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3e7ee490 HJ |
1 | /* |
2 | * | |
3 | * Copyright (c) 2009, Microsoft Corporation. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms and conditions of the GNU General Public License, | |
7 | * version 2, as published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope it will be useful, but WITHOUT | |
10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
12 | * more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License along with | |
15 | * this program; if not, write to the Free Software Foundation, Inc., 59 Temple | |
16 | * Place - Suite 330, Boston, MA 02111-1307 USA. | |
17 | * | |
18 | * Authors: | |
19 | * Haiyang Zhang <haiyangz@microsoft.com> | |
20 | * Hank Janssen <hjanssen@microsoft.com> | |
b2a5a585 | 21 | * K. Y. Srinivasan <kys@microsoft.com> |
3e7ee490 HJ |
22 | * |
23 | */ | |
0a46618d | 24 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
3e7ee490 | 25 | |
a0086dc5 GKH |
26 | #include <linux/kernel.h> |
27 | #include <linux/mm.h> | |
46a97191 | 28 | #include <linux/hyperv.h> |
3f335ea2 | 29 | |
0f2a6619 | 30 | #include "hyperv_vmbus.h" |
3e7ee490 | 31 | |
3e7ee490 | 32 | |
b2a5a585 S |
33 | /* |
34 | * hv_get_next_write_location() | |
35 | * | |
36 | * Get the next write location for the specified ring buffer | |
37 | * | |
38 | */ | |
4d643114 | 39 | static inline u32 |
2b8a912e | 40 | hv_get_next_write_location(struct hv_ring_buffer_info *ring_info) |
3e7ee490 | 41 | { |
fc8c72eb | 42 | u32 next = ring_info->ring_buffer->write_index; |
3e7ee490 | 43 | |
3e7ee490 HJ |
44 | return next; |
45 | } | |
46 | ||
b2a5a585 S |
47 | /* |
48 | * hv_set_next_write_location() | |
49 | * | |
50 | * Set the next write location for the specified ring buffer | |
51 | * | |
52 | */ | |
3e7ee490 | 53 | static inline void |
2b8a912e | 54 | hv_set_next_write_location(struct hv_ring_buffer_info *ring_info, |
fc8c72eb | 55 | u32 next_write_location) |
3e7ee490 | 56 | { |
fc8c72eb | 57 | ring_info->ring_buffer->write_index = next_write_location; |
3e7ee490 HJ |
58 | } |
59 | ||
b2a5a585 S |
60 | /* |
61 | * hv_get_next_read_location() | |
62 | * | |
63 | * Get the next read location for the specified ring buffer | |
64 | */ | |
4d643114 | 65 | static inline u32 |
2b8a912e | 66 | hv_get_next_read_location(struct hv_ring_buffer_info *ring_info) |
3e7ee490 | 67 | { |
fc8c72eb | 68 | u32 next = ring_info->ring_buffer->read_index; |
3e7ee490 | 69 | |
3e7ee490 HJ |
70 | return next; |
71 | } | |
72 | ||
b2a5a585 S |
73 | /* |
74 | * hv_get_next_readlocation_withoffset() | |
75 | * | |
76 | * Get the next read location + offset for the specified ring buffer. | |
77 | * This allows the caller to skip | |
78 | */ | |
4d643114 | 79 | static inline u32 |
2b8a912e | 80 | hv_get_next_readlocation_withoffset(struct hv_ring_buffer_info *ring_info, |
1ac58644 | 81 | u32 offset) |
3e7ee490 | 82 | { |
fc8c72eb | 83 | u32 next = ring_info->ring_buffer->read_index; |
3e7ee490 | 84 | |
fc8c72eb HZ |
85 | next += offset; |
86 | next %= ring_info->ring_datasize; | |
3e7ee490 HJ |
87 | |
88 | return next; | |
89 | } | |
90 | ||
b2a5a585 S |
91 | /* |
92 | * | |
93 | * hv_set_next_read_location() | |
94 | * | |
95 | * Set the next read location for the specified ring buffer | |
96 | * | |
97 | */ | |
3e7ee490 | 98 | static inline void |
2b8a912e | 99 | hv_set_next_read_location(struct hv_ring_buffer_info *ring_info, |
fc8c72eb | 100 | u32 next_read_location) |
3e7ee490 | 101 | { |
fc8c72eb | 102 | ring_info->ring_buffer->read_index = next_read_location; |
3e7ee490 HJ |
103 | } |
104 | ||
105 | ||
b2a5a585 S |
106 | /* |
107 | * | |
108 | * hv_get_ring_buffer() | |
109 | * | |
110 | * Get the start of the ring buffer | |
111 | */ | |
8282c400 | 112 | static inline void * |
2b8a912e | 113 | hv_get_ring_buffer(struct hv_ring_buffer_info *ring_info) |
3e7ee490 | 114 | { |
fc8c72eb | 115 | return (void *)ring_info->ring_buffer->buffer; |
3e7ee490 HJ |
116 | } |
117 | ||
118 | ||
b2a5a585 S |
119 | /* |
120 | * | |
121 | * hv_get_ring_buffersize() | |
122 | * | |
123 | * Get the size of the ring buffer | |
124 | */ | |
4d643114 | 125 | static inline u32 |
2b8a912e | 126 | hv_get_ring_buffersize(struct hv_ring_buffer_info *ring_info) |
3e7ee490 | 127 | { |
fc8c72eb | 128 | return ring_info->ring_datasize; |
3e7ee490 HJ |
129 | } |
130 | ||
b2a5a585 S |
131 | /* |
132 | * | |
133 | * hv_get_ring_bufferindices() | |
134 | * | |
135 | * Get the read and write indices as u64 of the specified ring buffer | |
136 | * | |
137 | */ | |
59471438 | 138 | static inline u64 |
2b8a912e | 139 | hv_get_ring_bufferindices(struct hv_ring_buffer_info *ring_info) |
3e7ee490 | 140 | { |
fc8c72eb | 141 | return (u64)ring_info->ring_buffer->write_index << 32; |
3e7ee490 HJ |
142 | } |
143 | ||
8f1136ae S |
144 | /* |
145 | * | |
146 | * hv_copyfrom_ringbuffer() | |
147 | * | |
148 | * Helper routine to copy to source from ring buffer. | |
149 | * Assume there is enough room. Handles wrap-around in src case only!! | |
150 | * | |
151 | */ | |
152 | static u32 hv_copyfrom_ringbuffer( | |
153 | struct hv_ring_buffer_info *ring_info, | |
154 | void *dest, | |
155 | u32 destlen, | |
156 | u32 start_read_offset) | |
157 | { | |
158 | void *ring_buffer = hv_get_ring_buffer(ring_info); | |
159 | u32 ring_buffer_size = hv_get_ring_buffersize(ring_info); | |
160 | ||
161 | u32 frag_len; | |
162 | ||
163 | /* wrap-around detected at the src */ | |
164 | if (destlen > ring_buffer_size - start_read_offset) { | |
165 | frag_len = ring_buffer_size - start_read_offset; | |
166 | ||
167 | memcpy(dest, ring_buffer + start_read_offset, frag_len); | |
168 | memcpy(dest + frag_len, ring_buffer, destlen - frag_len); | |
169 | } else | |
170 | ||
171 | memcpy(dest, ring_buffer + start_read_offset, destlen); | |
172 | ||
173 | ||
174 | start_read_offset += destlen; | |
175 | start_read_offset %= ring_buffer_size; | |
176 | ||
177 | return start_read_offset; | |
178 | } | |
179 | ||
180 | ||
7581578d S |
181 | /* |
182 | * | |
183 | * hv_copyto_ringbuffer() | |
184 | * | |
185 | * Helper routine to copy from source to ring buffer. | |
186 | * Assume there is enough room. Handles wrap-around in dest case only!! | |
187 | * | |
188 | */ | |
189 | static u32 hv_copyto_ringbuffer( | |
fc8c72eb HZ |
190 | struct hv_ring_buffer_info *ring_info, |
191 | u32 start_write_offset, | |
192 | void *src, | |
7581578d S |
193 | u32 srclen) |
194 | { | |
195 | void *ring_buffer = hv_get_ring_buffer(ring_info); | |
196 | u32 ring_buffer_size = hv_get_ring_buffersize(ring_info); | |
197 | u32 frag_len; | |
198 | ||
199 | /* wrap-around detected! */ | |
200 | if (srclen > ring_buffer_size - start_write_offset) { | |
201 | frag_len = ring_buffer_size - start_write_offset; | |
202 | memcpy(ring_buffer + start_write_offset, src, frag_len); | |
203 | memcpy(ring_buffer, src + frag_len, srclen - frag_len); | |
204 | } else | |
205 | memcpy(ring_buffer + start_write_offset, src, srclen); | |
3e7ee490 | 206 | |
7581578d S |
207 | start_write_offset += srclen; |
208 | start_write_offset %= ring_buffer_size; | |
209 | ||
210 | return start_write_offset; | |
211 | } | |
3e7ee490 | 212 | |
b2a5a585 S |
213 | /* |
214 | * | |
215 | * hv_ringbuffer_get_debuginfo() | |
216 | * | |
217 | * Get various debug metrics for the specified ring buffer | |
218 | * | |
219 | */ | |
a75b61d5 | 220 | void hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info, |
80682b7a | 221 | struct hv_ring_buffer_debug_info *debug_info) |
3e7ee490 | 222 | { |
fc8c72eb HZ |
223 | u32 bytes_avail_towrite; |
224 | u32 bytes_avail_toread; | |
3e7ee490 | 225 | |
fc8c72eb | 226 | if (ring_info->ring_buffer) { |
2b8a912e | 227 | hv_get_ringbuffer_availbytes(ring_info, |
fc8c72eb HZ |
228 | &bytes_avail_toread, |
229 | &bytes_avail_towrite); | |
3e7ee490 | 230 | |
fc8c72eb HZ |
231 | debug_info->bytes_avail_toread = bytes_avail_toread; |
232 | debug_info->bytes_avail_towrite = bytes_avail_towrite; | |
82f8bd40 | 233 | debug_info->current_read_index = |
fc8c72eb | 234 | ring_info->ring_buffer->read_index; |
82f8bd40 | 235 | debug_info->current_write_index = |
fc8c72eb | 236 | ring_info->ring_buffer->write_index; |
82f8bd40 | 237 | debug_info->current_interrupt_mask = |
fc8c72eb | 238 | ring_info->ring_buffer->interrupt_mask; |
3e7ee490 HJ |
239 | } |
240 | } | |
241 | ||
242 | ||
b2a5a585 S |
243 | /* |
244 | * | |
245 | * hv_get_ringbuffer_interrupt_mask() | |
246 | * | |
247 | * Get the interrupt mask for the specified ring buffer | |
248 | * | |
249 | */ | |
decc49da | 250 | u32 hv_get_ringbuffer_interrupt_mask(struct hv_ring_buffer_info *rbi) |
3e7ee490 | 251 | { |
82f8bd40 | 252 | return rbi->ring_buffer->interrupt_mask; |
3e7ee490 HJ |
253 | } |
254 | ||
b2a5a585 S |
255 | /* |
256 | * | |
257 | * hv_ringbuffer_init() | |
258 | * | |
259 | *Initialize the ring buffer | |
260 | * | |
261 | */ | |
72a95cbc | 262 | int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info, |
fc8c72eb | 263 | void *buffer, u32 buflen) |
3e7ee490 | 264 | { |
4a1b3acc | 265 | if (sizeof(struct hv_ring_buffer) != PAGE_SIZE) |
3324fb40 | 266 | return -EINVAL; |
3e7ee490 | 267 | |
fc8c72eb | 268 | memset(ring_info, 0, sizeof(struct hv_ring_buffer_info)); |
3e7ee490 | 269 | |
fc8c72eb HZ |
270 | ring_info->ring_buffer = (struct hv_ring_buffer *)buffer; |
271 | ring_info->ring_buffer->read_index = | |
272 | ring_info->ring_buffer->write_index = 0; | |
3e7ee490 | 273 | |
fc8c72eb HZ |
274 | ring_info->ring_size = buflen; |
275 | ring_info->ring_datasize = buflen - sizeof(struct hv_ring_buffer); | |
3e7ee490 | 276 | |
fc8c72eb | 277 | spin_lock_init(&ring_info->ring_lock); |
3e7ee490 HJ |
278 | |
279 | return 0; | |
280 | } | |
281 | ||
b2a5a585 S |
282 | /* |
283 | * | |
284 | * hv_ringbuffer_cleanup() | |
285 | * | |
286 | * Cleanup the ring buffer | |
287 | * | |
288 | */ | |
2dba688b | 289 | void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info) |
3e7ee490 | 290 | { |
3e7ee490 HJ |
291 | } |
292 | ||
b2a5a585 S |
293 | /* |
294 | * | |
295 | * hv_ringbuffer_write() | |
296 | * | |
297 | * Write to the ring buffer | |
298 | * | |
299 | */ | |
633c4dce | 300 | int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, |
3523a805 | 301 | struct scatterlist *sglist, u32 sgcount) |
3e7ee490 | 302 | { |
4408f531 | 303 | int i = 0; |
fc8c72eb HZ |
304 | u32 bytes_avail_towrite; |
305 | u32 bytes_avail_toread; | |
306 | u32 totalbytes_towrite = 0; | |
3e7ee490 | 307 | |
b219b3f7 | 308 | struct scatterlist *sg; |
66a60543 | 309 | u32 next_write_location; |
fc8c72eb | 310 | u64 prev_indices = 0; |
a98f96ee | 311 | unsigned long flags; |
3e7ee490 | 312 | |
b219b3f7 | 313 | for_each_sg(sglist, sg, sgcount, i) |
3e7ee490 | 314 | { |
fc8c72eb | 315 | totalbytes_towrite += sg->length; |
3e7ee490 HJ |
316 | } |
317 | ||
fc8c72eb | 318 | totalbytes_towrite += sizeof(u64); |
3e7ee490 | 319 | |
fc8c72eb | 320 | spin_lock_irqsave(&outring_info->ring_lock, flags); |
3e7ee490 | 321 | |
2b8a912e | 322 | hv_get_ringbuffer_availbytes(outring_info, |
fc8c72eb HZ |
323 | &bytes_avail_toread, |
324 | &bytes_avail_towrite); | |
3e7ee490 | 325 | |
3e7ee490 | 326 | |
4408f531 B |
327 | /* If there is only room for the packet, assume it is full. */ |
328 | /* Otherwise, the next time around, we think the ring buffer */ | |
454f18a9 | 329 | /* is empty since the read index == write index */ |
fc8c72eb | 330 | if (bytes_avail_towrite <= totalbytes_towrite) { |
fc8c72eb | 331 | spin_unlock_irqrestore(&outring_info->ring_lock, flags); |
d2598f01 | 332 | return -EAGAIN; |
3e7ee490 HJ |
333 | } |
334 | ||
454f18a9 | 335 | /* Write to the ring buffer */ |
2b8a912e | 336 | next_write_location = hv_get_next_write_location(outring_info); |
3e7ee490 | 337 | |
b219b3f7 | 338 | for_each_sg(sglist, sg, sgcount, i) |
3e7ee490 | 339 | { |
2b8a912e | 340 | next_write_location = hv_copyto_ringbuffer(outring_info, |
fc8c72eb | 341 | next_write_location, |
b219b3f7 NP |
342 | sg_virt(sg), |
343 | sg->length); | |
3e7ee490 HJ |
344 | } |
345 | ||
454f18a9 | 346 | /* Set previous packet start */ |
2b8a912e | 347 | prev_indices = hv_get_ring_bufferindices(outring_info); |
3e7ee490 | 348 | |
2b8a912e | 349 | next_write_location = hv_copyto_ringbuffer(outring_info, |
fc8c72eb HZ |
350 | next_write_location, |
351 | &prev_indices, | |
b219b3f7 | 352 | sizeof(u64)); |
3e7ee490 | 353 | |
454f18a9 | 354 | /* Make sure we flush all writes before updating the writeIndex */ |
e690b5a9 | 355 | smp_wmb(); |
3e7ee490 | 356 | |
454f18a9 | 357 | /* Now, update the write location */ |
2b8a912e | 358 | hv_set_next_write_location(outring_info, next_write_location); |
3e7ee490 | 359 | |
3e7ee490 | 360 | |
fc8c72eb | 361 | spin_unlock_irqrestore(&outring_info->ring_lock, flags); |
3e7ee490 HJ |
362 | return 0; |
363 | } | |
364 | ||
365 | ||
b2a5a585 S |
366 | /* |
367 | * | |
368 | * hv_ringbuffer_peek() | |
369 | * | |
370 | * Read without advancing the read index | |
371 | * | |
372 | */ | |
a89186c2 | 373 | int hv_ringbuffer_peek(struct hv_ring_buffer_info *Inring_info, |
fc8c72eb | 374 | void *Buffer, u32 buflen) |
3e7ee490 | 375 | { |
fc8c72eb HZ |
376 | u32 bytes_avail_towrite; |
377 | u32 bytes_avail_toread; | |
378 | u32 next_read_location = 0; | |
a98f96ee | 379 | unsigned long flags; |
3e7ee490 | 380 | |
fc8c72eb | 381 | spin_lock_irqsave(&Inring_info->ring_lock, flags); |
3e7ee490 | 382 | |
2b8a912e | 383 | hv_get_ringbuffer_availbytes(Inring_info, |
fc8c72eb HZ |
384 | &bytes_avail_toread, |
385 | &bytes_avail_towrite); | |
3e7ee490 | 386 | |
454f18a9 | 387 | /* Make sure there is something to read */ |
fc8c72eb | 388 | if (bytes_avail_toread < buflen) { |
3e7ee490 | 389 | |
fc8c72eb | 390 | spin_unlock_irqrestore(&Inring_info->ring_lock, flags); |
3e7ee490 | 391 | |
d2598f01 | 392 | return -EAGAIN; |
3e7ee490 HJ |
393 | } |
394 | ||
454f18a9 | 395 | /* Convert to byte offset */ |
2b8a912e | 396 | next_read_location = hv_get_next_read_location(Inring_info); |
3e7ee490 | 397 | |
2b8a912e | 398 | next_read_location = hv_copyfrom_ringbuffer(Inring_info, |
4408f531 | 399 | Buffer, |
fc8c72eb HZ |
400 | buflen, |
401 | next_read_location); | |
3e7ee490 | 402 | |
fc8c72eb | 403 | spin_unlock_irqrestore(&Inring_info->ring_lock, flags); |
3e7ee490 HJ |
404 | |
405 | return 0; | |
406 | } | |
407 | ||
408 | ||
b2a5a585 S |
409 | /* |
410 | * | |
411 | * hv_ringbuffer_read() | |
412 | * | |
413 | * Read and advance the read index | |
414 | * | |
415 | */ | |
38397c8a | 416 | int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer, |
fc8c72eb | 417 | u32 buflen, u32 offset) |
3e7ee490 | 418 | { |
fc8c72eb HZ |
419 | u32 bytes_avail_towrite; |
420 | u32 bytes_avail_toread; | |
421 | u32 next_read_location = 0; | |
422 | u64 prev_indices = 0; | |
a98f96ee | 423 | unsigned long flags; |
3e7ee490 | 424 | |
fc8c72eb | 425 | if (buflen <= 0) |
a16e1485 | 426 | return -EINVAL; |
3e7ee490 | 427 | |
fc8c72eb | 428 | spin_lock_irqsave(&inring_info->ring_lock, flags); |
3e7ee490 | 429 | |
2b8a912e | 430 | hv_get_ringbuffer_availbytes(inring_info, |
fc8c72eb HZ |
431 | &bytes_avail_toread, |
432 | &bytes_avail_towrite); | |
3e7ee490 | 433 | |
454f18a9 | 434 | /* Make sure there is something to read */ |
fc8c72eb | 435 | if (bytes_avail_toread < buflen) { |
fc8c72eb | 436 | spin_unlock_irqrestore(&inring_info->ring_lock, flags); |
3e7ee490 | 437 | |
d2598f01 | 438 | return -EAGAIN; |
3e7ee490 HJ |
439 | } |
440 | ||
1ac58644 | 441 | next_read_location = |
2b8a912e | 442 | hv_get_next_readlocation_withoffset(inring_info, offset); |
3e7ee490 | 443 | |
2b8a912e | 444 | next_read_location = hv_copyfrom_ringbuffer(inring_info, |
fc8c72eb HZ |
445 | buffer, |
446 | buflen, | |
447 | next_read_location); | |
3e7ee490 | 448 | |
2b8a912e | 449 | next_read_location = hv_copyfrom_ringbuffer(inring_info, |
fc8c72eb | 450 | &prev_indices, |
4408f531 | 451 | sizeof(u64), |
fc8c72eb | 452 | next_read_location); |
3e7ee490 | 453 | |
454f18a9 | 454 | /* Make sure all reads are done before we update the read index since */ |
4408f531 B |
455 | /* the writer may start writing to the read area once the read index */ |
456 | /*is updated */ | |
ef0d5b23 | 457 | smp_mb(); |
3e7ee490 | 458 | |
454f18a9 | 459 | /* Update the read index */ |
2b8a912e | 460 | hv_set_next_read_location(inring_info, next_read_location); |
3e7ee490 | 461 | |
fc8c72eb | 462 | spin_unlock_irqrestore(&inring_info->ring_lock, flags); |
3e7ee490 HJ |
463 | |
464 | return 0; | |
465 | } |