drivers/thunderbolt/path.c

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