251 lines
6.5 KiB
C
251 lines
6.5 KiB
C
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/*
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* This file is provided under a dual BSD/GPLv2 license. When using or
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* redistributing this file, you may do so under either license.
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*
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* GPL LICENSE SUMMARY
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*
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* Copyright (C) 2015 EMC Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* BSD LICENSE
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*
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* Copyright (C) 2015 EMC Corporation. All Rights Reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copy
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* PCIe NTB Pingpong Linux driver
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*
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* Contact Information:
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* Allen Hubbe <Allen.Hubbe@emc.com>
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*/
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/* Note: load this module with option 'dyndbg=+p' */
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/dma-mapping.h>
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#include <linux/pci.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/ntb.h>
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#define DRIVER_NAME "ntb_pingpong"
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#define DRIVER_DESCRIPTION "PCIe NTB Simple Pingpong Client"
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#define DRIVER_LICENSE "Dual BSD/GPL"
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#define DRIVER_VERSION "1.0"
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#define DRIVER_RELDATE "24 March 2015"
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#define DRIVER_AUTHOR "Allen Hubbe <Allen.Hubbe@emc.com>"
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MODULE_LICENSE(DRIVER_LICENSE);
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MODULE_VERSION(DRIVER_VERSION);
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MODULE_AUTHOR(DRIVER_AUTHOR);
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MODULE_DESCRIPTION(DRIVER_DESCRIPTION);
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static unsigned int unsafe;
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module_param(unsafe, uint, 0644);
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MODULE_PARM_DESC(unsafe, "Run even though ntb operations may be unsafe");
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static unsigned int delay_ms = 1000;
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module_param(delay_ms, uint, 0644);
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MODULE_PARM_DESC(delay_ms, "Milliseconds to delay the response to peer");
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static unsigned long db_init = 0x7;
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module_param(db_init, ulong, 0644);
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MODULE_PARM_DESC(delay_ms, "Initial doorbell bits to ring on the peer");
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struct pp_ctx {
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struct ntb_dev *ntb;
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u64 db_bits;
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/* synchronize access to db_bits by ping and pong */
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spinlock_t db_lock;
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struct timer_list db_timer;
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unsigned long db_delay;
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};
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static void pp_ping(unsigned long ctx)
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{
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struct pp_ctx *pp = (void *)ctx;
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unsigned long irqflags;
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u64 db_bits, db_mask;
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u32 spad_rd, spad_wr;
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spin_lock_irqsave(&pp->db_lock, irqflags);
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{
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db_mask = ntb_db_valid_mask(pp->ntb);
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db_bits = ntb_db_read(pp->ntb);
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if (db_bits) {
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dev_dbg(&pp->ntb->dev,
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"Masked pongs %#llx\n",
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db_bits);
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ntb_db_clear(pp->ntb, db_bits);
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}
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db_bits = ((pp->db_bits | db_bits) << 1) & db_mask;
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if (!db_bits)
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db_bits = db_init;
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spad_rd = ntb_spad_read(pp->ntb, 0);
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spad_wr = spad_rd + 1;
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dev_dbg(&pp->ntb->dev,
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"Ping bits %#llx read %#x write %#x\n",
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db_bits, spad_rd, spad_wr);
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ntb_peer_spad_write(pp->ntb, 0, spad_wr);
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ntb_peer_db_set(pp->ntb, db_bits);
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ntb_db_clear_mask(pp->ntb, db_mask);
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pp->db_bits = 0;
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}
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spin_unlock_irqrestore(&pp->db_lock, irqflags);
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}
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static void pp_link_event(void *ctx)
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{
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struct pp_ctx *pp = ctx;
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if (ntb_link_is_up(pp->ntb, NULL, NULL) == 1) {
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dev_dbg(&pp->ntb->dev, "link is up\n");
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pp_ping((unsigned long)pp);
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} else {
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dev_dbg(&pp->ntb->dev, "link is down\n");
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del_timer(&pp->db_timer);
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}
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}
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static void pp_db_event(void *ctx, int vec)
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{
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struct pp_ctx *pp = ctx;
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u64 db_bits, db_mask;
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unsigned long irqflags;
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spin_lock_irqsave(&pp->db_lock, irqflags);
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{
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db_mask = ntb_db_vector_mask(pp->ntb, vec);
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db_bits = db_mask & ntb_db_read(pp->ntb);
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ntb_db_set_mask(pp->ntb, db_mask);
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ntb_db_clear(pp->ntb, db_bits);
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pp->db_bits |= db_bits;
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mod_timer(&pp->db_timer, jiffies + pp->db_delay);
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dev_dbg(&pp->ntb->dev,
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"Pong vec %d bits %#llx\n",
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vec, db_bits);
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}
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spin_unlock_irqrestore(&pp->db_lock, irqflags);
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}
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static const struct ntb_ctx_ops pp_ops = {
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.link_event = pp_link_event,
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.db_event = pp_db_event,
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};
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static int pp_probe(struct ntb_client *client,
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struct ntb_dev *ntb)
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{
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struct pp_ctx *pp;
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int rc;
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if (ntb_db_is_unsafe(ntb)) {
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dev_dbg(&ntb->dev, "doorbell is unsafe\n");
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if (!unsafe) {
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rc = -EINVAL;
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goto err_pp;
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}
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}
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if (ntb_spad_is_unsafe(ntb)) {
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dev_dbg(&ntb->dev, "scratchpad is unsafe\n");
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if (!unsafe) {
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rc = -EINVAL;
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goto err_pp;
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}
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}
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pp = kmalloc(sizeof(*pp), GFP_KERNEL);
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if (!pp) {
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rc = -ENOMEM;
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goto err_pp;
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}
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pp->ntb = ntb;
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pp->db_bits = 0;
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spin_lock_init(&pp->db_lock);
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setup_timer(&pp->db_timer, pp_ping, (unsigned long)pp);
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pp->db_delay = msecs_to_jiffies(delay_ms);
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rc = ntb_set_ctx(ntb, pp, &pp_ops);
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if (rc)
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goto err_ctx;
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ntb_link_enable(ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
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ntb_link_event(ntb);
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return 0;
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err_ctx:
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kfree(pp);
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err_pp:
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return rc;
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}
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static void pp_remove(struct ntb_client *client,
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struct ntb_dev *ntb)
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{
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struct pp_ctx *pp = ntb->ctx;
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ntb_clear_ctx(ntb);
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del_timer_sync(&pp->db_timer);
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ntb_link_disable(ntb);
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kfree(pp);
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}
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static struct ntb_client pp_client = {
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.ops = {
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.probe = pp_probe,
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.remove = pp_remove,
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},
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};
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module_ntb_client(pp_client);
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