1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 /* Copyright (C) 2015-2018 Netronome Systems, Inc. */
3
4 /*
5 * nfp_resource.c
6 * Author: Jakub Kicinski <jakub.kicinski@netronome.com>
7 * Jason McMullan <jason.mcmullan@netronome.com>
8 */
9 #include <linux/delay.h>
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12
13 #include "crc32.h"
14 #include "nfp.h"
15 #include "nfp_cpp.h"
16 #include "nfp6000/nfp6000.h"
17
18 #define NFP_RESOURCE_TBL_TARGET NFP_CPP_TARGET_MU
19 #define NFP_RESOURCE_TBL_BASE 0x8100000000ULL
20
21 /* NFP Resource Table self-identifier */
22 #define NFP_RESOURCE_TBL_NAME "nfp.res"
23 #define NFP_RESOURCE_TBL_KEY 0x00000000 /* Special key for entry 0 */
24
25 #define NFP_RESOURCE_ENTRY_NAME_SZ 8
26
27 /**
28 * struct nfp_resource_entry - Resource table entry
29 * @mutex: NFP CPP Lock
30 * @mutex.owner: NFP CPP Lock, interface owner
31 * @mutex.key: NFP CPP Lock, posix_crc32(name, 8)
32 * @region: Memory region descriptor
33 * @region.name: ASCII, zero padded name
34 * @region.reserved: padding
35 * @region.cpp_action: CPP Action
36 * @region.cpp_token: CPP Token
37 * @region.cpp_target: CPP Target ID
38 * @region.page_offset: 256-byte page offset into target's CPP address
39 * @region.page_size: size, in 256-byte pages
40 */
41 struct nfp_resource_entry {
42 struct nfp_resource_entry_mutex {
43 u32 owner;
44 u32 key;
45 } mutex;
46 struct nfp_resource_entry_region {
47 u8 name[NFP_RESOURCE_ENTRY_NAME_SZ];
48 u8 reserved[5];
49 u8 cpp_action;
50 u8 cpp_token;
51 u8 cpp_target;
52 u32 page_offset;
53 u32 page_size;
54 } region;
55 };
56
57 #define NFP_RESOURCE_TBL_SIZE 4096
58 #define NFP_RESOURCE_TBL_ENTRIES (NFP_RESOURCE_TBL_SIZE / \
59 sizeof(struct nfp_resource_entry))
60
61 struct nfp_resource {
62 char name[NFP_RESOURCE_ENTRY_NAME_SZ + 1];
63 u32 cpp_id;
64 u64 addr;
65 u64 size;
66 struct nfp_cpp_mutex *mutex;
67 };
68
nfp_cpp_resource_find(struct nfp_cpp * cpp,struct nfp_resource * res)69 static int nfp_cpp_resource_find(struct nfp_cpp *cpp, struct nfp_resource *res)
70 {
71 struct nfp_resource_entry entry;
72 u32 cpp_id, key;
73 int ret, i;
74
75 cpp_id = NFP_CPP_ID(NFP_RESOURCE_TBL_TARGET, 3, 0); /* Atomic read */
76
77 /* Search for a matching entry */
78 if (!strcmp(res->name, NFP_RESOURCE_TBL_NAME)) {
79 nfp_err(cpp, "Grabbing device lock not supported\n");
80 return -EOPNOTSUPP;
81 }
82 key = crc32_posix(res->name, NFP_RESOURCE_ENTRY_NAME_SZ);
83
84 for (i = 0; i < NFP_RESOURCE_TBL_ENTRIES; i++) {
85 u64 addr = NFP_RESOURCE_TBL_BASE +
86 sizeof(struct nfp_resource_entry) * i;
87
88 ret = nfp_cpp_read(cpp, cpp_id, addr, &entry, sizeof(entry));
89 if (ret != sizeof(entry))
90 return -EIO;
91
92 if (entry.mutex.key != key)
93 continue;
94
95 /* Found key! */
96 res->mutex =
97 nfp_cpp_mutex_alloc(cpp,
98 NFP_RESOURCE_TBL_TARGET, addr, key);
99 res->cpp_id = NFP_CPP_ID(entry.region.cpp_target,
100 entry.region.cpp_action,
101 entry.region.cpp_token);
102 res->addr = (u64)entry.region.page_offset << 8;
103 res->size = (u64)entry.region.page_size << 8;
104
105 return 0;
106 }
107
108 return -ENOENT;
109 }
110
111 static int
nfp_resource_try_acquire(struct nfp_cpp * cpp,struct nfp_resource * res,struct nfp_cpp_mutex * dev_mutex)112 nfp_resource_try_acquire(struct nfp_cpp *cpp, struct nfp_resource *res,
113 struct nfp_cpp_mutex *dev_mutex)
114 {
115 int err;
116
117 if (nfp_cpp_mutex_lock(dev_mutex))
118 return -EINVAL;
119
120 err = nfp_cpp_resource_find(cpp, res);
121 if (err)
122 goto err_unlock_dev;
123
124 err = nfp_cpp_mutex_trylock(res->mutex);
125 if (err)
126 goto err_res_mutex_free;
127
128 nfp_cpp_mutex_unlock(dev_mutex);
129
130 return 0;
131
132 err_res_mutex_free:
133 nfp_cpp_mutex_free(res->mutex);
134 err_unlock_dev:
135 nfp_cpp_mutex_unlock(dev_mutex);
136
137 return err;
138 }
139
140 /**
141 * nfp_resource_acquire() - Acquire a resource handle
142 * @cpp: NFP CPP handle
143 * @name: Name of the resource
144 *
145 * NOTE: This function locks the acquired resource
146 *
147 * Return: NFP Resource handle, or ERR_PTR()
148 */
149 struct nfp_resource *
nfp_resource_acquire(struct nfp_cpp * cpp,const char * name)150 nfp_resource_acquire(struct nfp_cpp *cpp, const char *name)
151 {
152 unsigned long warn_at = jiffies + NFP_MUTEX_WAIT_FIRST_WARN * HZ;
153 unsigned long err_at = jiffies + NFP_MUTEX_WAIT_ERROR * HZ;
154 struct nfp_cpp_mutex *dev_mutex;
155 struct nfp_resource *res;
156 int err;
157
158 res = kzalloc(sizeof(*res), GFP_KERNEL);
159 if (!res)
160 return ERR_PTR(-ENOMEM);
161
162 strncpy(res->name, name, NFP_RESOURCE_ENTRY_NAME_SZ);
163
164 dev_mutex = nfp_cpp_mutex_alloc(cpp, NFP_RESOURCE_TBL_TARGET,
165 NFP_RESOURCE_TBL_BASE,
166 NFP_RESOURCE_TBL_KEY);
167 if (!dev_mutex) {
168 kfree(res);
169 return ERR_PTR(-ENOMEM);
170 }
171
172 for (;;) {
173 err = nfp_resource_try_acquire(cpp, res, dev_mutex);
174 if (!err)
175 break;
176 if (err != -EBUSY)
177 goto err_free;
178
179 err = msleep_interruptible(1);
180 if (err != 0) {
181 err = -ERESTARTSYS;
182 goto err_free;
183 }
184
185 if (time_is_before_eq_jiffies(warn_at)) {
186 warn_at = jiffies + NFP_MUTEX_WAIT_NEXT_WARN * HZ;
187 nfp_warn(cpp, "Warning: waiting for NFP resource %s\n",
188 name);
189 }
190 if (time_is_before_eq_jiffies(err_at)) {
191 nfp_err(cpp, "Error: resource %s timed out\n", name);
192 err = -EBUSY;
193 goto err_free;
194 }
195 }
196
197 nfp_cpp_mutex_free(dev_mutex);
198
199 return res;
200
201 err_free:
202 nfp_cpp_mutex_free(dev_mutex);
203 kfree(res);
204 return ERR_PTR(err);
205 }
206
207 /**
208 * nfp_resource_release() - Release a NFP Resource handle
209 * @res: NFP Resource handle
210 *
211 * NOTE: This function implictly unlocks the resource handle
212 */
nfp_resource_release(struct nfp_resource * res)213 void nfp_resource_release(struct nfp_resource *res)
214 {
215 nfp_cpp_mutex_unlock(res->mutex);
216 nfp_cpp_mutex_free(res->mutex);
217 kfree(res);
218 }
219
220 /**
221 * nfp_resource_wait() - Wait for resource to appear
222 * @cpp: NFP CPP handle
223 * @name: Name of the resource
224 * @secs: Number of seconds to wait
225 *
226 * Wait for resource to appear in the resource table, grab and release
227 * its lock. The wait is jiffies-based, don't expect fine granularity.
228 *
229 * Return: 0 on success, errno otherwise.
230 */
nfp_resource_wait(struct nfp_cpp * cpp,const char * name,unsigned int secs)231 int nfp_resource_wait(struct nfp_cpp *cpp, const char *name, unsigned int secs)
232 {
233 unsigned long warn_at = jiffies + NFP_MUTEX_WAIT_FIRST_WARN * HZ;
234 unsigned long err_at = jiffies + secs * HZ;
235 struct nfp_resource *res;
236
237 while (true) {
238 res = nfp_resource_acquire(cpp, name);
239 if (!IS_ERR(res)) {
240 nfp_resource_release(res);
241 return 0;
242 }
243
244 if (PTR_ERR(res) != -ENOENT) {
245 nfp_err(cpp, "error waiting for resource %s: %ld\n",
246 name, PTR_ERR(res));
247 return PTR_ERR(res);
248 }
249 if (time_is_before_eq_jiffies(err_at)) {
250 nfp_err(cpp, "timeout waiting for resource %s\n", name);
251 return -ETIMEDOUT;
252 }
253 if (time_is_before_eq_jiffies(warn_at)) {
254 warn_at = jiffies + NFP_MUTEX_WAIT_NEXT_WARN * HZ;
255 nfp_info(cpp, "waiting for NFP resource %s\n", name);
256 }
257 if (msleep_interruptible(10)) {
258 nfp_err(cpp, "wait for resource %s interrupted\n",
259 name);
260 return -ERESTARTSYS;
261 }
262 }
263 }
264
265 /**
266 * nfp_resource_cpp_id() - Return the cpp_id of a resource handle
267 * @res: NFP Resource handle
268 *
269 * Return: NFP CPP ID
270 */
nfp_resource_cpp_id(struct nfp_resource * res)271 u32 nfp_resource_cpp_id(struct nfp_resource *res)
272 {
273 return res->cpp_id;
274 }
275
276 /**
277 * nfp_resource_name() - Return the name of a resource handle
278 * @res: NFP Resource handle
279 *
280 * Return: const char pointer to the name of the resource
281 */
nfp_resource_name(struct nfp_resource * res)282 const char *nfp_resource_name(struct nfp_resource *res)
283 {
284 return res->name;
285 }
286
287 /**
288 * nfp_resource_address() - Return the address of a resource handle
289 * @res: NFP Resource handle
290 *
291 * Return: Address of the resource
292 */
nfp_resource_address(struct nfp_resource * res)293 u64 nfp_resource_address(struct nfp_resource *res)
294 {
295 return res->addr;
296 }
297
298 /**
299 * nfp_resource_size() - Return the size in bytes of a resource handle
300 * @res: NFP Resource handle
301 *
302 * Return: Size of the resource in bytes
303 */
nfp_resource_size(struct nfp_resource * res)304 u64 nfp_resource_size(struct nfp_resource *res)
305 {
306 return res->size;
307 }
308
309 /**
310 * nfp_resource_table_init() - Run initial checks on the resource table
311 * @cpp: NFP CPP handle
312 *
313 * Start-of-day init procedure for resource table. Must be called before
314 * any local resource table users may exist.
315 *
316 * Return: 0 on success, -errno on failure
317 */
nfp_resource_table_init(struct nfp_cpp * cpp)318 int nfp_resource_table_init(struct nfp_cpp *cpp)
319 {
320 struct nfp_cpp_mutex *dev_mutex;
321 int i, err;
322
323 err = nfp_cpp_mutex_reclaim(cpp, NFP_RESOURCE_TBL_TARGET,
324 NFP_RESOURCE_TBL_BASE);
325 if (err < 0) {
326 nfp_err(cpp, "Error: failed to reclaim resource table mutex\n");
327 return err;
328 }
329 if (err)
330 nfp_warn(cpp, "Warning: busted main resource table mutex\n");
331
332 dev_mutex = nfp_cpp_mutex_alloc(cpp, NFP_RESOURCE_TBL_TARGET,
333 NFP_RESOURCE_TBL_BASE,
334 NFP_RESOURCE_TBL_KEY);
335 if (!dev_mutex)
336 return -ENOMEM;
337
338 if (nfp_cpp_mutex_lock(dev_mutex)) {
339 nfp_err(cpp, "Error: failed to claim resource table mutex\n");
340 nfp_cpp_mutex_free(dev_mutex);
341 return -EINVAL;
342 }
343
344 /* Resource 0 is the dev_mutex, start from 1 */
345 for (i = 1; i < NFP_RESOURCE_TBL_ENTRIES; i++) {
346 u64 addr = NFP_RESOURCE_TBL_BASE +
347 sizeof(struct nfp_resource_entry) * i;
348
349 err = nfp_cpp_mutex_reclaim(cpp, NFP_RESOURCE_TBL_TARGET, addr);
350 if (err < 0) {
351 nfp_err(cpp,
352 "Error: failed to reclaim resource %d mutex\n",
353 i);
354 goto err_unlock;
355 }
356 if (err)
357 nfp_warn(cpp, "Warning: busted resource %d mutex\n", i);
358 }
359
360 err = 0;
361 err_unlock:
362 nfp_cpp_mutex_unlock(dev_mutex);
363 nfp_cpp_mutex_free(dev_mutex);
364
365 return err;
366 }
367