linux/drivers/ntb/test/ntb_pingpong.c
Serge Semin c7aeb0afdc NTB: ntb_pp: Add full multi-port NTB API support
Current Ping Pong driver can't truly work with multi-port devices.
Additionally it requires the Scratchpad registers being available
on NTB device. This patches rewrites the driver so one would
perform the cyclic Ping-Pong algorithm around all the available
NTB peers and makes it working with NTB hardware, which doesn't
support Scratchpads, but such alternative as NTB Message register.
Additional cleanups are also added here.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
2018-01-28 22:17:24 -05:00

439 lines
10 KiB
C

/*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
*
* GPL LICENSE SUMMARY
*
* Copyright (C) 2015 EMC Corporation. All Rights Reserved.
* Copyright (C) 2017 T-Platforms. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* BSD LICENSE
*
* Copyright (C) 2015 EMC Corporation. All Rights Reserved.
* Copyright (C) 2017 T-Platforms. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copy
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* PCIe NTB Pingpong Linux driver
*/
/*
* How to use this tool, by example.
*
* Assuming $DBG_DIR is something like:
* '/sys/kernel/debug/ntb_perf/0000:00:03.0'
* Suppose aside from local device there is at least one remote device
* connected to NTB with index 0.
*-----------------------------------------------------------------------------
* Eg: install driver with specified delay between doorbell event and response
*
* root@self# insmod ntb_pingpong.ko delay_ms=1000
*-----------------------------------------------------------------------------
* Eg: get number of ping-pong cycles performed
*
* root@self# cat $DBG_DIR/count
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/bitops.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/hrtimer.h>
#include <linux/debugfs.h>
#include <linux/ntb.h>
#define DRIVER_NAME "ntb_pingpong"
#define DRIVER_VERSION "2.0"
MODULE_LICENSE("Dual BSD/GPL");
MODULE_VERSION(DRIVER_VERSION);
MODULE_AUTHOR("Allen Hubbe <Allen.Hubbe@emc.com>");
MODULE_DESCRIPTION("PCIe NTB Simple Pingpong Client");
static unsigned int unsafe;
module_param(unsafe, uint, 0644);
MODULE_PARM_DESC(unsafe, "Run even though ntb operations may be unsafe");
static unsigned int delay_ms = 1000;
module_param(delay_ms, uint, 0644);
MODULE_PARM_DESC(delay_ms, "Milliseconds to delay the response to peer");
struct pp_ctx {
struct ntb_dev *ntb;
struct hrtimer timer;
u64 in_db;
u64 out_db;
int out_pidx;
u64 nmask;
u64 pmask;
atomic_t count;
spinlock_t lock;
struct dentry *dbgfs_dir;
};
#define to_pp_timer(__timer) \
container_of(__timer, struct pp_ctx, timer)
static struct dentry *pp_dbgfs_topdir;
static int pp_find_next_peer(struct pp_ctx *pp)
{
u64 link, out_db;
int pidx;
link = ntb_link_is_up(pp->ntb, NULL, NULL);
/* Find next available peer */
if (link & pp->nmask) {
pidx = __ffs64(link & pp->nmask);
out_db = BIT_ULL(pidx + 1);
} else if (link & pp->pmask) {
pidx = __ffs64(link & pp->pmask);
out_db = BIT_ULL(pidx);
} else {
return -ENODEV;
}
spin_lock(&pp->lock);
pp->out_pidx = pidx;
pp->out_db = out_db;
spin_unlock(&pp->lock);
return 0;
}
static void pp_setup(struct pp_ctx *pp)
{
int ret;
ntb_db_set_mask(pp->ntb, pp->in_db);
hrtimer_cancel(&pp->timer);
ret = pp_find_next_peer(pp);
if (ret == -ENODEV) {
dev_dbg(&pp->ntb->dev, "Got no peers, so cancel\n");
return;
}
dev_dbg(&pp->ntb->dev, "Ping-pong started with port %d, db %#llx\n",
ntb_peer_port_number(pp->ntb, pp->out_pidx), pp->out_db);
hrtimer_start(&pp->timer, ms_to_ktime(delay_ms), HRTIMER_MODE_REL);
}
static void pp_clear(struct pp_ctx *pp)
{
hrtimer_cancel(&pp->timer);
ntb_db_set_mask(pp->ntb, pp->in_db);
dev_dbg(&pp->ntb->dev, "Ping-pong cancelled\n");
}
static void pp_ping(struct pp_ctx *pp)
{
u32 count;
count = atomic_read(&pp->count);
spin_lock(&pp->lock);
ntb_peer_spad_write(pp->ntb, pp->out_pidx, 0, count);
ntb_peer_msg_write(pp->ntb, pp->out_pidx, 0, count);
dev_dbg(&pp->ntb->dev, "Ping port %d spad %#x, msg %#x\n",
ntb_peer_port_number(pp->ntb, pp->out_pidx), count, count);
ntb_peer_db_set(pp->ntb, pp->out_db);
ntb_db_clear_mask(pp->ntb, pp->in_db);
spin_unlock(&pp->lock);
}
static void pp_pong(struct pp_ctx *pp)
{
u32 msg_data = -1, spad_data = -1;
int pidx = 0;
/* Read pong data */
spad_data = ntb_spad_read(pp->ntb, 0);
msg_data = ntb_msg_read(pp->ntb, &pidx, 0);
ntb_msg_clear_sts(pp->ntb, -1);
/*
* Scratchpad and message data may differ, since message register can't
* be rewritten unless status is cleared. Additionally either of them
* might be unsupported
*/
dev_dbg(&pp->ntb->dev, "Pong spad %#x, msg %#x (port %d)\n",
spad_data, msg_data, ntb_peer_port_number(pp->ntb, pidx));
atomic_inc(&pp->count);
ntb_db_set_mask(pp->ntb, pp->in_db);
ntb_db_clear(pp->ntb, pp->in_db);
hrtimer_start(&pp->timer, ms_to_ktime(delay_ms), HRTIMER_MODE_REL);
}
static enum hrtimer_restart pp_timer_func(struct hrtimer *t)
{
struct pp_ctx *pp = to_pp_timer(t);
pp_ping(pp);
return HRTIMER_NORESTART;
}
static void pp_link_event(void *ctx)
{
struct pp_ctx *pp = ctx;
pp_setup(pp);
}
static void pp_db_event(void *ctx, int vec)
{
struct pp_ctx *pp = ctx;
pp_pong(pp);
}
static const struct ntb_ctx_ops pp_ops = {
.link_event = pp_link_event,
.db_event = pp_db_event
};
static int pp_check_ntb(struct ntb_dev *ntb)
{
u64 pmask;
if (ntb_db_is_unsafe(ntb)) {
dev_dbg(&ntb->dev, "Doorbell is unsafe\n");
if (!unsafe)
return -EINVAL;
}
if (ntb_spad_is_unsafe(ntb)) {
dev_dbg(&ntb->dev, "Scratchpad is unsafe\n");
if (!unsafe)
return -EINVAL;
}
pmask = GENMASK_ULL(ntb_peer_port_count(ntb), 0);
if ((ntb_db_valid_mask(ntb) & pmask) != pmask) {
dev_err(&ntb->dev, "Unsupported DB configuration\n");
return -EINVAL;
}
if (ntb_spad_count(ntb) < 1 && ntb_msg_count(ntb) < 1) {
dev_err(&ntb->dev, "Scratchpads and messages unsupported\n");
return -EINVAL;
} else if (ntb_spad_count(ntb) < 1) {
dev_dbg(&ntb->dev, "Scratchpads unsupported\n");
} else if (ntb_msg_count(ntb) < 1) {
dev_dbg(&ntb->dev, "Messages unsupported\n");
}
return 0;
}
static struct pp_ctx *pp_create_data(struct ntb_dev *ntb)
{
struct pp_ctx *pp;
pp = devm_kzalloc(&ntb->dev, sizeof(*pp), GFP_KERNEL);
if (!pp)
return ERR_PTR(-ENOMEM);
pp->ntb = ntb;
atomic_set(&pp->count, 0);
spin_lock_init(&pp->lock);
hrtimer_init(&pp->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
pp->timer.function = pp_timer_func;
return pp;
}
static void pp_init_flds(struct pp_ctx *pp)
{
int pidx, lport, pcnt;
/* Find global port index */
lport = ntb_port_number(pp->ntb);
pcnt = ntb_peer_port_count(pp->ntb);
for (pidx = 0; pidx < pcnt; pidx++) {
if (lport < ntb_peer_port_number(pp->ntb, pidx))
break;
}
pp->in_db = BIT_ULL(pidx);
pp->pmask = GENMASK_ULL(pidx, 0) >> 1;
pp->nmask = GENMASK_ULL(pcnt - 1, pidx);
dev_dbg(&pp->ntb->dev, "Inbound db %#llx, prev %#llx, next %#llx\n",
pp->in_db, pp->pmask, pp->nmask);
}
static int pp_mask_events(struct pp_ctx *pp)
{
u64 db_mask, msg_mask;
int ret;
db_mask = ntb_db_valid_mask(pp->ntb);
ret = ntb_db_set_mask(pp->ntb, db_mask);
if (ret)
return ret;
/* Skip message events masking if unsupported */
if (ntb_msg_count(pp->ntb) < 1)
return 0;
msg_mask = ntb_msg_outbits(pp->ntb) | ntb_msg_inbits(pp->ntb);
return ntb_msg_set_mask(pp->ntb, msg_mask);
}
static int pp_setup_ctx(struct pp_ctx *pp)
{
int ret;
ret = ntb_set_ctx(pp->ntb, pp, &pp_ops);
if (ret)
return ret;
ntb_link_enable(pp->ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
/* Might be not necessary */
ntb_link_event(pp->ntb);
return 0;
}
static void pp_clear_ctx(struct pp_ctx *pp)
{
ntb_link_disable(pp->ntb);
ntb_clear_ctx(pp->ntb);
}
static void pp_setup_dbgfs(struct pp_ctx *pp)
{
struct pci_dev *pdev = pp->ntb->pdev;
void *ret;
pp->dbgfs_dir = debugfs_create_dir(pci_name(pdev), pp_dbgfs_topdir);
ret = debugfs_create_atomic_t("count", 0600, pp->dbgfs_dir, &pp->count);
if (!ret)
dev_warn(&pp->ntb->dev, "DebugFS unsupported\n");
}
static void pp_clear_dbgfs(struct pp_ctx *pp)
{
debugfs_remove_recursive(pp->dbgfs_dir);
}
static int pp_probe(struct ntb_client *client, struct ntb_dev *ntb)
{
struct pp_ctx *pp;
int ret;
ret = pp_check_ntb(ntb);
if (ret)
return ret;
pp = pp_create_data(ntb);
if (IS_ERR(pp))
return PTR_ERR(pp);
pp_init_flds(pp);
ret = pp_mask_events(pp);
if (ret)
return ret;
ret = pp_setup_ctx(pp);
if (ret)
return ret;
pp_setup_dbgfs(pp);
return 0;
}
static void pp_remove(struct ntb_client *client, struct ntb_dev *ntb)
{
struct pp_ctx *pp = ntb->ctx;
pp_clear_dbgfs(pp);
pp_clear_ctx(pp);
pp_clear(pp);
}
static struct ntb_client pp_client = {
.ops = {
.probe = pp_probe,
.remove = pp_remove
}
};
static int __init pp_init(void)
{
int ret;
if (debugfs_initialized())
pp_dbgfs_topdir = debugfs_create_dir(KBUILD_MODNAME, NULL);
ret = ntb_register_client(&pp_client);
if (ret)
debugfs_remove_recursive(pp_dbgfs_topdir);
return ret;
}
module_init(pp_init);
static void __exit pp_exit(void)
{
ntb_unregister_client(&pp_client);
debugfs_remove_recursive(pp_dbgfs_topdir);
}
module_exit(pp_exit);