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