1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Thunderbolt Cactus Ridge driver - path/tunnel functionality
4  *
5  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
6  */
7 
8 #include <linux/slab.h>
9 #include <linux/errno.h>
10 
11 #include "tb.h"
12 
13 
tb_dump_hop(struct tb_port * port,struct tb_regs_hop * hop)14 static void tb_dump_hop(struct tb_port *port, struct tb_regs_hop *hop)
15 {
16 	tb_port_info(port, " Hop through port %d to hop %d (%s)\n",
17 		     hop->out_port, hop->next_hop,
18 		     hop->enable ? "enabled" : "disabled");
19 	tb_port_info(port, "  Weight: %d Priority: %d Credits: %d Drop: %d\n",
20 		     hop->weight, hop->priority,
21 		     hop->initial_credits, hop->drop_packages);
22 	tb_port_info(port, "   Counter enabled: %d Counter index: %d\n",
23 		     hop->counter_enable, hop->counter);
24 	tb_port_info(port, "  Flow Control (In/Eg): %d/%d Shared Buffer (In/Eg): %d/%d\n",
25 		     hop->ingress_fc, hop->egress_fc,
26 		     hop->ingress_shared_buffer, hop->egress_shared_buffer);
27 	tb_port_info(port, "  Unknown1: %#x Unknown2: %#x Unknown3: %#x\n",
28 		     hop->unknown1, hop->unknown2, hop->unknown3);
29 }
30 
31 /**
32  * tb_path_alloc() - allocate a thunderbolt path
33  *
34  * Return: Returns a tb_path on success or NULL on failure.
35  */
tb_path_alloc(struct tb * tb,int num_hops)36 struct tb_path *tb_path_alloc(struct tb *tb, int num_hops)
37 {
38 	struct tb_path *path = kzalloc(sizeof(*path), GFP_KERNEL);
39 	if (!path)
40 		return NULL;
41 	path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
42 	if (!path->hops) {
43 		kfree(path);
44 		return NULL;
45 	}
46 	path->tb = tb;
47 	path->path_length = num_hops;
48 	return path;
49 }
50 
51 /**
52  * tb_path_free() - free a deactivated path
53  */
tb_path_free(struct tb_path * path)54 void tb_path_free(struct tb_path *path)
55 {
56 	if (path->activated) {
57 		tb_WARN(path->tb, "trying to free an activated path\n")
58 		return;
59 	}
60 	kfree(path->hops);
61 	kfree(path);
62 }
63 
__tb_path_deallocate_nfc(struct tb_path * path,int first_hop)64 static void __tb_path_deallocate_nfc(struct tb_path *path, int first_hop)
65 {
66 	int i, res;
67 	for (i = first_hop; i < path->path_length; i++) {
68 		res = tb_port_add_nfc_credits(path->hops[i].in_port,
69 					      -path->nfc_credits);
70 		if (res)
71 			tb_port_warn(path->hops[i].in_port,
72 				     "nfc credits deallocation failed for hop %d\n",
73 				     i);
74 	}
75 }
76 
__tb_path_deactivate_hops(struct tb_path * path,int first_hop)77 static void __tb_path_deactivate_hops(struct tb_path *path, int first_hop)
78 {
79 	int i, res;
80 	struct tb_regs_hop hop = { };
81 	for (i = first_hop; i < path->path_length; i++) {
82 		res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
83 				    2 * path->hops[i].in_hop_index, 2);
84 		if (res)
85 			tb_port_warn(path->hops[i].in_port,
86 				     "hop deactivation failed for hop %d, index %d\n",
87 				     i, path->hops[i].in_hop_index);
88 	}
89 }
90 
tb_path_deactivate(struct tb_path * path)91 void tb_path_deactivate(struct tb_path *path)
92 {
93 	if (!path->activated) {
94 		tb_WARN(path->tb, "trying to deactivate an inactive path\n");
95 		return;
96 	}
97 	tb_info(path->tb,
98 		"deactivating path from %llx:%x to %llx:%x\n",
99 		tb_route(path->hops[0].in_port->sw),
100 		path->hops[0].in_port->port,
101 		tb_route(path->hops[path->path_length - 1].out_port->sw),
102 		path->hops[path->path_length - 1].out_port->port);
103 	__tb_path_deactivate_hops(path, 0);
104 	__tb_path_deallocate_nfc(path, 0);
105 	path->activated = false;
106 }
107 
108 /**
109  * tb_path_activate() - activate a path
110  *
111  * Activate a path starting with the last hop and iterating backwards. The
112  * caller must fill path->hops before calling tb_path_activate().
113  *
114  * Return: Returns 0 on success or an error code on failure.
115  */
tb_path_activate(struct tb_path * path)116 int tb_path_activate(struct tb_path *path)
117 {
118 	int i, res;
119 	enum tb_path_port out_mask, in_mask;
120 	if (path->activated) {
121 		tb_WARN(path->tb, "trying to activate already activated path\n");
122 		return -EINVAL;
123 	}
124 
125 	tb_info(path->tb,
126 		"activating path from %llx:%x to %llx:%x\n",
127 		tb_route(path->hops[0].in_port->sw),
128 		path->hops[0].in_port->port,
129 		tb_route(path->hops[path->path_length - 1].out_port->sw),
130 		path->hops[path->path_length - 1].out_port->port);
131 
132 	/* Clear counters. */
133 	for (i = path->path_length - 1; i >= 0; i--) {
134 		if (path->hops[i].in_counter_index == -1)
135 			continue;
136 		res = tb_port_clear_counter(path->hops[i].in_port,
137 					    path->hops[i].in_counter_index);
138 		if (res)
139 			goto err;
140 	}
141 
142 	/* Add non flow controlled credits. */
143 	for (i = path->path_length - 1; i >= 0; i--) {
144 		res = tb_port_add_nfc_credits(path->hops[i].in_port,
145 					      path->nfc_credits);
146 		if (res) {
147 			__tb_path_deallocate_nfc(path, i);
148 			goto err;
149 		}
150 	}
151 
152 	/* Activate hops. */
153 	for (i = path->path_length - 1; i >= 0; i--) {
154 		struct tb_regs_hop hop = { 0 };
155 
156 		/*
157 		 * We do (currently) not tear down paths setup by the firmeware.
158 		 * If a firmware device is unplugged and plugged in again then
159 		 * it can happen that we reuse some of the hops from the (now
160 		 * defunct) firmeware path. This causes the hotplug operation to
161 		 * fail (the pci device does not show up). Clearing the hop
162 		 * before overwriting it fixes the problem.
163 		 *
164 		 * Should be removed once we discover and tear down firmeware
165 		 * paths.
166 		 */
167 		res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
168 				    2 * path->hops[i].in_hop_index, 2);
169 		if (res) {
170 			__tb_path_deactivate_hops(path, i);
171 			__tb_path_deallocate_nfc(path, 0);
172 			goto err;
173 		}
174 
175 		/* dword 0 */
176 		hop.next_hop = path->hops[i].next_hop_index;
177 		hop.out_port = path->hops[i].out_port->port;
178 		/* TODO: figure out why these are good values */
179 		hop.initial_credits = (i == path->path_length - 1) ? 16 : 7;
180 		hop.unknown1 = 0;
181 		hop.enable = 1;
182 
183 		/* dword 1 */
184 		out_mask = (i == path->path_length - 1) ?
185 				TB_PATH_DESTINATION : TB_PATH_INTERNAL;
186 		in_mask = (i == 0) ? TB_PATH_SOURCE : TB_PATH_INTERNAL;
187 		hop.weight = path->weight;
188 		hop.unknown2 = 0;
189 		hop.priority = path->priority;
190 		hop.drop_packages = path->drop_packages;
191 		hop.counter = path->hops[i].in_counter_index;
192 		hop.counter_enable = path->hops[i].in_counter_index != -1;
193 		hop.ingress_fc = path->ingress_fc_enable & in_mask;
194 		hop.egress_fc = path->egress_fc_enable & out_mask;
195 		hop.ingress_shared_buffer = path->ingress_shared_buffer
196 					    & in_mask;
197 		hop.egress_shared_buffer = path->egress_shared_buffer
198 					    & out_mask;
199 		hop.unknown3 = 0;
200 
201 		tb_port_info(path->hops[i].in_port, "Writing hop %d, index %d",
202 			     i, path->hops[i].in_hop_index);
203 		tb_dump_hop(path->hops[i].in_port, &hop);
204 		res = tb_port_write(path->hops[i].in_port, &hop, TB_CFG_HOPS,
205 				    2 * path->hops[i].in_hop_index, 2);
206 		if (res) {
207 			__tb_path_deactivate_hops(path, i);
208 			__tb_path_deallocate_nfc(path, 0);
209 			goto err;
210 		}
211 	}
212 	path->activated = true;
213 	tb_info(path->tb, "path activation complete\n");
214 	return 0;
215 err:
216 	tb_WARN(path->tb, "path activation failed\n");
217 	return res;
218 }
219 
220 /**
221  * tb_path_is_invalid() - check whether any ports on the path are invalid
222  *
223  * Return: Returns true if the path is invalid, false otherwise.
224  */
tb_path_is_invalid(struct tb_path * path)225 bool tb_path_is_invalid(struct tb_path *path)
226 {
227 	int i = 0;
228 	for (i = 0; i < path->path_length; i++) {
229 		if (path->hops[i].in_port->sw->is_unplugged)
230 			return true;
231 		if (path->hops[i].out_port->sw->is_unplugged)
232 			return true;
233 	}
234 	return false;
235 }
236