linux/drivers/thunderbolt/path.c
Mika Westerberg a11b88add4 thunderbolt: Add bandwidth management for Display Port tunnels
Titan Ridge supports Display Port 1.4 which adds HBR3 (High Bit Rate)
rates that may be up to 8.1 Gb/s over 4 lanes. This translates to
effective data bandwidth of 25.92 Gb/s (as 8/10 encoding is removed by
the DP adapters when going over Thunderbolt fabric). If another high
rate monitor is connected we may need to reduce the bandwidth it
consumes so that it fits into the total 40 Gb/s available on the
Thunderbolt fabric.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2019-11-02 12:13:31 +03:00

582 lines
15 KiB
C

// 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
*
* Follows a path starting from @src and @src_hopid to the last output
* port of the path. Allocates HopIDs for the visited ports. 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)
{
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->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
if (!path->hops) {
kfree(path);
return NULL;
}
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 (tb_port_alloc_in_hopid(p, h, h) < 0)
goto err;
out_port = &sw->ports[hop.out_port];
next_hop = hop.next_hop;
if (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;
h = next_hop;
p = out_port->remote;
}
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;
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;
/*
* Number of hops on a path is the distance between the two
* switches plus the source adapter port.
*/
num_hops = abs(tb_route_length(tb_route(src->sw)) -
tb_route_length(tb_route(dst->sw))) + 1;
path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
if (!path->hops) {
kfree(path);
return NULL;
}
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)
{
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->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 */
hop.ingress_fc = 0;
hop.egress_fc = 0;
hop.ingress_shared_buffer = 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:%x to %llx:%x\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
*
* 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:%x to %llx:%x\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->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
*
* 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_switch_on_path() - Does the path go through certain switch
* @path: Path to check
* @sw: Switch to check
*
* Goes over all hops on path and checks if @sw is any of them.
* Direction does not matter.
*/
bool tb_path_switch_on_path(const struct tb_path *path,
const struct tb_switch *sw)
{
int i;
for (i = 0; i < path->path_length; i++) {
if (path->hops[i].in_port->sw == sw ||
path->hops[i].out_port->sw == sw)
return true;
}
return false;
}