summaryrefslogtreecommitdiffstats
path: root/drivers/thunderbolt/path.c
blob: ff49ad880bfd4723f0aff43e89403170a84aed27 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
// SPDX-License-Identifier: GPL-2.0
/*
 * Thunderbolt Cactus Ridge driver - path/tunnel functionality
 *
 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
 */

#include <linux/slab.h>
#include <linux/errno.h>

#include "tb.h"


static void tb_dump_hop(struct tb_port *port, struct tb_regs_hop *hop)
{
	tb_port_info(port, " Hop through port %d to hop %d (%s)\n",
		     hop->out_port, hop->next_hop,
		     hop->enable ? "enabled" : "disabled");
	tb_port_info(port, "  Weight: %d Priority: %d Credits: %d Drop: %d\n",
		     hop->weight, hop->priority,
		     hop->initial_credits, hop->drop_packages);
	tb_port_info(port, "   Counter enabled: %d Counter index: %d\n",
		     hop->counter_enable, hop->counter);
	tb_port_info(port, "  Flow Control (In/Eg): %d/%d Shared Buffer (In/Eg): %d/%d\n",
		     hop->ingress_fc, hop->egress_fc,
		     hop->ingress_shared_buffer, hop->egress_shared_buffer);
	tb_port_info(port, "  Unknown1: %#x Unknown2: %#x Unknown3: %#x\n",
		     hop->unknown1, hop->unknown2, hop->unknown3);
}

/**
 * tb_path_alloc() - allocate a thunderbolt path
 *
 * Return: Returns a tb_path on success or NULL on failure.
 */
struct tb_path *tb_path_alloc(struct tb *tb, int num_hops)
{
	struct tb_path *path = kzalloc(sizeof(*path), GFP_KERNEL);
	if (!path)
		return NULL;
	path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
	if (!path->hops) {
		kfree(path);
		return NULL;
	}
	path->tb = tb;
	path->path_length = num_hops;
	return path;
}

/**
 * tb_path_free() - free a deactivated path
 */
void tb_path_free(struct tb_path *path)
{
	if (path->activated) {
		tb_WARN(path->tb, "trying to free an activated path\n")
		return;
	}
	kfree(path->hops);
	kfree(path);
}

static void __tb_path_deallocate_nfc(struct tb_path *path, int first_hop)
{
	int i, res;
	for (i = first_hop; i < path->path_length; i++) {
		res = tb_port_add_nfc_credits(path->hops[i].in_port,
					      -path->nfc_credits);
		if (res)
			tb_port_warn(path->hops[i].in_port,
				     "nfc credits deallocation failed for hop %d\n",
				     i);
	}
}

static void __tb_path_deactivate_hops(struct tb_path *path, int first_hop)
{
	int i, res;
	struct tb_regs_hop hop = { };
	for (i = first_hop; i < path->path_length; i++) {
		res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
				    2 * path->hops[i].in_hop_index, 2);
		if (res)
			tb_port_warn(path->hops[i].in_port,
				     "hop deactivation failed for hop %d, index %d\n",
				     i, path->hops[i].in_hop_index);
	}
}

void tb_path_deactivate(struct tb_path *path)
{
	if (!path->activated) {
		tb_WARN(path->tb, "trying to deactivate an inactive path\n");
		return;
	}
	tb_info(path->tb,
		"deactivating path from %llx:%x to %llx:%x\n",
		tb_route(path->hops[0].in_port->sw),
		path->hops[0].in_port->port,
		tb_route(path->hops[path->path_length - 1].out_port->sw),
		path->hops[path->path_length - 1].out_port->port);
	__tb_path_deactivate_hops(path, 0);
	__tb_path_deallocate_nfc(path, 0);
	path->activated = false;
}

/**
 * tb_path_activate() - activate a path
 *
 * Activate a path starting with the last hop and iterating backwards. The
 * caller must fill path->hops before calling tb_path_activate().
 *
 * Return: Returns 0 on success or an error code on failure.
 */
int tb_path_activate(struct tb_path *path)
{
	int i, res;
	enum tb_path_port out_mask, in_mask;
	if (path->activated) {
		tb_WARN(path->tb, "trying to activate already activated path\n");
		return -EINVAL;
	}

	tb_info(path->tb,
		"activating path from %llx:%x to %llx:%x\n",
		tb_route(path->hops[0].in_port->sw),
		path->hops[0].in_port->port,
		tb_route(path->hops[path->path_length - 1].out_port->sw),
		path->hops[path->path_length - 1].out_port->port);

	/* Clear counters. */
	for (i = path->path_length - 1; i >= 0; i--) {
		if (path->hops[i].in_counter_index == -1)
			continue;
		res = tb_port_clear_counter(path->hops[i].in_port,
					    path->hops[i].in_counter_index);
		if (res)
			goto err;
	}

	/* Add non flow controlled credits. */
	for (i = path->path_length - 1; i >= 0; i--) {
		res = tb_port_add_nfc_credits(path->hops[i].in_port,
					      path->nfc_credits);
		if (res) {
			__tb_path_deallocate_nfc(path, i);
			goto err;
		}
	}

	/* Activate hops. */
	for (i = path->path_length - 1; i >= 0; i--) {
		struct tb_regs_hop hop = { 0 };

		/*
		 * We do (currently) not tear down paths setup by the firmeware.
		 * If a firmware device is unplugged and plugged in again then
		 * it can happen that we reuse some of the hops from the (now
		 * defunct) firmeware path. This causes the hotplug operation to
		 * fail (the pci device does not show up). Clearing the hop
		 * before overwriting it fixes the problem.
		 *
		 * Should be removed once we discover and tear down firmeware
		 * paths.
		 */
		res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
				    2 * path->hops[i].in_hop_index, 2);
		if (res) {
			__tb_path_deactivate_hops(path, i);
			__tb_path_deallocate_nfc(path, 0);
			goto err;
		}

		/* dword 0 */
		hop.next_hop = path->hops[i].next_hop_index;
		hop.out_port = path->hops[i].out_port->port;
		/* TODO: figure out why these are good values */
		hop.initial_credits = (i == path->path_length - 1) ? 16 : 7;
		hop.unknown1 = 0;
		hop.enable = 1;

		/* dword 1 */
		out_mask = (i == path->path_length - 1) ?
				TB_PATH_DESTINATION : TB_PATH_INTERNAL;
		in_mask = (i == 0) ? TB_PATH_SOURCE : TB_PATH_INTERNAL;
		hop.weight = path->weight;
		hop.unknown2 = 0;
		hop.priority = path->priority;
		hop.drop_packages = path->drop_packages;
		hop.counter = path->hops[i].in_counter_index;
		hop.counter_enable = path->hops[i].in_counter_index != -1;
		hop.ingress_fc = path->ingress_fc_enable & in_mask;
		hop.egress_fc = path->egress_fc_enable & out_mask;
		hop.ingress_shared_buffer = path->ingress_shared_buffer
					    & in_mask;
		hop.egress_shared_buffer = path->egress_shared_buffer
					    & out_mask;
		hop.unknown3 = 0;

		tb_port_info(path->hops[i].in_port, "Writing hop %d, index %d",
			     i, path->hops[i].in_hop_index);
		tb_dump_hop(path->hops[i].in_port, &hop);
		res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
				    2 * path->hops[i].in_hop_index, 2);
		if (res) {
			__tb_path_deactivate_hops(path, i);
			__tb_path_deallocate_nfc(path, 0);
			goto err;
		}
	}
	path->activated = true;
	tb_info(path->tb, "path activation complete\n");
	return 0;
err:
	tb_WARN(path->tb, "path activation failed\n");
	return res;
}

/**
 * tb_path_is_invalid() - check whether any ports on the path are invalid
 *
 * Return: Returns true if the path is invalid, false otherwise.
 */
bool tb_path_is_invalid(struct tb_path *path)
{
	int i = 0;
	for (i = 0; i < path->path_length; i++) {
		if (path->hops[i].in_port->sw->is_unplugged)
			return true;
		if (path->hops[i].out_port->sw->is_unplugged)
			return true;
	}
	return false;
}