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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Incremental bus scan, based on bus topology4 *5 * Copyright (C) 2004-2006 Kristian Hoegsberg <krh@bitplanet.net>6 */7 8#include <linux/bug.h>9#include <linux/errno.h>10#include <linux/firewire.h>11#include <linux/firewire-constants.h>12#include <linux/jiffies.h>13#include <linux/kernel.h>14#include <linux/list.h>15#include <linux/module.h>16#include <linux/slab.h>17#include <linux/spinlock.h>18 19#include <linux/atomic.h>20#include <asm/byteorder.h>21 22#include "core.h"23#include "phy-packet-definitions.h"24#include <trace/events/firewire.h>25 26static struct fw_node *fw_node_create(u32 sid, int port_count, int color)27{28 struct fw_node *node;29 30 node = kzalloc(struct_size(node, ports, port_count), GFP_ATOMIC);31 if (node == NULL)32 return NULL;33 34 node->color = color;35 node->node_id = LOCAL_BUS | phy_packet_self_id_get_phy_id(sid);36 node->link_on = phy_packet_self_id_zero_get_link_active(sid);37 // NOTE: Only two bits, thus only for SCODE_100, SCODE_200, SCODE_400, and SCODE_BETA.38 node->phy_speed = phy_packet_self_id_zero_get_scode(sid);39 node->initiated_reset = phy_packet_self_id_zero_get_initiated_reset(sid);40 node->port_count = port_count;41 42 kref_init(&node->kref);43 INIT_LIST_HEAD(&node->link);44 45 return node;46}47 48/*49 * Compute the maximum hop count for this node and it's children. The50 * maximum hop count is the maximum number of connections between any51 * two nodes in the subtree rooted at this node. We need this for52 * setting the gap count. As we build the tree bottom up in53 * build_tree() below, this is fairly easy to do: for each node we54 * maintain the max hop count and the max depth, ie the number of hops55 * to the furthest leaf. Computing the max hop count breaks down into56 * two cases: either the path goes through this node, in which case57 * the hop count is the sum of the two biggest child depths plus 2.58 * Or it could be the case that the max hop path is entirely59 * containted in a child tree, in which case the max hop count is just60 * the max hop count of this child.61 */62static void update_hop_count(struct fw_node *node)63{64 int depths[2] = { -1, -1 };65 int max_child_hops = 0;66 int i;67 68 for (i = 0; i < node->port_count; i++) {69 if (node->ports[i] == NULL)70 continue;71 72 if (node->ports[i]->max_hops > max_child_hops)73 max_child_hops = node->ports[i]->max_hops;74 75 if (node->ports[i]->max_depth > depths[0]) {76 depths[1] = depths[0];77 depths[0] = node->ports[i]->max_depth;78 } else if (node->ports[i]->max_depth > depths[1])79 depths[1] = node->ports[i]->max_depth;80 }81 82 node->max_depth = depths[0] + 1;83 node->max_hops = max(max_child_hops, depths[0] + depths[1] + 2);84}85 86static inline struct fw_node *fw_node(struct list_head *l)87{88 return list_entry(l, struct fw_node, link);89}90 91/*92 * This function builds the tree representation of the topology given93 * by the self IDs from the latest bus reset. During the construction94 * of the tree, the function checks that the self IDs are valid and95 * internally consistent. On success this function returns the96 * fw_node corresponding to the local card otherwise NULL.97 */98static struct fw_node *build_tree(struct fw_card *card, const u32 *sid, int self_id_count,99 unsigned int generation)100{101 struct self_id_sequence_enumerator enumerator = {102 .cursor = sid,103 .quadlet_count = self_id_count,104 };105 struct fw_node *node, *child, *local_node, *irm_node;106 struct list_head stack;107 int phy_id, stack_depth;108 int gap_count;109 bool beta_repeaters_present;110 111 local_node = NULL;112 node = NULL;113 INIT_LIST_HEAD(&stack);114 stack_depth = 0;115 phy_id = 0;116 irm_node = NULL;117 gap_count = phy_packet_self_id_zero_get_gap_count(*sid);118 beta_repeaters_present = false;119 120 while (enumerator.quadlet_count > 0) {121 unsigned int child_port_count = 0;122 unsigned int total_port_count = 0;123 unsigned int parent_count = 0;124 unsigned int quadlet_count;125 const u32 *self_id_sequence;126 unsigned int port_capacity;127 enum phy_packet_self_id_port_status port_status;128 unsigned int port_index;129 struct list_head *h;130 int i;131 132 self_id_sequence = self_id_sequence_enumerator_next(&enumerator, &quadlet_count);133 if (IS_ERR(self_id_sequence)) {134 if (PTR_ERR(self_id_sequence) != -ENODATA) {135 fw_err(card, "inconsistent extended self IDs: %ld\n",136 PTR_ERR(self_id_sequence));137 return NULL;138 }139 break;140 }141 142 port_capacity = self_id_sequence_get_port_capacity(quadlet_count);143 trace_self_id_sequence(card->index, self_id_sequence, quadlet_count, generation);144 145 for (port_index = 0; port_index < port_capacity; ++port_index) {146 port_status = self_id_sequence_get_port_status(self_id_sequence, quadlet_count,147 port_index);148 switch (port_status) {149 case PHY_PACKET_SELF_ID_PORT_STATUS_CHILD:150 ++child_port_count;151 fallthrough;152 case PHY_PACKET_SELF_ID_PORT_STATUS_PARENT:153 case PHY_PACKET_SELF_ID_PORT_STATUS_NCONN:154 ++total_port_count;155 fallthrough;156 case PHY_PACKET_SELF_ID_PORT_STATUS_NONE:157 default:158 break;159 }160 }161 162 if (phy_id != phy_packet_self_id_get_phy_id(self_id_sequence[0])) {163 fw_err(card, "PHY ID mismatch in self ID: %d != %d\n",164 phy_id, phy_packet_self_id_get_phy_id(self_id_sequence[0]));165 return NULL;166 }167 168 if (child_port_count > stack_depth) {169 fw_err(card, "topology stack underflow\n");170 return NULL;171 }172 173 /*174 * Seek back from the top of our stack to find the175 * start of the child nodes for this node.176 */177 for (i = 0, h = &stack; i < child_port_count; i++)178 h = h->prev;179 /*180 * When the stack is empty, this yields an invalid value,181 * but that pointer will never be dereferenced.182 */183 child = fw_node(h);184 185 node = fw_node_create(self_id_sequence[0], total_port_count, card->color);186 if (node == NULL) {187 fw_err(card, "out of memory while building topology\n");188 return NULL;189 }190 191 if (phy_id == (card->node_id & 0x3f))192 local_node = node;193 194 if (phy_packet_self_id_zero_get_contender(self_id_sequence[0]))195 irm_node = node;196 197 for (port_index = 0; port_index < total_port_count; ++port_index) {198 port_status = self_id_sequence_get_port_status(self_id_sequence, quadlet_count,199 port_index);200 switch (port_status) {201 case PHY_PACKET_SELF_ID_PORT_STATUS_PARENT:202 // Who's your daddy? We dont know the parent node at this time, so203 // we temporarily abuse node->color for remembering the entry in204 // the node->ports array where the parent node should be. Later,205 // when we handle the parent node, we fix up the reference.206 ++parent_count;207 node->color = port_index;208 break;209 210 case PHY_PACKET_SELF_ID_PORT_STATUS_CHILD:211 node->ports[port_index] = child;212 // Fix up parent reference for this child node.213 child->ports[child->color] = node;214 child->color = card->color;215 child = fw_node(child->link.next);216 break;217 case PHY_PACKET_SELF_ID_PORT_STATUS_NCONN:218 case PHY_PACKET_SELF_ID_PORT_STATUS_NONE:219 default:220 break;221 }222 }223 224 // Check that the node reports exactly one parent port, except for the root, which225 // of course should have no parents.226 if ((enumerator.quadlet_count == 0 && parent_count != 0) ||227 (enumerator.quadlet_count > 0 && parent_count != 1)) {228 fw_err(card, "parent port inconsistency for node %d: "229 "parent_count=%d\n", phy_id, parent_count);230 return NULL;231 }232 233 /* Pop the child nodes off the stack and push the new node. */234 __list_del(h->prev, &stack);235 list_add_tail(&node->link, &stack);236 stack_depth += 1 - child_port_count;237 238 if (node->phy_speed == SCODE_BETA && parent_count + child_port_count > 1)239 beta_repeaters_present = true;240 241 // If PHYs report different gap counts, set an invalid count which will force a gap242 // count reconfiguration and a reset.243 if (phy_packet_self_id_zero_get_gap_count(self_id_sequence[0]) != gap_count)244 gap_count = 0;245 246 update_hop_count(node);247 248 phy_id++;249 }250 251 card->root_node = node;252 card->irm_node = irm_node;253 card->gap_count = gap_count;254 card->beta_repeaters_present = beta_repeaters_present;255 256 return local_node;257}258 259typedef void (*fw_node_callback_t)(struct fw_card * card,260 struct fw_node * node,261 struct fw_node * parent);262 263static void for_each_fw_node(struct fw_card *card, struct fw_node *root,264 fw_node_callback_t callback)265{266 struct list_head list;267 struct fw_node *node, *next, *child, *parent;268 int i;269 270 INIT_LIST_HEAD(&list);271 272 fw_node_get(root);273 list_add_tail(&root->link, &list);274 parent = NULL;275 list_for_each_entry(node, &list, link) {276 node->color = card->color;277 278 for (i = 0; i < node->port_count; i++) {279 child = node->ports[i];280 if (!child)281 continue;282 if (child->color == card->color)283 parent = child;284 else {285 fw_node_get(child);286 list_add_tail(&child->link, &list);287 }288 }289 290 callback(card, node, parent);291 }292 293 list_for_each_entry_safe(node, next, &list, link)294 fw_node_put(node);295}296 297static void report_lost_node(struct fw_card *card,298 struct fw_node *node, struct fw_node *parent)299{300 fw_node_event(card, node, FW_NODE_DESTROYED);301 fw_node_put(node);302 303 /* Topology has changed - reset bus manager retry counter */304 card->bm_retries = 0;305}306 307static void report_found_node(struct fw_card *card,308 struct fw_node *node, struct fw_node *parent)309{310 int b_path = (node->phy_speed == SCODE_BETA);311 312 if (parent != NULL) {313 /* min() macro doesn't work here with gcc 3.4 */314 node->max_speed = parent->max_speed < node->phy_speed ?315 parent->max_speed : node->phy_speed;316 node->b_path = parent->b_path && b_path;317 } else {318 node->max_speed = node->phy_speed;319 node->b_path = b_path;320 }321 322 fw_node_event(card, node, FW_NODE_CREATED);323 324 /* Topology has changed - reset bus manager retry counter */325 card->bm_retries = 0;326}327 328/* Must be called with card->lock held */329void fw_destroy_nodes(struct fw_card *card)330{331 card->color++;332 if (card->local_node != NULL)333 for_each_fw_node(card, card->local_node, report_lost_node);334 card->local_node = NULL;335}336 337static void move_tree(struct fw_node *node0, struct fw_node *node1, int port)338{339 struct fw_node *tree;340 int i;341 342 tree = node1->ports[port];343 node0->ports[port] = tree;344 for (i = 0; i < tree->port_count; i++) {345 if (tree->ports[i] == node1) {346 tree->ports[i] = node0;347 break;348 }349 }350}351 352/*353 * Compare the old topology tree for card with the new one specified by root.354 * Queue the nodes and mark them as either found, lost or updated.355 * Update the nodes in the card topology tree as we go.356 */357static void update_tree(struct fw_card *card, struct fw_node *root)358{359 struct list_head list0, list1;360 struct fw_node *node0, *node1, *next1;361 int i, event;362 363 INIT_LIST_HEAD(&list0);364 list_add_tail(&card->local_node->link, &list0);365 INIT_LIST_HEAD(&list1);366 list_add_tail(&root->link, &list1);367 368 node0 = fw_node(list0.next);369 node1 = fw_node(list1.next);370 371 while (&node0->link != &list0) {372 WARN_ON(node0->port_count != node1->port_count);373 374 if (node0->link_on && !node1->link_on)375 event = FW_NODE_LINK_OFF;376 else if (!node0->link_on && node1->link_on)377 event = FW_NODE_LINK_ON;378 else if (node1->initiated_reset && node1->link_on)379 event = FW_NODE_INITIATED_RESET;380 else381 event = FW_NODE_UPDATED;382 383 node0->node_id = node1->node_id;384 node0->color = card->color;385 node0->link_on = node1->link_on;386 node0->initiated_reset = node1->initiated_reset;387 node0->max_hops = node1->max_hops;388 node1->color = card->color;389 fw_node_event(card, node0, event);390 391 if (card->root_node == node1)392 card->root_node = node0;393 if (card->irm_node == node1)394 card->irm_node = node0;395 396 for (i = 0; i < node0->port_count; i++) {397 if (node0->ports[i] && node1->ports[i]) {398 /*399 * This port didn't change, queue the400 * connected node for further401 * investigation.402 */403 if (node0->ports[i]->color == card->color)404 continue;405 list_add_tail(&node0->ports[i]->link, &list0);406 list_add_tail(&node1->ports[i]->link, &list1);407 } else if (node0->ports[i]) {408 /*409 * The nodes connected here were410 * unplugged; unref the lost nodes and411 * queue FW_NODE_LOST callbacks for412 * them.413 */414 415 for_each_fw_node(card, node0->ports[i],416 report_lost_node);417 node0->ports[i] = NULL;418 } else if (node1->ports[i]) {419 /*420 * One or more node were connected to421 * this port. Move the new nodes into422 * the tree and queue FW_NODE_CREATED423 * callbacks for them.424 */425 move_tree(node0, node1, i);426 for_each_fw_node(card, node0->ports[i],427 report_found_node);428 }429 }430 431 node0 = fw_node(node0->link.next);432 next1 = fw_node(node1->link.next);433 fw_node_put(node1);434 node1 = next1;435 }436}437 438static void update_topology_map(struct fw_card *card,439 u32 *self_ids, int self_id_count)440{441 int node_count = (card->root_node->node_id & 0x3f) + 1;442 __be32 *map = card->topology_map;443 444 *map++ = cpu_to_be32((self_id_count + 2) << 16);445 *map++ = cpu_to_be32(be32_to_cpu(card->topology_map[1]) + 1);446 *map++ = cpu_to_be32((node_count << 16) | self_id_count);447 448 while (self_id_count--)449 *map++ = cpu_to_be32p(self_ids++);450 451 fw_compute_block_crc(card->topology_map);452}453 454void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation,455 int self_id_count, u32 *self_ids, bool bm_abdicate)456{457 struct fw_node *local_node;458 459 trace_bus_reset_handle(card->index, generation, node_id, bm_abdicate, self_ids, self_id_count);460 461 guard(spinlock_irqsave)(&card->lock);462 463 /*464 * If the selfID buffer is not the immediate successor of the465 * previously processed one, we cannot reliably compare the466 * old and new topologies.467 */468 if (!is_next_generation(generation, card->generation) &&469 card->local_node != NULL) {470 fw_destroy_nodes(card);471 card->bm_retries = 0;472 }473 474 card->broadcast_channel_allocated = card->broadcast_channel_auto_allocated;475 card->node_id = node_id;476 /*477 * Update node_id before generation to prevent anybody from using478 * a stale node_id together with a current generation.479 */480 smp_wmb();481 card->generation = generation;482 card->reset_jiffies = get_jiffies_64();483 card->bm_node_id = 0xffff;484 card->bm_abdicate = bm_abdicate;485 fw_schedule_bm_work(card, 0);486 487 local_node = build_tree(card, self_ids, self_id_count, generation);488 489 update_topology_map(card, self_ids, self_id_count);490 491 card->color++;492 493 if (local_node == NULL) {494 fw_err(card, "topology build failed\n");495 /* FIXME: We need to issue a bus reset in this case. */496 } else if (card->local_node == NULL) {497 card->local_node = local_node;498 for_each_fw_node(card, local_node, report_found_node);499 } else {500 update_tree(card, local_node);501 }502}503EXPORT_SYMBOL(fw_core_handle_bus_reset);504