Root/drivers/firewire/core-topology.c

1/*
2 * Incremental bus scan, based on bus topology
3 *
4 * Copyright (C) 2004-2006 Kristian Hoegsberg <krh@bitplanet.net>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software Foundation,
18 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 */
20
21#include <linux/bug.h>
22#include <linux/errno.h>
23#include <linux/firewire.h>
24#include <linux/firewire-constants.h>
25#include <linux/jiffies.h>
26#include <linux/kernel.h>
27#include <linux/list.h>
28#include <linux/module.h>
29#include <linux/slab.h>
30#include <linux/spinlock.h>
31
32#include <linux/atomic.h>
33#include <asm/byteorder.h>
34
35#include "core.h"
36
37#define SELF_ID_PHY_ID(q) (((q) >> 24) & 0x3f)
38#define SELF_ID_EXTENDED(q) (((q) >> 23) & 0x01)
39#define SELF_ID_LINK_ON(q) (((q) >> 22) & 0x01)
40#define SELF_ID_GAP_COUNT(q) (((q) >> 16) & 0x3f)
41#define SELF_ID_PHY_SPEED(q) (((q) >> 14) & 0x03)
42#define SELF_ID_CONTENDER(q) (((q) >> 11) & 0x01)
43#define SELF_ID_PHY_INITIATOR(q) (((q) >> 1) & 0x01)
44#define SELF_ID_MORE_PACKETS(q) (((q) >> 0) & 0x01)
45
46#define SELF_ID_EXT_SEQUENCE(q) (((q) >> 20) & 0x07)
47
48#define SELFID_PORT_CHILD 0x3
49#define SELFID_PORT_PARENT 0x2
50#define SELFID_PORT_NCONN 0x1
51#define SELFID_PORT_NONE 0x0
52
53static u32 *count_ports(u32 *sid, int *total_port_count, int *child_port_count)
54{
55    u32 q;
56    int port_type, shift, seq;
57
58    *total_port_count = 0;
59    *child_port_count = 0;
60
61    shift = 6;
62    q = *sid;
63    seq = 0;
64
65    while (1) {
66        port_type = (q >> shift) & 0x03;
67        switch (port_type) {
68        case SELFID_PORT_CHILD:
69            (*child_port_count)++;
70        case SELFID_PORT_PARENT:
71        case SELFID_PORT_NCONN:
72            (*total_port_count)++;
73        case SELFID_PORT_NONE:
74            break;
75        }
76
77        shift -= 2;
78        if (shift == 0) {
79            if (!SELF_ID_MORE_PACKETS(q))
80                return sid + 1;
81
82            shift = 16;
83            sid++;
84            q = *sid;
85
86            /*
87             * Check that the extra packets actually are
88             * extended self ID packets and that the
89             * sequence numbers in the extended self ID
90             * packets increase as expected.
91             */
92
93            if (!SELF_ID_EXTENDED(q) ||
94                seq != SELF_ID_EXT_SEQUENCE(q))
95                return NULL;
96
97            seq++;
98        }
99    }
100}
101
102static int get_port_type(u32 *sid, int port_index)
103{
104    int index, shift;
105
106    index = (port_index + 5) / 8;
107    shift = 16 - ((port_index + 5) & 7) * 2;
108    return (sid[index] >> shift) & 0x03;
109}
110
111static struct fw_node *fw_node_create(u32 sid, int port_count, int color)
112{
113    struct fw_node *node;
114
115    node = kzalloc(sizeof(*node) + port_count * sizeof(node->ports[0]),
116               GFP_ATOMIC);
117    if (node == NULL)
118        return NULL;
119
120    node->color = color;
121    node->node_id = LOCAL_BUS | SELF_ID_PHY_ID(sid);
122    node->link_on = SELF_ID_LINK_ON(sid);
123    node->phy_speed = SELF_ID_PHY_SPEED(sid);
124    node->initiated_reset = SELF_ID_PHY_INITIATOR(sid);
125    node->port_count = port_count;
126
127    atomic_set(&node->ref_count, 1);
128    INIT_LIST_HEAD(&node->link);
129
130    return node;
131}
132
133/*
134 * Compute the maximum hop count for this node and it's children. The
135 * maximum hop count is the maximum number of connections between any
136 * two nodes in the subtree rooted at this node. We need this for
137 * setting the gap count. As we build the tree bottom up in
138 * build_tree() below, this is fairly easy to do: for each node we
139 * maintain the max hop count and the max depth, ie the number of hops
140 * to the furthest leaf. Computing the max hop count breaks down into
141 * two cases: either the path goes through this node, in which case
142 * the hop count is the sum of the two biggest child depths plus 2.
143 * Or it could be the case that the max hop path is entirely
144 * containted in a child tree, in which case the max hop count is just
145 * the max hop count of this child.
146 */
147static void update_hop_count(struct fw_node *node)
148{
149    int depths[2] = { -1, -1 };
150    int max_child_hops = 0;
151    int i;
152
153    for (i = 0; i < node->port_count; i++) {
154        if (node->ports[i] == NULL)
155            continue;
156
157        if (node->ports[i]->max_hops > max_child_hops)
158            max_child_hops = node->ports[i]->max_hops;
159
160        if (node->ports[i]->max_depth > depths[0]) {
161            depths[1] = depths[0];
162            depths[0] = node->ports[i]->max_depth;
163        } else if (node->ports[i]->max_depth > depths[1])
164            depths[1] = node->ports[i]->max_depth;
165    }
166
167    node->max_depth = depths[0] + 1;
168    node->max_hops = max(max_child_hops, depths[0] + depths[1] + 2);
169}
170
171static inline struct fw_node *fw_node(struct list_head *l)
172{
173    return list_entry(l, struct fw_node, link);
174}
175
176/*
177 * This function builds the tree representation of the topology given
178 * by the self IDs from the latest bus reset. During the construction
179 * of the tree, the function checks that the self IDs are valid and
180 * internally consistent. On success this function returns the
181 * fw_node corresponding to the local card otherwise NULL.
182 */
183static struct fw_node *build_tree(struct fw_card *card,
184                  u32 *sid, int self_id_count)
185{
186    struct fw_node *node, *child, *local_node, *irm_node;
187    struct list_head stack, *h;
188    u32 *next_sid, *end, q;
189    int i, port_count, child_port_count, phy_id, parent_count, stack_depth;
190    int gap_count;
191    bool beta_repeaters_present;
192
193    local_node = NULL;
194    node = NULL;
195    INIT_LIST_HEAD(&stack);
196    stack_depth = 0;
197    end = sid + self_id_count;
198    phy_id = 0;
199    irm_node = NULL;
200    gap_count = SELF_ID_GAP_COUNT(*sid);
201    beta_repeaters_present = false;
202
203    while (sid < end) {
204        next_sid = count_ports(sid, &port_count, &child_port_count);
205
206        if (next_sid == NULL) {
207            fw_err(card, "inconsistent extended self IDs\n");
208            return NULL;
209        }
210
211        q = *sid;
212        if (phy_id != SELF_ID_PHY_ID(q)) {
213            fw_err(card, "PHY ID mismatch in self ID: %d != %d\n",
214                   phy_id, SELF_ID_PHY_ID(q));
215            return NULL;
216        }
217
218        if (child_port_count > stack_depth) {
219            fw_err(card, "topology stack underflow\n");
220            return NULL;
221        }
222
223        /*
224         * Seek back from the top of our stack to find the
225         * start of the child nodes for this node.
226         */
227        for (i = 0, h = &stack; i < child_port_count; i++)
228            h = h->prev;
229        /*
230         * When the stack is empty, this yields an invalid value,
231         * but that pointer will never be dereferenced.
232         */
233        child = fw_node(h);
234
235        node = fw_node_create(q, port_count, card->color);
236        if (node == NULL) {
237            fw_err(card, "out of memory while building topology\n");
238            return NULL;
239        }
240
241        if (phy_id == (card->node_id & 0x3f))
242            local_node = node;
243
244        if (SELF_ID_CONTENDER(q))
245            irm_node = node;
246
247        parent_count = 0;
248
249        for (i = 0; i < port_count; i++) {
250            switch (get_port_type(sid, i)) {
251            case SELFID_PORT_PARENT:
252                /*
253                 * Who's your daddy? We dont know the
254                 * parent node at this time, so we
255                 * temporarily abuse node->color for
256                 * remembering the entry in the
257                 * node->ports array where the parent
258                 * node should be. Later, when we
259                 * handle the parent node, we fix up
260                 * the reference.
261                 */
262                parent_count++;
263                node->color = i;
264                break;
265
266            case SELFID_PORT_CHILD:
267                node->ports[i] = child;
268                /*
269                 * Fix up parent reference for this
270                 * child node.
271                 */
272                child->ports[child->color] = node;
273                child->color = card->color;
274                child = fw_node(child->link.next);
275                break;
276            }
277        }
278
279        /*
280         * Check that the node reports exactly one parent
281         * port, except for the root, which of course should
282         * have no parents.
283         */
284        if ((next_sid == end && parent_count != 0) ||
285            (next_sid < end && parent_count != 1)) {
286            fw_err(card, "parent port inconsistency for node %d: "
287                   "parent_count=%d\n", phy_id, parent_count);
288            return NULL;
289        }
290
291        /* Pop the child nodes off the stack and push the new node. */
292        __list_del(h->prev, &stack);
293        list_add_tail(&node->link, &stack);
294        stack_depth += 1 - child_port_count;
295
296        if (node->phy_speed == SCODE_BETA &&
297            parent_count + child_port_count > 1)
298            beta_repeaters_present = true;
299
300        /*
301         * If PHYs report different gap counts, set an invalid count
302         * which will force a gap count reconfiguration and a reset.
303         */
304        if (SELF_ID_GAP_COUNT(q) != gap_count)
305            gap_count = 0;
306
307        update_hop_count(node);
308
309        sid = next_sid;
310        phy_id++;
311    }
312
313    card->root_node = node;
314    card->irm_node = irm_node;
315    card->gap_count = gap_count;
316    card->beta_repeaters_present = beta_repeaters_present;
317
318    return local_node;
319}
320
321typedef void (*fw_node_callback_t)(struct fw_card * card,
322                   struct fw_node * node,
323                   struct fw_node * parent);
324
325static void for_each_fw_node(struct fw_card *card, struct fw_node *root,
326                 fw_node_callback_t callback)
327{
328    struct list_head list;
329    struct fw_node *node, *next, *child, *parent;
330    int i;
331
332    INIT_LIST_HEAD(&list);
333
334    fw_node_get(root);
335    list_add_tail(&root->link, &list);
336    parent = NULL;
337    list_for_each_entry(node, &list, link) {
338        node->color = card->color;
339
340        for (i = 0; i < node->port_count; i++) {
341            child = node->ports[i];
342            if (!child)
343                continue;
344            if (child->color == card->color)
345                parent = child;
346            else {
347                fw_node_get(child);
348                list_add_tail(&child->link, &list);
349            }
350        }
351
352        callback(card, node, parent);
353    }
354
355    list_for_each_entry_safe(node, next, &list, link)
356        fw_node_put(node);
357}
358
359static void report_lost_node(struct fw_card *card,
360                 struct fw_node *node, struct fw_node *parent)
361{
362    fw_node_event(card, node, FW_NODE_DESTROYED);
363    fw_node_put(node);
364
365    /* Topology has changed - reset bus manager retry counter */
366    card->bm_retries = 0;
367}
368
369static void report_found_node(struct fw_card *card,
370                  struct fw_node *node, struct fw_node *parent)
371{
372    int b_path = (node->phy_speed == SCODE_BETA);
373
374    if (parent != NULL) {
375        /* min() macro doesn't work here with gcc 3.4 */
376        node->max_speed = parent->max_speed < node->phy_speed ?
377                    parent->max_speed : node->phy_speed;
378        node->b_path = parent->b_path && b_path;
379    } else {
380        node->max_speed = node->phy_speed;
381        node->b_path = b_path;
382    }
383
384    fw_node_event(card, node, FW_NODE_CREATED);
385
386    /* Topology has changed - reset bus manager retry counter */
387    card->bm_retries = 0;
388}
389
390void fw_destroy_nodes(struct fw_card *card)
391{
392    unsigned long flags;
393
394    spin_lock_irqsave(&card->lock, flags);
395    card->color++;
396    if (card->local_node != NULL)
397        for_each_fw_node(card, card->local_node, report_lost_node);
398    card->local_node = NULL;
399    spin_unlock_irqrestore(&card->lock, flags);
400}
401
402static void move_tree(struct fw_node *node0, struct fw_node *node1, int port)
403{
404    struct fw_node *tree;
405    int i;
406
407    tree = node1->ports[port];
408    node0->ports[port] = tree;
409    for (i = 0; i < tree->port_count; i++) {
410        if (tree->ports[i] == node1) {
411            tree->ports[i] = node0;
412            break;
413        }
414    }
415}
416
417/*
418 * Compare the old topology tree for card with the new one specified by root.
419 * Queue the nodes and mark them as either found, lost or updated.
420 * Update the nodes in the card topology tree as we go.
421 */
422static void update_tree(struct fw_card *card, struct fw_node *root)
423{
424    struct list_head list0, list1;
425    struct fw_node *node0, *node1, *next1;
426    int i, event;
427
428    INIT_LIST_HEAD(&list0);
429    list_add_tail(&card->local_node->link, &list0);
430    INIT_LIST_HEAD(&list1);
431    list_add_tail(&root->link, &list1);
432
433    node0 = fw_node(list0.next);
434    node1 = fw_node(list1.next);
435
436    while (&node0->link != &list0) {
437        WARN_ON(node0->port_count != node1->port_count);
438
439        if (node0->link_on && !node1->link_on)
440            event = FW_NODE_LINK_OFF;
441        else if (!node0->link_on && node1->link_on)
442            event = FW_NODE_LINK_ON;
443        else if (node1->initiated_reset && node1->link_on)
444            event = FW_NODE_INITIATED_RESET;
445        else
446            event = FW_NODE_UPDATED;
447
448        node0->node_id = node1->node_id;
449        node0->color = card->color;
450        node0->link_on = node1->link_on;
451        node0->initiated_reset = node1->initiated_reset;
452        node0->max_hops = node1->max_hops;
453        node1->color = card->color;
454        fw_node_event(card, node0, event);
455
456        if (card->root_node == node1)
457            card->root_node = node0;
458        if (card->irm_node == node1)
459            card->irm_node = node0;
460
461        for (i = 0; i < node0->port_count; i++) {
462            if (node0->ports[i] && node1->ports[i]) {
463                /*
464                 * This port didn't change, queue the
465                 * connected node for further
466                 * investigation.
467                 */
468                if (node0->ports[i]->color == card->color)
469                    continue;
470                list_add_tail(&node0->ports[i]->link, &list0);
471                list_add_tail(&node1->ports[i]->link, &list1);
472            } else if (node0->ports[i]) {
473                /*
474                 * The nodes connected here were
475                 * unplugged; unref the lost nodes and
476                 * queue FW_NODE_LOST callbacks for
477                 * them.
478                 */
479
480                for_each_fw_node(card, node0->ports[i],
481                         report_lost_node);
482                node0->ports[i] = NULL;
483            } else if (node1->ports[i]) {
484                /*
485                 * One or more node were connected to
486                 * this port. Move the new nodes into
487                 * the tree and queue FW_NODE_CREATED
488                 * callbacks for them.
489                 */
490                move_tree(node0, node1, i);
491                for_each_fw_node(card, node0->ports[i],
492                         report_found_node);
493            }
494        }
495
496        node0 = fw_node(node0->link.next);
497        next1 = fw_node(node1->link.next);
498        fw_node_put(node1);
499        node1 = next1;
500    }
501}
502
503static void update_topology_map(struct fw_card *card,
504                u32 *self_ids, int self_id_count)
505{
506    int node_count = (card->root_node->node_id & 0x3f) + 1;
507    __be32 *map = card->topology_map;
508
509    *map++ = cpu_to_be32((self_id_count + 2) << 16);
510    *map++ = cpu_to_be32(be32_to_cpu(card->topology_map[1]) + 1);
511    *map++ = cpu_to_be32((node_count << 16) | self_id_count);
512
513    while (self_id_count--)
514        *map++ = cpu_to_be32p(self_ids++);
515
516    fw_compute_block_crc(card->topology_map);
517}
518
519void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation,
520                  int self_id_count, u32 *self_ids, bool bm_abdicate)
521{
522    struct fw_node *local_node;
523    unsigned long flags;
524
525    /*
526     * If the selfID buffer is not the immediate successor of the
527     * previously processed one, we cannot reliably compare the
528     * old and new topologies.
529     */
530    if (!is_next_generation(generation, card->generation) &&
531        card->local_node != NULL) {
532        fw_destroy_nodes(card);
533        card->bm_retries = 0;
534    }
535
536    spin_lock_irqsave(&card->lock, flags);
537
538    card->broadcast_channel_allocated = card->broadcast_channel_auto_allocated;
539    card->node_id = node_id;
540    /*
541     * Update node_id before generation to prevent anybody from using
542     * a stale node_id together with a current generation.
543     */
544    smp_wmb();
545    card->generation = generation;
546    card->reset_jiffies = get_jiffies_64();
547    card->bm_node_id = 0xffff;
548    card->bm_abdicate = bm_abdicate;
549    fw_schedule_bm_work(card, 0);
550
551    local_node = build_tree(card, self_ids, self_id_count);
552
553    update_topology_map(card, self_ids, self_id_count);
554
555    card->color++;
556
557    if (local_node == NULL) {
558        fw_err(card, "topology build failed\n");
559        /* FIXME: We need to issue a bus reset in this case. */
560    } else if (card->local_node == NULL) {
561        card->local_node = local_node;
562        for_each_fw_node(card, local_node, report_found_node);
563    } else {
564        update_tree(card, local_node);
565    }
566
567    spin_unlock_irqrestore(&card->lock, flags);
568}
569EXPORT_SYMBOL(fw_core_handle_bus_reset);
570

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