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acrn-kernel/drivers/firewire/core-topology.c

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/*
* Incremental bus scan, based on bus topology
*
* Copyright (C) 2004-2006 Kristian Hoegsberg <krh@bitplanet.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#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)++;
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(sizeof(*node) + port_count * sizeof(node->ports[0]),
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;
atomic_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);
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