1 /*
2 * Copyright (C) 2015-2017 Netronome Systems, Inc.
3 *
4 * This software is dual licensed under the GNU General License Version 2,
5 * June 1991 as shown in the file COPYING in the top-level directory of this
6 * source tree or the BSD 2-Clause License provided below. You have the
7 * option to license this software under the complete terms of either license.
8 *
9 * The BSD 2-Clause License:
10 *
11 * Redistribution and use in source and binary forms, with or
12 * without modification, are permitted provided that the following
13 * conditions are met:
14 *
15 * 1. Redistributions of source code must retain the above
16 * copyright notice, this list of conditions and the following
17 * disclaimer.
18 *
19 * 2. Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials
22 * provided with the distribution.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31 * SOFTWARE.
32 */
33
34 /*
35 * nfp_resource.c
36 * Author: Jakub Kicinski <jakub.kicinski@netronome.com>
37 * Jason McMullan <jason.mcmullan@netronome.com>
38 */
39 #include <linux/delay.h>
40 #include <linux/kernel.h>
41 #include <linux/slab.h>
42
43 #include "crc32.h"
44 #include "nfp.h"
45 #include "nfp_cpp.h"
46 #include "nfp6000/nfp6000.h"
47
48 #define NFP_RESOURCE_TBL_TARGET NFP_CPP_TARGET_MU
49 #define NFP_RESOURCE_TBL_BASE 0x8100000000ULL
50
51 /* NFP Resource Table self-identifier */
52 #define NFP_RESOURCE_TBL_NAME "nfp.res"
53 #define NFP_RESOURCE_TBL_KEY 0x00000000 /* Special key for entry 0 */
54
55 #define NFP_RESOURCE_ENTRY_NAME_SZ 8
56
57 /**
58 * struct nfp_resource_entry - Resource table entry
59 * @owner: NFP CPP Lock, interface owner
60 * @key: NFP CPP Lock, posix_crc32(name, 8)
61 * @region: Memory region descriptor
62 * @name: ASCII, zero padded name
63 * @reserved
64 * @cpp_action: CPP Action
65 * @cpp_token: CPP Token
66 * @cpp_target: CPP Target ID
67 * @page_offset: 256-byte page offset into target's CPP address
68 * @page_size: size, in 256-byte pages
69 */
70 struct nfp_resource_entry {
71 struct nfp_resource_entry_mutex {
72 u32 owner;
73 u32 key;
74 } mutex;
75 struct nfp_resource_entry_region {
76 u8 name[NFP_RESOURCE_ENTRY_NAME_SZ];
77 u8 reserved[5];
78 u8 cpp_action;
79 u8 cpp_token;
80 u8 cpp_target;
81 u32 page_offset;
82 u32 page_size;
83 } region;
84 };
85
86 #define NFP_RESOURCE_TBL_SIZE 4096
87 #define NFP_RESOURCE_TBL_ENTRIES (NFP_RESOURCE_TBL_SIZE / \
88 sizeof(struct nfp_resource_entry))
89
90 struct nfp_resource {
91 char name[NFP_RESOURCE_ENTRY_NAME_SZ + 1];
92 u32 cpp_id;
93 u64 addr;
94 u64 size;
95 struct nfp_cpp_mutex *mutex;
96 };
97
nfp_cpp_resource_find(struct nfp_cpp * cpp,struct nfp_resource * res)98 static int nfp_cpp_resource_find(struct nfp_cpp *cpp, struct nfp_resource *res)
99 {
100 char name_pad[NFP_RESOURCE_ENTRY_NAME_SZ] = {};
101 struct nfp_resource_entry entry;
102 u32 cpp_id, key;
103 int ret, i;
104
105 cpp_id = NFP_CPP_ID(NFP_RESOURCE_TBL_TARGET, 3, 0); /* Atomic read */
106
107 strncpy(name_pad, res->name, sizeof(name_pad));
108
109 /* Search for a matching entry */
110 if (!memcmp(name_pad, NFP_RESOURCE_TBL_NAME "\0\0\0\0\0\0\0\0", 8)) {
111 nfp_err(cpp, "Grabbing device lock not supported\n");
112 return -EOPNOTSUPP;
113 }
114 key = crc32_posix(name_pad, sizeof(name_pad));
115
116 for (i = 0; i < NFP_RESOURCE_TBL_ENTRIES; i++) {
117 u64 addr = NFP_RESOURCE_TBL_BASE +
118 sizeof(struct nfp_resource_entry) * i;
119
120 ret = nfp_cpp_read(cpp, cpp_id, addr, &entry, sizeof(entry));
121 if (ret != sizeof(entry))
122 return -EIO;
123
124 if (entry.mutex.key != key)
125 continue;
126
127 /* Found key! */
128 res->mutex =
129 nfp_cpp_mutex_alloc(cpp,
130 NFP_RESOURCE_TBL_TARGET, addr, key);
131 res->cpp_id = NFP_CPP_ID(entry.region.cpp_target,
132 entry.region.cpp_action,
133 entry.region.cpp_token);
134 res->addr = (u64)entry.region.page_offset << 8;
135 res->size = (u64)entry.region.page_size << 8;
136
137 return 0;
138 }
139
140 return -ENOENT;
141 }
142
143 static int
nfp_resource_try_acquire(struct nfp_cpp * cpp,struct nfp_resource * res,struct nfp_cpp_mutex * dev_mutex)144 nfp_resource_try_acquire(struct nfp_cpp *cpp, struct nfp_resource *res,
145 struct nfp_cpp_mutex *dev_mutex)
146 {
147 int err;
148
149 if (nfp_cpp_mutex_lock(dev_mutex))
150 return -EINVAL;
151
152 err = nfp_cpp_resource_find(cpp, res);
153 if (err)
154 goto err_unlock_dev;
155
156 err = nfp_cpp_mutex_trylock(res->mutex);
157 if (err)
158 goto err_res_mutex_free;
159
160 nfp_cpp_mutex_unlock(dev_mutex);
161
162 return 0;
163
164 err_res_mutex_free:
165 nfp_cpp_mutex_free(res->mutex);
166 err_unlock_dev:
167 nfp_cpp_mutex_unlock(dev_mutex);
168
169 return err;
170 }
171
172 /**
173 * nfp_resource_acquire() - Acquire a resource handle
174 * @cpp: NFP CPP handle
175 * @name: Name of the resource
176 *
177 * NOTE: This function locks the acquired resource
178 *
179 * Return: NFP Resource handle, or ERR_PTR()
180 */
181 struct nfp_resource *
nfp_resource_acquire(struct nfp_cpp * cpp,const char * name)182 nfp_resource_acquire(struct nfp_cpp *cpp, const char *name)
183 {
184 unsigned long warn_at = jiffies + NFP_MUTEX_WAIT_FIRST_WARN * HZ;
185 unsigned long err_at = jiffies + NFP_MUTEX_WAIT_ERROR * HZ;
186 struct nfp_cpp_mutex *dev_mutex;
187 struct nfp_resource *res;
188 int err;
189
190 res = kzalloc(sizeof(*res), GFP_KERNEL);
191 if (!res)
192 return ERR_PTR(-ENOMEM);
193
194 strncpy(res->name, name, NFP_RESOURCE_ENTRY_NAME_SZ);
195
196 dev_mutex = nfp_cpp_mutex_alloc(cpp, NFP_RESOURCE_TBL_TARGET,
197 NFP_RESOURCE_TBL_BASE,
198 NFP_RESOURCE_TBL_KEY);
199 if (!dev_mutex) {
200 kfree(res);
201 return ERR_PTR(-ENOMEM);
202 }
203
204 for (;;) {
205 err = nfp_resource_try_acquire(cpp, res, dev_mutex);
206 if (!err)
207 break;
208 if (err != -EBUSY)
209 goto err_free;
210
211 err = msleep_interruptible(1);
212 if (err != 0) {
213 err = -ERESTARTSYS;
214 goto err_free;
215 }
216
217 if (time_is_before_eq_jiffies(warn_at)) {
218 warn_at = jiffies + NFP_MUTEX_WAIT_NEXT_WARN * HZ;
219 nfp_warn(cpp, "Warning: waiting for NFP resource %s\n",
220 name);
221 }
222 if (time_is_before_eq_jiffies(err_at)) {
223 nfp_err(cpp, "Error: resource %s timed out\n", name);
224 err = -EBUSY;
225 goto err_free;
226 }
227 }
228
229 nfp_cpp_mutex_free(dev_mutex);
230
231 return res;
232
233 err_free:
234 nfp_cpp_mutex_free(dev_mutex);
235 kfree(res);
236 return ERR_PTR(err);
237 }
238
239 /**
240 * nfp_resource_release() - Release a NFP Resource handle
241 * @res: NFP Resource handle
242 *
243 * NOTE: This function implictly unlocks the resource handle
244 */
nfp_resource_release(struct nfp_resource * res)245 void nfp_resource_release(struct nfp_resource *res)
246 {
247 nfp_cpp_mutex_unlock(res->mutex);
248 nfp_cpp_mutex_free(res->mutex);
249 kfree(res);
250 }
251
252 /**
253 * nfp_resource_wait() - Wait for resource to appear
254 * @cpp: NFP CPP handle
255 * @name: Name of the resource
256 * @secs: Number of seconds to wait
257 *
258 * Wait for resource to appear in the resource table, grab and release
259 * its lock. The wait is jiffies-based, don't expect fine granularity.
260 *
261 * Return: 0 on success, errno otherwise.
262 */
nfp_resource_wait(struct nfp_cpp * cpp,const char * name,unsigned int secs)263 int nfp_resource_wait(struct nfp_cpp *cpp, const char *name, unsigned int secs)
264 {
265 unsigned long warn_at = jiffies + NFP_MUTEX_WAIT_FIRST_WARN * HZ;
266 unsigned long err_at = jiffies + secs * HZ;
267 struct nfp_resource *res;
268
269 while (true) {
270 res = nfp_resource_acquire(cpp, name);
271 if (!IS_ERR(res)) {
272 nfp_resource_release(res);
273 return 0;
274 }
275
276 if (PTR_ERR(res) != -ENOENT) {
277 nfp_err(cpp, "error waiting for resource %s: %ld\n",
278 name, PTR_ERR(res));
279 return PTR_ERR(res);
280 }
281 if (time_is_before_eq_jiffies(err_at)) {
282 nfp_err(cpp, "timeout waiting for resource %s\n", name);
283 return -ETIMEDOUT;
284 }
285 if (time_is_before_eq_jiffies(warn_at)) {
286 warn_at = jiffies + NFP_MUTEX_WAIT_NEXT_WARN * HZ;
287 nfp_info(cpp, "waiting for NFP resource %s\n", name);
288 }
289 if (msleep_interruptible(10)) {
290 nfp_err(cpp, "wait for resource %s interrupted\n",
291 name);
292 return -ERESTARTSYS;
293 }
294 }
295 }
296
297 /**
298 * nfp_resource_cpp_id() - Return the cpp_id of a resource handle
299 * @res: NFP Resource handle
300 *
301 * Return: NFP CPP ID
302 */
nfp_resource_cpp_id(struct nfp_resource * res)303 u32 nfp_resource_cpp_id(struct nfp_resource *res)
304 {
305 return res->cpp_id;
306 }
307
308 /**
309 * nfp_resource_name() - Return the name of a resource handle
310 * @res: NFP Resource handle
311 *
312 * Return: const char pointer to the name of the resource
313 */
nfp_resource_name(struct nfp_resource * res)314 const char *nfp_resource_name(struct nfp_resource *res)
315 {
316 return res->name;
317 }
318
319 /**
320 * nfp_resource_address() - Return the address of a resource handle
321 * @res: NFP Resource handle
322 *
323 * Return: Address of the resource
324 */
nfp_resource_address(struct nfp_resource * res)325 u64 nfp_resource_address(struct nfp_resource *res)
326 {
327 return res->addr;
328 }
329
330 /**
331 * nfp_resource_size() - Return the size in bytes of a resource handle
332 * @res: NFP Resource handle
333 *
334 * Return: Size of the resource in bytes
335 */
nfp_resource_size(struct nfp_resource * res)336 u64 nfp_resource_size(struct nfp_resource *res)
337 {
338 return res->size;
339 }
340