drivers/net/phy/phy_link_topology.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Infrastructure to handle all PHY devices connected to a given netdev,
   4  * either directly or indirectly attached.
   5  *
   6  * Copyright (c) 2023 Maxime Chevallier<maxime.chevallier@bootlin.com>
   7  */
   8
   9 #include <linux/phy_link_topology.h>
  10 #include <linux/phy.h>
  11 #include <linux/rtnetlink.h>
  12 #include <linux/xarray.h>
  13
  14 static int netdev_alloc_phy_link_topology(struct net_device *dev)
  15 {
  16         struct phy_link_topology *topo;
  17
  18         topo = kzalloc(sizeof(*topo), GFP_KERNEL);
  19         if (!topo)
  20                 return -ENOMEM;
  21
  22         xa_init_flags(&topo->phys, XA_FLAGS_ALLOC1);
  23         topo->next_phy_index = 1;
  24
  25         dev->link_topo = topo;
  26
  27         return 0;
  28 }
  29
  30 int phy_link_topo_add_phy(struct net_device *dev,
  31                           struct phy_device *phy,
  32                           enum phy_upstream upt, void *upstream)
  33 {
  34         struct phy_link_topology *topo = dev->link_topo;
  35         struct phy_device_node *pdn;
  36         int ret;
  37
  38         if (!topo) {
  39                 ret = netdev_alloc_phy_link_topology(dev);
  40                 if (ret)
  41                         return ret;
  42
  43                 topo = dev->link_topo;
  44         }
  45
  46         pdn = kzalloc(sizeof(*pdn), GFP_KERNEL);
  47         if (!pdn)
  48                 return -ENOMEM;
  49
  50         pdn->phy = phy;
  51         switch (upt) {
  52         case PHY_UPSTREAM_MAC:
  53                 pdn->upstream.netdev = (struct net_device *)upstream;
  54                 if (phy_on_sfp(phy))
  55                         pdn->parent_sfp_bus = pdn->upstream.netdev->sfp_bus;
  56                 break;
  57         case PHY_UPSTREAM_PHY:
  58                 pdn->upstream.phydev = (struct phy_device *)upstream;
  59                 if (phy_on_sfp(phy))
  60                         pdn->parent_sfp_bus = pdn->upstream.phydev->sfp_bus;
  61                 break;
  62         default:
  63                 ret = -EINVAL;
  64                 goto err;
  65         }
  66         pdn->upstream_type = upt;
  67
  68         /* Attempt to re-use a previously allocated phy_index */
  69         if (phy->phyindex)
  70                 ret = xa_insert(&topo->phys, phy->phyindex, pdn, GFP_KERNEL);
  71         else
  72                 ret = xa_alloc_cyclic(&topo->phys, &phy->phyindex, pdn,
  73                                       xa_limit_32b, &topo->next_phy_index,
  74                                       GFP_KERNEL);
  75
  76         if (ret)
  77                 goto err;
  78
  79         return 0;
  80
  81 err:
  82         kfree(pdn);
  83         return ret;
  84 }
  85 EXPORT_SYMBOL_GPL(phy_link_topo_add_phy);
  86
  87 void phy_link_topo_del_phy(struct net_device *dev,
  88                            struct phy_device *phy)
  89 {
  90         struct phy_link_topology *topo = dev->link_topo;
  91         struct phy_device_node *pdn;
  92
  93         if (!topo)
  94                 return;
  95
  96         pdn = xa_erase(&topo->phys, phy->phyindex);
  97
  98         /* We delete the PHY from the topology, however we don't re-set the
  99          * phy->phyindex field. If the PHY isn't gone, we can re-assign it the
 100          * same index next time it's added back to the topology
 101          */
 102
 103         kfree(pdn);
 104 }
 105 EXPORT_SYMBOL_GPL(phy_link_topo_del_phy);