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963de473 AH |
1 | /* |
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. | |
4 | * | |
5 | * GPL LICENSE SUMMARY | |
6 | * | |
7 | * Copyright (C) 2015 EMC Corporation. All Rights Reserved. | |
8 | * | |
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. | |
12 | * | |
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. | |
17 | * | |
18 | * BSD LICENSE | |
19 | * | |
20 | * Copyright (C) 2015 EMC Corporation. All Rights Reserved. | |
21 | * | |
22 | * Redistribution and use in source and binary forms, with or without | |
23 | * modification, are permitted provided that the following conditions | |
24 | * are met: | |
25 | * | |
26 | * * Redistributions of source code must retain the above copyright | |
27 | * notice, this list of conditions and the following disclaimer. | |
28 | * * Redistributions in binary form must reproduce the above copy | |
29 | * notice, this list of conditions and the following disclaimer in | |
30 | * the documentation and/or other materials provided with the | |
31 | * distribution. | |
32 | * * Neither the name of Intel Corporation nor the names of its | |
33 | * contributors may be used to endorse or promote products derived | |
34 | * from this software without specific prior written permission. | |
35 | * | |
36 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
37 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
38 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
39 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
40 | * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
41 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
42 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
43 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
44 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
45 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
46 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
47 | * | |
48 | * PCIe NTB Pingpong Linux driver | |
49 | * | |
50 | * Contact Information: | |
51 | * Allen Hubbe <Allen.Hubbe@emc.com> | |
52 | */ | |
53 | ||
54 | /* Note: load this module with option 'dyndbg=+p' */ | |
55 | ||
56 | #include <linux/init.h> | |
57 | #include <linux/kernel.h> | |
58 | #include <linux/module.h> | |
59 | ||
60 | #include <linux/dma-mapping.h> | |
61 | #include <linux/pci.h> | |
62 | #include <linux/slab.h> | |
63 | #include <linux/spinlock.h> | |
64 | ||
65 | #include <linux/ntb.h> | |
66 | ||
67 | #define DRIVER_NAME "ntb_pingpong" | |
68 | #define DRIVER_DESCRIPTION "PCIe NTB Simple Pingpong Client" | |
69 | ||
70 | #define DRIVER_LICENSE "Dual BSD/GPL" | |
71 | #define DRIVER_VERSION "1.0" | |
72 | #define DRIVER_RELDATE "24 March 2015" | |
73 | #define DRIVER_AUTHOR "Allen Hubbe <Allen.Hubbe@emc.com>" | |
74 | ||
75 | MODULE_LICENSE(DRIVER_LICENSE); | |
76 | MODULE_VERSION(DRIVER_VERSION); | |
77 | MODULE_AUTHOR(DRIVER_AUTHOR); | |
78 | MODULE_DESCRIPTION(DRIVER_DESCRIPTION); | |
79 | ||
80 | static unsigned int unsafe; | |
81 | module_param(unsafe, uint, 0644); | |
82 | MODULE_PARM_DESC(unsafe, "Run even though ntb operations may be unsafe"); | |
83 | ||
84 | static unsigned int delay_ms = 1000; | |
85 | module_param(delay_ms, uint, 0644); | |
86 | MODULE_PARM_DESC(delay_ms, "Milliseconds to delay the response to peer"); | |
87 | ||
88 | static unsigned long db_init = 0x7; | |
89 | module_param(db_init, ulong, 0644); | |
90 | MODULE_PARM_DESC(delay_ms, "Initial doorbell bits to ring on the peer"); | |
91 | ||
92 | struct pp_ctx { | |
93 | struct ntb_dev *ntb; | |
94 | u64 db_bits; | |
95 | /* synchronize access to db_bits by ping and pong */ | |
96 | spinlock_t db_lock; | |
97 | struct timer_list db_timer; | |
98 | unsigned long db_delay; | |
99 | }; | |
100 | ||
101 | static void pp_ping(unsigned long ctx) | |
102 | { | |
103 | struct pp_ctx *pp = (void *)ctx; | |
104 | unsigned long irqflags; | |
105 | u64 db_bits, db_mask; | |
106 | u32 spad_rd, spad_wr; | |
107 | ||
108 | spin_lock_irqsave(&pp->db_lock, irqflags); | |
109 | { | |
110 | db_mask = ntb_db_valid_mask(pp->ntb); | |
111 | db_bits = ntb_db_read(pp->ntb); | |
112 | ||
113 | if (db_bits) { | |
114 | dev_dbg(&pp->ntb->dev, | |
115 | "Masked pongs %#llx\n", | |
116 | db_bits); | |
117 | ntb_db_clear(pp->ntb, db_bits); | |
118 | } | |
119 | ||
120 | db_bits = ((pp->db_bits | db_bits) << 1) & db_mask; | |
121 | ||
122 | if (!db_bits) | |
123 | db_bits = db_init; | |
124 | ||
125 | spad_rd = ntb_spad_read(pp->ntb, 0); | |
126 | spad_wr = spad_rd + 1; | |
127 | ||
128 | dev_dbg(&pp->ntb->dev, | |
129 | "Ping bits %#llx read %#x write %#x\n", | |
130 | db_bits, spad_rd, spad_wr); | |
131 | ||
132 | ntb_peer_spad_write(pp->ntb, 0, spad_wr); | |
133 | ntb_peer_db_set(pp->ntb, db_bits); | |
134 | ntb_db_clear_mask(pp->ntb, db_mask); | |
135 | ||
136 | pp->db_bits = 0; | |
137 | } | |
138 | spin_unlock_irqrestore(&pp->db_lock, irqflags); | |
139 | } | |
140 | ||
141 | static void pp_link_event(void *ctx) | |
142 | { | |
143 | struct pp_ctx *pp = ctx; | |
144 | ||
145 | if (ntb_link_is_up(pp->ntb, NULL, NULL) == 1) { | |
146 | dev_dbg(&pp->ntb->dev, "link is up\n"); | |
147 | pp_ping((unsigned long)pp); | |
148 | } else { | |
149 | dev_dbg(&pp->ntb->dev, "link is down\n"); | |
150 | del_timer(&pp->db_timer); | |
151 | } | |
152 | } | |
153 | ||
154 | static void pp_db_event(void *ctx, int vec) | |
155 | { | |
156 | struct pp_ctx *pp = ctx; | |
157 | u64 db_bits, db_mask; | |
158 | unsigned long irqflags; | |
159 | ||
160 | spin_lock_irqsave(&pp->db_lock, irqflags); | |
161 | { | |
162 | db_mask = ntb_db_vector_mask(pp->ntb, vec); | |
163 | db_bits = db_mask & ntb_db_read(pp->ntb); | |
164 | ntb_db_set_mask(pp->ntb, db_mask); | |
165 | ntb_db_clear(pp->ntb, db_bits); | |
166 | ||
167 | pp->db_bits |= db_bits; | |
168 | ||
169 | mod_timer(&pp->db_timer, jiffies + pp->db_delay); | |
170 | ||
171 | dev_dbg(&pp->ntb->dev, | |
172 | "Pong vec %d bits %#llx\n", | |
173 | vec, db_bits); | |
174 | } | |
175 | spin_unlock_irqrestore(&pp->db_lock, irqflags); | |
176 | } | |
177 | ||
178 | static const struct ntb_ctx_ops pp_ops = { | |
179 | .link_event = pp_link_event, | |
180 | .db_event = pp_db_event, | |
181 | }; | |
182 | ||
183 | static int pp_probe(struct ntb_client *client, | |
184 | struct ntb_dev *ntb) | |
185 | { | |
186 | struct pp_ctx *pp; | |
187 | int rc; | |
188 | ||
189 | if (ntb_db_is_unsafe(ntb)) { | |
190 | dev_dbg(&ntb->dev, "doorbell is unsafe\n"); | |
191 | if (!unsafe) { | |
192 | rc = -EINVAL; | |
193 | goto err_pp; | |
194 | } | |
195 | } | |
196 | ||
197 | if (ntb_spad_is_unsafe(ntb)) { | |
198 | dev_dbg(&ntb->dev, "scratchpad is unsafe\n"); | |
199 | if (!unsafe) { | |
200 | rc = -EINVAL; | |
201 | goto err_pp; | |
202 | } | |
203 | } | |
204 | ||
205 | pp = kmalloc(sizeof(*pp), GFP_KERNEL); | |
206 | if (!pp) { | |
207 | rc = -ENOMEM; | |
208 | goto err_pp; | |
209 | } | |
210 | ||
211 | pp->ntb = ntb; | |
212 | pp->db_bits = 0; | |
213 | spin_lock_init(&pp->db_lock); | |
214 | setup_timer(&pp->db_timer, pp_ping, (unsigned long)pp); | |
215 | pp->db_delay = msecs_to_jiffies(delay_ms); | |
216 | ||
217 | rc = ntb_set_ctx(ntb, pp, &pp_ops); | |
218 | if (rc) | |
219 | goto err_ctx; | |
220 | ||
221 | ntb_link_enable(ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO); | |
222 | ntb_link_event(ntb); | |
223 | ||
224 | return 0; | |
225 | ||
226 | err_ctx: | |
227 | kfree(pp); | |
228 | err_pp: | |
229 | return rc; | |
230 | } | |
231 | ||
232 | static void pp_remove(struct ntb_client *client, | |
233 | struct ntb_dev *ntb) | |
234 | { | |
235 | struct pp_ctx *pp = ntb->ctx; | |
236 | ||
237 | ntb_clear_ctx(ntb); | |
238 | del_timer_sync(&pp->db_timer); | |
239 | ntb_link_disable(ntb); | |
240 | ||
241 | kfree(pp); | |
242 | } | |
243 | ||
244 | static struct ntb_client pp_client = { | |
245 | .ops = { | |
246 | .probe = pp_probe, | |
247 | .remove = pp_remove, | |
248 | }, | |
249 | }; | |
250 | module_ntb_client(pp_client); |