OpenCloudOS-Kernel/drivers/ntb/test/ntb_pingpong.c

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/*
* 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.
*
* 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.
*
* 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
*
* Contact Information:
* Allen Hubbe <Allen.Hubbe@emc.com>
*/
/* Note: load this module with option 'dyndbg=+p' */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
#include <linux/ntb.h>
#define DRIVER_NAME "ntb_pingpong"
#define DRIVER_DESCRIPTION "PCIe NTB Simple Pingpong Client"
#define DRIVER_LICENSE "Dual BSD/GPL"
#define DRIVER_VERSION "1.0"
#define DRIVER_RELDATE "24 March 2015"
#define DRIVER_AUTHOR "Allen Hubbe <Allen.Hubbe@emc.com>"
MODULE_LICENSE(DRIVER_LICENSE);
MODULE_VERSION(DRIVER_VERSION);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESCRIPTION);
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");
static unsigned long db_init = 0x7;
module_param(db_init, ulong, 0644);
MODULE_PARM_DESC(delay_ms, "Initial doorbell bits to ring on the peer");
struct pp_ctx {
struct ntb_dev *ntb;
u64 db_bits;
/* synchronize access to db_bits by ping and pong */
spinlock_t db_lock;
struct timer_list db_timer;
unsigned long db_delay;
struct dentry *debugfs_node_dir;
struct dentry *debugfs_count;
atomic_t count;
};
static struct dentry *pp_debugfs_dir;
static void pp_ping(unsigned long ctx)
{
struct pp_ctx *pp = (void *)ctx;
unsigned long irqflags;
u64 db_bits, db_mask;
u32 spad_rd, spad_wr;
spin_lock_irqsave(&pp->db_lock, irqflags);
{
db_mask = ntb_db_valid_mask(pp->ntb);
db_bits = ntb_db_read(pp->ntb);
if (db_bits) {
dev_dbg(&pp->ntb->dev,
"Masked pongs %#llx\n",
db_bits);
ntb_db_clear(pp->ntb, db_bits);
}
db_bits = ((pp->db_bits | db_bits) << 1) & db_mask;
if (!db_bits)
db_bits = db_init;
spad_rd = ntb_spad_read(pp->ntb, 0);
spad_wr = spad_rd + 1;
dev_dbg(&pp->ntb->dev,
"Ping bits %#llx read %#x write %#x\n",
db_bits, spad_rd, spad_wr);
ntb_peer_spad_write(pp->ntb, 0, spad_wr);
ntb_peer_db_set(pp->ntb, db_bits);
ntb_db_clear_mask(pp->ntb, db_mask);
pp->db_bits = 0;
}
spin_unlock_irqrestore(&pp->db_lock, irqflags);
}
static void pp_link_event(void *ctx)
{
struct pp_ctx *pp = ctx;
if (ntb_link_is_up(pp->ntb, NULL, NULL) == 1) {
dev_dbg(&pp->ntb->dev, "link is up\n");
pp_ping((unsigned long)pp);
} else {
dev_dbg(&pp->ntb->dev, "link is down\n");
del_timer(&pp->db_timer);
}
}
static void pp_db_event(void *ctx, int vec)
{
struct pp_ctx *pp = ctx;
u64 db_bits, db_mask;
unsigned long irqflags;
spin_lock_irqsave(&pp->db_lock, irqflags);
{
db_mask = ntb_db_vector_mask(pp->ntb, vec);
db_bits = db_mask & ntb_db_read(pp->ntb);
ntb_db_set_mask(pp->ntb, db_mask);
ntb_db_clear(pp->ntb, db_bits);
pp->db_bits |= db_bits;
mod_timer(&pp->db_timer, jiffies + pp->db_delay);
dev_dbg(&pp->ntb->dev,
"Pong vec %d bits %#llx\n",
vec, db_bits);
atomic_inc(&pp->count);
}
spin_unlock_irqrestore(&pp->db_lock, irqflags);
}
static int pp_debugfs_setup(struct pp_ctx *pp)
{
struct pci_dev *pdev = pp->ntb->pdev;
if (!pp_debugfs_dir)
return -ENODEV;
pp->debugfs_node_dir = debugfs_create_dir(pci_name(pdev),
pp_debugfs_dir);
if (!pp->debugfs_node_dir)
return -ENODEV;
pp->debugfs_count = debugfs_create_atomic_t("count", S_IRUSR | S_IWUSR,
pp->debugfs_node_dir,
&pp->count);
if (!pp->debugfs_count)
return -ENODEV;
return 0;
}
static const struct ntb_ctx_ops pp_ops = {
.link_event = pp_link_event,
.db_event = pp_db_event,
};
static int pp_probe(struct ntb_client *client,
struct ntb_dev *ntb)
{
struct pp_ctx *pp;
int rc;
if (ntb_db_is_unsafe(ntb)) {
dev_dbg(&ntb->dev, "doorbell is unsafe\n");
if (!unsafe) {
rc = -EINVAL;
goto err_pp;
}
}
if (ntb_spad_is_unsafe(ntb)) {
dev_dbg(&ntb->dev, "scratchpad is unsafe\n");
if (!unsafe) {
rc = -EINVAL;
goto err_pp;
}
}
pp = kmalloc(sizeof(*pp), GFP_KERNEL);
if (!pp) {
rc = -ENOMEM;
goto err_pp;
}
pp->ntb = ntb;
pp->db_bits = 0;
atomic_set(&pp->count, 0);
spin_lock_init(&pp->db_lock);
setup_timer(&pp->db_timer, pp_ping, (unsigned long)pp);
pp->db_delay = msecs_to_jiffies(delay_ms);
rc = ntb_set_ctx(ntb, pp, &pp_ops);
if (rc)
goto err_ctx;
rc = pp_debugfs_setup(pp);
if (rc)
goto err_ctx;
ntb_link_enable(ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
ntb_link_event(ntb);
return 0;
err_ctx:
kfree(pp);
err_pp:
return rc;
}
static void pp_remove(struct ntb_client *client,
struct ntb_dev *ntb)
{
struct pp_ctx *pp = ntb->ctx;
debugfs_remove_recursive(pp->debugfs_node_dir);
ntb_clear_ctx(ntb);
del_timer_sync(&pp->db_timer);
ntb_link_disable(ntb);
kfree(pp);
}
static struct ntb_client pp_client = {
.ops = {
.probe = pp_probe,
.remove = pp_remove,
},
};
static int __init pp_init(void)
{
int rc;
if (debugfs_initialized())
pp_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
rc = ntb_register_client(&pp_client);
if (rc)
goto err_client;
return 0;
err_client:
debugfs_remove_recursive(pp_debugfs_dir);
return rc;
}
module_init(pp_init);
static void __exit pp_exit(void)
{
ntb_unregister_client(&pp_client);
debugfs_remove_recursive(pp_debugfs_dir);
}
module_exit(pp_exit);