436 lines
10 KiB
C
436 lines
10 KiB
C
/*
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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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* Copyright (C) 2017 T-Platforms. 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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* Copyright (C) 2017 T-Platforms. 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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/*
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* How to use this tool, by example.
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*
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* Assuming $DBG_DIR is something like:
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* '/sys/kernel/debug/ntb_perf/0000:00:03.0'
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* Suppose aside from local device there is at least one remote device
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* connected to NTB with index 0.
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*-----------------------------------------------------------------------------
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* Eg: install driver with specified delay between doorbell event and response
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*
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* root@self# insmod ntb_pingpong.ko delay_ms=1000
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*-----------------------------------------------------------------------------
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* Eg: get number of ping-pong cycles performed
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*
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* root@self# cat $DBG_DIR/count
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*/
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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/device.h>
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#include <linux/bitops.h>
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#include <linux/pci.h>
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#include <linux/slab.h>
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#include <linux/hrtimer.h>
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#include <linux/debugfs.h>
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#include <linux/ntb.h>
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#define DRIVER_NAME "ntb_pingpong"
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#define DRIVER_VERSION "2.0"
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MODULE_LICENSE("Dual BSD/GPL");
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MODULE_VERSION(DRIVER_VERSION);
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MODULE_AUTHOR("Allen Hubbe <Allen.Hubbe@emc.com>");
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MODULE_DESCRIPTION("PCIe NTB Simple Pingpong Client");
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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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struct pp_ctx {
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struct ntb_dev *ntb;
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struct hrtimer timer;
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u64 in_db;
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u64 out_db;
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int out_pidx;
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u64 nmask;
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u64 pmask;
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atomic_t count;
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spinlock_t lock;
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struct dentry *dbgfs_dir;
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};
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#define to_pp_timer(__timer) \
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container_of(__timer, struct pp_ctx, timer)
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static struct dentry *pp_dbgfs_topdir;
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static int pp_find_next_peer(struct pp_ctx *pp)
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{
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u64 link, out_db;
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int pidx;
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link = ntb_link_is_up(pp->ntb, NULL, NULL);
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/* Find next available peer */
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if (link & pp->nmask) {
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pidx = __ffs64(link & pp->nmask);
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out_db = BIT_ULL(pidx + 1);
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} else if (link & pp->pmask) {
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pidx = __ffs64(link & pp->pmask);
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out_db = BIT_ULL(pidx);
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} else {
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return -ENODEV;
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}
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spin_lock(&pp->lock);
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pp->out_pidx = pidx;
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pp->out_db = out_db;
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spin_unlock(&pp->lock);
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return 0;
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}
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static void pp_setup(struct pp_ctx *pp)
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{
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int ret;
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ntb_db_set_mask(pp->ntb, pp->in_db);
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hrtimer_cancel(&pp->timer);
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ret = pp_find_next_peer(pp);
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if (ret == -ENODEV) {
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dev_dbg(&pp->ntb->dev, "Got no peers, so cancel\n");
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return;
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}
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dev_dbg(&pp->ntb->dev, "Ping-pong started with port %d, db %#llx\n",
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ntb_peer_port_number(pp->ntb, pp->out_pidx), pp->out_db);
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hrtimer_start(&pp->timer, ms_to_ktime(delay_ms), HRTIMER_MODE_REL);
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}
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static void pp_clear(struct pp_ctx *pp)
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{
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hrtimer_cancel(&pp->timer);
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ntb_db_set_mask(pp->ntb, pp->in_db);
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dev_dbg(&pp->ntb->dev, "Ping-pong cancelled\n");
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}
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static void pp_ping(struct pp_ctx *pp)
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{
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u32 count;
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count = atomic_read(&pp->count);
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spin_lock(&pp->lock);
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ntb_peer_spad_write(pp->ntb, pp->out_pidx, 0, count);
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ntb_peer_msg_write(pp->ntb, pp->out_pidx, 0, count);
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dev_dbg(&pp->ntb->dev, "Ping port %d spad %#x, msg %#x\n",
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ntb_peer_port_number(pp->ntb, pp->out_pidx), count, count);
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ntb_peer_db_set(pp->ntb, pp->out_db);
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ntb_db_clear_mask(pp->ntb, pp->in_db);
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spin_unlock(&pp->lock);
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}
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static void pp_pong(struct pp_ctx *pp)
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{
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u32 msg_data = -1, spad_data = -1;
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int pidx = 0;
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/* Read pong data */
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spad_data = ntb_spad_read(pp->ntb, 0);
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msg_data = ntb_msg_read(pp->ntb, &pidx, 0);
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ntb_msg_clear_sts(pp->ntb, -1);
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/*
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* Scratchpad and message data may differ, since message register can't
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* be rewritten unless status is cleared. Additionally either of them
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* might be unsupported
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*/
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dev_dbg(&pp->ntb->dev, "Pong spad %#x, msg %#x (port %d)\n",
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spad_data, msg_data, ntb_peer_port_number(pp->ntb, pidx));
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atomic_inc(&pp->count);
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ntb_db_set_mask(pp->ntb, pp->in_db);
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ntb_db_clear(pp->ntb, pp->in_db);
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hrtimer_start(&pp->timer, ms_to_ktime(delay_ms), HRTIMER_MODE_REL);
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}
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static enum hrtimer_restart pp_timer_func(struct hrtimer *t)
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{
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struct pp_ctx *pp = to_pp_timer(t);
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pp_ping(pp);
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return HRTIMER_NORESTART;
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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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pp_setup(pp);
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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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pp_pong(pp);
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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_check_ntb(struct ntb_dev *ntb)
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{
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u64 pmask;
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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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return -EINVAL;
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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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return -EINVAL;
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}
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pmask = GENMASK_ULL(ntb_peer_port_count(ntb), 0);
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if ((ntb_db_valid_mask(ntb) & pmask) != pmask) {
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dev_err(&ntb->dev, "Unsupported DB configuration\n");
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return -EINVAL;
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}
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if (ntb_spad_count(ntb) < 1 && ntb_msg_count(ntb) < 1) {
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dev_err(&ntb->dev, "Scratchpads and messages unsupported\n");
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return -EINVAL;
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} else if (ntb_spad_count(ntb) < 1) {
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dev_dbg(&ntb->dev, "Scratchpads unsupported\n");
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} else if (ntb_msg_count(ntb) < 1) {
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dev_dbg(&ntb->dev, "Messages unsupported\n");
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}
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return 0;
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}
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static struct pp_ctx *pp_create_data(struct ntb_dev *ntb)
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{
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struct pp_ctx *pp;
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pp = devm_kzalloc(&ntb->dev, sizeof(*pp), GFP_KERNEL);
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if (!pp)
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return ERR_PTR(-ENOMEM);
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pp->ntb = ntb;
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atomic_set(&pp->count, 0);
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spin_lock_init(&pp->lock);
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hrtimer_init(&pp->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
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pp->timer.function = pp_timer_func;
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return pp;
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}
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static void pp_init_flds(struct pp_ctx *pp)
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{
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int pidx, lport, pcnt;
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/* Find global port index */
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lport = ntb_port_number(pp->ntb);
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pcnt = ntb_peer_port_count(pp->ntb);
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for (pidx = 0; pidx < pcnt; pidx++) {
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if (lport < ntb_peer_port_number(pp->ntb, pidx))
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break;
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}
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pp->in_db = BIT_ULL(pidx);
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pp->pmask = GENMASK_ULL(pidx, 0) >> 1;
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pp->nmask = GENMASK_ULL(pcnt - 1, pidx);
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dev_dbg(&pp->ntb->dev, "Inbound db %#llx, prev %#llx, next %#llx\n",
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pp->in_db, pp->pmask, pp->nmask);
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}
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static int pp_mask_events(struct pp_ctx *pp)
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{
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u64 db_mask, msg_mask;
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int ret;
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db_mask = ntb_db_valid_mask(pp->ntb);
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ret = ntb_db_set_mask(pp->ntb, db_mask);
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if (ret)
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return ret;
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/* Skip message events masking if unsupported */
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if (ntb_msg_count(pp->ntb) < 1)
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return 0;
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msg_mask = ntb_msg_outbits(pp->ntb) | ntb_msg_inbits(pp->ntb);
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return ntb_msg_set_mask(pp->ntb, msg_mask);
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}
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static int pp_setup_ctx(struct pp_ctx *pp)
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{
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int ret;
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ret = ntb_set_ctx(pp->ntb, pp, &pp_ops);
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if (ret)
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return ret;
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ntb_link_enable(pp->ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
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/* Might be not necessary */
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ntb_link_event(pp->ntb);
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return 0;
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}
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static void pp_clear_ctx(struct pp_ctx *pp)
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{
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ntb_link_disable(pp->ntb);
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ntb_clear_ctx(pp->ntb);
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}
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static void pp_setup_dbgfs(struct pp_ctx *pp)
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{
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struct pci_dev *pdev = pp->ntb->pdev;
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pp->dbgfs_dir = debugfs_create_dir(pci_name(pdev), pp_dbgfs_topdir);
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debugfs_create_atomic_t("count", 0600, pp->dbgfs_dir, &pp->count);
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}
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static void pp_clear_dbgfs(struct pp_ctx *pp)
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{
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debugfs_remove_recursive(pp->dbgfs_dir);
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}
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static int pp_probe(struct ntb_client *client, struct ntb_dev *ntb)
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{
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struct pp_ctx *pp;
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int ret;
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ret = pp_check_ntb(ntb);
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if (ret)
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return ret;
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pp = pp_create_data(ntb);
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if (IS_ERR(pp))
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return PTR_ERR(pp);
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pp_init_flds(pp);
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ret = pp_mask_events(pp);
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if (ret)
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return ret;
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ret = pp_setup_ctx(pp);
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if (ret)
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return ret;
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pp_setup_dbgfs(pp);
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return 0;
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}
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static void pp_remove(struct ntb_client *client, struct ntb_dev *ntb)
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{
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struct pp_ctx *pp = ntb->ctx;
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pp_clear_dbgfs(pp);
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pp_clear_ctx(pp);
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pp_clear(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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static int __init pp_init(void)
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{
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int ret;
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if (debugfs_initialized())
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pp_dbgfs_topdir = debugfs_create_dir(KBUILD_MODNAME, NULL);
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ret = ntb_register_client(&pp_client);
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if (ret)
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debugfs_remove_recursive(pp_dbgfs_topdir);
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return ret;
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}
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module_init(pp_init);
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static void __exit pp_exit(void)
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{
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ntb_unregister_client(&pp_client);
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debugfs_remove_recursive(pp_dbgfs_topdir);
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}
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module_exit(pp_exit);
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