2 * This file is provided under a dual BSD/GPLv2 license. When using or
3 * redistributing this file, you may do so under either license.
7 * Copyright (C) 2015 EMC Corporation. All Rights Reserved.
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of version 2 of the GNU General Public License as
11 * published by the Free Software Foundation.
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
20 * Copyright (C) 2015 EMC Corporation. All Rights Reserved.
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23 * modification, are permitted provided that the following conditions
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46 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
48 * PCIe NTB Pingpong Linux driver
50 * Contact Information:
51 * Allen Hubbe <Allen.Hubbe@emc.com>
54 /* Note: load this module with option 'dyndbg=+p' */
56 #include <linux/init.h>
57 #include <linux/kernel.h>
58 #include <linux/module.h>
60 #include <linux/dma-mapping.h>
61 #include <linux/pci.h>
62 #include <linux/slab.h>
63 #include <linux/spinlock.h>
64 #include <linux/debugfs.h>
66 #include <linux/ntb.h>
68 #define DRIVER_NAME "ntb_pingpong"
69 #define DRIVER_DESCRIPTION "PCIe NTB Simple Pingpong Client"
71 #define DRIVER_LICENSE "Dual BSD/GPL"
72 #define DRIVER_VERSION "1.0"
73 #define DRIVER_RELDATE "24 March 2015"
74 #define DRIVER_AUTHOR "Allen Hubbe <Allen.Hubbe@emc.com>"
76 MODULE_LICENSE(DRIVER_LICENSE);
77 MODULE_VERSION(DRIVER_VERSION);
78 MODULE_AUTHOR(DRIVER_AUTHOR);
79 MODULE_DESCRIPTION(DRIVER_DESCRIPTION);
81 static unsigned int unsafe;
82 module_param(unsafe, uint, 0644);
83 MODULE_PARM_DESC(unsafe, "Run even though ntb operations may be unsafe");
85 static unsigned int delay_ms = 1000;
86 module_param(delay_ms, uint, 0644);
87 MODULE_PARM_DESC(delay_ms, "Milliseconds to delay the response to peer");
89 static unsigned long db_init = 0x7;
90 module_param(db_init, ulong, 0644);
91 MODULE_PARM_DESC(db_init, "Initial doorbell bits to ring on the peer");
93 /* Only two-ports NTB devices are supported */
94 #define PIDX NTB_DEF_PEER_IDX
99 /* synchronize access to db_bits by ping and pong */
101 struct timer_list db_timer;
102 unsigned long db_delay;
103 struct dentry *debugfs_node_dir;
104 struct dentry *debugfs_count;
108 static struct dentry *pp_debugfs_dir;
110 static void pp_ping(struct timer_list *t)
112 struct pp_ctx *pp = from_timer(pp, t, db_timer);
113 unsigned long irqflags;
114 u64 db_bits, db_mask;
115 u32 spad_rd, spad_wr;
117 spin_lock_irqsave(&pp->db_lock, irqflags);
119 db_mask = ntb_db_valid_mask(pp->ntb);
120 db_bits = ntb_db_read(pp->ntb);
123 dev_dbg(&pp->ntb->dev,
124 "Masked pongs %#llx\n",
126 ntb_db_clear(pp->ntb, db_bits);
129 db_bits = ((pp->db_bits | db_bits) << 1) & db_mask;
134 spad_rd = ntb_spad_read(pp->ntb, 0);
135 spad_wr = spad_rd + 1;
137 dev_dbg(&pp->ntb->dev,
138 "Ping bits %#llx read %#x write %#x\n",
139 db_bits, spad_rd, spad_wr);
141 ntb_peer_spad_write(pp->ntb, PIDX, 0, spad_wr);
142 ntb_peer_db_set(pp->ntb, db_bits);
143 ntb_db_clear_mask(pp->ntb, db_mask);
147 spin_unlock_irqrestore(&pp->db_lock, irqflags);
150 static void pp_link_event(void *ctx)
152 struct pp_ctx *pp = ctx;
154 if (ntb_link_is_up(pp->ntb, NULL, NULL) == 1) {
155 dev_dbg(&pp->ntb->dev, "link is up\n");
156 pp_ping(&pp->db_timer);
158 dev_dbg(&pp->ntb->dev, "link is down\n");
159 del_timer(&pp->db_timer);
163 static void pp_db_event(void *ctx, int vec)
165 struct pp_ctx *pp = ctx;
166 u64 db_bits, db_mask;
167 unsigned long irqflags;
169 spin_lock_irqsave(&pp->db_lock, irqflags);
171 db_mask = ntb_db_vector_mask(pp->ntb, vec);
172 db_bits = db_mask & ntb_db_read(pp->ntb);
173 ntb_db_set_mask(pp->ntb, db_mask);
174 ntb_db_clear(pp->ntb, db_bits);
176 pp->db_bits |= db_bits;
178 mod_timer(&pp->db_timer, jiffies + pp->db_delay);
180 dev_dbg(&pp->ntb->dev,
181 "Pong vec %d bits %#llx\n",
183 atomic_inc(&pp->count);
185 spin_unlock_irqrestore(&pp->db_lock, irqflags);
188 static int pp_debugfs_setup(struct pp_ctx *pp)
190 struct pci_dev *pdev = pp->ntb->pdev;
195 pp->debugfs_node_dir = debugfs_create_dir(pci_name(pdev),
197 if (!pp->debugfs_node_dir)
200 pp->debugfs_count = debugfs_create_atomic_t("count", S_IRUSR | S_IWUSR,
201 pp->debugfs_node_dir,
203 if (!pp->debugfs_count)
209 static const struct ntb_ctx_ops pp_ops = {
210 .link_event = pp_link_event,
211 .db_event = pp_db_event,
214 static int pp_probe(struct ntb_client *client,
220 if (ntb_db_is_unsafe(ntb)) {
221 dev_dbg(&ntb->dev, "doorbell is unsafe\n");
228 if (ntb_spad_count(ntb) < 1) {
229 dev_dbg(&ntb->dev, "no enough scratchpads\n");
234 if (ntb_spad_is_unsafe(ntb)) {
235 dev_dbg(&ntb->dev, "scratchpad is unsafe\n");
242 if (ntb_peer_port_count(ntb) != NTB_DEF_PEER_CNT)
243 dev_warn(&ntb->dev, "multi-port NTB is unsupported\n");
245 pp = kmalloc(sizeof(*pp), GFP_KERNEL);
253 atomic_set(&pp->count, 0);
254 spin_lock_init(&pp->db_lock);
255 timer_setup(&pp->db_timer, pp_ping, 0);
256 pp->db_delay = msecs_to_jiffies(delay_ms);
258 rc = ntb_set_ctx(ntb, pp, &pp_ops);
262 rc = pp_debugfs_setup(pp);
266 ntb_link_enable(ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
277 static void pp_remove(struct ntb_client *client,
280 struct pp_ctx *pp = ntb->ctx;
282 debugfs_remove_recursive(pp->debugfs_node_dir);
285 del_timer_sync(&pp->db_timer);
286 ntb_link_disable(ntb);
291 static struct ntb_client pp_client = {
298 static int __init pp_init(void)
302 if (debugfs_initialized())
303 pp_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
305 rc = ntb_register_client(&pp_client);
312 debugfs_remove_recursive(pp_debugfs_dir);
315 module_init(pp_init);
317 static void __exit pp_exit(void)
319 ntb_unregister_client(&pp_client);
320 debugfs_remove_recursive(pp_debugfs_dir);
322 module_exit(pp_exit);