drivers/thunderbolt/path.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Thunderbolt Cactus Ridge driver - path/tunnel functionality
   4  *
   5  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
   6  */
   7
   8 #include <linux/slab.h>
   9 #include <linux/errno.h>
  10
  11 #include "tb.h"
  12
  13
  14 static void tb_dump_hop(struct tb_port *port, struct tb_regs_hop *hop)
  15 {
  16         tb_port_info(port, " Hop through port %d to hop %d (%s)\n",
  17                      hop->out_port, hop->next_hop,
  18                      hop->enable ? "enabled" : "disabled");
  19         tb_port_info(port, "  Weight: %d Priority: %d Credits: %d Drop: %d\n",
  20                      hop->weight, hop->priority,
  21                      hop->initial_credits, hop->drop_packages);
  22         tb_port_info(port, "   Counter enabled: %d Counter index: %d\n",
  23                      hop->counter_enable, hop->counter);
  24         tb_port_info(port, "  Flow Control (In/Eg): %d/%d Shared Buffer (In/Eg): %d/%d\n",
  25                      hop->ingress_fc, hop->egress_fc,
  26                      hop->ingress_shared_buffer, hop->egress_shared_buffer);
  27         tb_port_info(port, "  Unknown1: %#x Unknown2: %#x Unknown3: %#x\n",
  28                      hop->unknown1, hop->unknown2, hop->unknown3);
  29 }
  30
  31 /**
  32  * tb_path_alloc() - allocate a thunderbolt path
  33  *
  34  * Return: Returns a tb_path on success or NULL on failure.
  35  */
  36 struct tb_path *tb_path_alloc(struct tb *tb, int num_hops)
  37 {
  38         struct tb_path *path = kzalloc(sizeof(*path), GFP_KERNEL);
  39         if (!path)
  40                 return NULL;
  41         path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
  42         if (!path->hops) {
  43                 kfree(path);
  44                 return NULL;
  45         }
  46         path->tb = tb;
  47         path->path_length = num_hops;
  48         return path;
  49 }
  50
  51 /**
  52  * tb_path_free() - free a deactivated path
  53  */
  54 void tb_path_free(struct tb_path *path)
  55 {
  56         if (path->activated) {
  57                 tb_WARN(path->tb, "trying to free an activated path\n")
  58                 return;
  59         }
  60         kfree(path->hops);
  61         kfree(path);
  62 }
  63
  64 static void __tb_path_deallocate_nfc(struct tb_path *path, int first_hop)
  65 {
  66         int i, res;
  67         for (i = first_hop; i < path->path_length; i++) {
  68                 res = tb_port_add_nfc_credits(path->hops[i].in_port,
  69                                               -path->nfc_credits);
  70                 if (res)
  71                         tb_port_warn(path->hops[i].in_port,
  72                                      "nfc credits deallocation failed for hop %d\n",
  73                                      i);
  74         }
  75 }
  76
  77 static void __tb_path_deactivate_hops(struct tb_path *path, int first_hop)
  78 {
  79         int i, res;
  80         struct tb_regs_hop hop = { };
  81         for (i = first_hop; i < path->path_length; i++) {
  82                 res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
  83                                     2 * path->hops[i].in_hop_index, 2);
  84                 if (res)
  85                         tb_port_warn(path->hops[i].in_port,
  86                                      "hop deactivation failed for hop %d, index %d\n",
  87                                      i, path->hops[i].in_hop_index);
  88         }
  89 }
  90
  91 void tb_path_deactivate(struct tb_path *path)
  92 {
  93         if (!path->activated) {
  94                 tb_WARN(path->tb, "trying to deactivate an inactive path\n");
  95                 return;
  96         }
  97         tb_info(path->tb,
  98                 "deactivating path from %llx:%x to %llx:%x\n",
  99                 tb_route(path->hops[0].in_port->sw),
 100                 path->hops[0].in_port->port,
 101                 tb_route(path->hops[path->path_length - 1].out_port->sw),
 102                 path->hops[path->path_length - 1].out_port->port);
 103         __tb_path_deactivate_hops(path, 0);
 104         __tb_path_deallocate_nfc(path, 0);
 105         path->activated = false;
 106 }
 107
 108 /**
 109  * tb_path_activate() - activate a path
 110  *
 111  * Activate a path starting with the last hop and iterating backwards. The
 112  * caller must fill path->hops before calling tb_path_activate().
 113  *
 114  * Return: Returns 0 on success or an error code on failure.
 115  */
 116 int tb_path_activate(struct tb_path *path)
 117 {
 118         int i, res;
 119         enum tb_path_port out_mask, in_mask;
 120         if (path->activated) {
 121                 tb_WARN(path->tb, "trying to activate already activated path\n");
 122                 return -EINVAL;
 123         }
 124
 125         tb_info(path->tb,
 126                 "activating path from %llx:%x to %llx:%x\n",
 127                 tb_route(path->hops[0].in_port->sw),
 128                 path->hops[0].in_port->port,
 129                 tb_route(path->hops[path->path_length - 1].out_port->sw),
 130                 path->hops[path->path_length - 1].out_port->port);
 131
 132         /* Clear counters. */
 133         for (i = path->path_length - 1; i >= 0; i--) {
 134                 if (path->hops[i].in_counter_index == -1)
 135                         continue;
 136                 res = tb_port_clear_counter(path->hops[i].in_port,
 137                                             path->hops[i].in_counter_index);
 138                 if (res)
 139                         goto err;
 140         }
 141
 142         /* Add non flow controlled credits. */
 143         for (i = path->path_length - 1; i >= 0; i--) {
 144                 res = tb_port_add_nfc_credits(path->hops[i].in_port,
 145                                               path->nfc_credits);
 146                 if (res) {
 147                         __tb_path_deallocate_nfc(path, i);
 148                         goto err;
 149                 }
 150         }
 151
 152         /* Activate hops. */
 153         for (i = path->path_length - 1; i >= 0; i--) {
 154                 struct tb_regs_hop hop = { 0 };
 155
 156                 /*
 157                  * We do (currently) not tear down paths setup by the firmeware.
 158                  * If a firmware device is unplugged and plugged in again then
 159                  * it can happen that we reuse some of the hops from the (now
 160                  * defunct) firmeware path. This causes the hotplug operation to
 161                  * fail (the pci device does not show up). Clearing the hop
 162                  * before overwriting it fixes the problem.
 163                  *
 164                  * Should be removed once we discover and tear down firmeware
 165                  * paths.
 166                  */
 167                 res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
 168                                     2 * path->hops[i].in_hop_index, 2);
 169                 if (res) {
 170                         __tb_path_deactivate_hops(path, i);
 171                         __tb_path_deallocate_nfc(path, 0);
 172                         goto err;
 173                 }
 174
 175                 /* dword 0 */
 176                 hop.next_hop = path->hops[i].next_hop_index;
 177                 hop.out_port = path->hops[i].out_port->port;
 178                 /* TODO: figure out why these are good values */
 179                 hop.initial_credits = (i == path->path_length - 1) ? 16 : 7;
 180                 hop.unknown1 = 0;
 181                 hop.enable = 1;
 182
 183                 /* dword 1 */
 184                 out_mask = (i == path->path_length - 1) ?
 185                                 TB_PATH_DESTINATION : TB_PATH_INTERNAL;
 186                 in_mask = (i == 0) ? TB_PATH_SOURCE : TB_PATH_INTERNAL;
 187                 hop.weight = path->weight;
 188                 hop.unknown2 = 0;
 189                 hop.priority = path->priority;
 190                 hop.drop_packages = path->drop_packages;
 191                 hop.counter = path->hops[i].in_counter_index;
 192                 hop.counter_enable = path->hops[i].in_counter_index != -1;
 193                 hop.ingress_fc = path->ingress_fc_enable & in_mask;
 194                 hop.egress_fc = path->egress_fc_enable & out_mask;
 195                 hop.ingress_shared_buffer = path->ingress_shared_buffer
 196                                             & in_mask;
 197                 hop.egress_shared_buffer = path->egress_shared_buffer
 198                                             & out_mask;
 199                 hop.unknown3 = 0;
 200
 201                 tb_port_info(path->hops[i].in_port, "Writing hop %d, index %d",
 202                              i, path->hops[i].in_hop_index);
 203                 tb_dump_hop(path->hops[i].in_port, &hop);
 204                 res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
 205                                     2 * path->hops[i].in_hop_index, 2);
 206                 if (res) {
 207                         __tb_path_deactivate_hops(path, i);
 208                         __tb_path_deallocate_nfc(path, 0);
 209                         goto err;
 210                 }
 211         }
 212         path->activated = true;
 213         tb_info(path->tb, "path activation complete\n");
 214         return 0;
 215 err:
 216         tb_WARN(path->tb, "path activation failed\n");
 217         return res;
 218 }
 219
 220 /**
 221  * tb_path_is_invalid() - check whether any ports on the path are invalid
 222  *
 223  * Return: Returns true if the path is invalid, false otherwise.
 224  */
 225 bool tb_path_is_invalid(struct tb_path *path)
 226 {
 227         int i = 0;
 228         for (i = 0; i < path->path_length; i++) {
 229                 if (path->hops[i].in_port->sw->is_unplugged)
 230                         return true;
 231                 if (path->hops[i].out_port->sw->is_unplugged)
 232                         return true;
 233         }
 234         return false;
 235 }