1 files changed, 614 insertions, 0 deletions

diff --git a/drivers/thunderbolt/path.c b/drivers/thunderbolt/path.c
new file mode 100644
index 000000000..ee03fd75a
--- /dev/null
+++ b/drivers/thunderbolt/path.c
@@ -0,0 +1,614 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Thunderbolt driver - path/tunnel functionality
+ *
+ * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
+ * Copyright (C) 2019, Intel Corporation
+ */
+
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/ktime.h>
+
+#include "tb.h"
+
+static void tb_dump_hop(const struct tb_path_hop *hop, const struct tb_regs_hop *regs)
+{
+	const struct tb_port *port = hop->in_port;
+
+	tb_port_dbg(port, " In HopID: %d => Out port: %d Out HopID: %d\n",
+		    hop->in_hop_index, regs->out_port, regs->next_hop);
+	tb_port_dbg(port, "  Weight: %d Priority: %d Credits: %d Drop: %d\n",
+		    regs->weight, regs->priority,
+		    regs->initial_credits, regs->drop_packages);
+	tb_port_dbg(port, "   Counter enabled: %d Counter index: %d\n",
+		    regs->counter_enable, regs->counter);
+	tb_port_dbg(port, "  Flow Control (In/Eg): %d/%d Shared Buffer (In/Eg): %d/%d\n",
+		    regs->ingress_fc, regs->egress_fc,
+		    regs->ingress_shared_buffer, regs->egress_shared_buffer);
+	tb_port_dbg(port, "  Unknown1: %#x Unknown2: %#x Unknown3: %#x\n",
+		    regs->unknown1, regs->unknown2, regs->unknown3);
+}
+
+static struct tb_port *tb_path_find_dst_port(struct tb_port *src, int src_hopid,
+					     int dst_hopid)
+{
+	struct tb_port *port, *out_port = NULL;
+	struct tb_regs_hop hop;
+	struct tb_switch *sw;
+	int i, ret, hopid;
+
+	hopid = src_hopid;
+	port = src;
+
+	for (i = 0; port && i < TB_PATH_MAX_HOPS; i++) {
+		sw = port->sw;
+
+		ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hopid, 2);
+		if (ret) {
+			tb_port_warn(port, "failed to read path at %d\n", hopid);
+			return NULL;
+		}
+
+		if (!hop.enable)
+			return NULL;
+
+		out_port = &sw->ports[hop.out_port];
+		hopid = hop.next_hop;
+		port = out_port->remote;
+	}
+
+	return out_port && hopid == dst_hopid ? out_port : NULL;
+}
+
+static int tb_path_find_src_hopid(struct tb_port *src,
+	const struct tb_port *dst, int dst_hopid)
+{
+	struct tb_port *out;
+	int i;
+
+	for (i = TB_PATH_MIN_HOPID; i <= src->config.max_in_hop_id; i++) {
+		out = tb_path_find_dst_port(src, i, dst_hopid);
+		if (out == dst)
+			return i;
+	}
+
+	return 0;
+}
+
+/**
+ * tb_path_discover() - Discover a path
+ * @src: First input port of a path
+ * @src_hopid: Starting HopID of a path (%-1 if don't care)
+ * @dst: Expected destination port of the path (%NULL if don't care)
+ * @dst_hopid: HopID to the @dst (%-1 if don't care)
+ * @last: Last port is filled here if not %NULL
+ * @name: Name of the path
+ * @alloc_hopid: Allocate HopIDs for the ports
+ *
+ * Follows a path starting from @src and @src_hopid to the last output
+ * port of the path. Allocates HopIDs for the visited ports (if
+ * @alloc_hopid is true). Call tb_path_free() to release the path and
+ * allocated HopIDs when the path is not needed anymore.
+ *
+ * Note function discovers also incomplete paths so caller should check
+ * that the @dst port is the expected one. If it is not, the path can be
+ * cleaned up by calling tb_path_deactivate() before tb_path_free().
+ *
+ * Return: Discovered path on success, %NULL in case of failure
+ */
+struct tb_path *tb_path_discover(struct tb_port *src, int src_hopid,
+				 struct tb_port *dst, int dst_hopid,
+				 struct tb_port **last, const char *name,
+				 bool alloc_hopid)
+{
+	struct tb_port *out_port;
+	struct tb_regs_hop hop;
+	struct tb_path *path;
+	struct tb_switch *sw;
+	struct tb_port *p;
+	size_t num_hops;
+	int ret, i, h;
+
+	if (src_hopid < 0 && dst) {
+		/*
+		 * For incomplete paths the intermediate HopID can be
+		 * different from the one used by the protocol adapter
+		 * so in that case find a path that ends on @dst with
+		 * matching @dst_hopid. That should give us the correct
+		 * HopID for the @src.
+		 */
+		src_hopid = tb_path_find_src_hopid(src, dst, dst_hopid);
+		if (!src_hopid)
+			return NULL;
+	}
+
+	p = src;
+	h = src_hopid;
+	num_hops = 0;
+
+	for (i = 0; p && i < TB_PATH_MAX_HOPS; i++) {
+		sw = p->sw;
+
+		ret = tb_port_read(p, &hop, TB_CFG_HOPS, 2 * h, 2);
+		if (ret) {
+			tb_port_warn(p, "failed to read path at %d\n", h);
+			return NULL;
+		}
+
+		/* If the hop is not enabled we got an incomplete path */
+		if (!hop.enable)
+			break;
+
+		out_port = &sw->ports[hop.out_port];
+		if (last)
+			*last = out_port;
+
+		h = hop.next_hop;
+		p = out_port->remote;
+		num_hops++;
+	}
+
+	path = kzalloc(sizeof(*path), GFP_KERNEL);
+	if (!path)
+		return NULL;
+
+	path->name = name;
+	path->tb = src->sw->tb;
+	path->path_length = num_hops;
+	path->activated = true;
+	path->alloc_hopid = alloc_hopid;
+
+	path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
+	if (!path->hops) {
+		kfree(path);
+		return NULL;
+	}
+
+	tb_dbg(path->tb, "discovering %s path starting from %llx:%u\n",
+	       path->name, tb_route(src->sw), src->port);
+
+	p = src;
+	h = src_hopid;
+
+	for (i = 0; i < num_hops; i++) {
+		int next_hop;
+
+		sw = p->sw;
+
+		ret = tb_port_read(p, &hop, TB_CFG_HOPS, 2 * h, 2);
+		if (ret) {
+			tb_port_warn(p, "failed to read path at %d\n", h);
+			goto err;
+		}
+
+		if (alloc_hopid && tb_port_alloc_in_hopid(p, h, h) < 0)
+			goto err;
+
+		out_port = &sw->ports[hop.out_port];
+		next_hop = hop.next_hop;
+
+		if (alloc_hopid &&
+		    tb_port_alloc_out_hopid(out_port, next_hop, next_hop) < 0) {
+			tb_port_release_in_hopid(p, h);
+			goto err;
+		}
+
+		path->hops[i].in_port = p;
+		path->hops[i].in_hop_index = h;
+		path->hops[i].in_counter_index = -1;
+		path->hops[i].out_port = out_port;
+		path->hops[i].next_hop_index = next_hop;
+
+		tb_dump_hop(&path->hops[i], &hop);
+
+		h = next_hop;
+		p = out_port->remote;
+	}
+
+	tb_dbg(path->tb, "path discovery complete\n");
+	return path;
+
+err:
+	tb_port_warn(src, "failed to discover path starting at HopID %d\n",
+		     src_hopid);
+	tb_path_free(path);
+	return NULL;
+}
+
+/**
+ * tb_path_alloc() - allocate a thunderbolt path between two ports
+ * @tb: Domain pointer
+ * @src: Source port of the path
+ * @src_hopid: HopID used for the first ingress port in the path
+ * @dst: Destination port of the path
+ * @dst_hopid: HopID used for the last egress port in the path
+ * @link_nr: Preferred link if there are dual links on the path
+ * @name: Name of the path
+ *
+ * Creates path between two ports starting with given @src_hopid. Reserves
+ * HopIDs for each port (they can be different from @src_hopid depending on
+ * how many HopIDs each port already have reserved). If there are dual
+ * links on the path, prioritizes using @link_nr but takes into account
+ * that the lanes may be bonded.
+ *
+ * Return: Returns a tb_path on success or NULL on failure.
+ */
+struct tb_path *tb_path_alloc(struct tb *tb, struct tb_port *src, int src_hopid,
+			      struct tb_port *dst, int dst_hopid, int link_nr,
+			      const char *name)
+{
+	struct tb_port *in_port, *out_port, *first_port, *last_port;
+	int in_hopid, out_hopid;
+	struct tb_path *path;
+	size_t num_hops;
+	int i, ret;
+
+	path = kzalloc(sizeof(*path), GFP_KERNEL);
+	if (!path)
+		return NULL;
+
+	first_port = last_port = NULL;
+	i = 0;
+	tb_for_each_port_on_path(src, dst, in_port) {
+		if (!first_port)
+			first_port = in_port;
+		last_port = in_port;
+		i++;
+	}
+
+	/* Check that src and dst are reachable */
+	if (first_port != src || last_port != dst) {
+		kfree(path);
+		return NULL;
+	}
+
+	/* Each hop takes two ports */
+	num_hops = i / 2;
+
+	path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
+	if (!path->hops) {
+		kfree(path);
+		return NULL;
+	}
+
+	path->alloc_hopid = true;
+
+	in_hopid = src_hopid;
+	out_port = NULL;
+
+	for (i = 0; i < num_hops; i++) {
+		in_port = tb_next_port_on_path(src, dst, out_port);
+		if (!in_port)
+			goto err;
+
+		/* When lanes are bonded primary link must be used */
+		if (!in_port->bonded && in_port->dual_link_port &&
+		    in_port->link_nr != link_nr)
+			in_port = in_port->dual_link_port;
+
+		ret = tb_port_alloc_in_hopid(in_port, in_hopid, in_hopid);
+		if (ret < 0)
+			goto err;
+		in_hopid = ret;
+
+		out_port = tb_next_port_on_path(src, dst, in_port);
+		if (!out_port)
+			goto err;
+
+		/*
+		 * Pick up right port when going from non-bonded to
+		 * bonded or from bonded to non-bonded.
+		 */
+		if (out_port->dual_link_port) {
+			if (!in_port->bonded && out_port->bonded &&
+			    out_port->link_nr) {
+				/*
+				 * Use primary link when going from
+				 * non-bonded to bonded.
+				 */
+				out_port = out_port->dual_link_port;
+			} else if (!out_port->bonded &&
+				   out_port->link_nr != link_nr) {
+				/*
+				 * If out port is not bonded follow
+				 * link_nr.
+				 */
+				out_port = out_port->dual_link_port;
+			}
+		}
+
+		if (i == num_hops - 1)
+			ret = tb_port_alloc_out_hopid(out_port, dst_hopid,
+						      dst_hopid);
+		else
+			ret = tb_port_alloc_out_hopid(out_port, -1, -1);
+
+		if (ret < 0)
+			goto err;
+		out_hopid = ret;
+
+		path->hops[i].in_hop_index = in_hopid;
+		path->hops[i].in_port = in_port;
+		path->hops[i].in_counter_index = -1;
+		path->hops[i].out_port = out_port;
+		path->hops[i].next_hop_index = out_hopid;
+
+		in_hopid = out_hopid;
+	}
+
+	path->tb = tb;
+	path->path_length = num_hops;
+	path->name = name;
+
+	return path;
+
+err:
+	tb_path_free(path);
+	return NULL;
+}
+
+/**
+ * tb_path_free() - free a path
+ * @path: Path to free
+ *
+ * Frees a path. The path does not need to be deactivated.
+ */
+void tb_path_free(struct tb_path *path)
+{
+	if (path->alloc_hopid) {
+		int i;
+
+		for (i = 0; i < path->path_length; i++) {
+			const struct tb_path_hop *hop = &path->hops[i];
+
+			if (hop->in_port)
+				tb_port_release_in_hopid(hop->in_port,
+							 hop->in_hop_index);
+			if (hop->out_port)
+				tb_port_release_out_hopid(hop->out_port,
+							  hop->next_hop_index);
+		}
+	}
+
+	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->hops[i].nfc_credits);
+		if (res)
+			tb_port_warn(path->hops[i].in_port,
+				     "nfc credits deallocation failed for hop %d\n",
+				     i);
+	}
+}
+
+static int __tb_path_deactivate_hop(struct tb_port *port, int hop_index,
+				    bool clear_fc)
+{
+	struct tb_regs_hop hop;
+	ktime_t timeout;
+	int ret;
+
+	/* Disable the path */
+	ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
+	if (ret)
+		return ret;
+
+	/* Already disabled */
+	if (!hop.enable)
+		return 0;
+
+	hop.enable = 0;
+
+	ret = tb_port_write(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
+	if (ret)
+		return ret;
+
+	/* Wait until it is drained */
+	timeout = ktime_add_ms(ktime_get(), 500);
+	do {
+		ret = tb_port_read(port, &hop, TB_CFG_HOPS, 2 * hop_index, 2);
+		if (ret)
+			return ret;
+
+		if (!hop.pending) {
+			if (clear_fc) {
+				/*
+				 * Clear flow control. Protocol adapters
+				 * IFC and ISE bits are vendor defined
+				 * in the USB4 spec so we clear them
+				 * only for pre-USB4 adapters.
+				 */
+				if (!tb_switch_is_usb4(port->sw)) {
+					hop.ingress_fc = 0;
+					hop.ingress_shared_buffer = 0;
+				}
+				hop.egress_fc = 0;
+				hop.egress_shared_buffer = 0;
+
+				return tb_port_write(port, &hop, TB_CFG_HOPS,
+						     2 * hop_index, 2);
+			}
+
+			return 0;
+		}
+
+		usleep_range(10, 20);
+	} while (ktime_before(ktime_get(), timeout));
+
+	return -ETIMEDOUT;
+}
+
+static void __tb_path_deactivate_hops(struct tb_path *path, int first_hop)
+{
+	int i, res;
+
+	for (i = first_hop; i < path->path_length; i++) {
+		res = __tb_path_deactivate_hop(path->hops[i].in_port,
+					       path->hops[i].in_hop_index,
+					       path->clear_fc);
+		if (res && res != -ENODEV)
+			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_dbg(path->tb,
+	       "deactivating %s path from %llx:%u to %llx:%u\n",
+	       path->name, 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
+ * @path: Path to activate
+ *
+ * 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_dbg(path->tb,
+	       "activating %s path from %llx:%u to %llx:%u\n",
+	       path->name, 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->hops[i].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 };
+
+		/* If it is left active deactivate it first */
+		__tb_path_deactivate_hop(path->hops[i].in_port,
+				path->hops[i].in_hop_index, path->clear_fc);
+
+		/* dword 0 */
+		hop.next_hop = path->hops[i].next_hop_index;
+		hop.out_port = path->hops[i].out_port->port;
+		hop.initial_credits = path->hops[i].initial_credits;
+		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_dbg(path->hops[i].in_port, "Writing hop %d\n", i);
+		tb_dump_hop(&path->hops[i], &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_dbg(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
+ * @path: Path to check
+ *
+ * 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;
+}
+
+/**
+ * tb_path_port_on_path() - Does the path go through certain port
+ * @path: Path to check
+ * @port: Switch to check
+ *
+ * Goes over all hops on path and checks if @port is any of them.
+ * Direction does not matter.
+ */
+bool tb_path_port_on_path(const struct tb_path *path, const struct tb_port *port)
+{
+	int i;
+
+	for (i = 0; i < path->path_length; i++) {
+		if (path->hops[i].in_port == port ||
+		    path->hops[i].out_port == port)
+			return true;
+	}
+
+	return false;
+}