target/linux/generic/backport-5.4/717-v5.5-net-sfp-rework-upstream-interface.patch

   1 From 863b5b6941f9f43b924393b6ba2b36647e7dee42 Mon Sep 17 00:00:00 2001
   2 From: Russell King <rmk+kernel@armlinux.org.uk>
   3 Date: Thu, 7 Nov 2019 17:06:08 +0000
   4 Subject: [PATCH 615/660] net: sfp: rework upstream interface
   5
   6 The current upstream interface is an all-or-nothing, which is
   7 sub-optimal for future changes, as it doesn't allow the upstream driver
   8 to prepare for the SFP module becoming available, as it is at boot.
   9
  10 Switch to a find-sfp-bus, add-upstream, del-upstream, put-sfp-bus
  11 interface structure instead, which allows the upstream driver to
  12 prepare for a module being available as soon as add-upstream is called.
  13
  14 Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
  15 ---
  16  drivers/net/phy/phylink.c | 10 +++--
  17  drivers/net/phy/sfp-bus.c | 92 +++++++++++++++++++++++++++------------
  18  include/linux/sfp.h       | 25 +++++++----
  19  3 files changed, 88 insertions(+), 39 deletions(-)
  20
  21 --- a/drivers/net/phy/phylink.c
  22 +++ b/drivers/net/phy/phylink.c
  23 @@ -568,7 +568,7 @@ static int phylink_register_sfp(struct p
  24         struct sfp_bus *bus;
  25         int ret;
  26
  27 -       bus = sfp_register_upstream_node(fwnode, pl, &sfp_phylink_ops);
  28 +       bus = sfp_bus_find_fwnode(fwnode);
  29         if (IS_ERR(bus)) {
  30                 ret = PTR_ERR(bus);
  31                 phylink_err(pl, "unable to attach SFP bus: %d\n", ret);
  32 @@ -577,7 +577,10 @@ static int phylink_register_sfp(struct p
  33
  34         pl->sfp_bus = bus;
  35
  36 -       return 0;
  37 +       ret = sfp_bus_add_upstream(bus, pl, &sfp_phylink_ops);
  38 +       sfp_bus_put(bus);
  39 +
  40 +       return ret;
  41  }
  42
  43  /**
  44 @@ -675,8 +678,7 @@ EXPORT_SYMBOL_GPL(phylink_create);
  45   */
  46  void phylink_destroy(struct phylink *pl)
  47  {
  48 -       if (pl->sfp_bus)
  49 -               sfp_unregister_upstream(pl->sfp_bus);
  50 +       sfp_bus_del_upstream(pl->sfp_bus);
  51         if (pl->link_gpio)
  52                 gpiod_put(pl->link_gpio);
  53
  54 --- a/drivers/net/phy/sfp-bus.c
  55 +++ b/drivers/net/phy/sfp-bus.c
  56 @@ -329,10 +329,19 @@ static void sfp_bus_release(struct kref
  57         kfree(bus);
  58  }
  59
  60 -static void sfp_bus_put(struct sfp_bus *bus)
  61 +/**
  62 + * sfp_bus_put() - put a reference on the &struct sfp_bus
  63 + * bus: the &struct sfp_bus found via sfp_bus_find_fwnode()
  64 + *
  65 + * Put a reference on the &struct sfp_bus and free the underlying structure
  66 + * if this was the last reference.
  67 + */
  68 +void sfp_bus_put(struct sfp_bus *bus)
  69  {
  70 -       kref_put_mutex(&bus->kref, sfp_bus_release, &sfp_mutex);
  71 +       if (bus)
  72 +               kref_put_mutex(&bus->kref, sfp_bus_release, &sfp_mutex);
  73  }
  74 +EXPORT_SYMBOL_GPL(sfp_bus_put);
  75
  76  static int sfp_register_bus(struct sfp_bus *bus)
  77  {
  78 @@ -348,11 +357,11 @@ static int sfp_register_bus(struct sfp_b
  79                                 return ret;
  80                 }
  81         }
  82 +       bus->registered = true;
  83         bus->socket_ops->attach(bus->sfp);
  84         if (bus->started)
  85                 bus->socket_ops->start(bus->sfp);
  86         bus->upstream_ops->attach(bus->upstream, bus);
  87 -       bus->registered = true;
  88         return 0;
  89  }
  90
  91 @@ -446,13 +455,12 @@ static void sfp_upstream_clear(struct sf
  92  }
  93
  94  /**
  95 - * sfp_register_upstream_node() - parse and register the neighbouring device
  96 + * sfp_bus_find_fwnode() - parse and locate the SFP bus from fwnode
  97   * @fwnode: firmware node for the parent device (MAC or PHY)
  98 - * @upstream: the upstream private data
  99 - * @ops: the upstream's &struct sfp_upstream_ops
 100   *
 101 - * Parse the parent device's firmware node for a SFP bus, and register the
 102 - * SFP bus using sfp_register_upstream().
 103 + * Parse the parent device's firmware node for a SFP bus, and locate
 104 + * the sfp_bus structure, incrementing its reference count.  This must
 105 + * be put via sfp_bus_put() when done.
 106   *
 107   * Returns: on success, a pointer to the sfp_bus structure,
 108   *         %NULL if no SFP is specified,
 109 @@ -462,9 +470,7 @@ static void sfp_upstream_clear(struct sf
 110   *             %-ENOMEM if we failed to allocate the bus.
 111   *             an error from the upstream's connect_phy() method.
 112   */
 113 -struct sfp_bus *sfp_register_upstream_node(struct fwnode_handle *fwnode,
 114 -                                          void *upstream,
 115 -                                          const struct sfp_upstream_ops *ops)
 116 +struct sfp_bus *sfp_bus_find_fwnode(struct fwnode_handle *fwnode)
 117  {
 118         struct fwnode_reference_args ref;
 119         struct sfp_bus *bus;
 120 @@ -482,7 +488,39 @@ struct sfp_bus *sfp_register_upstream_no
 121         if (!bus)
 122                 return ERR_PTR(-ENOMEM);
 123
 124 +       return bus;
 125 +}
 126 +EXPORT_SYMBOL_GPL(sfp_bus_find_fwnode);
 127 +
 128 +/**
 129 + * sfp_bus_add_upstream() - parse and register the neighbouring device
 130 + * @bus: the &struct sfp_bus found via sfp_bus_find_fwnode()
 131 + * @upstream: the upstream private data
 132 + * @ops: the upstream's &struct sfp_upstream_ops
 133 + *
 134 + * Add upstream driver for the SFP bus, and if the bus is complete, register
 135 + * the SFP bus using sfp_register_upstream().  This takes a reference on the
 136 + * bus, so it is safe to put the bus after this call.
 137 + *
 138 + * Returns: on success, a pointer to the sfp_bus structure,
 139 + *         %NULL if no SFP is specified,
 140 + *         on failure, an error pointer value:
 141 + *             corresponding to the errors detailed for
 142 + *             fwnode_property_get_reference_args().
 143 + *             %-ENOMEM if we failed to allocate the bus.
 144 + *             an error from the upstream's connect_phy() method.
 145 + */
 146 +int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
 147 +                        const struct sfp_upstream_ops *ops)
 148 +{
 149 +       int ret;
 150 +
 151 +       /* If no bus, return success */
 152 +       if (!bus)
 153 +               return 0;
 154 +
 155         rtnl_lock();
 156 +       kref_get(&bus->kref);
 157         bus->upstream_ops = ops;
 158         bus->upstream = upstream;
 159
 160 @@ -495,33 +533,33 @@ struct sfp_bus *sfp_register_upstream_no
 161         }
 162         rtnl_unlock();
 163
 164 -       if (ret) {
 165 +       if (ret)
 166                 sfp_bus_put(bus);
 167 -               bus = ERR_PTR(ret);
 168 -       }
 169
 170 -       return bus;
 171 +       return ret;
 172  }
 173 -EXPORT_SYMBOL_GPL(sfp_register_upstream_node);
 174 +EXPORT_SYMBOL_GPL(sfp_bus_add_upstream);
 175
 176  /**
 177 - * sfp_unregister_upstream() - Unregister sfp bus
 178 + * sfp_bus_del_upstream() - Delete a sfp bus
 179   * @bus: a pointer to the &struct sfp_bus structure for the sfp module
 180   *
 181 - * Unregister a previously registered upstream connection for the SFP
 182 - * module. @bus is returned from sfp_register_upstream().
 183 + * Delete a previously registered upstream connection for the SFP
 184 + * module. @bus should have been added by sfp_bus_add_upstream().
 185   */
 186 -void sfp_unregister_upstream(struct sfp_bus *bus)
 187 +void sfp_bus_del_upstream(struct sfp_bus *bus)
 188  {
 189 -       rtnl_lock();
 190 -       if (bus->sfp)
 191 -               sfp_unregister_bus(bus);
 192 -       sfp_upstream_clear(bus);
 193 -       rtnl_unlock();
 194 +       if (bus) {
 195 +               rtnl_lock();
 196 +               if (bus->sfp)
 197 +                       sfp_unregister_bus(bus);
 198 +               sfp_upstream_clear(bus);
 199 +               rtnl_unlock();
 200
 201 -       sfp_bus_put(bus);
 202 +               sfp_bus_put(bus);
 203 +       }
 204  }
 205 -EXPORT_SYMBOL_GPL(sfp_unregister_upstream);
 206 +EXPORT_SYMBOL_GPL(sfp_bus_del_upstream);
 207
 208  /* Socket driver entry points */
 209  int sfp_add_phy(struct sfp_bus *bus, struct phy_device *phydev)
 210 --- a/include/linux/sfp.h
 211 +++ b/include/linux/sfp.h
 212 @@ -508,10 +508,11 @@ int sfp_get_module_eeprom(struct sfp_bus
 213                           u8 *data);
 214  void sfp_upstream_start(struct sfp_bus *bus);
 215  void sfp_upstream_stop(struct sfp_bus *bus);
 216 -struct sfp_bus *sfp_register_upstream_node(struct fwnode_handle *fwnode,
 217 -                                          void *upstream,
 218 -                                          const struct sfp_upstream_ops *ops);
 219 -void sfp_unregister_upstream(struct sfp_bus *bus);
 220 +void sfp_bus_put(struct sfp_bus *bus);
 221 +struct sfp_bus *sfp_bus_find_fwnode(struct fwnode_handle *fwnode);
 222 +int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
 223 +                        const struct sfp_upstream_ops *ops);
 224 +void sfp_bus_del_upstream(struct sfp_bus *bus);
 225  #else
 226  static inline int sfp_parse_port(struct sfp_bus *bus,
 227                                  const struct sfp_eeprom_id *id,
 228 @@ -553,14 +554,22 @@ static inline void sfp_upstream_stop(str
 229  {
 230  }
 231
 232 -static inline struct sfp_bus *sfp_register_upstream_node(
 233 -       struct fwnode_handle *fwnode, void *upstream,
 234 -       const struct sfp_upstream_ops *ops)
 235 +static inline void sfp_bus_put(struct sfp_bus *bus)
 236 +{
 237 +}
 238 +
 239 +static inline struct sfp_bus *sfp_bus_find_fwnode(struct fwnode_handle *fwnode)
 240  {
 241         return NULL;
 242  }
 243
 244 -static inline void sfp_unregister_upstream(struct sfp_bus *bus)
 245 +static int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
 246 +                               const struct sfp_upstream_ops *ops)
 247 +{
 248 +       return 0;
 249 +}
 250 +
 251 +static inline void sfp_bus_del_upstream(struct sfp_bus *bus)
 252  {
 253  }
 254  #endif