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Commit 520b6702 authored by Andreas Noever's avatar Andreas Noever Committed by Greg Kroah-Hartman
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thunderbolt: Add path setup code. 



A thunderbolt path is a unidirectional channel between two thunderbolt
ports. Two such paths are needed to establish a pci tunnel.

This patch introduces struct tb_path as well as a set of tb_path_*
methods which are used to activate & deactivate paths.

Signed-off-by: default avatarAndreas Noever <andreas.noever@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 053596d9

drivers/thunderbolt/Makefile

+1 −1
Original line number Diff line number Diff line 
obj-${CONFIG_THUNDERBOLT} := thunderbolt.o

thunderbolt-objs := nhi.o ctl.o tb.o switch.o cap.o

thunderbolt-objs := nhi.o ctl.o tb.o switch.o cap.o path.o

drivers/thunderbolt/path.c

0 → 100644
+215 −0
Original line number Diff line number Diff line 
/*

 * 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;



		/* 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;

}

drivers/thunderbolt/switch.c

+34 −0
Original line number Diff line number Diff line
@@ -138,6 +138,40 @@ int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged) 
	return 0;

}



/**

 * tb_port_add_nfc_credits() - add/remove non flow controlled credits to port

 *

 * Change the number of NFC credits allocated to @port by @credits. To remove

 * NFC credits pass a negative amount of credits.

 *

 * Return: Returns 0 on success or an error code on failure.

 */

int tb_port_add_nfc_credits(struct tb_port *port, int credits)

{

	if (credits == 0)

		return 0;

	tb_port_info(port,

		     "adding %#x NFC credits (%#x -> %#x)",

		     credits,

		     port->config.nfc_credits,

		     port->config.nfc_credits + credits);

	port->config.nfc_credits += credits;

	return tb_port_write(port, &port->config.nfc_credits,

			     TB_CFG_PORT, 4, 1);

}



/**

 * tb_port_clear_counter() - clear a counter in TB_CFG_COUNTER

 *

 * Return: Returns 0 on success or an error code on failure.

 */

int tb_port_clear_counter(struct tb_port *port, int counter)

{

	u32 zero[3] = { 0, 0, 0 };

	tb_port_info(port, "clearing counter %d\n", counter);

	return tb_port_write(port, zero, TB_CFG_COUNTERS, 3 * counter, 3);

}



/**

 * tb_init_port() - initialize a port

 *

drivers/thunderbolt/tb.h

+62 −0
Original line number Diff line number Diff line
@@ -34,6 +34,60 @@ struct tb_port { 
	u8 port; /* port number on switch */

};



/**

 * struct tb_path_hop - routing information for a tb_path

 *

 * Hop configuration is always done on the IN port of a switch.

 * in_port and out_port have to be on the same switch. Packets arriving on

 * in_port with "hop" = in_hop_index will get routed to through out_port. The

 * next hop to take (on out_port->remote) is determined by next_hop_index.

 *

 * in_counter_index is the index of a counter (in TB_CFG_COUNTERS) on the in

 * port.

 */

struct tb_path_hop {

	struct tb_port *in_port;

	struct tb_port *out_port;

	int in_hop_index;

	int in_counter_index; /* write -1 to disable counters for this hop. */

	int next_hop_index;

};



/**

 * enum tb_path_port - path options mask

 */

enum tb_path_port {

	TB_PATH_NONE = 0,

	TB_PATH_SOURCE = 1, /* activate on the first hop (out of src) */

	TB_PATH_INTERNAL = 2, /* activate on other hops (not the first/last) */

	TB_PATH_DESTINATION = 4, /* activate on the last hop (into dst) */

	TB_PATH_ALL = 7,

};



/**

 * struct tb_path - a unidirectional path between two ports

 *

 * A path consists of a number of hops (see tb_path_hop). To establish a PCIe

 * tunnel two paths have to be created between the two PCIe ports.

 *

 */

struct tb_path {

	struct tb *tb;

	int nfc_credits; /* non flow controlled credits */

	enum tb_path_port ingress_shared_buffer;

	enum tb_path_port egress_shared_buffer;

	enum tb_path_port ingress_fc_enable;

	enum tb_path_port egress_fc_enable;



	int priority:3;

	int weight:4;

	bool drop_packages;

	bool activated;

	struct tb_path_hop *hops;

	int path_length; /* number of hops */

};





/**

 * struct tb - main thunderbolt bus structure

 */
@@ -165,9 +219,17 @@ void tb_sw_set_unpplugged(struct tb_switch *sw); 
struct tb_switch *get_switch_at_route(struct tb_switch *sw, u64 route);



int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged);

int tb_port_add_nfc_credits(struct tb_port *port, int credits);

int tb_port_clear_counter(struct tb_port *port, int counter);



int tb_find_cap(struct tb_port *port, enum tb_cfg_space space, u32 value);



struct tb_path *tb_path_alloc(struct tb *tb, int num_hops);

void tb_path_free(struct tb_path *path);

int tb_path_activate(struct tb_path *path);

void tb_path_deactivate(struct tb_path *path);

bool tb_path_is_invalid(struct tb_path *path);





static inline int tb_route_length(u64 route)

{