1/* 2 * Intel Wireless WiMAX Connection 2400m 3 * USB RX handling 4 * 5 * 6 * Copyright (C) 2007-2008 Intel Corporation. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * * Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * * Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in 16 * the documentation and/or other materials provided with the 17 * distribution. 18 * * Neither the name of Intel Corporation nor the names of its 19 * contributors may be used to endorse or promote products derived 20 * from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 23 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 25 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 26 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 28 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 32 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 * 34 * 35 * Intel Corporation <linux-wimax@intel.com> 36 * Yanir Lubetkin <yanirx.lubetkin@intel.com> 37 * - Initial implementation 38 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com> 39 * - Use skb_clone(), break up processing in chunks 40 * - Split transport/device specific 41 * - Make buffer size dynamic to exert less memory pressure 42 * 43 * 44 * This handles the RX path on USB. 45 * 46 * When a notification is received that says 'there is RX data ready', 47 * we call i2400mu_rx_kick(); that wakes up the RX kthread, which 48 * reads a buffer from USB and passes it to i2400m_rx() in the generic 49 * handling code. The RX buffer has an specific format that is 50 * described in rx.c. 51 * 52 * We use a kernel thread in a loop because: 53 * 54 * - we want to be able to call the USB power management get/put 55 * functions (blocking) before each transaction. 56 * 57 * - We might get a lot of notifications and we don't want to submit 58 * a zillion reads; by serializing, we are throttling. 59 * 60 * - RX data processing can get heavy enough so that it is not 61 * appropriate for doing it in the USB callback; thus we run it in a 62 * process context. 63 * 64 * We provide a read buffer of an arbitrary size (short of a page); if 65 * the callback reports -EOVERFLOW, it means it was too small, so we 66 * just double the size and retry (being careful to append, as 67 * sometimes the device provided some data). Every now and then we 68 * check if the average packet size is smaller than the current packet 69 * size and if so, we halve it. At the end, the size of the 70 * preallocated buffer should be following the average received 71 * transaction size, adapting dynamically to it. 72 * 73 * ROADMAP 74 * 75 * i2400mu_rx_kick() Called from notif.c when we get a 76 * 'data ready' notification 77 * i2400mu_rxd() Kernel RX daemon 78 * i2400mu_rx() Receive USB data 79 * i2400m_rx() Send data to generic i2400m RX handling 80 * 81 * i2400mu_rx_setup() called from i2400mu_bus_dev_start() 82 * 83 * i2400mu_rx_release() called from i2400mu_bus_dev_stop() 84 */ 85#include <linux/workqueue.h> 86#include <linux/slab.h> 87#include <linux/usb.h> 88#include "i2400m-usb.h" 89 90 91#define D_SUBMODULE rx 92#include "usb-debug-levels.h" 93 94/* 95 * Dynamic RX size 96 * 97 * We can't let the rx_size be a multiple of 512 bytes (the RX 98 * endpoint's max packet size). On some USB host controllers (we 99 * haven't been able to fully characterize which), if the device is 100 * about to send (for example) X bytes and we only post a buffer to 101 * receive n*512, it will fail to mark that as babble (so that 102 * i2400mu_rx() [case -EOVERFLOW] can resize the buffer and get the 103 * rest). 104 * 105 * So on growing or shrinking, if it is a multiple of the 106 * maxpacketsize, we remove some (instead of incresing some, so in a 107 * buddy allocator we try to waste less space). 108 * 109 * Note we also need a hook for this on i2400mu_rx() -- when we do the 110 * first read, we are sure we won't hit this spot because 111 * i240mm->rx_size has been set properly. However, if we have to 112 * double because of -EOVERFLOW, when we launch the read to get the 113 * rest of the data, we *have* to make sure that also is not a 114 * multiple of the max_pkt_size. 115 */ 116 117static 118size_t i2400mu_rx_size_grow(struct i2400mu *i2400mu) 119{ 120 struct device *dev = &i2400mu->usb_iface->dev; 121 size_t rx_size; 122 const size_t max_pkt_size = 512; 123 124 rx_size = 2 * i2400mu->rx_size; 125 if (rx_size % max_pkt_size == 0) { 126 rx_size -= 8; 127 d_printf(1, dev, 128 "RX: expected size grew to %zu [adjusted -8] " 129 "from %zu\n", 130 rx_size, i2400mu->rx_size); 131 } else 132 d_printf(1, dev, 133 "RX: expected size grew to %zu from %zu\n", 134 rx_size, i2400mu->rx_size); 135 return rx_size; 136} 137 138 139static 140void i2400mu_rx_size_maybe_shrink(struct i2400mu *i2400mu) 141{ 142 const size_t max_pkt_size = 512; 143 struct device *dev = &i2400mu->usb_iface->dev; 144 145 if (unlikely(i2400mu->rx_size_cnt >= 100 146 && i2400mu->rx_size_auto_shrink)) { 147 size_t avg_rx_size = 148 i2400mu->rx_size_acc / i2400mu->rx_size_cnt; 149 size_t new_rx_size = i2400mu->rx_size / 2; 150 if (avg_rx_size < new_rx_size) { 151 if (new_rx_size % max_pkt_size == 0) { 152 new_rx_size -= 8; 153 d_printf(1, dev, 154 "RX: expected size shrank to %zu " 155 "[adjusted -8] from %zu\n", 156 new_rx_size, i2400mu->rx_size); 157 } else 158 d_printf(1, dev, 159 "RX: expected size shrank to %zu " 160 "from %zu\n", 161 new_rx_size, i2400mu->rx_size); 162 i2400mu->rx_size = new_rx_size; 163 i2400mu->rx_size_cnt = 0; 164 i2400mu->rx_size_acc = i2400mu->rx_size; 165 } 166 } 167} 168 169/* 170 * Receive a message with payloads from the USB bus into an skb 171 * 172 * @i2400mu: USB device descriptor 173 * @rx_skb: skb where to place the received message 174 * 175 * Deals with all the USB-specifics of receiving, dynamically 176 * increasing the buffer size if so needed. Returns the payload in the 177 * skb, ready to process. On a zero-length packet, we retry. 178 * 179 * On soft USB errors, we retry (until they become too frequent and 180 * then are promoted to hard); on hard USB errors, we reset the 181 * device. On other errors (skb realloacation, we just drop it and 182 * hope for the next invocation to solve it). 183 * 184 * Returns: pointer to the skb if ok, ERR_PTR on error. 185 * NOTE: this function might realloc the skb (if it is too small), 186 * so always update with the one returned. 187 * ERR_PTR() is < 0 on error. 188 * Will return NULL if it cannot reallocate -- this can be 189 * considered a transient retryable error. 190 */ 191static 192struct sk_buff *i2400mu_rx(struct i2400mu *i2400mu, struct sk_buff *rx_skb) 193{ 194 int result = 0; 195 struct device *dev = &i2400mu->usb_iface->dev; 196 int usb_pipe, read_size, rx_size, do_autopm; 197 struct usb_endpoint_descriptor *epd; 198 const size_t max_pkt_size = 512; 199 200 d_fnstart(4, dev, "(i2400mu %p)\n", i2400mu); 201 do_autopm = atomic_read(&i2400mu->do_autopm); 202 result = do_autopm ? 203 usb_autopm_get_interface(i2400mu->usb_iface) : 0; 204 if (result < 0) { 205 dev_err(dev, "RX: can't get autopm: %d\n", result); 206 do_autopm = 0; 207 } 208 epd = usb_get_epd(i2400mu->usb_iface, i2400mu->endpoint_cfg.bulk_in); 209 usb_pipe = usb_rcvbulkpipe(i2400mu->usb_dev, epd->bEndpointAddress); 210retry: 211 rx_size = skb_end_pointer(rx_skb) - rx_skb->data - rx_skb->len; 212 if (unlikely(rx_size % max_pkt_size == 0)) { 213 rx_size -= 8; 214 d_printf(1, dev, "RX: rx_size adapted to %d [-8]\n", rx_size); 215 } 216 result = usb_bulk_msg( 217 i2400mu->usb_dev, usb_pipe, rx_skb->data + rx_skb->len, 218 rx_size, &read_size, 200); 219 usb_mark_last_busy(i2400mu->usb_dev); 220 switch (result) { 221 case 0: 222 if (read_size == 0) 223 goto retry; /* ZLP, just resubmit */ 224 skb_put(rx_skb, read_size); 225 break; 226 case -EPIPE: 227 /* 228 * Stall -- maybe the device is choking with our 229 * requests. Clear it and give it some time. If they 230 * happen to often, it might be another symptom, so we 231 * reset. 232 * 233 * No error handling for usb_clear_halt(0; if it 234 * works, the retry works; if it fails, this switch 235 * does the error handling for us. 236 */ 237 if (edc_inc(&i2400mu->urb_edc, 238 10 * EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME)) { 239 dev_err(dev, "BM-CMD: too many stalls in " 240 "URB; resetting device\n"); 241 goto do_reset; 242 } 243 usb_clear_halt(i2400mu->usb_dev, usb_pipe); 244 msleep(10); /* give the device some time */ 245 goto retry; 246 case -EINVAL: /* while removing driver */ 247 case -ENODEV: /* dev disconnect ... */ 248 case -ENOENT: /* just ignore it */ 249 case -ESHUTDOWN: 250 case -ECONNRESET: 251 break; 252 case -EOVERFLOW: { /* too small, reallocate */ 253 struct sk_buff *new_skb; 254 rx_size = i2400mu_rx_size_grow(i2400mu); 255 if (rx_size <= (1 << 16)) /* cap it */ 256 i2400mu->rx_size = rx_size; 257 else if (printk_ratelimit()) { 258 dev_err(dev, "BUG? rx_size up to %d\n", rx_size); 259 result = -EINVAL; 260 goto out; 261 } 262 skb_put(rx_skb, read_size); 263 new_skb = skb_copy_expand(rx_skb, 0, rx_size - rx_skb->len, 264 GFP_KERNEL); 265 if (new_skb == NULL) { 266 kfree_skb(rx_skb); 267 rx_skb = NULL; 268 goto out; /* drop it...*/ 269 } 270 kfree_skb(rx_skb); 271 rx_skb = new_skb; 272 i2400mu->rx_size_cnt = 0; 273 i2400mu->rx_size_acc = i2400mu->rx_size; 274 d_printf(1, dev, "RX: size changed to %d, received %d, " 275 "copied %d, capacity %ld\n", 276 rx_size, read_size, rx_skb->len, 277 (long) skb_end_offset(new_skb)); 278 goto retry; 279 } 280 /* In most cases, it happens due to the hardware scheduling a 281 * read when there was no data - unfortunately, we have no way 282 * to tell this timeout from a USB timeout. So we just ignore 283 * it. */ 284 case -ETIMEDOUT: 285 dev_err(dev, "RX: timeout: %d\n", result); 286 result = 0; 287 break; 288 default: /* Any error */ 289 if (edc_inc(&i2400mu->urb_edc, 290 EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME)) 291 goto error_reset; 292 dev_err(dev, "RX: error receiving URB: %d, retrying\n", result); 293 goto retry; 294 } 295out: 296 if (do_autopm) 297 usb_autopm_put_interface(i2400mu->usb_iface); 298 d_fnend(4, dev, "(i2400mu %p) = %p\n", i2400mu, rx_skb); 299 return rx_skb; 300 301error_reset: 302 dev_err(dev, "RX: maximum errors in URB exceeded; " 303 "resetting device\n"); 304do_reset: 305 usb_queue_reset_device(i2400mu->usb_iface); 306 rx_skb = ERR_PTR(result); 307 goto out; 308} 309 310 311/* 312 * Kernel thread for USB reception of data 313 * 314 * This thread waits for a kick; once kicked, it will allocate an skb 315 * and receive a single message to it from USB (using 316 * i2400mu_rx()). Once received, it is passed to the generic i2400m RX 317 * code for processing. 318 * 319 * When done processing, it runs some dirty statistics to verify if 320 * the last 100 messages received were smaller than half of the 321 * current RX buffer size. In that case, the RX buffer size is 322 * halved. This will helps lowering the pressure on the memory 323 * allocator. 324 * 325 * Hard errors force the thread to exit. 326 */ 327static 328int i2400mu_rxd(void *_i2400mu) 329{ 330 int result = 0; 331 struct i2400mu *i2400mu = _i2400mu; 332 struct i2400m *i2400m = &i2400mu->i2400m; 333 struct device *dev = &i2400mu->usb_iface->dev; 334 struct net_device *net_dev = i2400m->wimax_dev.net_dev; 335 size_t pending; 336 int rx_size; 337 struct sk_buff *rx_skb; 338 unsigned long flags; 339 340 d_fnstart(4, dev, "(i2400mu %p)\n", i2400mu); 341 spin_lock_irqsave(&i2400m->rx_lock, flags); 342 BUG_ON(i2400mu->rx_kthread != NULL); 343 i2400mu->rx_kthread = current; 344 spin_unlock_irqrestore(&i2400m->rx_lock, flags); 345 while (1) { 346 d_printf(2, dev, "RX: waiting for messages\n"); 347 pending = 0; 348 wait_event_interruptible( 349 i2400mu->rx_wq, 350 (kthread_should_stop() /* check this first! */ 351 || (pending = atomic_read(&i2400mu->rx_pending_count))) 352 ); 353 if (kthread_should_stop()) 354 break; 355 if (pending == 0) 356 continue; 357 rx_size = i2400mu->rx_size; 358 d_printf(2, dev, "RX: reading up to %d bytes\n", rx_size); 359 rx_skb = __netdev_alloc_skb(net_dev, rx_size, GFP_KERNEL); 360 if (rx_skb == NULL) { 361 dev_err(dev, "RX: can't allocate skb [%d bytes]\n", 362 rx_size); 363 msleep(50); /* give it some time? */ 364 continue; 365 } 366 367 /* Receive the message with the payloads */ 368 rx_skb = i2400mu_rx(i2400mu, rx_skb); 369 result = PTR_ERR(rx_skb); 370 if (IS_ERR(rx_skb)) 371 goto out; 372 atomic_dec(&i2400mu->rx_pending_count); 373 if (rx_skb == NULL || rx_skb->len == 0) { 374 /* some "ignorable" condition */ 375 kfree_skb(rx_skb); 376 continue; 377 } 378 379 /* Deliver the message to the generic i2400m code */ 380 i2400mu->rx_size_cnt++; 381 i2400mu->rx_size_acc += rx_skb->len; 382 result = i2400m_rx(i2400m, rx_skb); 383 if (result == -EIO 384 && edc_inc(&i2400mu->urb_edc, 385 EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME)) { 386 goto error_reset; 387 } 388 389 /* Maybe adjust RX buffer size */ 390 i2400mu_rx_size_maybe_shrink(i2400mu); 391 } 392 result = 0; 393out: 394 spin_lock_irqsave(&i2400m->rx_lock, flags); 395 i2400mu->rx_kthread = NULL; 396 spin_unlock_irqrestore(&i2400m->rx_lock, flags); 397 d_fnend(4, dev, "(i2400mu %p) = %d\n", i2400mu, result); 398 return result; 399 400error_reset: 401 dev_err(dev, "RX: maximum errors in received buffer exceeded; " 402 "resetting device\n"); 403 usb_queue_reset_device(i2400mu->usb_iface); 404 goto out; 405} 406 407 408/* 409 * Start reading from the device 410 * 411 * @i2400m: device instance 412 * 413 * Notify the RX thread that there is data pending. 414 */ 415void i2400mu_rx_kick(struct i2400mu *i2400mu) 416{ 417 struct i2400m *i2400m = &i2400mu->i2400m; 418 struct device *dev = &i2400mu->usb_iface->dev; 419 420 d_fnstart(3, dev, "(i2400mu %p)\n", i2400m); 421 atomic_inc(&i2400mu->rx_pending_count); 422 wake_up_all(&i2400mu->rx_wq); 423 d_fnend(3, dev, "(i2400m %p) = void\n", i2400m); 424} 425 426 427int i2400mu_rx_setup(struct i2400mu *i2400mu) 428{ 429 int result = 0; 430 struct i2400m *i2400m = &i2400mu->i2400m; 431 struct device *dev = &i2400mu->usb_iface->dev; 432 struct wimax_dev *wimax_dev = &i2400m->wimax_dev; 433 struct task_struct *kthread; 434 435 kthread = kthread_run(i2400mu_rxd, i2400mu, "%s-rx", 436 wimax_dev->name); 437 /* the kthread function sets i2400mu->rx_thread */ 438 if (IS_ERR(kthread)) { 439 result = PTR_ERR(kthread); 440 dev_err(dev, "RX: cannot start thread: %d\n", result); 441 } 442 return result; 443} 444 445 446void i2400mu_rx_release(struct i2400mu *i2400mu) 447{ 448 unsigned long flags; 449 struct i2400m *i2400m = &i2400mu->i2400m; 450 struct device *dev = i2400m_dev(i2400m); 451 struct task_struct *kthread; 452 453 spin_lock_irqsave(&i2400m->rx_lock, flags); 454 kthread = i2400mu->rx_kthread; 455 i2400mu->rx_kthread = NULL; 456 spin_unlock_irqrestore(&i2400m->rx_lock, flags); 457 if (kthread) 458 kthread_stop(kthread); 459 else 460 d_printf(1, dev, "RX: kthread had already exited\n"); 461} 462 463