1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Copyright (C) ST-Ericsson AB 2013 4 * Authors: Vicram Arv 5 * Dmitry Tarnyagin <dmitry.tarnyagin@lockless.no> 6 * Sjur Brendeland 7 */ 8#include <linux/module.h> 9#include <linux/if_arp.h> 10#include <linux/virtio.h> 11#include <linux/vringh.h> 12#include <linux/debugfs.h> 13#include <linux/spinlock.h> 14#include <linux/genalloc.h> 15#include <linux/interrupt.h> 16#include <linux/netdevice.h> 17#include <linux/rtnetlink.h> 18#include <linux/virtio_ids.h> 19#include <linux/virtio_caif.h> 20#include <linux/virtio_ring.h> 21#include <linux/dma-mapping.h> 22#include <net/caif/caif_dev.h> 23#include <linux/virtio_config.h> 24 25MODULE_LICENSE("GPL v2"); 26MODULE_AUTHOR("Vicram Arv"); 27MODULE_AUTHOR("Sjur Brendeland"); 28MODULE_DESCRIPTION("Virtio CAIF Driver"); 29 30/* NAPI schedule quota */ 31#define CFV_DEFAULT_QUOTA 32 32 33/* Defaults used if virtio config space is unavailable */ 34#define CFV_DEF_MTU_SIZE 4096 35#define CFV_DEF_HEADROOM 32 36#define CFV_DEF_TAILROOM 32 37 38/* Required IP header alignment */ 39#define IP_HDR_ALIGN 4 40 41/* struct cfv_napi_contxt - NAPI context info 42 * @riov: IOV holding data read from the ring. Note that riov may 43 * still hold data when cfv_rx_poll() returns. 44 * @head: Last descriptor ID we received from vringh_getdesc_kern. 45 * We use this to put descriptor back on the used ring. USHRT_MAX is 46 * used to indicate invalid head-id. 47 */ 48struct cfv_napi_context { 49 struct vringh_kiov riov; 50 unsigned short head; 51}; 52 53/* struct cfv_stats - statistics for debugfs 54 * @rx_napi_complete: Number of NAPI completions (RX) 55 * @rx_napi_resched: Number of calls where the full quota was used (RX) 56 * @rx_nomem: Number of SKB alloc failures (RX) 57 * @rx_kicks: Number of RX kicks 58 * @tx_full_ring: Number times TX ring was full 59 * @tx_no_mem: Number of times TX went out of memory 60 * @tx_flow_on: Number of flow on (TX) 61 * @tx_kicks: Number of TX kicks 62 */ 63struct cfv_stats { 64 u32 rx_napi_complete; 65 u32 rx_napi_resched; 66 u32 rx_nomem; 67 u32 rx_kicks; 68 u32 tx_full_ring; 69 u32 tx_no_mem; 70 u32 tx_flow_on; 71 u32 tx_kicks; 72}; 73 74/* struct cfv_info - Caif Virtio control structure 75 * @cfdev: caif common header 76 * @vdev: Associated virtio device 77 * @vr_rx: rx/downlink host vring 78 * @vq_tx: tx/uplink virtqueue 79 * @ndev: CAIF link layer device 80 * @watermark_tx: indicates number of free descriptors we need 81 * to reopen the tx-queues after overload. 82 * @tx_lock: protects vq_tx from concurrent use 83 * @tx_release_tasklet: Tasklet for freeing consumed TX buffers 84 * @napi: Napi context used in cfv_rx_poll() 85 * @ctx: Context data used in cfv_rx_poll() 86 * @tx_hr: transmit headroom 87 * @rx_hr: receive headroom 88 * @tx_tr: transmit tail room 89 * @rx_tr: receive tail room 90 * @mtu: transmit max size 91 * @mru: receive max size 92 * @allocsz: size of dma memory reserved for TX buffers 93 * @alloc_addr: virtual address to dma memory for TX buffers 94 * @alloc_dma: dma address to dma memory for TX buffers 95 * @genpool: Gen Pool used for allocating TX buffers 96 * @reserved_mem: Pointer to memory reserve allocated from genpool 97 * @reserved_size: Size of memory reserve allocated from genpool 98 * @stats: Statistics exposed in sysfs 99 * @debugfs: Debugfs dentry for statistic counters 100 */ 101struct cfv_info { 102 struct caif_dev_common cfdev; 103 struct virtio_device *vdev; 104 struct vringh *vr_rx; 105 struct virtqueue *vq_tx; 106 struct net_device *ndev; 107 unsigned int watermark_tx; 108 /* Protect access to vq_tx */ 109 spinlock_t tx_lock; 110 struct tasklet_struct tx_release_tasklet; 111 struct napi_struct napi; 112 struct cfv_napi_context ctx; 113 u16 tx_hr; 114 u16 rx_hr; 115 u16 tx_tr; 116 u16 rx_tr; 117 u32 mtu; 118 u32 mru; 119 size_t allocsz; 120 void *alloc_addr; 121 dma_addr_t alloc_dma; 122 struct gen_pool *genpool; 123 unsigned long reserved_mem; 124 size_t reserved_size; 125 struct cfv_stats stats; 126 struct dentry *debugfs; 127}; 128 129/* struct buf_info - maintains transmit buffer data handle 130 * @size: size of transmit buffer 131 * @dma_handle: handle to allocated dma device memory area 132 * @vaddr: virtual address mapping to allocated memory area 133 */ 134struct buf_info { 135 size_t size; 136 u8 *vaddr; 137}; 138 139/* Called from virtio device, in IRQ context */ 140static void cfv_release_cb(struct virtqueue *vq_tx) 141{ 142 struct cfv_info *cfv = vq_tx->vdev->priv; 143 144 ++cfv->stats.tx_kicks; 145 tasklet_schedule(&cfv->tx_release_tasklet); 146} 147 148static void free_buf_info(struct cfv_info *cfv, struct buf_info *buf_info) 149{ 150 if (!buf_info) 151 return; 152 gen_pool_free(cfv->genpool, (unsigned long) buf_info->vaddr, 153 buf_info->size); 154 kfree(buf_info); 155} 156 157/* This is invoked whenever the remote processor completed processing 158 * a TX msg we just sent, and the buffer is put back to the used ring. 159 */ 160static void cfv_release_used_buf(struct virtqueue *vq_tx) 161{ 162 struct cfv_info *cfv = vq_tx->vdev->priv; 163 unsigned long flags; 164 165 BUG_ON(vq_tx != cfv->vq_tx); 166 167 for (;;) { 168 unsigned int len; 169 struct buf_info *buf_info; 170 171 /* Get used buffer from used ring to recycle used descriptors */ 172 spin_lock_irqsave(&cfv->tx_lock, flags); 173 buf_info = virtqueue_get_buf(vq_tx, &len); 174 spin_unlock_irqrestore(&cfv->tx_lock, flags); 175 176 /* Stop looping if there are no more buffers to free */ 177 if (!buf_info) 178 break; 179 180 free_buf_info(cfv, buf_info); 181 182 /* watermark_tx indicates if we previously stopped the tx 183 * queues. If we have enough free stots in the virtio ring, 184 * re-establish memory reserved and open up tx queues. 185 */ 186 if (cfv->vq_tx->num_free <= cfv->watermark_tx) 187 continue; 188 189 /* Re-establish memory reserve */ 190 if (cfv->reserved_mem == 0 && cfv->genpool) 191 cfv->reserved_mem = 192 gen_pool_alloc(cfv->genpool, 193 cfv->reserved_size); 194 195 /* Open up the tx queues */ 196 if (cfv->reserved_mem) { 197 cfv->watermark_tx = 198 virtqueue_get_vring_size(cfv->vq_tx); 199 netif_tx_wake_all_queues(cfv->ndev); 200 /* Buffers are recycled in cfv_netdev_tx, so 201 * disable notifications when queues are opened. 202 */ 203 virtqueue_disable_cb(cfv->vq_tx); 204 ++cfv->stats.tx_flow_on; 205 } else { 206 /* if no memory reserve, wait for more free slots */ 207 WARN_ON(cfv->watermark_tx > 208 virtqueue_get_vring_size(cfv->vq_tx)); 209 cfv->watermark_tx += 210 virtqueue_get_vring_size(cfv->vq_tx) / 4; 211 } 212 } 213} 214 215/* Allocate a SKB and copy packet data to it */ 216static struct sk_buff *cfv_alloc_and_copy_skb(int *err, 217 struct cfv_info *cfv, 218 u8 *frm, u32 frm_len) 219{ 220 struct sk_buff *skb; 221 u32 cfpkt_len, pad_len; 222 223 *err = 0; 224 /* Verify that packet size with down-link header and mtu size */ 225 if (frm_len > cfv->mru || frm_len <= cfv->rx_hr + cfv->rx_tr) { 226 netdev_err(cfv->ndev, 227 "Invalid frmlen:%u mtu:%u hr:%d tr:%d\n", 228 frm_len, cfv->mru, cfv->rx_hr, 229 cfv->rx_tr); 230 *err = -EPROTO; 231 return NULL; 232 } 233 234 cfpkt_len = frm_len - (cfv->rx_hr + cfv->rx_tr); 235 pad_len = (unsigned long)(frm + cfv->rx_hr) & (IP_HDR_ALIGN - 1); 236 237 skb = netdev_alloc_skb(cfv->ndev, frm_len + pad_len); 238 if (!skb) { 239 *err = -ENOMEM; 240 return NULL; 241 } 242 243 skb_reserve(skb, cfv->rx_hr + pad_len); 244 245 skb_put_data(skb, frm + cfv->rx_hr, cfpkt_len); 246 return skb; 247} 248 249/* Get packets from the host vring */ 250static int cfv_rx_poll(struct napi_struct *napi, int quota) 251{ 252 struct cfv_info *cfv = container_of(napi, struct cfv_info, napi); 253 int rxcnt = 0; 254 int err = 0; 255 void *buf; 256 struct sk_buff *skb; 257 struct vringh_kiov *riov = &cfv->ctx.riov; 258 unsigned int skb_len; 259 260 do { 261 skb = NULL; 262 263 /* Put the previous iovec back on the used ring and 264 * fetch a new iovec if we have processed all elements. 265 */ 266 if (riov->i == riov->used) { 267 if (cfv->ctx.head != USHRT_MAX) { 268 vringh_complete_kern(cfv->vr_rx, 269 cfv->ctx.head, 270 0); 271 cfv->ctx.head = USHRT_MAX; 272 } 273 274 err = vringh_getdesc_kern( 275 cfv->vr_rx, 276 riov, 277 NULL, 278 &cfv->ctx.head, 279 GFP_ATOMIC); 280 281 if (err <= 0) 282 goto exit; 283 } 284 285 buf = phys_to_virt((unsigned long) riov->iov[riov->i].iov_base); 286 /* TODO: Add check on valid buffer address */ 287 288 skb = cfv_alloc_and_copy_skb(&err, cfv, buf, 289 riov->iov[riov->i].iov_len); 290 if (unlikely(err)) 291 goto exit; 292 293 /* Push received packet up the stack. */ 294 skb_len = skb->len; 295 skb->protocol = htons(ETH_P_CAIF); 296 skb_reset_mac_header(skb); 297 skb->dev = cfv->ndev; 298 err = netif_receive_skb(skb); 299 if (unlikely(err)) { 300 ++cfv->ndev->stats.rx_dropped; 301 } else { 302 ++cfv->ndev->stats.rx_packets; 303 cfv->ndev->stats.rx_bytes += skb_len; 304 } 305 306 ++riov->i; 307 ++rxcnt; 308 } while (rxcnt < quota); 309 310 ++cfv->stats.rx_napi_resched; 311 goto out; 312 313exit: 314 switch (err) { 315 case 0: 316 ++cfv->stats.rx_napi_complete; 317 318 /* Really out of packets? (stolen from virtio_net)*/ 319 napi_complete(napi); 320 if (unlikely(!vringh_notify_enable_kern(cfv->vr_rx)) && 321 napi_schedule_prep(napi)) { 322 vringh_notify_disable_kern(cfv->vr_rx); 323 __napi_schedule(napi); 324 } 325 break; 326 327 case -ENOMEM: 328 ++cfv->stats.rx_nomem; 329 dev_kfree_skb(skb); 330 /* Stop NAPI poll on OOM, we hope to be polled later */ 331 napi_complete(napi); 332 vringh_notify_enable_kern(cfv->vr_rx); 333 break; 334 335 default: 336 /* We're doomed, any modem fault is fatal */ 337 netdev_warn(cfv->ndev, "Bad ring, disable device\n"); 338 cfv->ndev->stats.rx_dropped = riov->used - riov->i; 339 napi_complete(napi); 340 vringh_notify_disable_kern(cfv->vr_rx); 341 netif_carrier_off(cfv->ndev); 342 break; 343 } 344out: 345 if (rxcnt && vringh_need_notify_kern(cfv->vr_rx) > 0) 346 vringh_notify(cfv->vr_rx); 347 return rxcnt; 348} 349 350static void cfv_recv(struct virtio_device *vdev, struct vringh *vr_rx) 351{ 352 struct cfv_info *cfv = vdev->priv; 353 354 ++cfv->stats.rx_kicks; 355 vringh_notify_disable_kern(cfv->vr_rx); 356 napi_schedule(&cfv->napi); 357} 358 359static void cfv_destroy_genpool(struct cfv_info *cfv) 360{ 361 if (cfv->alloc_addr) 362 dma_free_coherent(cfv->vdev->dev.parent->parent, 363 cfv->allocsz, cfv->alloc_addr, 364 cfv->alloc_dma); 365 366 if (!cfv->genpool) 367 return; 368 gen_pool_free(cfv->genpool, cfv->reserved_mem, 369 cfv->reserved_size); 370 gen_pool_destroy(cfv->genpool); 371 cfv->genpool = NULL; 372} 373 374static int cfv_create_genpool(struct cfv_info *cfv) 375{ 376 int err; 377 378 /* dma_alloc can only allocate whole pages, and we need a more 379 * fine graned allocation so we use genpool. We ask for space needed 380 * by IP and a full ring. If the dma allcoation fails we retry with a 381 * smaller allocation size. 382 */ 383 err = -ENOMEM; 384 cfv->allocsz = (virtqueue_get_vring_size(cfv->vq_tx) * 385 (ETH_DATA_LEN + cfv->tx_hr + cfv->tx_tr) * 11)/10; 386 if (cfv->allocsz <= (num_possible_cpus() + 1) * cfv->ndev->mtu) 387 return -EINVAL; 388 389 for (;;) { 390 if (cfv->allocsz <= num_possible_cpus() * cfv->ndev->mtu) { 391 netdev_info(cfv->ndev, "Not enough device memory\n"); 392 return -ENOMEM; 393 } 394 395 cfv->alloc_addr = dma_alloc_coherent( 396 cfv->vdev->dev.parent->parent, 397 cfv->allocsz, &cfv->alloc_dma, 398 GFP_ATOMIC); 399 if (cfv->alloc_addr) 400 break; 401 402 cfv->allocsz = (cfv->allocsz * 3) >> 2; 403 } 404 405 netdev_dbg(cfv->ndev, "Allocated %zd bytes from dma-memory\n", 406 cfv->allocsz); 407 408 /* Allocate on 128 bytes boundaries (1 << 7)*/ 409 cfv->genpool = gen_pool_create(7, -1); 410 if (!cfv->genpool) 411 goto err; 412 413 err = gen_pool_add_virt(cfv->genpool, (unsigned long)cfv->alloc_addr, 414 (phys_addr_t)virt_to_phys(cfv->alloc_addr), 415 cfv->allocsz, -1); 416 if (err) 417 goto err; 418 419 /* Reserve some memory for low memory situations. If we hit the roof 420 * in the memory pool, we stop TX flow and release the reserve. 421 */ 422 cfv->reserved_size = num_possible_cpus() * cfv->ndev->mtu; 423 cfv->reserved_mem = gen_pool_alloc(cfv->genpool, 424 cfv->reserved_size); 425 if (!cfv->reserved_mem) { 426 err = -ENOMEM; 427 goto err; 428 } 429 430 cfv->watermark_tx = virtqueue_get_vring_size(cfv->vq_tx); 431 return 0; 432err: 433 cfv_destroy_genpool(cfv); 434 return err; 435} 436 437/* Enable the CAIF interface and allocate the memory-pool */ 438static int cfv_netdev_open(struct net_device *netdev) 439{ 440 struct cfv_info *cfv = netdev_priv(netdev); 441 442 if (cfv_create_genpool(cfv)) 443 return -ENOMEM; 444 445 netif_carrier_on(netdev); 446 napi_enable(&cfv->napi); 447 448 /* Schedule NAPI to read any pending packets */ 449 napi_schedule(&cfv->napi); 450 return 0; 451} 452 453/* Disable the CAIF interface and free the memory-pool */ 454static int cfv_netdev_close(struct net_device *netdev) 455{ 456 struct cfv_info *cfv = netdev_priv(netdev); 457 unsigned long flags; 458 struct buf_info *buf_info; 459 460 /* Disable interrupts, queues and NAPI polling */ 461 netif_carrier_off(netdev); 462 virtqueue_disable_cb(cfv->vq_tx); 463 vringh_notify_disable_kern(cfv->vr_rx); 464 napi_disable(&cfv->napi); 465 466 /* Release any TX buffers on both used and available rings */ 467 cfv_release_used_buf(cfv->vq_tx); 468 spin_lock_irqsave(&cfv->tx_lock, flags); 469 while ((buf_info = virtqueue_detach_unused_buf(cfv->vq_tx))) 470 free_buf_info(cfv, buf_info); 471 spin_unlock_irqrestore(&cfv->tx_lock, flags); 472 473 /* Release all dma allocated memory and destroy the pool */ 474 cfv_destroy_genpool(cfv); 475 return 0; 476} 477 478/* Allocate a buffer in dma-memory and copy skb to it */ 479static struct buf_info *cfv_alloc_and_copy_to_shm(struct cfv_info *cfv, 480 struct sk_buff *skb, 481 struct scatterlist *sg) 482{ 483 struct caif_payload_info *info = (void *)&skb->cb; 484 struct buf_info *buf_info = NULL; 485 u8 pad_len, hdr_ofs; 486 487 if (!cfv->genpool) 488 goto err; 489 490 if (unlikely(cfv->tx_hr + skb->len + cfv->tx_tr > cfv->mtu)) { 491 netdev_warn(cfv->ndev, "Invalid packet len (%d > %d)\n", 492 cfv->tx_hr + skb->len + cfv->tx_tr, cfv->mtu); 493 goto err; 494 } 495 496 buf_info = kmalloc(sizeof(struct buf_info), GFP_ATOMIC); 497 if (unlikely(!buf_info)) 498 goto err; 499 500 /* Make the IP header aligned in the buffer */ 501 hdr_ofs = cfv->tx_hr + info->hdr_len; 502 pad_len = hdr_ofs & (IP_HDR_ALIGN - 1); 503 buf_info->size = cfv->tx_hr + skb->len + cfv->tx_tr + pad_len; 504 505 /* allocate dma memory buffer */ 506 buf_info->vaddr = (void *)gen_pool_alloc(cfv->genpool, buf_info->size); 507 if (unlikely(!buf_info->vaddr)) 508 goto err; 509 510 /* copy skbuf contents to send buffer */ 511 skb_copy_bits(skb, 0, buf_info->vaddr + cfv->tx_hr + pad_len, skb->len); 512 sg_init_one(sg, buf_info->vaddr + pad_len, 513 skb->len + cfv->tx_hr + cfv->rx_hr); 514 515 return buf_info; 516err: 517 kfree(buf_info); 518 return NULL; 519} 520 521/* Put the CAIF packet on the virtio ring and kick the receiver */ 522static netdev_tx_t cfv_netdev_tx(struct sk_buff *skb, struct net_device *netdev) 523{ 524 struct cfv_info *cfv = netdev_priv(netdev); 525 struct buf_info *buf_info; 526 struct scatterlist sg; 527 unsigned long flags; 528 bool flow_off = false; 529 int ret; 530 531 /* garbage collect released buffers */ 532 cfv_release_used_buf(cfv->vq_tx); 533 spin_lock_irqsave(&cfv->tx_lock, flags); 534 535 /* Flow-off check takes into account number of cpus to make sure 536 * virtqueue will not be overfilled in any possible smp conditions. 537 * 538 * Flow-on is triggered when sufficient buffers are freed 539 */ 540 if (unlikely(cfv->vq_tx->num_free <= num_present_cpus())) { 541 flow_off = true; 542 cfv->stats.tx_full_ring++; 543 } 544 545 /* If we run out of memory, we release the memory reserve and retry 546 * allocation. 547 */ 548 buf_info = cfv_alloc_and_copy_to_shm(cfv, skb, &sg); 549 if (unlikely(!buf_info)) { 550 cfv->stats.tx_no_mem++; 551 flow_off = true; 552 553 if (cfv->reserved_mem && cfv->genpool) { 554 gen_pool_free(cfv->genpool, cfv->reserved_mem, 555 cfv->reserved_size); 556 cfv->reserved_mem = 0; 557 buf_info = cfv_alloc_and_copy_to_shm(cfv, skb, &sg); 558 } 559 } 560 561 if (unlikely(flow_off)) { 562 /* Turn flow on when a 1/4 of the descriptors are released */ 563 cfv->watermark_tx = virtqueue_get_vring_size(cfv->vq_tx) / 4; 564 /* Enable notifications of recycled TX buffers */ 565 virtqueue_enable_cb(cfv->vq_tx); 566 netif_tx_stop_all_queues(netdev); 567 } 568 569 if (unlikely(!buf_info)) { 570 /* If the memory reserve does it's job, this shouldn't happen */ 571 netdev_warn(cfv->ndev, "Out of gen_pool memory\n"); 572 goto err; 573 } 574 575 ret = virtqueue_add_outbuf(cfv->vq_tx, &sg, 1, buf_info, GFP_ATOMIC); 576 if (unlikely((ret < 0))) { 577 /* If flow control works, this shouldn't happen */ 578 netdev_warn(cfv->ndev, "Failed adding buffer to TX vring:%d\n", 579 ret); 580 goto err; 581 } 582 583 /* update netdev statistics */ 584 cfv->ndev->stats.tx_packets++; 585 cfv->ndev->stats.tx_bytes += skb->len; 586 spin_unlock_irqrestore(&cfv->tx_lock, flags); 587 588 /* tell the remote processor it has a pending message to read */ 589 virtqueue_kick(cfv->vq_tx); 590 591 dev_kfree_skb(skb); 592 return NETDEV_TX_OK; 593err: 594 spin_unlock_irqrestore(&cfv->tx_lock, flags); 595 cfv->ndev->stats.tx_dropped++; 596 free_buf_info(cfv, buf_info); 597 dev_kfree_skb(skb); 598 return NETDEV_TX_OK; 599} 600 601static void cfv_tx_release_tasklet(struct tasklet_struct *t) 602{ 603 struct cfv_info *cfv = from_tasklet(cfv, t, tx_release_tasklet); 604 cfv_release_used_buf(cfv->vq_tx); 605} 606 607static const struct net_device_ops cfv_netdev_ops = { 608 .ndo_open = cfv_netdev_open, 609 .ndo_stop = cfv_netdev_close, 610 .ndo_start_xmit = cfv_netdev_tx, 611}; 612 613static void cfv_netdev_setup(struct net_device *netdev) 614{ 615 netdev->netdev_ops = &cfv_netdev_ops; 616 netdev->type = ARPHRD_CAIF; 617 netdev->tx_queue_len = 100; 618 netdev->flags = IFF_POINTOPOINT | IFF_NOARP; 619 netdev->mtu = CFV_DEF_MTU_SIZE; 620 netdev->needs_free_netdev = true; 621} 622 623/* Create debugfs counters for the device */ 624static inline void debugfs_init(struct cfv_info *cfv) 625{ 626 cfv->debugfs = debugfs_create_dir(netdev_name(cfv->ndev), NULL); 627 628 debugfs_create_u32("rx-napi-complete", 0400, cfv->debugfs, 629 &cfv->stats.rx_napi_complete); 630 debugfs_create_u32("rx-napi-resched", 0400, cfv->debugfs, 631 &cfv->stats.rx_napi_resched); 632 debugfs_create_u32("rx-nomem", 0400, cfv->debugfs, 633 &cfv->stats.rx_nomem); 634 debugfs_create_u32("rx-kicks", 0400, cfv->debugfs, 635 &cfv->stats.rx_kicks); 636 debugfs_create_u32("tx-full-ring", 0400, cfv->debugfs, 637 &cfv->stats.tx_full_ring); 638 debugfs_create_u32("tx-no-mem", 0400, cfv->debugfs, 639 &cfv->stats.tx_no_mem); 640 debugfs_create_u32("tx-kicks", 0400, cfv->debugfs, 641 &cfv->stats.tx_kicks); 642 debugfs_create_u32("tx-flow-on", 0400, cfv->debugfs, 643 &cfv->stats.tx_flow_on); 644} 645 646/* Setup CAIF for the a virtio device */ 647static int cfv_probe(struct virtio_device *vdev) 648{ 649 vq_callback_t *vq_cbs = cfv_release_cb; 650 vrh_callback_t *vrh_cbs = cfv_recv; 651 const char *names = "output"; 652 const char *cfv_netdev_name = "cfvrt"; 653 struct net_device *netdev; 654 struct cfv_info *cfv; 655 int err; 656 657 netdev = alloc_netdev(sizeof(struct cfv_info), cfv_netdev_name, 658 NET_NAME_UNKNOWN, cfv_netdev_setup); 659 if (!netdev) 660 return -ENOMEM; 661 662 cfv = netdev_priv(netdev); 663 cfv->vdev = vdev; 664 cfv->ndev = netdev; 665 666 spin_lock_init(&cfv->tx_lock); 667 668 /* Get the RX virtio ring. This is a "host side vring". */ 669 err = -ENODEV; 670 if (!vdev->vringh_config || !vdev->vringh_config->find_vrhs) 671 goto err; 672 673 err = vdev->vringh_config->find_vrhs(vdev, 1, &cfv->vr_rx, &vrh_cbs); 674 if (err) 675 goto err; 676 677 /* Get the TX virtio ring. This is a "guest side vring". */ 678 err = virtio_find_vqs(vdev, 1, &cfv->vq_tx, &vq_cbs, &names, NULL); 679 if (err) 680 goto err; 681 682 /* Get the CAIF configuration from virtio config space, if available */ 683 if (vdev->config->get) { 684 virtio_cread(vdev, struct virtio_caif_transf_config, headroom, 685 &cfv->tx_hr); 686 virtio_cread(vdev, struct virtio_caif_transf_config, headroom, 687 &cfv->rx_hr); 688 virtio_cread(vdev, struct virtio_caif_transf_config, tailroom, 689 &cfv->tx_tr); 690 virtio_cread(vdev, struct virtio_caif_transf_config, tailroom, 691 &cfv->rx_tr); 692 virtio_cread(vdev, struct virtio_caif_transf_config, mtu, 693 &cfv->mtu); 694 virtio_cread(vdev, struct virtio_caif_transf_config, mtu, 695 &cfv->mru); 696 } else { 697 cfv->tx_hr = CFV_DEF_HEADROOM; 698 cfv->rx_hr = CFV_DEF_HEADROOM; 699 cfv->tx_tr = CFV_DEF_TAILROOM; 700 cfv->rx_tr = CFV_DEF_TAILROOM; 701 cfv->mtu = CFV_DEF_MTU_SIZE; 702 cfv->mru = CFV_DEF_MTU_SIZE; 703 } 704 705 netdev->needed_headroom = cfv->tx_hr; 706 netdev->needed_tailroom = cfv->tx_tr; 707 708 /* Disable buffer release interrupts unless we have stopped TX queues */ 709 virtqueue_disable_cb(cfv->vq_tx); 710 711 netdev->mtu = cfv->mtu - cfv->tx_tr; 712 vdev->priv = cfv; 713 714 /* Initialize NAPI poll context data */ 715 vringh_kiov_init(&cfv->ctx.riov, NULL, 0); 716 cfv->ctx.head = USHRT_MAX; 717 netif_napi_add_weight(netdev, &cfv->napi, cfv_rx_poll, 718 CFV_DEFAULT_QUOTA); 719 720 tasklet_setup(&cfv->tx_release_tasklet, cfv_tx_release_tasklet); 721 722 /* Carrier is off until netdevice is opened */ 723 netif_carrier_off(netdev); 724 725 /* serialize netdev register + virtio_device_ready() with ndo_open() */ 726 rtnl_lock(); 727 728 /* register Netdev */ 729 err = register_netdevice(netdev); 730 if (err) { 731 rtnl_unlock(); 732 dev_err(&vdev->dev, "Unable to register netdev (%d)\n", err); 733 goto err; 734 } 735 736 virtio_device_ready(vdev); 737 738 rtnl_unlock(); 739 740 debugfs_init(cfv); 741 742 return 0; 743err: 744 netdev_warn(cfv->ndev, "CAIF Virtio probe failed:%d\n", err); 745 746 if (cfv->vr_rx) 747 vdev->vringh_config->del_vrhs(cfv->vdev); 748 if (cfv->vdev) 749 vdev->config->del_vqs(cfv->vdev); 750 free_netdev(netdev); 751 return err; 752} 753 754static void cfv_remove(struct virtio_device *vdev) 755{ 756 struct cfv_info *cfv = vdev->priv; 757 758 rtnl_lock(); 759 dev_close(cfv->ndev); 760 rtnl_unlock(); 761 762 tasklet_kill(&cfv->tx_release_tasklet); 763 debugfs_remove_recursive(cfv->debugfs); 764 765 vringh_kiov_cleanup(&cfv->ctx.riov); 766 virtio_reset_device(vdev); 767 vdev->vringh_config->del_vrhs(cfv->vdev); 768 cfv->vr_rx = NULL; 769 vdev->config->del_vqs(cfv->vdev); 770 unregister_netdev(cfv->ndev); 771} 772 773static struct virtio_device_id id_table[] = { 774 { VIRTIO_ID_CAIF, VIRTIO_DEV_ANY_ID }, 775 { 0 }, 776}; 777 778static unsigned int features[] = { 779}; 780 781static struct virtio_driver caif_virtio_driver = { 782 .feature_table = features, 783 .feature_table_size = ARRAY_SIZE(features), 784 .driver.name = KBUILD_MODNAME, 785 .driver.owner = THIS_MODULE, 786 .id_table = id_table, 787 .probe = cfv_probe, 788 .remove = cfv_remove, 789}; 790 791module_virtio_driver(caif_virtio_driver); 792MODULE_DEVICE_TABLE(virtio, id_table); 793