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
 14static 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 */
 36struct 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 */
 54void 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
 64static 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
 77static 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
 91void 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 */
116int 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;
215err:
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 */
225bool 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}