root/drivers/char/virtio_console.c

DEFINITIONS

1. find_port_by_vtermno
2. find_port_by_devt_in_portdev
3. find_port_by_devt
4. find_port_by_id
5. find_port_by_vq
6. is_console_port
7. is_rproc_serial
8. use_multiport
9. free_buf
10. reclaim_dma_bufs
11. alloc_buf
12. get_inbuf
13. add_inbuf
14. discard_port_data
15. port_has_data
16. __send_control_msg
17. send_control_msg
18. reclaim_consumed_buffers
19. __send_to_port
20. fill_readbuf
21. will_read_block
22. will_write_block
23. port_fops_read
24. wait_port_writable
25. port_fops_write
26. pipe_to_sg
27. port_fops_splice_write
28. port_fops_poll
29. port_fops_release
30. port_fops_open
31. port_fops_fasync
32. put_chars
33. get_chars
34. resize_console
35. notifier_add_vio
36. notifier_del_vio
37. virtio_cons_early_init
38. init_port_console
39. show_port_name
40. port_debugfs_show
41. set_console_size
42. fill_queue
43. send_sigio_to_port
44. add_port
45. remove_port
46. remove_port_data
47. unplug_port
48. handle_control_message
49. control_work_handler
50. flush_bufs
51. out_intr
52. in_intr
53. control_intr
54. config_intr
55. config_work_handler
56. init_vqs
57. remove_vqs
58. virtcons_remove
59. virtcons_probe
60. virtcons_freeze
61. virtcons_restore
62. fini

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
   4  * Copyright (C) 2009, 2010, 2011 Red Hat, Inc.
   5  * Copyright (C) 2009, 2010, 2011 Amit Shah <amit.shah@redhat.com>
   6  */
   7 #include <linux/cdev.h>
   8 #include <linux/debugfs.h>
   9 #include <linux/completion.h>
  10 #include <linux/device.h>
  11 #include <linux/err.h>
  12 #include <linux/freezer.h>
  13 #include <linux/fs.h>
  14 #include <linux/splice.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/init.h>
  17 #include <linux/list.h>
  18 #include <linux/poll.h>
  19 #include <linux/sched.h>
  20 #include <linux/slab.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/virtio.h>
  23 #include <linux/virtio_console.h>
  24 #include <linux/wait.h>
  25 #include <linux/workqueue.h>
  26 #include <linux/module.h>
  27 #include <linux/dma-mapping.h>
  28 #include "../tty/hvc/hvc_console.h"
  29 
  30 #define is_rproc_enabled IS_ENABLED(CONFIG_REMOTEPROC)
  31 
  32 /*
  33  * This is a global struct for storing common data for all the devices
  34  * this driver handles.
  35  *
  36  * Mainly, it has a linked list for all the consoles in one place so
  37  * that callbacks from hvc for get_chars(), put_chars() work properly
  38  * across multiple devices and multiple ports per device.
  39  */
  40 struct ports_driver_data {
  41         /* Used for registering chardevs */
  42         struct class *class;
  43 
  44         /* Used for exporting per-port information to debugfs */
  45         struct dentry *debugfs_dir;
  46 
  47         /* List of all the devices we're handling */
  48         struct list_head portdevs;
  49 
  50         /*
  51          * This is used to keep track of the number of hvc consoles
  52          * spawned by this driver.  This number is given as the first
  53          * argument to hvc_alloc().  To correctly map an initial
  54          * console spawned via hvc_instantiate to the console being
  55          * hooked up via hvc_alloc, we need to pass the same vtermno.
  56          *
  57          * We also just assume the first console being initialised was
  58          * the first one that got used as the initial console.
  59          */
  60         unsigned int next_vtermno;
  61 
  62         /* All the console devices handled by this driver */
  63         struct list_head consoles;
  64 };
  65 static struct ports_driver_data pdrvdata = { .next_vtermno = 1};
  66 
  67 static DEFINE_SPINLOCK(pdrvdata_lock);
  68 static DECLARE_COMPLETION(early_console_added);
  69 
  70 /* This struct holds information that's relevant only for console ports */
  71 struct console {
  72         /* We'll place all consoles in a list in the pdrvdata struct */
  73         struct list_head list;
  74 
  75         /* The hvc device associated with this console port */
  76         struct hvc_struct *hvc;
  77 
  78         /* The size of the console */
  79         struct winsize ws;
  80 
  81         /*
  82          * This number identifies the number that we used to register
  83          * with hvc in hvc_instantiate() and hvc_alloc(); this is the
  84          * number passed on by the hvc callbacks to us to
  85          * differentiate between the other console ports handled by
  86          * this driver
  87          */
  88         u32 vtermno;
  89 };
  90 
  91 struct port_buffer {
  92         char *buf;
  93 
  94         /* size of the buffer in *buf above */
  95         size_t size;
  96 
  97         /* used length of the buffer */
  98         size_t len;
  99         /* offset in the buf from which to consume data */
 100         size_t offset;
 101 
 102         /* DMA address of buffer */
 103         dma_addr_t dma;
 104 
 105         /* Device we got DMA memory from */
 106         struct device *dev;
 107 
 108         /* List of pending dma buffers to free */
 109         struct list_head list;
 110 
 111         /* If sgpages == 0 then buf is used */
 112         unsigned int sgpages;
 113 
 114         /* sg is used if spages > 0. sg must be the last in is struct */
 115         struct scatterlist sg[0];
 116 };
 117 
 118 /*
 119  * This is a per-device struct that stores data common to all the
 120  * ports for that device (vdev->priv).
 121  */
 122 struct ports_device {
 123         /* Next portdev in the list, head is in the pdrvdata struct */
 124         struct list_head list;
 125 
 126         /*
 127          * Workqueue handlers where we process deferred work after
 128          * notification
 129          */
 130         struct work_struct control_work;
 131         struct work_struct config_work;
 132 
 133         struct list_head ports;
 134 
 135         /* To protect the list of ports */
 136         spinlock_t ports_lock;
 137 
 138         /* To protect the vq operations for the control channel */
 139         spinlock_t c_ivq_lock;
 140         spinlock_t c_ovq_lock;
 141 
 142         /* max. number of ports this device can hold */
 143         u32 max_nr_ports;
 144 
 145         /* The virtio device we're associated with */
 146         struct virtio_device *vdev;
 147 
 148         /*
 149          * A couple of virtqueues for the control channel: one for
 150          * guest->host transfers, one for host->guest transfers
 151          */
 152         struct virtqueue *c_ivq, *c_ovq;
 153 
 154         /*
 155          * A control packet buffer for guest->host requests, protected
 156          * by c_ovq_lock.
 157          */
 158         struct virtio_console_control cpkt;
 159 
 160         /* Array of per-port IO virtqueues */
 161         struct virtqueue **in_vqs, **out_vqs;
 162 
 163         /* Major number for this device.  Ports will be created as minors. */
 164         int chr_major;
 165 };
 166 
 167 struct port_stats {
 168         unsigned long bytes_sent, bytes_received, bytes_discarded;
 169 };
 170 
 171 /* This struct holds the per-port data */
 172 struct port {
 173         /* Next port in the list, head is in the ports_device */
 174         struct list_head list;
 175 
 176         /* Pointer to the parent virtio_console device */
 177         struct ports_device *portdev;
 178 
 179         /* The current buffer from which data has to be fed to readers */
 180         struct port_buffer *inbuf;
 181 
 182         /*
 183          * To protect the operations on the in_vq associated with this
 184          * port.  Has to be a spinlock because it can be called from
 185          * interrupt context (get_char()).
 186          */
 187         spinlock_t inbuf_lock;
 188 
 189         /* Protect the operations on the out_vq. */
 190         spinlock_t outvq_lock;
 191 
 192         /* The IO vqs for this port */
 193         struct virtqueue *in_vq, *out_vq;
 194 
 195         /* File in the debugfs directory that exposes this port's information */
 196         struct dentry *debugfs_file;
 197 
 198         /*
 199          * Keep count of the bytes sent, received and discarded for
 200          * this port for accounting and debugging purposes.  These
 201          * counts are not reset across port open / close events.
 202          */
 203         struct port_stats stats;
 204 
 205         /*
 206          * The entries in this struct will be valid if this port is
 207          * hooked up to an hvc console
 208          */
 209         struct console cons;
 210 
 211         /* Each port associates with a separate char device */
 212         struct cdev *cdev;
 213         struct device *dev;
 214 
 215         /* Reference-counting to handle port hot-unplugs and file operations */
 216         struct kref kref;
 217 
 218         /* A waitqueue for poll() or blocking read operations */
 219         wait_queue_head_t waitqueue;
 220 
 221         /* The 'name' of the port that we expose via sysfs properties */
 222         char *name;
 223 
 224         /* We can notify apps of host connect / disconnect events via SIGIO */
 225         struct fasync_struct *async_queue;
 226 
 227         /* The 'id' to identify the port with the Host */
 228         u32 id;
 229 
 230         bool outvq_full;
 231 
 232         /* Is the host device open */
 233         bool host_connected;
 234 
 235         /* We should allow only one process to open a port */
 236         bool guest_connected;
 237 };
 238 
 239 /* This is the very early arch-specified put chars function. */
 240 static int (*early_put_chars)(u32, const char *, int);
 241 
 242 static struct port *find_port_by_vtermno(u32 vtermno)
 243 {
 244         struct port *port;
 245         struct console *cons;
 246         unsigned long flags;
 247 
 248         spin_lock_irqsave(&pdrvdata_lock, flags);
 249         list_for_each_entry(cons, &pdrvdata.consoles, list) {
 250                 if (cons->vtermno == vtermno) {
 251                         port = container_of(cons, struct port, cons);
 252                         goto out;
 253                 }
 254         }
 255         port = NULL;
 256 out:
 257         spin_unlock_irqrestore(&pdrvdata_lock, flags);
 258         return port;
 259 }
 260 
 261 static struct port *find_port_by_devt_in_portdev(struct ports_device *portdev,
 262                                                  dev_t dev)
 263 {
 264         struct port *port;
 265         unsigned long flags;
 266 
 267         spin_lock_irqsave(&portdev->ports_lock, flags);
 268         list_for_each_entry(port, &portdev->ports, list) {
 269                 if (port->cdev->dev == dev) {
 270                         kref_get(&port->kref);
 271                         goto out;
 272                 }
 273         }
 274         port = NULL;
 275 out:
 276         spin_unlock_irqrestore(&portdev->ports_lock, flags);
 277 
 278         return port;
 279 }
 280 
 281 static struct port *find_port_by_devt(dev_t dev)
 282 {
 283         struct ports_device *portdev;
 284         struct port *port;
 285         unsigned long flags;
 286 
 287         spin_lock_irqsave(&pdrvdata_lock, flags);
 288         list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
 289                 port = find_port_by_devt_in_portdev(portdev, dev);
 290                 if (port)
 291                         goto out;
 292         }
 293         port = NULL;
 294 out:
 295         spin_unlock_irqrestore(&pdrvdata_lock, flags);
 296         return port;
 297 }
 298 
 299 static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
 300 {
 301         struct port *port;
 302         unsigned long flags;
 303 
 304         spin_lock_irqsave(&portdev->ports_lock, flags);
 305         list_for_each_entry(port, &portdev->ports, list)
 306                 if (port->id == id)
 307                         goto out;
 308         port = NULL;
 309 out:
 310         spin_unlock_irqrestore(&portdev->ports_lock, flags);
 311 
 312         return port;
 313 }
 314 
 315 static struct port *find_port_by_vq(struct ports_device *portdev,
 316                                     struct virtqueue *vq)
 317 {
 318         struct port *port;
 319         unsigned long flags;
 320 
 321         spin_lock_irqsave(&portdev->ports_lock, flags);
 322         list_for_each_entry(port, &portdev->ports, list)
 323                 if (port->in_vq == vq || port->out_vq == vq)
 324                         goto out;
 325         port = NULL;
 326 out:
 327         spin_unlock_irqrestore(&portdev->ports_lock, flags);
 328         return port;
 329 }
 330 
 331 static bool is_console_port(struct port *port)
 332 {
 333         if (port->cons.hvc)
 334                 return true;
 335         return false;
 336 }
 337 
 338 static bool is_rproc_serial(const struct virtio_device *vdev)
 339 {
 340         return is_rproc_enabled && vdev->id.device == VIRTIO_ID_RPROC_SERIAL;
 341 }
 342 
 343 static inline bool use_multiport(struct ports_device *portdev)
 344 {
 345         /*
 346          * This condition can be true when put_chars is called from
 347          * early_init
 348          */
 349         if (!portdev->vdev)
 350                 return false;
 351         return __virtio_test_bit(portdev->vdev, VIRTIO_CONSOLE_F_MULTIPORT);
 352 }
 353 
 354 static DEFINE_SPINLOCK(dma_bufs_lock);
 355 static LIST_HEAD(pending_free_dma_bufs);
 356 
 357 static void free_buf(struct port_buffer *buf, bool can_sleep)
 358 {
 359         unsigned int i;
 360 
 361         for (i = 0; i < buf->sgpages; i++) {
 362                 struct page *page = sg_page(&buf->sg[i]);
 363                 if (!page)
 364                         break;
 365                 put_page(page);
 366         }
 367 
 368         if (!buf->dev) {
 369                 kfree(buf->buf);
 370         } else if (is_rproc_enabled) {
 371                 unsigned long flags;
 372 
 373                 /* dma_free_coherent requires interrupts to be enabled. */
 374                 if (!can_sleep) {
 375                         /* queue up dma-buffers to be freed later */
 376                         spin_lock_irqsave(&dma_bufs_lock, flags);
 377                         list_add_tail(&buf->list, &pending_free_dma_bufs);
 378                         spin_unlock_irqrestore(&dma_bufs_lock, flags);
 379                         return;
 380                 }
 381                 dma_free_coherent(buf->dev, buf->size, buf->buf, buf->dma);
 382 
 383                 /* Release device refcnt and allow it to be freed */
 384                 put_device(buf->dev);
 385         }
 386 
 387         kfree(buf);
 388 }
 389 
 390 static void reclaim_dma_bufs(void)
 391 {
 392         unsigned long flags;
 393         struct port_buffer *buf, *tmp;
 394         LIST_HEAD(tmp_list);
 395 
 396         if (list_empty(&pending_free_dma_bufs))
 397                 return;
 398 
 399         /* Create a copy of the pending_free_dma_bufs while holding the lock */
 400         spin_lock_irqsave(&dma_bufs_lock, flags);
 401         list_cut_position(&tmp_list, &pending_free_dma_bufs,
 402                           pending_free_dma_bufs.prev);
 403         spin_unlock_irqrestore(&dma_bufs_lock, flags);
 404 
 405         /* Release the dma buffers, without irqs enabled */
 406         list_for_each_entry_safe(buf, tmp, &tmp_list, list) {
 407                 list_del(&buf->list);
 408                 free_buf(buf, true);
 409         }
 410 }
 411 
 412 static struct port_buffer *alloc_buf(struct virtio_device *vdev, size_t buf_size,
 413                                      int pages)
 414 {
 415         struct port_buffer *buf;
 416 
 417         reclaim_dma_bufs();
 418 
 419         /*
 420          * Allocate buffer and the sg list. The sg list array is allocated
 421          * directly after the port_buffer struct.
 422          */
 423         buf = kmalloc(struct_size(buf, sg, pages), GFP_KERNEL);
 424         if (!buf)
 425                 goto fail;
 426 
 427         buf->sgpages = pages;
 428         if (pages > 0) {
 429                 buf->dev = NULL;
 430                 buf->buf = NULL;
 431                 return buf;
 432         }
 433 
 434         if (is_rproc_serial(vdev)) {
 435                 /*
 436                  * Allocate DMA memory from ancestor. When a virtio
 437                  * device is created by remoteproc, the DMA memory is
 438                  * associated with the grandparent device:
 439                  * vdev => rproc => platform-dev.
 440                  */
 441                 if (!vdev->dev.parent || !vdev->dev.parent->parent)
 442                         goto free_buf;
 443                 buf->dev = vdev->dev.parent->parent;
 444 
 445                 /* Increase device refcnt to avoid freeing it */
 446                 get_device(buf->dev);
 447                 buf->buf = dma_alloc_coherent(buf->dev, buf_size, &buf->dma,
 448                                               GFP_KERNEL);
 449         } else {
 450                 buf->dev = NULL;
 451                 buf->buf = kmalloc(buf_size, GFP_KERNEL);
 452         }
 453 
 454         if (!buf->buf)
 455                 goto free_buf;
 456         buf->len = 0;
 457         buf->offset = 0;
 458         buf->size = buf_size;
 459         return buf;
 460 
 461 free_buf:
 462         kfree(buf);
 463 fail:
 464         return NULL;
 465 }
 466 
 467 /* Callers should take appropriate locks */
 468 static struct port_buffer *get_inbuf(struct port *port)
 469 {
 470         struct port_buffer *buf;
 471         unsigned int len;
 472 
 473         if (port->inbuf)
 474                 return port->inbuf;
 475 
 476         buf = virtqueue_get_buf(port->in_vq, &len);
 477         if (buf) {
 478                 buf->len = len;
 479                 buf->offset = 0;
 480                 port->stats.bytes_received += len;
 481         }
 482         return buf;
 483 }
 484 
 485 /*
 486  * Create a scatter-gather list representing our input buffer and put
 487  * it in the queue.
 488  *
 489  * Callers should take appropriate locks.
 490  */
 491 static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
 492 {
 493         struct scatterlist sg[1];
 494         int ret;
 495 
 496         sg_init_one(sg, buf->buf, buf->size);
 497 
 498         ret = virtqueue_add_inbuf(vq, sg, 1, buf, GFP_ATOMIC);
 499         virtqueue_kick(vq);
 500         if (!ret)
 501                 ret = vq->num_free;
 502         return ret;
 503 }
 504 
 505 /* Discard any unread data this port has. Callers lockers. */
 506 static void discard_port_data(struct port *port)
 507 {
 508         struct port_buffer *buf;
 509         unsigned int err;
 510 
 511         if (!port->portdev) {
 512                 /* Device has been unplugged.  vqs are already gone. */
 513                 return;
 514         }
 515         buf = get_inbuf(port);
 516 
 517         err = 0;
 518         while (buf) {
 519                 port->stats.bytes_discarded += buf->len - buf->offset;
 520                 if (add_inbuf(port->in_vq, buf) < 0) {
 521                         err++;
 522                         free_buf(buf, false);
 523                 }
 524                 port->inbuf = NULL;
 525                 buf = get_inbuf(port);
 526         }
 527         if (err)
 528                 dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
 529                          err);
 530 }
 531 
 532 static bool port_has_data(struct port *port)
 533 {
 534         unsigned long flags;
 535         bool ret;
 536 
 537         ret = false;
 538         spin_lock_irqsave(&port->inbuf_lock, flags);
 539         port->inbuf = get_inbuf(port);
 540         if (port->inbuf)
 541                 ret = true;
 542 
 543         spin_unlock_irqrestore(&port->inbuf_lock, flags);
 544         return ret;
 545 }
 546 
 547 static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
 548                                   unsigned int event, unsigned int value)
 549 {
 550         struct scatterlist sg[1];
 551         struct virtqueue *vq;
 552         unsigned int len;
 553 
 554         if (!use_multiport(portdev))
 555                 return 0;
 556 
 557         vq = portdev->c_ovq;
 558 
 559         spin_lock(&portdev->c_ovq_lock);
 560 
 561         portdev->cpkt.id = cpu_to_virtio32(portdev->vdev, port_id);
 562         portdev->cpkt.event = cpu_to_virtio16(portdev->vdev, event);
 563         portdev->cpkt.value = cpu_to_virtio16(portdev->vdev, value);
 564 
 565         sg_init_one(sg, &portdev->cpkt, sizeof(struct virtio_console_control));
 566 
 567         if (virtqueue_add_outbuf(vq, sg, 1, &portdev->cpkt, GFP_ATOMIC) == 0) {
 568                 virtqueue_kick(vq);
 569                 while (!virtqueue_get_buf(vq, &len)
 570                         && !virtqueue_is_broken(vq))
 571                         cpu_relax();
 572         }
 573 
 574         spin_unlock(&portdev->c_ovq_lock);
 575         return 0;
 576 }
 577 
 578 static ssize_t send_control_msg(struct port *port, unsigned int event,
 579                                 unsigned int value)
 580 {
 581         /* Did the port get unplugged before userspace closed it? */
 582         if (port->portdev)
 583                 return __send_control_msg(port->portdev, port->id, event, value);
 584         return 0;
 585 }
 586 
 587 
 588 /* Callers must take the port->outvq_lock */
 589 static void reclaim_consumed_buffers(struct port *port)
 590 {
 591         struct port_buffer *buf;
 592         unsigned int len;
 593 
 594         if (!port->portdev) {
 595                 /* Device has been unplugged.  vqs are already gone. */
 596                 return;
 597         }
 598         while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
 599                 free_buf(buf, false);
 600                 port->outvq_full = false;
 601         }
 602 }
 603 
 604 static ssize_t __send_to_port(struct port *port, struct scatterlist *sg,
 605                               int nents, size_t in_count,
 606                               void *data, bool nonblock)
 607 {
 608         struct virtqueue *out_vq;
 609         int err;
 610         unsigned long flags;
 611         unsigned int len;
 612 
 613         out_vq = port->out_vq;
 614 
 615         spin_lock_irqsave(&port->outvq_lock, flags);
 616 
 617         reclaim_consumed_buffers(port);
 618 
 619         err = virtqueue_add_outbuf(out_vq, sg, nents, data, GFP_ATOMIC);
 620 
 621         /* Tell Host to go! */
 622         virtqueue_kick(out_vq);
 623 
 624         if (err) {
 625                 in_count = 0;
 626                 goto done;
 627         }
 628 
 629         if (out_vq->num_free == 0)
 630                 port->outvq_full = true;
 631 
 632         if (nonblock)
 633                 goto done;
 634 
 635         /*
 636          * Wait till the host acknowledges it pushed out the data we
 637          * sent.  This is done for data from the hvc_console; the tty
 638          * operations are performed with spinlocks held so we can't
 639          * sleep here.  An alternative would be to copy the data to a
 640          * buffer and relax the spinning requirement.  The downside is
 641          * we need to kmalloc a GFP_ATOMIC buffer each time the
 642          * console driver writes something out.
 643          */
 644         while (!virtqueue_get_buf(out_vq, &len)
 645                 && !virtqueue_is_broken(out_vq))
 646                 cpu_relax();
 647 done:
 648         spin_unlock_irqrestore(&port->outvq_lock, flags);
 649 
 650         port->stats.bytes_sent += in_count;
 651         /*
 652          * We're expected to return the amount of data we wrote -- all
 653          * of it
 654          */
 655         return in_count;
 656 }
 657 
 658 /*
 659  * Give out the data that's requested from the buffer that we have
 660  * queued up.
 661  */
 662 static ssize_t fill_readbuf(struct port *port, char __user *out_buf,
 663                             size_t out_count, bool to_user)
 664 {
 665         struct port_buffer *buf;
 666         unsigned long flags;
 667 
 668         if (!out_count || !port_has_data(port))
 669                 return 0;
 670 
 671         buf = port->inbuf;
 672         out_count = min(out_count, buf->len - buf->offset);
 673 
 674         if (to_user) {
 675                 ssize_t ret;
 676 
 677                 ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
 678                 if (ret)
 679                         return -EFAULT;
 680         } else {
 681                 memcpy((__force char *)out_buf, buf->buf + buf->offset,
 682                        out_count);
 683         }
 684 
 685         buf->offset += out_count;
 686 
 687         if (buf->offset == buf->len) {
 688                 /*
 689                  * We're done using all the data in this buffer.
 690                  * Re-queue so that the Host can send us more data.
 691                  */
 692                 spin_lock_irqsave(&port->inbuf_lock, flags);
 693                 port->inbuf = NULL;
 694 
 695                 if (add_inbuf(port->in_vq, buf) < 0)
 696                         dev_warn(port->dev, "failed add_buf\n");
 697 
 698                 spin_unlock_irqrestore(&port->inbuf_lock, flags);
 699         }
 700         /* Return the number of bytes actually copied */
 701         return out_count;
 702 }
 703 
 704 /* The condition that must be true for polling to end */
 705 static bool will_read_block(struct port *port)
 706 {
 707         if (!port->guest_connected) {
 708                 /* Port got hot-unplugged. Let's exit. */
 709                 return false;
 710         }
 711         return !port_has_data(port) && port->host_connected;
 712 }
 713 
 714 static bool will_write_block(struct port *port)
 715 {
 716         bool ret;
 717 
 718         if (!port->guest_connected) {
 719                 /* Port got hot-unplugged. Let's exit. */
 720                 return false;
 721         }
 722         if (!port->host_connected)
 723                 return true;
 724 
 725         spin_lock_irq(&port->outvq_lock);
 726         /*
 727          * Check if the Host has consumed any buffers since we last
 728          * sent data (this is only applicable for nonblocking ports).
 729          */
 730         reclaim_consumed_buffers(port);
 731         ret = port->outvq_full;
 732         spin_unlock_irq(&port->outvq_lock);
 733 
 734         return ret;
 735 }
 736 
 737 static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
 738                               size_t count, loff_t *offp)
 739 {
 740         struct port *port;
 741         ssize_t ret;
 742 
 743         port = filp->private_data;
 744 
 745         /* Port is hot-unplugged. */
 746         if (!port->guest_connected)
 747                 return -ENODEV;
 748 
 749         if (!port_has_data(port)) {
 750                 /*
 751                  * If nothing's connected on the host just return 0 in
 752                  * case of list_empty; this tells the userspace app
 753                  * that there's no connection
 754                  */
 755                 if (!port->host_connected)
 756                         return 0;
 757                 if (filp->f_flags & O_NONBLOCK)
 758                         return -EAGAIN;
 759 
 760                 ret = wait_event_freezable(port->waitqueue,
 761                                            !will_read_block(port));
 762                 if (ret < 0)
 763                         return ret;
 764         }
 765         /* Port got hot-unplugged while we were waiting above. */
 766         if (!port->guest_connected)
 767                 return -ENODEV;
 768         /*
 769          * We could've received a disconnection message while we were
 770          * waiting for more data.
 771          *
 772          * This check is not clubbed in the if() statement above as we
 773          * might receive some data as well as the host could get
 774          * disconnected after we got woken up from our wait.  So we
 775          * really want to give off whatever data we have and only then
 776          * check for host_connected.
 777          */
 778         if (!port_has_data(port) && !port->host_connected)
 779                 return 0;
 780 
 781         return fill_readbuf(port, ubuf, count, true);
 782 }
 783 
 784 static int wait_port_writable(struct port *port, bool nonblock)
 785 {
 786         int ret;
 787 
 788         if (will_write_block(port)) {
 789                 if (nonblock)
 790                         return -EAGAIN;
 791 
 792                 ret = wait_event_freezable(port->waitqueue,
 793                                            !will_write_block(port));
 794                 if (ret < 0)
 795                         return ret;
 796         }
 797         /* Port got hot-unplugged. */
 798         if (!port->guest_connected)
 799                 return -ENODEV;
 800 
 801         return 0;
 802 }
 803 
 804 static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
 805                                size_t count, loff_t *offp)
 806 {
 807         struct port *port;
 808         struct port_buffer *buf;
 809         ssize_t ret;
 810         bool nonblock;
 811         struct scatterlist sg[1];
 812 
 813         /* Userspace could be out to fool us */
 814         if (!count)
 815                 return 0;
 816 
 817         port = filp->private_data;
 818 
 819         nonblock = filp->f_flags & O_NONBLOCK;
 820 
 821         ret = wait_port_writable(port, nonblock);
 822         if (ret < 0)
 823                 return ret;
 824 
 825         count = min((size_t)(32 * 1024), count);
 826 
 827         buf = alloc_buf(port->portdev->vdev, count, 0);
 828         if (!buf)
 829                 return -ENOMEM;
 830 
 831         ret = copy_from_user(buf->buf, ubuf, count);
 832         if (ret) {
 833                 ret = -EFAULT;
 834                 goto free_buf;
 835         }
 836 
 837         /*
 838          * We now ask send_buf() to not spin for generic ports -- we
 839          * can re-use the same code path that non-blocking file
 840          * descriptors take for blocking file descriptors since the
 841          * wait is already done and we're certain the write will go
 842          * through to the host.
 843          */
 844         nonblock = true;
 845         sg_init_one(sg, buf->buf, count);
 846         ret = __send_to_port(port, sg, 1, count, buf, nonblock);
 847 
 848         if (nonblock && ret > 0)
 849                 goto out;
 850 
 851 free_buf:
 852         free_buf(buf, true);
 853 out:
 854         return ret;
 855 }
 856 
 857 struct sg_list {
 858         unsigned int n;
 859         unsigned int size;
 860         size_t len;
 861         struct scatterlist *sg;
 862 };
 863 
 864 static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 865                         struct splice_desc *sd)
 866 {
 867         struct sg_list *sgl = sd->u.data;
 868         unsigned int offset, len;
 869 
 870         if (sgl->n == sgl->size)
 871                 return 0;
 872 
 873         /* Try lock this page */
 874         if (pipe_buf_steal(pipe, buf) == 0) {
 875                 /* Get reference and unlock page for moving */
 876                 get_page(buf->page);
 877                 unlock_page(buf->page);
 878 
 879                 len = min(buf->len, sd->len);
 880                 sg_set_page(&(sgl->sg[sgl->n]), buf->page, len, buf->offset);
 881         } else {
 882                 /* Failback to copying a page */
 883                 struct page *page = alloc_page(GFP_KERNEL);
 884                 char *src;
 885 
 886                 if (!page)
 887                         return -ENOMEM;
 888 
 889                 offset = sd->pos & ~PAGE_MASK;
 890 
 891                 len = sd->len;
 892                 if (len + offset > PAGE_SIZE)
 893                         len = PAGE_SIZE - offset;
 894 
 895                 src = kmap_atomic(buf->page);
 896                 memcpy(page_address(page) + offset, src + buf->offset, len);
 897                 kunmap_atomic(src);
 898 
 899                 sg_set_page(&(sgl->sg[sgl->n]), page, len, offset);
 900         }
 901         sgl->n++;
 902         sgl->len += len;
 903 
 904         return len;
 905 }
 906 
 907 /* Faster zero-copy write by splicing */
 908 static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
 909                                       struct file *filp, loff_t *ppos,
 910                                       size_t len, unsigned int flags)
 911 {
 912         struct port *port = filp->private_data;
 913         struct sg_list sgl;
 914         ssize_t ret;
 915         struct port_buffer *buf;
 916         struct splice_desc sd = {
 917                 .total_len = len,
 918                 .flags = flags,
 919                 .pos = *ppos,
 920                 .u.data = &sgl,
 921         };
 922 
 923         /*
 924          * Rproc_serial does not yet support splice. To support splice
 925          * pipe_to_sg() must allocate dma-buffers and copy content from
 926          * regular pages to dma pages. And alloc_buf and free_buf must
 927          * support allocating and freeing such a list of dma-buffers.
 928          */
 929         if (is_rproc_serial(port->out_vq->vdev))
 930                 return -EINVAL;
 931 
 932         /*
 933          * pipe->nrbufs == 0 means there are no data to transfer,
 934          * so this returns just 0 for no data.
 935          */
 936         pipe_lock(pipe);
 937         if (!pipe->nrbufs) {
 938                 ret = 0;
 939                 goto error_out;
 940         }
 941 
 942         ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK);
 943         if (ret < 0)
 944                 goto error_out;
 945 
 946         buf = alloc_buf(port->portdev->vdev, 0, pipe->nrbufs);
 947         if (!buf) {
 948                 ret = -ENOMEM;
 949                 goto error_out;
 950         }
 951 
 952         sgl.n = 0;
 953         sgl.len = 0;
 954         sgl.size = pipe->nrbufs;
 955         sgl.sg = buf->sg;
 956         sg_init_table(sgl.sg, sgl.size);
 957         ret = __splice_from_pipe(pipe, &sd, pipe_to_sg);
 958         pipe_unlock(pipe);
 959         if (likely(ret > 0))
 960                 ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true);
 961 
 962         if (unlikely(ret <= 0))
 963                 free_buf(buf, true);
 964         return ret;
 965 
 966 error_out:
 967         pipe_unlock(pipe);
 968         return ret;
 969 }
 970 
 971 static __poll_t port_fops_poll(struct file *filp, poll_table *wait)
 972 {
 973         struct port *port;
 974         __poll_t ret;
 975 
 976         port = filp->private_data;
 977         poll_wait(filp, &port->waitqueue, wait);
 978 
 979         if (!port->guest_connected) {
 980                 /* Port got unplugged */
 981                 return EPOLLHUP;
 982         }
 983         ret = 0;
 984         if (!will_read_block(port))
 985                 ret |= EPOLLIN | EPOLLRDNORM;
 986         if (!will_write_block(port))
 987                 ret |= EPOLLOUT;
 988         if (!port->host_connected)
 989                 ret |= EPOLLHUP;
 990 
 991         return ret;
 992 }
 993 
 994 static void remove_port(struct kref *kref);
 995 
 996 static int port_fops_release(struct inode *inode, struct file *filp)
 997 {
 998         struct port *port;
 999 
1000         port = filp->private_data;
1001 
1002         /* Notify host of port being closed */
1003         send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
1004 
1005         spin_lock_irq(&port->inbuf_lock);
1006         port->guest_connected = false;
1007 
1008         discard_port_data(port);
1009 
1010         spin_unlock_irq(&port->inbuf_lock);
1011 
1012         spin_lock_irq(&port->outvq_lock);
1013         reclaim_consumed_buffers(port);
1014         spin_unlock_irq(&port->outvq_lock);
1015 
1016         reclaim_dma_bufs();
1017         /*
1018          * Locks aren't necessary here as a port can't be opened after
1019          * unplug, and if a port isn't unplugged, a kref would already
1020          * exist for the port.  Plus, taking ports_lock here would
1021          * create a dependency on other locks taken by functions
1022          * inside remove_port if we're the last holder of the port,
1023          * creating many problems.
1024          */
1025         kref_put(&port->kref, remove_port);
1026 
1027         return 0;
1028 }
1029 
1030 static int port_fops_open(struct inode *inode, struct file *filp)
1031 {
1032         struct cdev *cdev = inode->i_cdev;
1033         struct port *port;
1034         int ret;
1035 
1036         /* We get the port with a kref here */
1037         port = find_port_by_devt(cdev->dev);
1038         if (!port) {
1039                 /* Port was unplugged before we could proceed */
1040                 return -ENXIO;
1041         }
1042         filp->private_data = port;
1043 
1044         /*
1045          * Don't allow opening of console port devices -- that's done
1046          * via /dev/hvc
1047          */
1048         if (is_console_port(port)) {
1049                 ret = -ENXIO;
1050                 goto out;
1051         }
1052 
1053         /* Allow only one process to open a particular port at a time */
1054         spin_lock_irq(&port->inbuf_lock);
1055         if (port->guest_connected) {
1056                 spin_unlock_irq(&port->inbuf_lock);
1057                 ret = -EBUSY;
1058                 goto out;
1059         }
1060 
1061         port->guest_connected = true;
1062         spin_unlock_irq(&port->inbuf_lock);
1063 
1064         spin_lock_irq(&port->outvq_lock);
1065         /*
1066          * There might be a chance that we missed reclaiming a few
1067          * buffers in the window of the port getting previously closed
1068          * and opening now.
1069          */
1070         reclaim_consumed_buffers(port);
1071         spin_unlock_irq(&port->outvq_lock);
1072 
1073         nonseekable_open(inode, filp);
1074 
1075         /* Notify host of port being opened */
1076         send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
1077 
1078         return 0;
1079 out:
1080         kref_put(&port->kref, remove_port);
1081         return ret;
1082 }
1083 
1084 static int port_fops_fasync(int fd, struct file *filp, int mode)
1085 {
1086         struct port *port;
1087 
1088         port = filp->private_data;
1089         return fasync_helper(fd, filp, mode, &port->async_queue);
1090 }
1091 
1092 /*
1093  * The file operations that we support: programs in the guest can open
1094  * a console device, read from it, write to it, poll for data and
1095  * close it.  The devices are at
1096  *   /dev/vport<device number>p<port number>
1097  */
1098 static const struct file_operations port_fops = {
1099         .owner = THIS_MODULE,
1100         .open  = port_fops_open,
1101         .read  = port_fops_read,
1102         .write = port_fops_write,
1103         .splice_write = port_fops_splice_write,
1104         .poll  = port_fops_poll,
1105         .release = port_fops_release,
1106         .fasync = port_fops_fasync,
1107         .llseek = no_llseek,
1108 };
1109 
1110 /*
1111  * The put_chars() callback is pretty straightforward.
1112  *
1113  * We turn the characters into a scatter-gather list, add it to the
1114  * output queue and then kick the Host.  Then we sit here waiting for
1115  * it to finish: inefficient in theory, but in practice
1116  * implementations will do it immediately.
1117  */
1118 static int put_chars(u32 vtermno, const char *buf, int count)
1119 {
1120         struct port *port;
1121         struct scatterlist sg[1];
1122         void *data;
1123         int ret;
1124 
1125         if (unlikely(early_put_chars))
1126                 return early_put_chars(vtermno, buf, count);
1127 
1128         port = find_port_by_vtermno(vtermno);
1129         if (!port)
1130                 return -EPIPE;
1131 
1132         data = kmemdup(buf, count, GFP_ATOMIC);
1133         if (!data)
1134                 return -ENOMEM;
1135 
1136         sg_init_one(sg, data, count);
1137         ret = __send_to_port(port, sg, 1, count, data, false);
1138         kfree(data);
1139         return ret;
1140 }
1141 
1142 /*
1143  * get_chars() is the callback from the hvc_console infrastructure
1144  * when an interrupt is received.
1145  *
1146  * We call out to fill_readbuf that gets us the required data from the
1147  * buffers that are queued up.
1148  */
1149 static int get_chars(u32 vtermno, char *buf, int count)
1150 {
1151         struct port *port;
1152 
1153         /* If we've not set up the port yet, we have no input to give. */
1154         if (unlikely(early_put_chars))
1155                 return 0;
1156 
1157         port = find_port_by_vtermno(vtermno);
1158         if (!port)
1159                 return -EPIPE;
1160 
1161         /* If we don't have an input queue yet, we can't get input. */
1162         BUG_ON(!port->in_vq);
1163 
1164         return fill_readbuf(port, (__force char __user *)buf, count, false);
1165 }
1166 
1167 static void resize_console(struct port *port)
1168 {
1169         struct virtio_device *vdev;
1170 
1171         /* The port could have been hot-unplugged */
1172         if (!port || !is_console_port(port))
1173                 return;
1174 
1175         vdev = port->portdev->vdev;
1176 
1177         /* Don't test F_SIZE at all if we're rproc: not a valid feature! */
1178         if (!is_rproc_serial(vdev) &&
1179             virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
1180                 hvc_resize(port->cons.hvc, port->cons.ws);
1181 }
1182 
1183 /* We set the configuration at this point, since we now have a tty */
1184 static int notifier_add_vio(struct hvc_struct *hp, int data)
1185 {
1186         struct port *port;
1187 
1188         port = find_port_by_vtermno(hp->vtermno);
1189         if (!port)
1190                 return -EINVAL;
1191 
1192         hp->irq_requested = 1;
1193         resize_console(port);
1194 
1195         return 0;
1196 }
1197 
1198 static void notifier_del_vio(struct hvc_struct *hp, int data)
1199 {
1200         hp->irq_requested = 0;
1201 }
1202 
1203 /* The operations for console ports. */
1204 static const struct hv_ops hv_ops = {
1205         .get_chars = get_chars,
1206         .put_chars = put_chars,
1207         .notifier_add = notifier_add_vio,
1208         .notifier_del = notifier_del_vio,
1209         .notifier_hangup = notifier_del_vio,
1210 };
1211 
1212 /*
1213  * Console drivers are initialized very early so boot messages can go
1214  * out, so we do things slightly differently from the generic virtio
1215  * initialization of the net and block drivers.
1216  *
1217  * At this stage, the console is output-only.  It's too early to set
1218  * up a virtqueue, so we let the drivers do some boutique early-output
1219  * thing.
1220  */
1221 int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
1222 {
1223         early_put_chars = put_chars;
1224         return hvc_instantiate(0, 0, &hv_ops);
1225 }
1226 
1227 static int init_port_console(struct port *port)
1228 {
1229         int ret;
1230 
1231         /*
1232          * The Host's telling us this port is a console port.  Hook it
1233          * up with an hvc console.
1234          *
1235          * To set up and manage our virtual console, we call
1236          * hvc_alloc().
1237          *
1238          * The first argument of hvc_alloc() is the virtual console
1239          * number.  The second argument is the parameter for the
1240          * notification mechanism (like irq number).  We currently
1241          * leave this as zero, virtqueues have implicit notifications.
1242          *
1243          * The third argument is a "struct hv_ops" containing the
1244          * put_chars() get_chars(), notifier_add() and notifier_del()
1245          * pointers.  The final argument is the output buffer size: we
1246          * can do any size, so we put PAGE_SIZE here.
1247          */
1248         port->cons.vtermno = pdrvdata.next_vtermno;
1249 
1250         port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
1251         if (IS_ERR(port->cons.hvc)) {
1252                 ret = PTR_ERR(port->cons.hvc);
1253                 dev_err(port->dev,
1254                         "error %d allocating hvc for port\n", ret);
1255                 port->cons.hvc = NULL;
1256                 return ret;
1257         }
1258         spin_lock_irq(&pdrvdata_lock);
1259         pdrvdata.next_vtermno++;
1260         list_add_tail(&port->cons.list, &pdrvdata.consoles);
1261         spin_unlock_irq(&pdrvdata_lock);
1262         port->guest_connected = true;
1263 
1264         /*
1265          * Start using the new console output if this is the first
1266          * console to come up.
1267          */
1268         if (early_put_chars)
1269                 early_put_chars = NULL;
1270 
1271         /* Notify host of port being opened */
1272         send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1273 
1274         return 0;
1275 }
1276 
1277 static ssize_t show_port_name(struct device *dev,
1278                               struct device_attribute *attr, char *buffer)
1279 {
1280         struct port *port;
1281 
1282         port = dev_get_drvdata(dev);
1283 
1284         return sprintf(buffer, "%s\n", port->name);
1285 }
1286 
1287 static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
1288 
1289 static struct attribute *port_sysfs_entries[] = {
1290         &dev_attr_name.attr,
1291         NULL
1292 };
1293 
1294 static const struct attribute_group port_attribute_group = {
1295         .name = NULL,           /* put in device directory */
1296         .attrs = port_sysfs_entries,
1297 };
1298 
1299 static int port_debugfs_show(struct seq_file *s, void *data)
1300 {
1301         struct port *port = s->private;
1302 
1303         seq_printf(s, "name: %s\n", port->name ? port->name : "");
1304         seq_printf(s, "guest_connected: %d\n", port->guest_connected);
1305         seq_printf(s, "host_connected: %d\n", port->host_connected);
1306         seq_printf(s, "outvq_full: %d\n", port->outvq_full);
1307         seq_printf(s, "bytes_sent: %lu\n", port->stats.bytes_sent);
1308         seq_printf(s, "bytes_received: %lu\n", port->stats.bytes_received);
1309         seq_printf(s, "bytes_discarded: %lu\n", port->stats.bytes_discarded);
1310         seq_printf(s, "is_console: %s\n",
1311                    is_console_port(port) ? "yes" : "no");
1312         seq_printf(s, "console_vtermno: %u\n", port->cons.vtermno);
1313 
1314         return 0;
1315 }
1316 
1317 DEFINE_SHOW_ATTRIBUTE(port_debugfs);
1318 
1319 static void set_console_size(struct port *port, u16 rows, u16 cols)
1320 {
1321         if (!port || !is_console_port(port))
1322                 return;
1323 
1324         port->cons.ws.ws_row = rows;
1325         port->cons.ws.ws_col = cols;
1326 }
1327 
1328 static int fill_queue(struct virtqueue *vq, spinlock_t *lock)
1329 {
1330         struct port_buffer *buf;
1331         int nr_added_bufs;
1332         int ret;
1333 
1334         nr_added_bufs = 0;
1335         do {
1336                 buf = alloc_buf(vq->vdev, PAGE_SIZE, 0);
1337                 if (!buf)
1338                         return -ENOMEM;
1339 
1340                 spin_lock_irq(lock);
1341                 ret = add_inbuf(vq, buf);
1342                 if (ret < 0) {
1343                         spin_unlock_irq(lock);
1344                         free_buf(buf, true);
1345                         return ret;
1346                 }
1347                 nr_added_bufs++;
1348                 spin_unlock_irq(lock);
1349         } while (ret > 0);
1350 
1351         return nr_added_bufs;
1352 }
1353 
1354 static void send_sigio_to_port(struct port *port)
1355 {
1356         if (port->async_queue && port->guest_connected)
1357                 kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
1358 }
1359 
1360 static int add_port(struct ports_device *portdev, u32 id)
1361 {
1362         char debugfs_name[16];
1363         struct port *port;
1364         dev_t devt;
1365         int err;
1366 
1367         port = kmalloc(sizeof(*port), GFP_KERNEL);
1368         if (!port) {
1369                 err = -ENOMEM;
1370                 goto fail;
1371         }
1372         kref_init(&port->kref);
1373 
1374         port->portdev = portdev;
1375         port->id = id;
1376 
1377         port->name = NULL;
1378         port->inbuf = NULL;
1379         port->cons.hvc = NULL;
1380         port->async_queue = NULL;
1381 
1382         port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
1383         port->cons.vtermno = 0;
1384 
1385         port->host_connected = port->guest_connected = false;
1386         port->stats = (struct port_stats) { 0 };
1387 
1388         port->outvq_full = false;
1389 
1390         port->in_vq = portdev->in_vqs[port->id];
1391         port->out_vq = portdev->out_vqs[port->id];
1392 
1393         port->cdev = cdev_alloc();
1394         if (!port->cdev) {
1395                 dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
1396                 err = -ENOMEM;
1397                 goto free_port;
1398         }
1399         port->cdev->ops = &port_fops;
1400 
1401         devt = MKDEV(portdev->chr_major, id);
1402         err = cdev_add(port->cdev, devt, 1);
1403         if (err < 0) {
1404                 dev_err(&port->portdev->vdev->dev,
1405                         "Error %d adding cdev for port %u\n", err, id);
1406                 goto free_cdev;
1407         }
1408         port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
1409                                   devt, port, "vport%up%u",
1410                                   port->portdev->vdev->index, id);
1411         if (IS_ERR(port->dev)) {
1412                 err = PTR_ERR(port->dev);
1413                 dev_err(&port->portdev->vdev->dev,
1414                         "Error %d creating device for port %u\n",
1415                         err, id);
1416                 goto free_cdev;
1417         }
1418 
1419         spin_lock_init(&port->inbuf_lock);
1420         spin_lock_init(&port->outvq_lock);
1421         init_waitqueue_head(&port->waitqueue);
1422 
1423         /* We can safely ignore ENOSPC because it means
1424          * the queue already has buffers. Buffers are removed
1425          * only by virtcons_remove(), not by unplug_port()
1426          */
1427         err = fill_queue(port->in_vq, &port->inbuf_lock);
1428         if (err < 0 && err != -ENOSPC) {
1429                 dev_err(port->dev, "Error allocating inbufs\n");
1430                 goto free_device;
1431         }
1432 
1433         if (is_rproc_serial(port->portdev->vdev))
1434                 /*
1435                  * For rproc_serial assume remote processor is connected.
1436                  * rproc_serial does not want the console port, only
1437                  * the generic port implementation.
1438                  */
1439                 port->host_connected = true;
1440         else if (!use_multiport(port->portdev)) {
1441                 /*
1442                  * If we're not using multiport support,
1443                  * this has to be a console port.
1444                  */
1445                 err = init_port_console(port);
1446                 if (err)
1447                         goto free_inbufs;
1448         }
1449 
1450         spin_lock_irq(&portdev->ports_lock);
1451         list_add_tail(&port->list, &port->portdev->ports);
1452         spin_unlock_irq(&portdev->ports_lock);
1453 
1454         /*
1455          * Tell the Host we're set so that it can send us various
1456          * configuration parameters for this port (eg, port name,
1457          * caching, whether this is a console port, etc.)
1458          */
1459         send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1460 
1461         if (pdrvdata.debugfs_dir) {
1462                 /*
1463                  * Finally, create the debugfs file that we can use to
1464                  * inspect a port's state at any time
1465                  */
1466                 snprintf(debugfs_name, sizeof(debugfs_name), "vport%up%u",
1467                          port->portdev->vdev->index, id);
1468                 port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
1469                                                          pdrvdata.debugfs_dir,
1470                                                          port,
1471                                                          &port_debugfs_fops);
1472         }
1473         return 0;
1474 
1475 free_inbufs:
1476 free_device:
1477         device_destroy(pdrvdata.class, port->dev->devt);
1478 free_cdev:
1479         cdev_del(port->cdev);
1480 free_port:
1481         kfree(port);
1482 fail:
1483         /* The host might want to notify management sw about port add failure */
1484         __send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
1485         return err;
1486 }
1487 
1488 /* No users remain, remove all port-specific data. */
1489 static void remove_port(struct kref *kref)
1490 {
1491         struct port *port;
1492 
1493         port = container_of(kref, struct port, kref);
1494 
1495         kfree(port);
1496 }
1497 
1498 static void remove_port_data(struct port *port)
1499 {
1500         spin_lock_irq(&port->inbuf_lock);
1501         /* Remove unused data this port might have received. */
1502         discard_port_data(port);
1503         spin_unlock_irq(&port->inbuf_lock);
1504 
1505         spin_lock_irq(&port->outvq_lock);
1506         reclaim_consumed_buffers(port);
1507         spin_unlock_irq(&port->outvq_lock);
1508 }
1509 
1510 /*
1511  * Port got unplugged.  Remove port from portdev's list and drop the
1512  * kref reference.  If no userspace has this port opened, it will
1513  * result in immediate removal the port.
1514  */
1515 static void unplug_port(struct port *port)
1516 {
1517         spin_lock_irq(&port->portdev->ports_lock);
1518         list_del(&port->list);
1519         spin_unlock_irq(&port->portdev->ports_lock);
1520 
1521         spin_lock_irq(&port->inbuf_lock);
1522         if (port->guest_connected) {
1523                 /* Let the app know the port is going down. */
1524                 send_sigio_to_port(port);
1525 
1526                 /* Do this after sigio is actually sent */
1527                 port->guest_connected = false;
1528                 port->host_connected = false;
1529 
1530                 wake_up_interruptible(&port->waitqueue);
1531         }
1532         spin_unlock_irq(&port->inbuf_lock);
1533 
1534         if (is_console_port(port)) {
1535                 spin_lock_irq(&pdrvdata_lock);
1536                 list_del(&port->cons.list);
1537                 spin_unlock_irq(&pdrvdata_lock);
1538                 hvc_remove(port->cons.hvc);
1539         }
1540 
1541         remove_port_data(port);
1542 
1543         /*
1544          * We should just assume the device itself has gone off --
1545          * else a close on an open port later will try to send out a
1546          * control message.
1547          */
1548         port->portdev = NULL;
1549 
1550         sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1551         device_destroy(pdrvdata.class, port->dev->devt);
1552         cdev_del(port->cdev);
1553 
1554         debugfs_remove(port->debugfs_file);
1555         kfree(port->name);
1556 
1557         /*
1558          * Locks around here are not necessary - a port can't be
1559          * opened after we removed the port struct from ports_list
1560          * above.
1561          */
1562         kref_put(&port->kref, remove_port);
1563 }
1564 
1565 /* Any private messages that the Host and Guest want to share */
1566 static void handle_control_message(struct virtio_device *vdev,
1567                                    struct ports_device *portdev,
1568                                    struct port_buffer *buf)
1569 {
1570         struct virtio_console_control *cpkt;
1571         struct port *port;
1572         size_t name_size;
1573         int err;
1574 
1575         cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1576 
1577         port = find_port_by_id(portdev, virtio32_to_cpu(vdev, cpkt->id));
1578         if (!port &&
1579             cpkt->event != cpu_to_virtio16(vdev, VIRTIO_CONSOLE_PORT_ADD)) {
1580                 /* No valid header at start of buffer.  Drop it. */
1581                 dev_dbg(&portdev->vdev->dev,
1582                         "Invalid index %u in control packet\n", cpkt->id);
1583                 return;
1584         }
1585 
1586         switch (virtio16_to_cpu(vdev, cpkt->event)) {
1587         case VIRTIO_CONSOLE_PORT_ADD:
1588                 if (port) {
1589                         dev_dbg(&portdev->vdev->dev,
1590                                 "Port %u already added\n", port->id);
1591                         send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1592                         break;
1593                 }
1594                 if (virtio32_to_cpu(vdev, cpkt->id) >=
1595                     portdev->max_nr_ports) {
1596                         dev_warn(&portdev->vdev->dev,
1597                                 "Request for adding port with "
1598                                 "out-of-bound id %u, max. supported id: %u\n",
1599                                 cpkt->id, portdev->max_nr_ports - 1);
1600                         break;
1601                 }
1602                 add_port(portdev, virtio32_to_cpu(vdev, cpkt->id));
1603                 break;
1604         case VIRTIO_CONSOLE_PORT_REMOVE:
1605                 unplug_port(port);
1606                 break;
1607         case VIRTIO_CONSOLE_CONSOLE_PORT:
1608                 if (!cpkt->value)
1609                         break;
1610                 if (is_console_port(port))
1611                         break;
1612 
1613                 init_port_console(port);
1614                 complete(&early_console_added);
1615                 /*
1616                  * Could remove the port here in case init fails - but
1617                  * have to notify the host first.
1618                  */
1619                 break;
1620         case VIRTIO_CONSOLE_RESIZE: {
1621                 struct {
1622                         __u16 rows;
1623                         __u16 cols;
1624                 } size;
1625 
1626                 if (!is_console_port(port))
1627                         break;
1628 
1629                 memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1630                        sizeof(size));
1631                 set_console_size(port, size.rows, size.cols);
1632 
1633                 port->cons.hvc->irq_requested = 1;
1634                 resize_console(port);
1635                 break;
1636         }
1637         case VIRTIO_CONSOLE_PORT_OPEN:
1638                 port->host_connected = virtio16_to_cpu(vdev, cpkt->value);
1639                 wake_up_interruptible(&port->waitqueue);
1640                 /*
1641                  * If the host port got closed and the host had any
1642                  * unconsumed buffers, we'll be able to reclaim them
1643                  * now.
1644                  */
1645                 spin_lock_irq(&port->outvq_lock);
1646                 reclaim_consumed_buffers(port);
1647                 spin_unlock_irq(&port->outvq_lock);
1648 
1649                 /*
1650                  * If the guest is connected, it'll be interested in
1651                  * knowing the host connection state changed.
1652                  */
1653                 spin_lock_irq(&port->inbuf_lock);
1654                 send_sigio_to_port(port);
1655                 spin_unlock_irq(&port->inbuf_lock);
1656                 break;
1657         case VIRTIO_CONSOLE_PORT_NAME:
1658                 /*
1659                  * If we woke up after hibernation, we can get this
1660                  * again.  Skip it in that case.
1661                  */
1662                 if (port->name)
1663                         break;
1664 
1665                 /*
1666                  * Skip the size of the header and the cpkt to get the size
1667                  * of the name that was sent
1668                  */
1669                 name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1670 
1671                 port->name = kmalloc(name_size, GFP_KERNEL);
1672                 if (!port->name) {
1673                         dev_err(port->dev,
1674                                 "Not enough space to store port name\n");
1675                         break;
1676                 }
1677                 strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1678                         name_size - 1);
1679                 port->name[name_size - 1] = 0;
1680 
1681                 /*
1682                  * Since we only have one sysfs attribute, 'name',
1683                  * create it only if we have a name for the port.
1684                  */
1685                 err = sysfs_create_group(&port->dev->kobj,
1686                                          &port_attribute_group);
1687                 if (err) {
1688                         dev_err(port->dev,
1689                                 "Error %d creating sysfs device attributes\n",
1690                                 err);
1691                 } else {
1692                         /*
1693                          * Generate a udev event so that appropriate
1694                          * symlinks can be created based on udev
1695                          * rules.
1696                          */
1697                         kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1698                 }
1699                 break;
1700         }
1701 }
1702 
1703 static void control_work_handler(struct work_struct *work)
1704 {
1705         struct ports_device *portdev;
1706         struct virtqueue *vq;
1707         struct port_buffer *buf;
1708         unsigned int len;
1709 
1710         portdev = container_of(work, struct ports_device, control_work);
1711         vq = portdev->c_ivq;
1712 
1713         spin_lock(&portdev->c_ivq_lock);
1714         while ((buf = virtqueue_get_buf(vq, &len))) {
1715                 spin_unlock(&portdev->c_ivq_lock);
1716 
1717                 buf->len = len;
1718                 buf->offset = 0;
1719 
1720                 handle_control_message(vq->vdev, portdev, buf);
1721 
1722                 spin_lock(&portdev->c_ivq_lock);
1723                 if (add_inbuf(portdev->c_ivq, buf) < 0) {
1724                         dev_warn(&portdev->vdev->dev,
1725                                  "Error adding buffer to queue\n");
1726                         free_buf(buf, false);
1727                 }
1728         }
1729         spin_unlock(&portdev->c_ivq_lock);
1730 }
1731 
1732 static void flush_bufs(struct virtqueue *vq, bool can_sleep)
1733 {
1734         struct port_buffer *buf;
1735         unsigned int len;
1736 
1737         while ((buf = virtqueue_get_buf(vq, &len)))
1738                 free_buf(buf, can_sleep);
1739 }
1740 
1741 static void out_intr(struct virtqueue *vq)
1742 {
1743         struct port *port;
1744 
1745         port = find_port_by_vq(vq->vdev->priv, vq);
1746         if (!port) {
1747                 flush_bufs(vq, false);
1748                 return;
1749         }
1750 
1751         wake_up_interruptible(&port->waitqueue);
1752 }
1753 
1754 static void in_intr(struct virtqueue *vq)
1755 {
1756         struct port *port;
1757         unsigned long flags;
1758 
1759         port = find_port_by_vq(vq->vdev->priv, vq);
1760         if (!port) {
1761                 flush_bufs(vq, false);
1762                 return;
1763         }
1764 
1765         spin_lock_irqsave(&port->inbuf_lock, flags);
1766         port->inbuf = get_inbuf(port);
1767 
1768         /*
1769          * Normally the port should not accept data when the port is
1770          * closed. For generic serial ports, the host won't (shouldn't)
1771          * send data till the guest is connected. But this condition
1772          * can be reached when a console port is not yet connected (no
1773          * tty is spawned) and the other side sends out data over the
1774          * vring, or when a remote devices start sending data before
1775          * the ports are opened.
1776          *
1777          * A generic serial port will discard data if not connected,
1778          * while console ports and rproc-serial ports accepts data at
1779          * any time. rproc-serial is initiated with guest_connected to
1780          * false because port_fops_open expects this. Console ports are
1781          * hooked up with an HVC console and is initialized with
1782          * guest_connected to true.
1783          */
1784 
1785         if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
1786                 discard_port_data(port);
1787 
1788         /* Send a SIGIO indicating new data in case the process asked for it */
1789         send_sigio_to_port(port);
1790 
1791         spin_unlock_irqrestore(&port->inbuf_lock, flags);
1792 
1793         wake_up_interruptible(&port->waitqueue);
1794 
1795         if (is_console_port(port) && hvc_poll(port->cons.hvc))
1796                 hvc_kick();
1797 }
1798 
1799 static void control_intr(struct virtqueue *vq)
1800 {
1801         struct ports_device *portdev;
1802 
1803         portdev = vq->vdev->priv;
1804         schedule_work(&portdev->control_work);
1805 }
1806 
1807 static void config_intr(struct virtio_device *vdev)
1808 {
1809         struct ports_device *portdev;
1810 
1811         portdev = vdev->priv;
1812 
1813         if (!use_multiport(portdev))
1814                 schedule_work(&portdev->config_work);
1815 }
1816 
1817 static void config_work_handler(struct work_struct *work)
1818 {
1819         struct ports_device *portdev;
1820 
1821         portdev = container_of(work, struct ports_device, config_work);
1822         if (!use_multiport(portdev)) {
1823                 struct virtio_device *vdev;
1824                 struct port *port;
1825                 u16 rows, cols;
1826 
1827                 vdev = portdev->vdev;
1828                 virtio_cread(vdev, struct virtio_console_config, cols, &cols);
1829                 virtio_cread(vdev, struct virtio_console_config, rows, &rows);
1830 
1831                 port = find_port_by_id(portdev, 0);
1832                 set_console_size(port, rows, cols);
1833 
1834                 /*
1835                  * We'll use this way of resizing only for legacy
1836                  * support.  For newer userspace
1837                  * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1838                  * to indicate console size changes so that it can be
1839                  * done per-port.
1840                  */
1841                 resize_console(port);
1842         }
1843 }
1844 
1845 static int init_vqs(struct ports_device *portdev)
1846 {
1847         vq_callback_t **io_callbacks;
1848         char **io_names;
1849         struct virtqueue **vqs;
1850         u32 i, j, nr_ports, nr_queues;
1851         int err;
1852 
1853         nr_ports = portdev->max_nr_ports;
1854         nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1855 
1856         vqs = kmalloc_array(nr_queues, sizeof(struct virtqueue *), GFP_KERNEL);
1857         io_callbacks = kmalloc_array(nr_queues, sizeof(vq_callback_t *),
1858                                      GFP_KERNEL);
1859         io_names = kmalloc_array(nr_queues, sizeof(char *), GFP_KERNEL);
1860         portdev->in_vqs = kmalloc_array(nr_ports, sizeof(struct virtqueue *),
1861                                         GFP_KERNEL);
1862         portdev->out_vqs = kmalloc_array(nr_ports, sizeof(struct virtqueue *),
1863                                          GFP_KERNEL);
1864         if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
1865             !portdev->out_vqs) {
1866                 err = -ENOMEM;
1867                 goto free;
1868         }
1869 
1870         /*
1871          * For backward compat (newer host but older guest), the host
1872          * spawns a console port first and also inits the vqs for port
1873          * 0 before others.
1874          */
1875         j = 0;
1876         io_callbacks[j] = in_intr;
1877         io_callbacks[j + 1] = out_intr;
1878         io_names[j] = "input";
1879         io_names[j + 1] = "output";
1880         j += 2;
1881 
1882         if (use_multiport(portdev)) {
1883                 io_callbacks[j] = control_intr;
1884                 io_callbacks[j + 1] = NULL;
1885                 io_names[j] = "control-i";
1886                 io_names[j + 1] = "control-o";
1887 
1888                 for (i = 1; i < nr_ports; i++) {
1889                         j += 2;
1890                         io_callbacks[j] = in_intr;
1891                         io_callbacks[j + 1] = out_intr;
1892                         io_names[j] = "input";
1893                         io_names[j + 1] = "output";
1894                 }
1895         }
1896         /* Find the queues. */
1897         err = virtio_find_vqs(portdev->vdev, nr_queues, vqs,
1898                               io_callbacks,
1899                               (const char **)io_names, NULL);
1900         if (err)
1901                 goto free;
1902 
1903         j = 0;
1904         portdev->in_vqs[0] = vqs[0];
1905         portdev->out_vqs[0] = vqs[1];
1906         j += 2;
1907         if (use_multiport(portdev)) {
1908                 portdev->c_ivq = vqs[j];
1909                 portdev->c_ovq = vqs[j + 1];
1910 
1911                 for (i = 1; i < nr_ports; i++) {
1912                         j += 2;
1913                         portdev->in_vqs[i] = vqs[j];
1914                         portdev->out_vqs[i] = vqs[j + 1];
1915                 }
1916         }
1917         kfree(io_names);
1918         kfree(io_callbacks);
1919         kfree(vqs);
1920 
1921         return 0;
1922 
1923 free:
1924         kfree(portdev->out_vqs);
1925         kfree(portdev->in_vqs);
1926         kfree(io_names);
1927         kfree(io_callbacks);
1928         kfree(vqs);
1929 
1930         return err;
1931 }
1932 
1933 static const struct file_operations portdev_fops = {
1934         .owner = THIS_MODULE,
1935 };
1936 
1937 static void remove_vqs(struct ports_device *portdev)
1938 {
1939         struct virtqueue *vq;
1940 
1941         virtio_device_for_each_vq(portdev->vdev, vq) {
1942                 struct port_buffer *buf;
1943 
1944                 flush_bufs(vq, true);
1945                 while ((buf = virtqueue_detach_unused_buf(vq)))
1946                         free_buf(buf, true);
1947         }
1948         portdev->vdev->config->del_vqs(portdev->vdev);
1949         kfree(portdev->in_vqs);
1950         kfree(portdev->out_vqs);
1951 }
1952 
1953 static void virtcons_remove(struct virtio_device *vdev)
1954 {
1955         struct ports_device *portdev;
1956         struct port *port, *port2;
1957 
1958         portdev = vdev->priv;
1959 
1960         spin_lock_irq(&pdrvdata_lock);
1961         list_del(&portdev->list);
1962         spin_unlock_irq(&pdrvdata_lock);
1963 
1964         /* Disable interrupts for vqs */
1965         vdev->config->reset(vdev);
1966         /* Finish up work that's lined up */
1967         if (use_multiport(portdev))
1968                 cancel_work_sync(&portdev->control_work);
1969         else
1970                 cancel_work_sync(&portdev->config_work);
1971 
1972         list_for_each_entry_safe(port, port2, &portdev->ports, list)
1973                 unplug_port(port);
1974 
1975         unregister_chrdev(portdev->chr_major, "virtio-portsdev");
1976 
1977         /*
1978          * When yanking out a device, we immediately lose the
1979          * (device-side) queues.  So there's no point in keeping the
1980          * guest side around till we drop our final reference.  This
1981          * also means that any ports which are in an open state will
1982          * have to just stop using the port, as the vqs are going
1983          * away.
1984          */
1985         remove_vqs(portdev);
1986         kfree(portdev);
1987 }
1988 
1989 /*
1990  * Once we're further in boot, we get probed like any other virtio
1991  * device.
1992  *
1993  * If the host also supports multiple console ports, we check the
1994  * config space to see how many ports the host has spawned.  We
1995  * initialize each port found.
1996  */
1997 static int virtcons_probe(struct virtio_device *vdev)
1998 {
1999         struct ports_device *portdev;
2000         int err;
2001         bool multiport;
2002         bool early = early_put_chars != NULL;
2003 
2004         /* We only need a config space if features are offered */
2005         if (!vdev->config->get &&
2006             (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)
2007              || virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT))) {
2008                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
2009                         __func__);
2010                 return -EINVAL;
2011         }
2012 
2013         /* Ensure to read early_put_chars now */
2014         barrier();
2015 
2016         portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
2017         if (!portdev) {
2018                 err = -ENOMEM;
2019                 goto fail;
2020         }
2021 
2022         /* Attach this portdev to this virtio_device, and vice-versa. */
2023         portdev->vdev = vdev;
2024         vdev->priv = portdev;
2025 
2026         portdev->chr_major = register_chrdev(0, "virtio-portsdev",
2027                                              &portdev_fops);
2028         if (portdev->chr_major < 0) {
2029                 dev_err(&vdev->dev,
2030                         "Error %d registering chrdev for device %u\n",
2031                         portdev->chr_major, vdev->index);
2032                 err = portdev->chr_major;
2033                 goto free;
2034         }
2035 
2036         multiport = false;
2037         portdev->max_nr_ports = 1;
2038 
2039         /* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
2040         if (!is_rproc_serial(vdev) &&
2041             virtio_cread_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
2042                                  struct virtio_console_config, max_nr_ports,
2043                                  &portdev->max_nr_ports) == 0) {
2044                 multiport = true;
2045         }
2046 
2047         err = init_vqs(portdev);
2048         if (err < 0) {
2049                 dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
2050                 goto free_chrdev;
2051         }
2052 
2053         spin_lock_init(&portdev->ports_lock);
2054         INIT_LIST_HEAD(&portdev->ports);
2055         INIT_LIST_HEAD(&portdev->list);
2056 
2057         virtio_device_ready(portdev->vdev);
2058 
2059         INIT_WORK(&portdev->config_work, &config_work_handler);
2060         INIT_WORK(&portdev->control_work, &control_work_handler);
2061 
2062         if (multiport) {
2063                 spin_lock_init(&portdev->c_ivq_lock);
2064                 spin_lock_init(&portdev->c_ovq_lock);
2065 
2066                 err = fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2067                 if (err < 0) {
2068                         dev_err(&vdev->dev,
2069                                 "Error allocating buffers for control queue\n");
2070                         /*
2071                          * The host might want to notify mgmt sw about device
2072                          * add failure.
2073                          */
2074                         __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2075                                            VIRTIO_CONSOLE_DEVICE_READY, 0);
2076                         /* Device was functional: we need full cleanup. */
2077                         virtcons_remove(vdev);
2078                         return err;
2079                 }
2080         } else {
2081                 /*
2082                  * For backward compatibility: Create a console port
2083                  * if we're running on older host.
2084                  */
2085                 add_port(portdev, 0);
2086         }
2087 
2088         spin_lock_irq(&pdrvdata_lock);
2089         list_add_tail(&portdev->list, &pdrvdata.portdevs);
2090         spin_unlock_irq(&pdrvdata_lock);
2091 
2092         __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2093                            VIRTIO_CONSOLE_DEVICE_READY, 1);
2094 
2095         /*
2096          * If there was an early virtio console, assume that there are no
2097          * other consoles. We need to wait until the hvc_alloc matches the
2098          * hvc_instantiate, otherwise tty_open will complain, resulting in
2099          * a "Warning: unable to open an initial console" boot failure.
2100          * Without multiport this is done in add_port above. With multiport
2101          * this might take some host<->guest communication - thus we have to
2102          * wait.
2103          */
2104         if (multiport && early)
2105                 wait_for_completion(&early_console_added);
2106 
2107         return 0;
2108 
2109 free_chrdev:
2110         unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2111 free:
2112         kfree(portdev);
2113 fail:
2114         return err;
2115 }
2116 
2117 static struct virtio_device_id id_table[] = {
2118         { VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
2119         { 0 },
2120 };
2121 
2122 static unsigned int features[] = {
2123         VIRTIO_CONSOLE_F_SIZE,
2124         VIRTIO_CONSOLE_F_MULTIPORT,
2125 };
2126 
2127 static struct virtio_device_id rproc_serial_id_table[] = {
2128 #if IS_ENABLED(CONFIG_REMOTEPROC)
2129         { VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
2130 #endif
2131         { 0 },
2132 };
2133 
2134 static unsigned int rproc_serial_features[] = {
2135 };
2136 
2137 #ifdef CONFIG_PM_SLEEP
2138 static int virtcons_freeze(struct virtio_device *vdev)
2139 {
2140         struct ports_device *portdev;
2141         struct port *port;
2142 
2143         portdev = vdev->priv;
2144 
2145         vdev->config->reset(vdev);
2146 
2147         if (use_multiport(portdev))
2148                 virtqueue_disable_cb(portdev->c_ivq);
2149         cancel_work_sync(&portdev->control_work);
2150         cancel_work_sync(&portdev->config_work);
2151         /*
2152          * Once more: if control_work_handler() was running, it would
2153          * enable the cb as the last step.
2154          */
2155         if (use_multiport(portdev))
2156                 virtqueue_disable_cb(portdev->c_ivq);
2157 
2158         list_for_each_entry(port, &portdev->ports, list) {
2159                 virtqueue_disable_cb(port->in_vq);
2160                 virtqueue_disable_cb(port->out_vq);
2161                 /*
2162                  * We'll ask the host later if the new invocation has
2163                  * the port opened or closed.
2164                  */
2165                 port->host_connected = false;
2166                 remove_port_data(port);
2167         }
2168         remove_vqs(portdev);
2169 
2170         return 0;
2171 }
2172 
2173 static int virtcons_restore(struct virtio_device *vdev)
2174 {
2175         struct ports_device *portdev;
2176         struct port *port;
2177         int ret;
2178 
2179         portdev = vdev->priv;
2180 
2181         ret = init_vqs(portdev);
2182         if (ret)
2183                 return ret;
2184 
2185         virtio_device_ready(portdev->vdev);
2186 
2187         if (use_multiport(portdev))
2188                 fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2189 
2190         list_for_each_entry(port, &portdev->ports, list) {
2191                 port->in_vq = portdev->in_vqs[port->id];
2192                 port->out_vq = portdev->out_vqs[port->id];
2193 
2194                 fill_queue(port->in_vq, &port->inbuf_lock);
2195 
2196                 /* Get port open/close status on the host */
2197                 send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
2198 
2199                 /*
2200                  * If a port was open at the time of suspending, we
2201                  * have to let the host know that it's still open.
2202                  */
2203                 if (port->guest_connected)
2204                         send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
2205         }
2206         return 0;
2207 }
2208 #endif
2209 
2210 static struct virtio_driver virtio_console = {
2211         .feature_table = features,
2212         .feature_table_size = ARRAY_SIZE(features),
2213         .driver.name =  KBUILD_MODNAME,
2214         .driver.owner = THIS_MODULE,
2215         .id_table =     id_table,
2216         .probe =        virtcons_probe,
2217         .remove =       virtcons_remove,
2218         .config_changed = config_intr,
2219 #ifdef CONFIG_PM_SLEEP
2220         .freeze =       virtcons_freeze,
2221         .restore =      virtcons_restore,
2222 #endif
2223 };
2224 
2225 static struct virtio_driver virtio_rproc_serial = {
2226         .feature_table = rproc_serial_features,
2227         .feature_table_size = ARRAY_SIZE(rproc_serial_features),
2228         .driver.name =  "virtio_rproc_serial",
2229         .driver.owner = THIS_MODULE,
2230         .id_table =     rproc_serial_id_table,
2231         .probe =        virtcons_probe,
2232         .remove =       virtcons_remove,
2233 };
2234 
2235 static int __init init(void)
2236 {
2237         int err;
2238 
2239         pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
2240         if (IS_ERR(pdrvdata.class)) {
2241                 err = PTR_ERR(pdrvdata.class);
2242                 pr_err("Error %d creating virtio-ports class\n", err);
2243                 return err;
2244         }
2245 
2246         pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
2247         if (!pdrvdata.debugfs_dir)
2248                 pr_warn("Error creating debugfs dir for virtio-ports\n");
2249         INIT_LIST_HEAD(&pdrvdata.consoles);
2250         INIT_LIST_HEAD(&pdrvdata.portdevs);
2251 
2252         err = register_virtio_driver(&virtio_console);
2253         if (err < 0) {
2254                 pr_err("Error %d registering virtio driver\n", err);
2255                 goto free;
2256         }
2257         err = register_virtio_driver(&virtio_rproc_serial);
2258         if (err < 0) {
2259                 pr_err("Error %d registering virtio rproc serial driver\n",
2260                        err);
2261                 goto unregister;
2262         }
2263         return 0;
2264 unregister:
2265         unregister_virtio_driver(&virtio_console);
2266 free:
2267         debugfs_remove_recursive(pdrvdata.debugfs_dir);
2268         class_destroy(pdrvdata.class);
2269         return err;
2270 }
2271 
2272 static void __exit fini(void)
2273 {
2274         reclaim_dma_bufs();
2275 
2276         unregister_virtio_driver(&virtio_console);
2277         unregister_virtio_driver(&virtio_rproc_serial);
2278 
2279         class_destroy(pdrvdata.class);
2280         debugfs_remove_recursive(pdrvdata.debugfs_dir);
2281 }
2282 module_init(init);
2283 module_exit(fini);
2284 
2285 MODULE_DEVICE_TABLE(virtio, id_table);
2286 MODULE_DESCRIPTION("Virtio console driver");
2287 MODULE_LICENSE("GPL");