drivers/ntb/test/ntb_pingpong.c - kernel/bruno - Git at Google

 /*
  * 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/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;
 };

 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);
 	}
 	spin_unlock_irqrestore(&pp->db_lock, irqflags);
 }

 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;
 	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;

 	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;

 	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,
 	},
 };
 module_ntb_client(pp_client);
	/*
	* 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/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;
	};

	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);
	}
	spin_unlock_irqrestore(&pp->db_lock, irqflags);
	}

	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;
	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;

	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;

	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,
	},
	};
	module_ntb_client(pp_client);