// SPDX-License-Identifier: GPL-2.0-or-later /* * Incremental bus scan, based on bus topology * * Copyright (C) 2004-2006 Kristian Hoegsberg <krh@bitplanet.net> */ #include <linux/bug.h> #include <linux/errno.h> #include <linux/firewire.h> #include <linux/firewire-constants.h> #include <linux/jiffies.h> #include <linux/kernel.h> #include <linux/list.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/atomic.h> #include <asm/byteorder.h> #include "core.h" #define SELF_ID_PHY_ID(q) (((q) >> 24) & 0x3f) #define SELF_ID_EXTENDED(q) (((q) >> 23) & 0x01) #define SELF_ID_LINK_ON(q) (((q) >> 22) & 0x01) #define SELF_ID_GAP_COUNT(q) (((q) >> 16) & 0x3f) #define SELF_ID_PHY_SPEED(q) (((q) >> 14) & 0x03) #define SELF_ID_CONTENDER(q) (((q) >> 11) & 0x01) #define SELF_ID_PHY_INITIATOR(q) (((q) >> 1) & 0x01) #define SELF_ID_MORE_PACKETS(q) (((q) >> 0) & 0x01) #define SELF_ID_EXT_SEQUENCE(q) (((q) >> 20) & 0x07) #define SELFID_PORT_CHILD 0x3 #define SELFID_PORT_PARENT 0x2 #define SELFID_PORT_NCONN 0x1 #define SELFID_PORT_NONE 0x0 static u32 *count_ports(u32 *sid, int *total_port_count, int *child_port_count) { u32 q; int port_type, shift, seq; *total_port_count = 0; *child_port_count = 0; shift = 6; q = *sid; seq = 0; while (1) { port_type = (q >> shift) & 0x03; switch (port_type) { case SELFID_PORT_CHILD: (*child_port_count)++; /* fall through */ case SELFID_PORT_PARENT: case SELFID_PORT_NCONN: (*total_port_count)++; case SELFID_PORT_NONE: break; } shift -= 2; if (shift == 0) { if (!SELF_ID_MORE_PACKETS(q)) return sid + 1; shift = 16; sid++; q = *sid; /* * Check that the extra packets actually are * extended self ID packets and that the * sequence numbers in the extended self ID * packets increase as expected. */ if (!SELF_ID_EXTENDED(q) || seq != SELF_ID_EXT_SEQUENCE(q)) return NULL; seq++; } } } static int get_port_type(u32 *sid, int port_index) { int index, shift; index = (port_index + 5) / 8; shift = 16 - ((port_index + 5) & 7) * 2; return (sid[index] >> shift) & 0x03; } static struct fw_node *fw_node_create(u32 sid, int port_count, int color) { struct fw_node *node; node = kzalloc(struct_size(node, ports, port_count), GFP_ATOMIC); if (node == NULL) return NULL; node->color = color; node->node_id = LOCAL_BUS | SELF_ID_PHY_ID(sid); node->link_on = SELF_ID_LINK_ON(sid); node->phy_speed = SELF_ID_PHY_SPEED(sid); node->initiated_reset = SELF_ID_PHY_INITIATOR(sid); node->port_count = port_count; refcount_set(&node->ref_count, 1); INIT_LIST_HEAD(&node->link); return node; } /* * Compute the maximum hop count for this node and it's children. The * maximum hop count is the maximum number of connections between any * two nodes in the subtree rooted at this node. We need this for * setting the gap count. As we build the tree bottom up in * build_tree() below, this is fairly easy to do: for each node we * maintain the max hop count and the max depth, ie the number of hops * to the furthest leaf. Computing the max hop count breaks down into * two cases: either the path goes through this node, in which case * the hop count is the sum of the two biggest child depths plus 2. * Or it could be the case that the max hop path is entirely * containted in a child tree, in which case the max hop count is just * the max hop count of this child. */ static void update_hop_count(struct fw_node *node) { int depths[2] = { -1, -1 }; int max_child_hops = 0; int i; for (i = 0; i < node->port_count; i++) { if (node->ports[i] == NULL) continue; if (node->ports[i]->max_hops > max_child_hops) max_child_hops = node->ports[i]->max_hops; if (node->ports[i]->max_depth > depths[0]) { depths[1] = depths[0]; depths[0] = node->ports[i]->max_depth; } else if (node->ports[i]->max_depth > depths[1]) depths[1] = node->ports[i]->max_depth; } node->max_depth = depths[0] + 1; node->max_hops = max(max_child_hops, depths[0] + depths[1] + 2); } static inline struct fw_node *fw_node(struct list_head *l) { return list_entry(l, struct fw_node, link); } /* * This function builds the tree representation of the topology given * by the self IDs from the latest bus reset. During the construction * of the tree, the function checks that the self IDs are valid and * internally consistent. On success this function returns the * fw_node corresponding to the local card otherwise NULL. */ static struct fw_node *build_tree(struct fw_card *card, u32 *sid, int self_id_count) { struct fw_node *node, *child, *local_node, *irm_node; struct list_head stack, *h; u32 *next_sid, *end, q; int i, port_count, child_port_count, phy_id, parent_count, stack_depth; int gap_count; bool beta_repeaters_present; local_node = NULL; node = NULL; INIT_LIST_HEAD(&stack); stack_depth = 0; end = sid + self_id_count; phy_id = 0; irm_node = NULL; gap_count = SELF_ID_GAP_COUNT(*sid); beta_repeaters_present = false; while (sid < end) { next_sid = count_ports(sid, &port_count, &child_port_count); if (next_sid == NULL) { fw_err(card, "inconsistent extended self IDs\n"); return NULL; } q = *sid; if (phy_id != SELF_ID_PHY_ID(q)) { fw_err(card, "PHY ID mismatch in self ID: %d != %d\n", phy_id, SELF_ID_PHY_ID(q)); return NULL; } if (child_port_count > stack_depth) { fw_err(card, "topology stack underflow\n"); return NULL; } /* * Seek back from the top of our stack to find the * start of the child nodes for this node. */ for (i = 0, h = &stack; i < child_port_count; i++) h = h->prev; /* * When the stack is empty, this yields an invalid value, * but that pointer will never be dereferenced. */ child = fw_node(h); node = fw_node_create(q, port_count, card->color); if (node == NULL) { fw_err(card, "out of memory while building topology\n"); return NULL; } if (phy_id == (card->node_id & 0x3f)) local_node = node; if (SELF_ID_CONTENDER(q)) irm_node = node; parent_count = 0; for (i = 0; i < port_count; i++) { switch (get_port_type(sid, i)) { case SELFID_PORT_PARENT: /* * Who's your daddy? We dont know the * parent node at this time, so we * temporarily abuse node->color for * remembering the entry in the * node->ports array where the parent * node should be. Later, when we * handle the parent node, we fix up * the reference. */ parent_count++; node->color = i; break; case SELFID_PORT_CHILD: node->ports[i] = child; /* * Fix up parent reference for this * child node. */ child->ports[child->color] = node; child->color = card->color; child = fw_node(child->link.next); break; } } /* * Check that the node reports exactly one parent * port, except for the root, which of course should * have no parents. */ if ((next_sid == end && parent_count != 0) || (next_sid < end && parent_count != 1)) { fw_err(card, "parent port inconsistency for node %d: " "parent_count=%d\n", phy_id, parent_count); return NULL; } /* Pop the child nodes off the stack and push the new node. */ __list_del(h->prev, &stack); list_add_tail(&node->link, &stack); stack_depth += 1 - child_port_count; if (node->phy_speed == SCODE_BETA && parent_count + child_port_count > 1) beta_repeaters_present = true; /* * If PHYs report different gap counts, set an invalid count * which will force a gap count reconfiguration and a reset. */ if (SELF_ID_GAP_COUNT(q) != gap_count) gap_count = 0; update_hop_count(node); sid = next_sid; phy_id++; } card->root_node = node; card->irm_node = irm_node; card->gap_count = gap_count; card->beta_repeaters_present = beta_repeaters_present; return local_node; } typedef void (*fw_node_callback_t)(struct fw_card * card, struct fw_node * node, struct fw_node * parent); static void for_each_fw_node(struct fw_card *card, struct fw_node *root, fw_node_callback_t callback) { struct list_head list; struct fw_node *node, *next, *child, *parent; int i; INIT_LIST_HEAD(&list); fw_node_get(root); list_add_tail(&root->link, &list); parent = NULL; list_for_each_entry(node, &list, link) { node->color = card->color; for (i = 0; i < node->port_count; i++) { child = node->ports[i]; if (!child) continue; if (child->color == card->color) parent = child; else { fw_node_get(child); list_add_tail(&child->link, &list); } } callback(card, node, parent); } list_for_each_entry_safe(node, next, &list, link) fw_node_put(node); } static void report_lost_node(struct fw_card *card, struct fw_node *node, struct fw_node *parent) { fw_node_event(card, node, FW_NODE_DESTROYED); fw_node_put(node); /* Topology has changed - reset bus manager retry counter */ card->bm_retries = 0; } static void report_found_node(struct fw_card *card, struct fw_node *node, struct fw_node *parent) { int b_path = (node->phy_speed == SCODE_BETA); if (parent != NULL) { /* min() macro doesn't work here with gcc 3.4 */ node->max_speed = parent->max_speed < node->phy_speed ? parent->max_speed : node->phy_speed; node->b_path = parent->b_path && b_path; } else { node->max_speed = node->phy_speed; node->b_path = b_path; } fw_node_event(card, node, FW_NODE_CREATED); /* Topology has changed - reset bus manager retry counter */ card->bm_retries = 0; } void fw_destroy_nodes(struct fw_card *card) { unsigned long flags; spin_lock_irqsave(&card->lock, flags); card->color++; if (card->local_node != NULL) for_each_fw_node(card, card->local_node, report_lost_node); card->local_node = NULL; spin_unlock_irqrestore(&card->lock, flags); } static void move_tree(struct fw_node *node0, struct fw_node *node1, int port) { struct fw_node *tree; int i; tree = node1->ports[port]; node0->ports[port] = tree; for (i = 0; i < tree->port_count; i++) { if (tree->ports[i] == node1) { tree->ports[i] = node0; break; } } } /* * Compare the old topology tree for card with the new one specified by root. * Queue the nodes and mark them as either found, lost or updated. * Update the nodes in the card topology tree as we go. */ static void update_tree(struct fw_card *card, struct fw_node *root) { struct list_head list0, list1; struct fw_node *node0, *node1, *next1; int i, event; INIT_LIST_HEAD(&list0); list_add_tail(&card->local_node->link, &list0); INIT_LIST_HEAD(&list1); list_add_tail(&root->link, &list1); node0 = fw_node(list0.next); node1 = fw_node(list1.next); while (&node0->link != &list0) { WARN_ON(node0->port_count != node1->port_count); if (node0->link_on && !node1->link_on) event = FW_NODE_LINK_OFF; else if (!node0->link_on && node1->link_on) event = FW_NODE_LINK_ON; else if (node1->initiated_reset && node1->link_on) event = FW_NODE_INITIATED_RESET; else event = FW_NODE_UPDATED; node0->node_id = node1->node_id; node0->color = card->color; node0->link_on = node1->link_on; node0->initiated_reset = node1->initiated_reset; node0->max_hops = node1->max_hops; node1->color = card->color; fw_node_event(card, node0, event); if (card->root_node == node1) card->root_node = node0; if (card->irm_node == node1) card->irm_node = node0; for (i = 0; i < node0->port_count; i++) { if (node0->ports[i] && node1->ports[i]) { /* * This port didn't change, queue the * connected node for further * investigation. */ if (node0->ports[i]->color == card->color) continue; list_add_tail(&node0->ports[i]->link, &list0); list_add_tail(&node1->ports[i]->link, &list1); } else if (node0->ports[i]) { /* * The nodes connected here were * unplugged; unref the lost nodes and * queue FW_NODE_LOST callbacks for * them. */ for_each_fw_node(card, node0->ports[i], report_lost_node); node0->ports[i] = NULL; } else if (node1->ports[i]) { /* * One or more node were connected to * this port. Move the new nodes into * the tree and queue FW_NODE_CREATED * callbacks for them. */ move_tree(node0, node1, i); for_each_fw_node(card, node0->ports[i], report_found_node); } } node0 = fw_node(node0->link.next); next1 = fw_node(node1->link.next); fw_node_put(node1); node1 = next1; } } static void update_topology_map(struct fw_card *card, u32 *self_ids, int self_id_count) { int node_count = (card->root_node->node_id & 0x3f) + 1; __be32 *map = card->topology_map; *map++ = cpu_to_be32((self_id_count + 2) << 16); *map++ = cpu_to_be32(be32_to_cpu(card->topology_map[1]) + 1); *map++ = cpu_to_be32((node_count << 16) | self_id_count); while (self_id_count--) *map++ = cpu_to_be32p(self_ids++); fw_compute_block_crc(card->topology_map); } void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation, int self_id_count, u32 *self_ids, bool bm_abdicate) { struct fw_node *local_node; unsigned long flags; /* * If the selfID buffer is not the immediate successor of the * previously processed one, we cannot reliably compare the * old and new topologies. */ if (!is_next_generation(generation, card->generation) && card->local_node != NULL) { fw_destroy_nodes(card); card->bm_retries = 0; } spin_lock_irqsave(&card->lock, flags); card->broadcast_channel_allocated = card->broadcast_channel_auto_allocated; card->node_id = node_id; /* * Update node_id before generation to prevent anybody from using * a stale node_id together with a current generation. */ smp_wmb(); card->generation = generation; card->reset_jiffies = get_jiffies_64(); card->bm_node_id = 0xffff; card->bm_abdicate = bm_abdicate; fw_schedule_bm_work(card, 0); local_node = build_tree(card, self_ids, self_id_count); update_topology_map(card, self_ids, self_id_count); card->color++; if (local_node == NULL) { fw_err(card, "topology build failed\n"); /* FIXME: We need to issue a bus reset in this case. */ } else if (card->local_node == NULL) { card->local_node = local_node; for_each_fw_node(card, local_node, report_found_node); } else { update_tree(card, local_node); } spin_unlock_irqrestore(&card->lock, flags); } EXPORT_SYMBOL(fw_core_handle_bus_reset);