target/linux/generic/backport-5.4/733-v5.5-net-sfp-split-power-mode-switching-from-probe.patch

   1 From fdff863a4ce3677907f64396e34c45025abb6600 Mon Sep 17 00:00:00 2001
   2 From: Russell King <rmk+kernel@armlinux.org.uk>
   3 Date: Tue, 5 Nov 2019 12:59:36 +0000
   4 Subject: [PATCH 631/660] net: sfp: split power mode switching from probe
   5
   6 Switch the power mode switching from the probe, so that we don't
   7 repeatedly re-probe the SFP device if there is a problem accessing
   8 the registers at I2C address 0x51.
   9
  10 In splitting this out, we can also fix a bug where we leave the module
  11 in high-power mode when the upstream device is detached but the module
  12 is still inserted.
  13
  14 Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
  15 ---
  16  drivers/net/phy/sfp.c | 101 ++++++++++++++++++++++++++----------------
  17  1 file changed, 64 insertions(+), 37 deletions(-)
  18
  19 --- a/drivers/net/phy/sfp.c
  20 +++ b/drivers/net/phy/sfp.c
  21 @@ -49,6 +49,7 @@ enum {
  22         SFP_MOD_EMPTY = 0,
  23         SFP_MOD_PROBE,
  24         SFP_MOD_HPOWER,
  25 +       SFP_MOD_WAITPWR,
  26         SFP_MOD_PRESENT,
  27         SFP_MOD_ERROR,
  28
  29 @@ -71,6 +72,7 @@ static const char  * const mod_state_str
  30         [SFP_MOD_EMPTY] = "empty",
  31         [SFP_MOD_PROBE] = "probe",
  32         [SFP_MOD_HPOWER] = "hpower",
  33 +       [SFP_MOD_WAITPWR] = "waitpwr",
  34         [SFP_MOD_PRESENT] = "present",
  35         [SFP_MOD_ERROR] = "error",
  36  };
  37 @@ -1423,37 +1425,34 @@ static int sfp_module_parse_power(struct
  38         return 0;
  39  }
  40
  41 -static int sfp_sm_mod_hpower(struct sfp *sfp)
  42 +static int sfp_sm_mod_hpower(struct sfp *sfp, bool enable)
  43  {
  44         u8 val;
  45         int err;
  46
  47 -       if (sfp->module_power_mW <= 1000)
  48 -               return 0;
  49 -
  50         err = sfp_read(sfp, true, SFP_EXT_STATUS, &val, sizeof(val));
  51         if (err != sizeof(val)) {
  52                 dev_err(sfp->dev, "Failed to read EEPROM: %d\n", err);
  53 -               err = -EAGAIN;
  54 -               goto err;
  55 +               return -EAGAIN;
  56         }
  57
  58 -       val |= BIT(0);
  59 +       if (enable)
  60 +               val |= BIT(0);
  61 +       else
  62 +               val &= ~BIT(0);
  63
  64         err = sfp_write(sfp, true, SFP_EXT_STATUS, &val, sizeof(val));
  65         if (err != sizeof(val)) {
  66                 dev_err(sfp->dev, "Failed to write EEPROM: %d\n", err);
  67 -               err = -EAGAIN;
  68 -               goto err;
  69 +               return -EAGAIN;
  70         }
  71
  72 -       dev_info(sfp->dev, "Module switched to %u.%uW power level\n",
  73 -                sfp->module_power_mW / 1000,
  74 -                (sfp->module_power_mW / 100) % 10);
  75 -       return T_HPOWER_LEVEL;
  76 +       if (enable)
  77 +               dev_info(sfp->dev, "Module switched to %u.%uW power level\n",
  78 +                        sfp->module_power_mW / 1000,
  79 +                        (sfp->module_power_mW / 100) % 10);
  80
  81 -err:
  82 -       return err;
  83 +       return 0;
  84  }
  85
  86  static int sfp_sm_mod_probe(struct sfp *sfp)
  87 @@ -1549,7 +1548,7 @@ static int sfp_sm_mod_probe(struct sfp *
  88         if (ret < 0)
  89                 return ret;
  90
  91 -       return sfp_sm_mod_hpower(sfp);
  92 +       return 0;
  93  }
  94
  95  static void sfp_sm_mod_remove(struct sfp *sfp)
  96 @@ -1594,13 +1593,22 @@ static void sfp_sm_device(struct sfp *sf
  97   */
  98  static void sfp_sm_module(struct sfp *sfp, unsigned int event)
  99  {
 100 -       /* Handle remove event globally, it resets this state machine.
 101 -        * Also deal with upstream detachment.
 102 -        */
 103 -       if (event == SFP_E_REMOVE || sfp->sm_dev_state < SFP_DEV_DOWN) {
 104 +       int err;
 105 +
 106 +       /* Handle remove event globally, it resets this state machine */
 107 +       if (event == SFP_E_REMOVE) {
 108                 if (sfp->sm_mod_state > SFP_MOD_PROBE)
 109                         sfp_sm_mod_remove(sfp);
 110 -               if (sfp->sm_mod_state != SFP_MOD_EMPTY)
 111 +               sfp_sm_mod_next(sfp, SFP_MOD_EMPTY, 0);
 112 +               return;
 113 +       }
 114 +
 115 +       /* Handle device detach globally */
 116 +       if (sfp->sm_dev_state < SFP_DEV_DOWN) {
 117 +               if (sfp->module_power_mW > 1000 &&
 118 +                   sfp->sm_mod_state > SFP_MOD_HPOWER)
 119 +                       sfp_sm_mod_hpower(sfp, false);
 120 +               if (sfp->sm_mod_state > SFP_MOD_EMPTY)
 121                         sfp_sm_mod_next(sfp, SFP_MOD_EMPTY, 0);
 122                 return;
 123         }
 124 @@ -1612,26 +1620,45 @@ static void sfp_sm_module(struct sfp *sf
 125                 break;
 126
 127         case SFP_MOD_PROBE:
 128 -               if (event == SFP_E_TIMEOUT) {
 129 -                       int val = sfp_sm_mod_probe(sfp);
 130 +               if (event != SFP_E_TIMEOUT)
 131 +                       break;
 132
 133 -                       if (val == 0)
 134 -                               sfp_sm_mod_next(sfp, SFP_MOD_PRESENT, 0);
 135 -                       else if (val > 0)
 136 -                               sfp_sm_mod_next(sfp, SFP_MOD_HPOWER, val);
 137 -                       else if (val != -EAGAIN)
 138 -                               sfp_sm_mod_next(sfp, SFP_MOD_ERROR, 0);
 139 -                       else
 140 -                               sfp_sm_set_timer(sfp, T_PROBE_RETRY);
 141 +               err = sfp_sm_mod_probe(sfp);
 142 +               if (err == -EAGAIN) {
 143 +                       sfp_sm_set_timer(sfp, T_PROBE_RETRY);
 144 +                       break;
 145                 }
 146 -               break;
 147 +               if (err < 0) {
 148 +                       sfp_sm_mod_next(sfp, SFP_MOD_ERROR, 0);
 149 +                       break;
 150 +               }
 151 +
 152 +               /* If this is a power level 1 module, we are done */
 153 +               if (sfp->module_power_mW <= 1000)
 154 +                       goto insert;
 155
 156 +               sfp_sm_mod_next(sfp, SFP_MOD_HPOWER, 0);
 157 +               /* fall through */
 158         case SFP_MOD_HPOWER:
 159 -               if (event == SFP_E_TIMEOUT) {
 160 -                       sfp_sm_mod_next(sfp, SFP_MOD_PRESENT, 0);
 161 +               /* Enable high power mode */
 162 +               err = sfp_sm_mod_hpower(sfp, true);
 163 +               if (err == 0)
 164 +                       sfp_sm_mod_next(sfp, SFP_MOD_WAITPWR, T_HPOWER_LEVEL);
 165 +               else if (err != -EAGAIN)
 166 +                       sfp_sm_mod_next(sfp, SFP_MOD_ERROR, 0);
 167 +               else
 168 +                       sfp_sm_set_timer(sfp, T_PROBE_RETRY);
 169 +               break;
 170 +
 171 +       case SFP_MOD_WAITPWR:
 172 +               /* Wait for T_HPOWER_LEVEL to time out */
 173 +               if (event != SFP_E_TIMEOUT)
 174                         break;
 175 -               }
 176 -               /* fallthrough */
 177 +
 178 +       insert:
 179 +               sfp_sm_mod_next(sfp, SFP_MOD_PRESENT, 0);
 180 +               break;
 181 +
 182         case SFP_MOD_PRESENT:
 183         case SFP_MOD_ERROR:
 184                 break;