 +#define T_PROBE_RETRY_SLOW     msecs_to_jiffies(5000)
  34 +#define R_PROBE_RETRY_SLOW     12
  35
  36  /* SFP modules appear to always have their PHY configured for bus address
  37   * 0x56 (which with mdio-i2c, translates to a PHY address of 22).
  38 @@ -204,6 +207,8 @@ struct sfp {
  39         struct delayed_work timeout;
  40         struct mutex sm_mutex;                  /* Protects state machine */
  41         unsigned char sm_mod_state;
  42 +       unsigned char sm_mod_tries_init;
  43 +       unsigned char sm_mod_tries;
  44         unsigned char sm_dev_state;
  45         unsigned short sm_state;
  46         unsigned int sm_retries;
  47 @@ -1457,7 +1462,7 @@ static int sfp_sm_mod_hpower(struct sfp
  48         return 0;
  49  }
  50
  51 -static int sfp_sm_mod_probe(struct sfp *sfp)
  52 +static int sfp_sm_mod_probe(struct sfp *sfp, bool report)
  53  {
  54         /* SFP module inserted - read I2C data */
  55         struct sfp_eeprom_id id;
  56 @@ -1467,7 +1472,8 @@ static int sfp_sm_mod_probe(struct sfp *
  57
  58         ret = sfp_read(sfp, false, 0, &id, sizeof(id));
  59         if (ret < 0) {
  60 -               dev_err(sfp->dev, "failed to read EEPROM: %d\n", ret);
  61 +               if (report)
  62 +                       dev_err(sfp->dev, "failed to read EEPROM: %d\n", ret);
  63                 return -EAGAIN;
  64         }
  65
  66 @@ -1614,8 +1620,11 @@ static void sfp_sm_module(struct sfp *sf
  67
  68         switch (sfp->sm_mod_state) {
  69         default:
  70 -               if (event == SFP_E_INSERT)
  71 +               if (event == SFP_E_INSERT) {
  72                         sfp_sm_mod_next(sfp, SFP_MOD_PROBE, T_SERIAL);
  73 +                       sfp->sm_mod_tries_init = R_PROBE_RETRY_INIT;
  74 +                       sfp->sm_mod_tries = R_PROBE_RETRY_SLOW;
  75 +               }
  76                 break;
  77
  78         case SFP_MOD_PROBE:
  79 @@ -1623,10 +1632,19 @@ static void sfp_sm_module(struct sfp *sf
  80                 if (event != SFP_E_TIMEOUT)
  81                         break;
  82
  83 -               err = sfp_sm_mod_probe(sfp);
  84 +               err = sfp_sm_mod_probe(sfp, sfp->sm_mod_tries == 1);
  85                 if (err == -EAGAIN) {
  86 -                       sfp_sm_set_timer(sfp, T_PROBE_RETRY);
  87 -                       break;
  88 +                       if (sfp->sm_mod_tries_init &&
  89 +                          --sfp->sm_mod_tries_init) {
  90 +                               sfp_sm_set_timer(sfp, T_PROBE_RETRY_INIT);
  91 +                               break;
  92 +                       } else if (sfp->sm_mod_tries && --sfp->sm_mod_tries) {
  93 +                               if (sfp->sm_mod_tries == R_PROBE_RETRY_SLOW - 1)
  94 +                                       dev_warn(sfp->dev,
  95 +                                                "please wait, module slow to respond\n");
  96 +                               sfp_sm_set_timer(sfp, T_PROBE_RETRY_SLOW);
  97 +                               break;
  98 +                       }
  99                 }
 100                 if (err < 0) {
 101                         sfp_sm_mod_next(sfp, SFP_MOD_ERROR, 0);
 102 @@ -1661,7 +1679,7 @@ static void sfp_sm_module(struct sfp *sf
 103                                 sfp_module_remove(sfp->sfp_bus);
 104                                 sfp_sm_mod_next(sfp, SFP_MOD_ERROR, 0);
 105                         } else {
 106 -                               sfp_sm_set_timer(sfp, T_PROBE_RETRY);
 107 +                               sfp_sm_set_timer(sfp, T_PROBE_RETRY_INIT);
 108                         }
 109                         break;
 110                 }