/*
* 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 <[email protected]>");
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);
else if (link & pp->pmask)
pidx = __ffs64(link & pp->pmask);
else
return -ENODEV;
out_db = BIT_ULL(ntb_peer_port_number(pp->ntb, pidx));
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, spad_data;
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(lport);
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;
pp->dbgfs_dir = debugfs_create_dir(pci_name(pdev), pp_dbgfs_topdir);
debugfs_create_atomic_t("count", 0600, pp->dbgfs_dir, &pp->count);
}
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);
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