target/linux/generic/backport-5.4/732-v5.5-net-sfp-track-upstream-s-attachment-state-in-state-m.patch

   1 From ec6036a58f979c66bbd5cd9d0d1c783a98c2c644 Mon Sep 17 00:00:00 2001
   2 From: Russell King <rmk+kernel@armlinux.org.uk>
   3 Date: Tue, 5 Nov 2019 12:57:40 +0000
   4 Subject: [PATCH 630/660] net: sfp: track upstream's attachment state in state
   5  machine
   6
   7 Track the upstream's attachment state in the state machine rather than
   8 maintaining a boolean, which ensures that we have a strict order of
   9 ATTACH followed by an UP event - we can never believe that a newly
  10 attached upstream will be anything but down.
  11
  12 Rearrange the order of state machines so we run the module state
  13 machine after the upstream device's state machine, so the module state
  14 machine can check the current state of the device and take action to
  15 e.g. reset back to empty state when the upstream is detached.
  16
  17 This is to allow the module detection to run independently of the
  18 network device becoming available.
  19
  20 Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
  21 ---
  22  drivers/net/phy/sfp.c | 42 +++++++++++++++++++++++++++++-------------
  23  1 file changed, 29 insertions(+), 13 deletions(-)
  24
  25 --- a/drivers/net/phy/sfp.c
  26 +++ b/drivers/net/phy/sfp.c
  27 @@ -34,6 +34,8 @@ enum {
  28
  29         SFP_E_INSERT = 0,
  30         SFP_E_REMOVE,
  31 +       SFP_E_DEV_ATTACH,
  32 +       SFP_E_DEV_DETACH,
  33         SFP_E_DEV_DOWN,
  34         SFP_E_DEV_UP,
  35         SFP_E_TX_FAULT,
  36 @@ -48,7 +50,8 @@ enum {
  37         SFP_MOD_PRESENT,
  38         SFP_MOD_ERROR,
  39
  40 -       SFP_DEV_DOWN = 0,
  41 +       SFP_DEV_DETACHED = 0,
  42 +       SFP_DEV_DOWN,
  43         SFP_DEV_UP,
  44
  45         SFP_S_DOWN = 0,
  46 @@ -78,6 +81,7 @@ static const char *mod_state_to_str(unsi
  47  }
  48
  49  static const char * const dev_state_strings[] = {
  50 +       [SFP_DEV_DETACHED] = "detached",
  51         [SFP_DEV_DOWN] = "down",
  52         [SFP_DEV_UP] = "up",
  53  };
  54 @@ -92,6 +96,8 @@ static const char *dev_state_to_str(unsi
  55  static const char * const event_strings[] = {
  56         [SFP_E_INSERT] = "insert",
  57         [SFP_E_REMOVE] = "remove",
  58 +       [SFP_E_DEV_ATTACH] = "dev_attach",
  59 +       [SFP_E_DEV_DETACH] = "dev_detach",
  60         [SFP_E_DEV_DOWN] = "dev_down",
  61         [SFP_E_DEV_UP] = "dev_up",
  62         [SFP_E_TX_FAULT] = "tx_fault",
  63 @@ -186,7 +192,6 @@ struct sfp {
  64         struct gpio_desc *gpio[GPIO_MAX];
  65         int gpio_irq[GPIO_MAX];
  66
  67 -       bool attached;
  68         struct mutex st_mutex;                  /* Protects state */
  69         unsigned int state;
  70         struct delayed_work poll;
  71 @@ -1494,17 +1499,26 @@ static void sfp_sm_mod_remove(struct sfp
  72         dev_info(sfp->dev, "module removed\n");
  73  }
  74
  75 -/* This state machine tracks the netdev up/down state */
  76 +/* This state machine tracks the upstream's state */
  77  static void sfp_sm_device(struct sfp *sfp, unsigned int event)
  78  {
  79         switch (sfp->sm_dev_state) {
  80         default:
  81 -               if (event == SFP_E_DEV_UP)
  82 +               if (event == SFP_E_DEV_ATTACH)
  83 +                       sfp->sm_dev_state = SFP_DEV_DOWN;
  84 +               break;
  85 +
  86 +       case SFP_DEV_DOWN:
  87 +               if (event == SFP_E_DEV_DETACH)
  88 +                       sfp->sm_dev_state = SFP_DEV_DETACHED;
  89 +               else if (event == SFP_E_DEV_UP)
  90                         sfp->sm_dev_state = SFP_DEV_UP;
  91                 break;
  92
  93         case SFP_DEV_UP:
  94 -               if (event == SFP_E_DEV_DOWN)
  95 +               if (event == SFP_E_DEV_DETACH)
  96 +                       sfp->sm_dev_state = SFP_DEV_DETACHED;
  97 +               else if (event == SFP_E_DEV_DOWN)
  98                         sfp->sm_dev_state = SFP_DEV_DOWN;
  99                 break;
 100         }
 101 @@ -1515,17 +1529,20 @@ static void sfp_sm_device(struct sfp *sf
 102   */
 103  static void sfp_sm_module(struct sfp *sfp, unsigned int event)
 104  {
 105 -       /* Handle remove event globally, it resets this state machine */
 106 -       if (event == SFP_E_REMOVE) {
 107 +       /* Handle remove event globally, it resets this state machine.
 108 +        * Also deal with upstream detachment.
 109 +        */
 110 +       if (event == SFP_E_REMOVE || sfp->sm_dev_state < SFP_DEV_DOWN) {
 111                 if (sfp->sm_mod_state > SFP_MOD_PROBE)
 112                         sfp_sm_mod_remove(sfp);
 113 -               sfp_sm_mod_next(sfp, SFP_MOD_EMPTY, 0);
 114 +               if (sfp->sm_mod_state != SFP_MOD_EMPTY)
 115 +                       sfp_sm_mod_next(sfp, SFP_MOD_EMPTY, 0);
 116                 return;
 117         }
 118
 119         switch (sfp->sm_mod_state) {
 120         default:
 121 -               if (event == SFP_E_INSERT && sfp->attached)
 122 +               if (event == SFP_E_INSERT)
 123                         sfp_sm_mod_next(sfp, SFP_MOD_PROBE, T_SERIAL);
 124                 break;
 125
 126 @@ -1691,8 +1708,8 @@ static void sfp_sm_event(struct sfp *sfp
 127                 sm_state_to_str(sfp->sm_state),
 128                 event_to_str(event));
 129
 130 -       sfp_sm_module(sfp, event);
 131         sfp_sm_device(sfp, event);
 132 +       sfp_sm_module(sfp, event);
 133         sfp_sm_main(sfp, event);
 134
 135         dev_dbg(sfp->dev, "SM: exit %s:%s:%s\n",
 136 @@ -1705,15 +1722,14 @@ static void sfp_sm_event(struct sfp *sfp
 137
 138  static void sfp_attach(struct sfp *sfp)
 139  {
 140 -       sfp->attached = true;
 141 +       sfp_sm_event(sfp, SFP_E_DEV_ATTACH);
 142         if (sfp->state & SFP_F_PRESENT)
 143                 sfp_sm_event(sfp, SFP_E_INSERT);
 144  }
 145
 146  static void sfp_detach(struct sfp *sfp)
 147  {
 148 -       sfp->attached = false;
 149 -       sfp_sm_event(sfp, SFP_E_REMOVE);
 150 +       sfp_sm_event(sfp, SFP_E_DEV_DETACH);
 151  }
 152
 153  static void sfp_start(struct sfp *sfp)