linux/drivers/char/virtio_console.c
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   1/*
   2 * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
   3 * Copyright (C) 2009, 2010, 2011 Red Hat, Inc.
   4 * Copyright (C) 2009, 2010, 2011 Amit Shah <amit.shah@redhat.com>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19 */
  20#include <linux/cdev.h>
  21#include <linux/debugfs.h>
  22#include <linux/completion.h>
  23#include <linux/device.h>
  24#include <linux/err.h>
  25#include <linux/freezer.h>
  26#include <linux/fs.h>
  27#include <linux/splice.h>
  28#include <linux/pagemap.h>
  29#include <linux/init.h>
  30#include <linux/list.h>
  31#include <linux/poll.h>
  32#include <linux/sched.h>
  33#include <linux/slab.h>
  34#include <linux/spinlock.h>
  35#include <linux/virtio.h>
  36#include <linux/virtio_console.h>
  37#include <linux/wait.h>
  38#include <linux/workqueue.h>
  39#include <linux/module.h>
  40#include <linux/dma-mapping.h>
  41#include <linux/kconfig.h>
  42#include "../tty/hvc/hvc_console.h"
  43
  44#define is_rproc_enabled IS_ENABLED(CONFIG_REMOTEPROC)
  45
  46/*
  47 * This is a global struct for storing common data for all the devices
  48 * this driver handles.
  49 *
  50 * Mainly, it has a linked list for all the consoles in one place so
  51 * that callbacks from hvc for get_chars(), put_chars() work properly
  52 * across multiple devices and multiple ports per device.
  53 */
  54struct ports_driver_data {
  55        /* Used for registering chardevs */
  56        struct class *class;
  57
  58        /* Used for exporting per-port information to debugfs */
  59        struct dentry *debugfs_dir;
  60
  61        /* List of all the devices we're handling */
  62        struct list_head portdevs;
  63
  64        /*
  65         * This is used to keep track of the number of hvc consoles
  66         * spawned by this driver.  This number is given as the first
  67         * argument to hvc_alloc().  To correctly map an initial
  68         * console spawned via hvc_instantiate to the console being
  69         * hooked up via hvc_alloc, we need to pass the same vtermno.
  70         *
  71         * We also just assume the first console being initialised was
  72         * the first one that got used as the initial console.
  73         */
  74        unsigned int next_vtermno;
  75
  76        /* All the console devices handled by this driver */
  77        struct list_head consoles;
  78};
  79static struct ports_driver_data pdrvdata;
  80
  81DEFINE_SPINLOCK(pdrvdata_lock);
  82DECLARE_COMPLETION(early_console_added);
  83
  84/* This struct holds information that's relevant only for console ports */
  85struct console {
  86        /* We'll place all consoles in a list in the pdrvdata struct */
  87        struct list_head list;
  88
  89        /* The hvc device associated with this console port */
  90        struct hvc_struct *hvc;
  91
  92        /* The size of the console */
  93        struct winsize ws;
  94
  95        /*
  96         * This number identifies the number that we used to register
  97         * with hvc in hvc_instantiate() and hvc_alloc(); this is the
  98         * number passed on by the hvc callbacks to us to
  99         * differentiate between the other console ports handled by
 100         * this driver
 101         */
 102        u32 vtermno;
 103};
 104
 105struct port_buffer {
 106        char *buf;
 107
 108        /* size of the buffer in *buf above */
 109        size_t size;
 110
 111        /* used length of the buffer */
 112        size_t len;
 113        /* offset in the buf from which to consume data */
 114        size_t offset;
 115
 116        /* DMA address of buffer */
 117        dma_addr_t dma;
 118
 119        /* Device we got DMA memory from */
 120        struct device *dev;
 121
 122        /* List of pending dma buffers to free */
 123        struct list_head list;
 124
 125        /* If sgpages == 0 then buf is used */
 126        unsigned int sgpages;
 127
 128        /* sg is used if spages > 0. sg must be the last in is struct */
 129        struct scatterlist sg[0];
 130};
 131
 132/*
 133 * This is a per-device struct that stores data common to all the
 134 * ports for that device (vdev->priv).
 135 */
 136struct ports_device {
 137        /* Next portdev in the list, head is in the pdrvdata struct */
 138        struct list_head list;
 139
 140        /*
 141         * Workqueue handlers where we process deferred work after
 142         * notification
 143         */
 144        struct work_struct control_work;
 145
 146        struct list_head ports;
 147
 148        /* To protect the list of ports */
 149        spinlock_t ports_lock;
 150
 151        /* To protect the vq operations for the control channel */
 152        spinlock_t c_ivq_lock;
 153        spinlock_t c_ovq_lock;
 154
 155        /* The current config space is stored here */
 156        struct virtio_console_config config;
 157
 158        /* The virtio device we're associated with */
 159        struct virtio_device *vdev;
 160
 161        /*
 162         * A couple of virtqueues for the control channel: one for
 163         * guest->host transfers, one for host->guest transfers
 164         */
 165        struct virtqueue *c_ivq, *c_ovq;
 166
 167        /* Array of per-port IO virtqueues */
 168        struct virtqueue **in_vqs, **out_vqs;
 169
 170        /* Major number for this device.  Ports will be created as minors. */
 171        int chr_major;
 172};
 173
 174struct port_stats {
 175        unsigned long bytes_sent, bytes_received, bytes_discarded;
 176};
 177
 178/* This struct holds the per-port data */
 179struct port {
 180        /* Next port in the list, head is in the ports_device */
 181        struct list_head list;
 182
 183        /* Pointer to the parent virtio_console device */
 184        struct ports_device *portdev;
 185
 186        /* The current buffer from which data has to be fed to readers */
 187        struct port_buffer *inbuf;
 188
 189        /*
 190         * To protect the operations on the in_vq associated with this
 191         * port.  Has to be a spinlock because it can be called from
 192         * interrupt context (get_char()).
 193         */
 194        spinlock_t inbuf_lock;
 195
 196        /* Protect the operations on the out_vq. */
 197        spinlock_t outvq_lock;
 198
 199        /* The IO vqs for this port */
 200        struct virtqueue *in_vq, *out_vq;
 201
 202        /* File in the debugfs directory that exposes this port's information */
 203        struct dentry *debugfs_file;
 204
 205        /*
 206         * Keep count of the bytes sent, received and discarded for
 207         * this port for accounting and debugging purposes.  These
 208         * counts are not reset across port open / close events.
 209         */
 210        struct port_stats stats;
 211
 212        /*
 213         * The entries in this struct will be valid if this port is
 214         * hooked up to an hvc console
 215         */
 216        struct console cons;
 217
 218        /* Each port associates with a separate char device */
 219        struct cdev *cdev;
 220        struct device *dev;
 221
 222        /* Reference-counting to handle port hot-unplugs and file operations */
 223        struct kref kref;
 224
 225        /* A waitqueue for poll() or blocking read operations */
 226        wait_queue_head_t waitqueue;
 227
 228        /* The 'name' of the port that we expose via sysfs properties */
 229        char *name;
 230
 231        /* We can notify apps of host connect / disconnect events via SIGIO */
 232        struct fasync_struct *async_queue;
 233
 234        /* The 'id' to identify the port with the Host */
 235        u32 id;
 236
 237        bool outvq_full;
 238
 239        /* Is the host device open */
 240        bool host_connected;
 241
 242        /* We should allow only one process to open a port */
 243        bool guest_connected;
 244};
 245
 246/* This is the very early arch-specified put chars function. */
 247static int (*early_put_chars)(u32, const char *, int);
 248
 249static struct port *find_port_by_vtermno(u32 vtermno)
 250{
 251        struct port *port;
 252        struct console *cons;
 253        unsigned long flags;
 254
 255        spin_lock_irqsave(&pdrvdata_lock, flags);
 256        list_for_each_entry(cons, &pdrvdata.consoles, list) {
 257                if (cons->vtermno == vtermno) {
 258                        port = container_of(cons, struct port, cons);
 259                        goto out;
 260                }
 261        }
 262        port = NULL;
 263out:
 264        spin_unlock_irqrestore(&pdrvdata_lock, flags);
 265        return port;
 266}
 267
 268static struct port *find_port_by_devt_in_portdev(struct ports_device *portdev,
 269                                                 dev_t dev)
 270{
 271        struct port *port;
 272        unsigned long flags;
 273
 274        spin_lock_irqsave(&portdev->ports_lock, flags);
 275        list_for_each_entry(port, &portdev->ports, list)
 276                if (port->cdev->dev == dev)
 277                        goto out;
 278        port = NULL;
 279out:
 280        spin_unlock_irqrestore(&portdev->ports_lock, flags);
 281
 282        return port;
 283}
 284
 285static struct port *find_port_by_devt(dev_t dev)
 286{
 287        struct ports_device *portdev;
 288        struct port *port;
 289        unsigned long flags;
 290
 291        spin_lock_irqsave(&pdrvdata_lock, flags);
 292        list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
 293                port = find_port_by_devt_in_portdev(portdev, dev);
 294                if (port)
 295                        goto out;
 296        }
 297        port = NULL;
 298out:
 299        spin_unlock_irqrestore(&pdrvdata_lock, flags);
 300        return port;
 301}
 302
 303static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
 304{
 305        struct port *port;
 306        unsigned long flags;
 307
 308        spin_lock_irqsave(&portdev->ports_lock, flags);
 309        list_for_each_entry(port, &portdev->ports, list)
 310                if (port->id == id)
 311                        goto out;
 312        port = NULL;
 313out:
 314        spin_unlock_irqrestore(&portdev->ports_lock, flags);
 315
 316        return port;
 317}
 318
 319static struct port *find_port_by_vq(struct ports_device *portdev,
 320                                    struct virtqueue *vq)
 321{
 322        struct port *port;
 323        unsigned long flags;
 324
 325        spin_lock_irqsave(&portdev->ports_lock, flags);
 326        list_for_each_entry(port, &portdev->ports, list)
 327                if (port->in_vq == vq || port->out_vq == vq)
 328                        goto out;
 329        port = NULL;
 330out:
 331        spin_unlock_irqrestore(&portdev->ports_lock, flags);
 332        return port;
 333}
 334
 335static bool is_console_port(struct port *port)
 336{
 337        if (port->cons.hvc)
 338                return true;
 339        return false;
 340}
 341
 342static bool is_rproc_serial(const struct virtio_device *vdev)
 343{
 344        return is_rproc_enabled && vdev->id.device == VIRTIO_ID_RPROC_SERIAL;
 345}
 346
 347static inline bool use_multiport(struct ports_device *portdev)
 348{
 349        /*
 350         * This condition can be true when put_chars is called from
 351         * early_init
 352         */
 353        if (!portdev->vdev)
 354                return 0;
 355        return portdev->vdev->features[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 356}
 357
 358static DEFINE_SPINLOCK(dma_bufs_lock);
 359static LIST_HEAD(pending_free_dma_bufs);
 360
 361static void free_buf(struct port_buffer *buf, bool can_sleep)
 362{
 363        unsigned int i;
 364
 365        for (i = 0; i < buf->sgpages; i++) {
 366                struct page *page = sg_page(&buf->sg[i]);
 367                if (!page)
 368                        break;
 369                put_page(page);
 370        }
 371
 372        if (!buf->dev) {
 373                kfree(buf->buf);
 374        } else if (is_rproc_enabled) {
 375                unsigned long flags;
 376
 377                /* dma_free_coherent requires interrupts to be enabled. */
 378                if (!can_sleep) {
 379                        /* queue up dma-buffers to be freed later */
 380                        spin_lock_irqsave(&dma_bufs_lock, flags);
 381                        list_add_tail(&buf->list, &pending_free_dma_bufs);
 382                        spin_unlock_irqrestore(&dma_bufs_lock, flags);
 383                        return;
 384                }
 385                dma_free_coherent(buf->dev, buf->size, buf->buf, buf->dma);
 386
 387                /* Release device refcnt and allow it to be freed */
 388                put_device(buf->dev);
 389        }
 390
 391        kfree(buf);
 392}
 393
 394static void reclaim_dma_bufs(void)
 395{
 396        unsigned long flags;
 397        struct port_buffer *buf, *tmp;
 398        LIST_HEAD(tmp_list);
 399
 400        if (list_empty(&pending_free_dma_bufs))
 401                return;
 402
 403        /* Create a copy of the pending_free_dma_bufs while holding the lock */
 404        spin_lock_irqsave(&dma_bufs_lock, flags);
 405        list_cut_position(&tmp_list, &pending_free_dma_bufs,
 406                          pending_free_dma_bufs.prev);
 407        spin_unlock_irqrestore(&dma_bufs_lock, flags);
 408
 409        /* Release the dma buffers, without irqs enabled */
 410        list_for_each_entry_safe(buf, tmp, &tmp_list, list) {
 411                list_del(&buf->list);
 412                free_buf(buf, true);
 413        }
 414}
 415
 416static struct port_buffer *alloc_buf(struct virtqueue *vq, size_t buf_size,
 417                                     int pages)
 418{
 419        struct port_buffer *buf;
 420
 421        reclaim_dma_bufs();
 422
 423        /*
 424         * Allocate buffer and the sg list. The sg list array is allocated
 425         * directly after the port_buffer struct.
 426         */
 427        buf = kmalloc(sizeof(*buf) + sizeof(struct scatterlist) * pages,
 428                      GFP_KERNEL);
 429        if (!buf)
 430                goto fail;
 431
 432        buf->sgpages = pages;
 433        if (pages > 0) {
 434                buf->dev = NULL;
 435                buf->buf = NULL;
 436                return buf;
 437        }
 438
 439        if (is_rproc_serial(vq->vdev)) {
 440                /*
 441                 * Allocate DMA memory from ancestor. When a virtio
 442                 * device is created by remoteproc, the DMA memory is
 443                 * associated with the grandparent device:
 444                 * vdev => rproc => platform-dev.
 445                 * The code here would have been less quirky if
 446                 * DMA_MEMORY_INCLUDES_CHILDREN had been supported
 447                 * in dma-coherent.c
 448                 */
 449                if (!vq->vdev->dev.parent || !vq->vdev->dev.parent->parent)
 450                        goto free_buf;
 451                buf->dev = vq->vdev->dev.parent->parent;
 452
 453                /* Increase device refcnt to avoid freeing it */
 454                get_device(buf->dev);
 455                buf->buf = dma_alloc_coherent(buf->dev, buf_size, &buf->dma,
 456                                              GFP_KERNEL);
 457        } else {
 458                buf->dev = NULL;
 459                buf->buf = kmalloc(buf_size, GFP_KERNEL);
 460        }
 461
 462        if (!buf->buf)
 463                goto free_buf;
 464        buf->len = 0;
 465        buf->offset = 0;
 466        buf->size = buf_size;
 467        return buf;
 468
 469free_buf:
 470        kfree(buf);
 471fail:
 472        return NULL;
 473}
 474
 475/* Callers should take appropriate locks */
 476static struct port_buffer *get_inbuf(struct port *port)
 477{
 478        struct port_buffer *buf;
 479        unsigned int len;
 480
 481        if (port->inbuf)
 482                return port->inbuf;
 483
 484        buf = virtqueue_get_buf(port->in_vq, &len);
 485        if (buf) {
 486                buf->len = len;
 487                buf->offset = 0;
 488                port->stats.bytes_received += len;
 489        }
 490        return buf;
 491}
 492
 493/*
 494 * Create a scatter-gather list representing our input buffer and put
 495 * it in the queue.
 496 *
 497 * Callers should take appropriate locks.
 498 */
 499static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
 500{
 501        struct scatterlist sg[1];
 502        int ret;
 503
 504        sg_init_one(sg, buf->buf, buf->size);
 505
 506        ret = virtqueue_add_buf(vq, sg, 0, 1, buf, GFP_ATOMIC);
 507        virtqueue_kick(vq);
 508        if (!ret)
 509                ret = vq->num_free;
 510        return ret;
 511}
 512
 513/* Discard any unread data this port has. Callers lockers. */
 514static void discard_port_data(struct port *port)
 515{
 516        struct port_buffer *buf;
 517        unsigned int err;
 518
 519        if (!port->portdev) {
 520                /* Device has been unplugged.  vqs are already gone. */
 521                return;
 522        }
 523        buf = get_inbuf(port);
 524
 525        err = 0;
 526        while (buf) {
 527                port->stats.bytes_discarded += buf->len - buf->offset;
 528                if (add_inbuf(port->in_vq, buf) < 0) {
 529                        err++;
 530                        free_buf(buf, false);
 531                }
 532                port->inbuf = NULL;
 533                buf = get_inbuf(port);
 534        }
 535        if (err)
 536                dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
 537                         err);
 538}
 539
 540static bool port_has_data(struct port *port)
 541{
 542        unsigned long flags;
 543        bool ret;
 544
 545        ret = false;
 546        spin_lock_irqsave(&port->inbuf_lock, flags);
 547        port->inbuf = get_inbuf(port);
 548        if (port->inbuf)
 549                ret = true;
 550
 551        spin_unlock_irqrestore(&port->inbuf_lock, flags);
 552        return ret;
 553}
 554
 555static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
 556                                  unsigned int event, unsigned int value)
 557{
 558        struct scatterlist sg[1];
 559        struct virtio_console_control cpkt;
 560        struct virtqueue *vq;
 561        unsigned int len;
 562
 563        if (!use_multiport(portdev))
 564                return 0;
 565
 566        cpkt.id = port_id;
 567        cpkt.event = event;
 568        cpkt.value = value;
 569
 570        vq = portdev->c_ovq;
 571
 572        sg_init_one(sg, &cpkt, sizeof(cpkt));
 573
 574        spin_lock(&portdev->c_ovq_lock);
 575        if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt, GFP_ATOMIC) == 0) {
 576                virtqueue_kick(vq);
 577                while (!virtqueue_get_buf(vq, &len))
 578                        cpu_relax();
 579        }
 580        spin_unlock(&portdev->c_ovq_lock);
 581        return 0;
 582}
 583
 584static ssize_t send_control_msg(struct port *port, unsigned int event,
 585                                unsigned int value)
 586{
 587        /* Did the port get unplugged before userspace closed it? */
 588        if (port->portdev)
 589                return __send_control_msg(port->portdev, port->id, event, value);
 590        return 0;
 591}
 592
 593
 594/* Callers must take the port->outvq_lock */
 595static void reclaim_consumed_buffers(struct port *port)
 596{
 597        struct port_buffer *buf;
 598        unsigned int len;
 599
 600        if (!port->portdev) {
 601                /* Device has been unplugged.  vqs are already gone. */
 602                return;
 603        }
 604        while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
 605                free_buf(buf, false);
 606                port->outvq_full = false;
 607        }
 608}
 609
 610static ssize_t __send_to_port(struct port *port, struct scatterlist *sg,
 611                              int nents, size_t in_count,
 612                              void *data, bool nonblock)
 613{
 614        struct virtqueue *out_vq;
 615        int err;
 616        unsigned long flags;
 617        unsigned int len;
 618
 619        out_vq = port->out_vq;
 620
 621        spin_lock_irqsave(&port->outvq_lock, flags);
 622
 623        reclaim_consumed_buffers(port);
 624
 625        err = virtqueue_add_buf(out_vq, sg, nents, 0, data, GFP_ATOMIC);
 626
 627        /* Tell Host to go! */
 628        virtqueue_kick(out_vq);
 629
 630        if (err) {
 631                in_count = 0;
 632                goto done;
 633        }
 634
 635        if (out_vq->num_free == 0)
 636                port->outvq_full = true;
 637
 638        if (nonblock)
 639                goto done;
 640
 641        /*
 642         * Wait till the host acknowledges it pushed out the data we
 643         * sent.  This is done for data from the hvc_console; the tty
 644         * operations are performed with spinlocks held so we can't
 645         * sleep here.  An alternative would be to copy the data to a
 646         * buffer and relax the spinning requirement.  The downside is
 647         * we need to kmalloc a GFP_ATOMIC buffer each time the
 648         * console driver writes something out.
 649         */
 650        while (!virtqueue_get_buf(out_vq, &len))
 651                cpu_relax();
 652done:
 653        spin_unlock_irqrestore(&port->outvq_lock, flags);
 654
 655        port->stats.bytes_sent += in_count;
 656        /*
 657         * We're expected to return the amount of data we wrote -- all
 658         * of it
 659         */
 660        return in_count;
 661}
 662
 663/*
 664 * Give out the data that's requested from the buffer that we have
 665 * queued up.
 666 */
 667static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count,
 668                            bool to_user)
 669{
 670        struct port_buffer *buf;
 671        unsigned long flags;
 672
 673        if (!out_count || !port_has_data(port))
 674                return 0;
 675
 676        buf = port->inbuf;
 677        out_count = min(out_count, buf->len - buf->offset);
 678
 679        if (to_user) {
 680                ssize_t ret;
 681
 682                ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
 683                if (ret)
 684                        return -EFAULT;
 685        } else {
 686                memcpy(out_buf, buf->buf + buf->offset, out_count);
 687        }
 688
 689        buf->offset += out_count;
 690
 691        if (buf->offset == buf->len) {
 692                /*
 693                 * We're done using all the data in this buffer.
 694                 * Re-queue so that the Host can send us more data.
 695                 */
 696                spin_lock_irqsave(&port->inbuf_lock, flags);
 697                port->inbuf = NULL;
 698
 699                if (add_inbuf(port->in_vq, buf) < 0)
 700                        dev_warn(port->dev, "failed add_buf\n");
 701
 702                spin_unlock_irqrestore(&port->inbuf_lock, flags);
 703        }
 704        /* Return the number of bytes actually copied */
 705        return out_count;
 706}
 707
 708/* The condition that must be true for polling to end */
 709static bool will_read_block(struct port *port)
 710{
 711        if (!port->guest_connected) {
 712                /* Port got hot-unplugged. Let's exit. */
 713                return false;
 714        }
 715        return !port_has_data(port) && port->host_connected;
 716}
 717
 718static bool will_write_block(struct port *port)
 719{
 720        bool ret;
 721
 722        if (!port->guest_connected) {
 723                /* Port got hot-unplugged. Let's exit. */
 724                return false;
 725        }
 726        if (!port->host_connected)
 727                return true;
 728
 729        spin_lock_irq(&port->outvq_lock);
 730        /*
 731         * Check if the Host has consumed any buffers since we last
 732         * sent data (this is only applicable for nonblocking ports).
 733         */
 734        reclaim_consumed_buffers(port);
 735        ret = port->outvq_full;
 736        spin_unlock_irq(&port->outvq_lock);
 737
 738        return ret;
 739}
 740
 741static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
 742                              size_t count, loff_t *offp)
 743{
 744        struct port *port;
 745        ssize_t ret;
 746
 747        port = filp->private_data;
 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. */
 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
 784static 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
 804static 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->out_vq, 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
 851free_buf:
 852        free_buf(buf, true);
 853out:
 854        return ret;
 855}
 856
 857struct sg_list {
 858        unsigned int n;
 859        unsigned int size;
 860        size_t len;
 861        struct scatterlist *sg;
 862};
 863
 864static 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 (buf->ops->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 = buf->ops->map(pipe, buf, 1);
 885                char *dst;
 886
 887                if (!page)
 888                        return -ENOMEM;
 889                dst = kmap(page);
 890
 891                offset = sd->pos & ~PAGE_MASK;
 892
 893                len = sd->len;
 894                if (len + offset > PAGE_SIZE)
 895                        len = PAGE_SIZE - offset;
 896
 897                memcpy(dst + offset, src + buf->offset, len);
 898
 899                kunmap(page);
 900                buf->ops->unmap(pipe, buf, src);
 901
 902                sg_set_page(&(sgl->sg[sgl->n]), page, len, offset);
 903        }
 904        sgl->n++;
 905        sgl->len += len;
 906
 907        return len;
 908}
 909
 910/* Faster zero-copy write by splicing */
 911static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
 912                                      struct file *filp, loff_t *ppos,
 913                                      size_t len, unsigned int flags)
 914{
 915        struct port *port = filp->private_data;
 916        struct sg_list sgl;
 917        ssize_t ret;
 918        struct port_buffer *buf;
 919        struct splice_desc sd = {
 920                .total_len = len,
 921                .flags = flags,
 922                .pos = *ppos,
 923                .u.data = &sgl,
 924        };
 925
 926        /*
 927         * Rproc_serial does not yet support splice. To support splice
 928         * pipe_to_sg() must allocate dma-buffers and copy content from
 929         * regular pages to dma pages. And alloc_buf and free_buf must
 930         * support allocating and freeing such a list of dma-buffers.
 931         */
 932        if (is_rproc_serial(port->out_vq->vdev))
 933                return -EINVAL;
 934
 935        ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK);
 936        if (ret < 0)
 937                return ret;
 938
 939        buf = alloc_buf(port->out_vq, 0, pipe->nrbufs);
 940        if (!buf)
 941                return -ENOMEM;
 942
 943        sgl.n = 0;
 944        sgl.len = 0;
 945        sgl.size = pipe->nrbufs;
 946        sgl.sg = buf->sg;
 947        sg_init_table(sgl.sg, sgl.size);
 948        ret = __splice_from_pipe(pipe, &sd, pipe_to_sg);
 949        if (likely(ret > 0))
 950                ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true);
 951
 952        if (unlikely(ret <= 0))
 953                free_buf(buf, true);
 954        return ret;
 955}
 956
 957static unsigned int port_fops_poll(struct file *filp, poll_table *wait)
 958{
 959        struct port *port;
 960        unsigned int ret;
 961
 962        port = filp->private_data;
 963        poll_wait(filp, &port->waitqueue, wait);
 964
 965        if (!port->guest_connected) {
 966                /* Port got unplugged */
 967                return POLLHUP;
 968        }
 969        ret = 0;
 970        if (!will_read_block(port))
 971                ret |= POLLIN | POLLRDNORM;
 972        if (!will_write_block(port))
 973                ret |= POLLOUT;
 974        if (!port->host_connected)
 975                ret |= POLLHUP;
 976
 977        return ret;
 978}
 979
 980static void remove_port(struct kref *kref);
 981
 982static int port_fops_release(struct inode *inode, struct file *filp)
 983{
 984        struct port *port;
 985
 986        port = filp->private_data;
 987
 988        /* Notify host of port being closed */
 989        send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
 990
 991        spin_lock_irq(&port->inbuf_lock);
 992        port->guest_connected = false;
 993
 994        discard_port_data(port);
 995
 996        spin_unlock_irq(&port->inbuf_lock);
 997
 998        spin_lock_irq(&port->outvq_lock);
 999        reclaim_consumed_buffers(port);
1000        spin_unlock_irq(&port->outvq_lock);
1001
1002        reclaim_dma_bufs();
1003        /*
1004         * Locks aren't necessary here as a port can't be opened after
1005         * unplug, and if a port isn't unplugged, a kref would already
1006         * exist for the port.  Plus, taking ports_lock here would
1007         * create a dependency on other locks taken by functions
1008         * inside remove_port if we're the last holder of the port,
1009         * creating many problems.
1010         */
1011        kref_put(&port->kref, remove_port);
1012
1013        return 0;
1014}
1015
1016static int port_fops_open(struct inode *inode, struct file *filp)
1017{
1018        struct cdev *cdev = inode->i_cdev;
1019        struct port *port;
1020        int ret;
1021
1022        port = find_port_by_devt(cdev->dev);
1023        filp->private_data = port;
1024
1025        /* Prevent against a port getting hot-unplugged at the same time */
1026        spin_lock_irq(&port->portdev->ports_lock);
1027        kref_get(&port->kref);
1028        spin_unlock_irq(&port->portdev->ports_lock);
1029
1030        /*
1031         * Don't allow opening of console port devices -- that's done
1032         * via /dev/hvc
1033         */
1034        if (is_console_port(port)) {
1035                ret = -ENXIO;
1036                goto out;
1037        }
1038
1039        /* Allow only one process to open a particular port at a time */
1040        spin_lock_irq(&port->inbuf_lock);
1041        if (port->guest_connected) {
1042                spin_unlock_irq(&port->inbuf_lock);
1043                ret = -EMFILE;
1044                goto out;
1045        }
1046
1047        port->guest_connected = true;
1048        spin_unlock_irq(&port->inbuf_lock);
1049
1050        spin_lock_irq(&port->outvq_lock);
1051        /*
1052         * There might be a chance that we missed reclaiming a few
1053         * buffers in the window of the port getting previously closed
1054         * and opening now.
1055         */
1056        reclaim_consumed_buffers(port);
1057        spin_unlock_irq(&port->outvq_lock);
1058
1059        nonseekable_open(inode, filp);
1060
1061        /* Notify host of port being opened */
1062        send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
1063
1064        return 0;
1065out:
1066        kref_put(&port->kref, remove_port);
1067        return ret;
1068}
1069
1070static int port_fops_fasync(int fd, struct file *filp, int mode)
1071{
1072        struct port *port;
1073
1074        port = filp->private_data;
1075        return fasync_helper(fd, filp, mode, &port->async_queue);
1076}
1077
1078/*
1079 * The file operations that we support: programs in the guest can open
1080 * a console device, read from it, write to it, poll for data and
1081 * close it.  The devices are at
1082 *   /dev/vport<device number>p<port number>
1083 */
1084static const struct file_operations port_fops = {
1085        .owner = THIS_MODULE,
1086        .open  = port_fops_open,
1087        .read  = port_fops_read,
1088        .write = port_fops_write,
1089        .splice_write = port_fops_splice_write,
1090        .poll  = port_fops_poll,
1091        .release = port_fops_release,
1092        .fasync = port_fops_fasync,
1093        .llseek = no_llseek,
1094};
1095
1096/*
1097 * The put_chars() callback is pretty straightforward.
1098 *
1099 * We turn the characters into a scatter-gather list, add it to the
1100 * output queue and then kick the Host.  Then we sit here waiting for
1101 * it to finish: inefficient in theory, but in practice
1102 * implementations will do it immediately (lguest's Launcher does).
1103 */
1104static int put_chars(u32 vtermno, const char *buf, int count)
1105{
1106        struct port *port;
1107        struct scatterlist sg[1];
1108
1109        if (unlikely(early_put_chars))
1110                return early_put_chars(vtermno, buf, count);
1111
1112        port = find_port_by_vtermno(vtermno);
1113        if (!port)
1114                return -EPIPE;
1115
1116        sg_init_one(sg, buf, count);
1117        return __send_to_port(port, sg, 1, count, (void *)buf, false);
1118}
1119
1120/*
1121 * get_chars() is the callback from the hvc_console infrastructure
1122 * when an interrupt is received.
1123 *
1124 * We call out to fill_readbuf that gets us the required data from the
1125 * buffers that are queued up.
1126 */
1127static int get_chars(u32 vtermno, char *buf, int count)
1128{
1129        struct port *port;
1130
1131        /* If we've not set up the port yet, we have no input to give. */
1132        if (unlikely(early_put_chars))
1133                return 0;
1134
1135        port = find_port_by_vtermno(vtermno);
1136        if (!port)
1137                return -EPIPE;
1138
1139        /* If we don't have an input queue yet, we can't get input. */
1140        BUG_ON(!port->in_vq);
1141
1142        return fill_readbuf(port, buf, count, false);
1143}
1144
1145static void resize_console(struct port *port)
1146{
1147        struct virtio_device *vdev;
1148
1149        /* The port could have been hot-unplugged */
1150        if (!port || !is_console_port(port))
1151                return;
1152
1153        vdev = port->portdev->vdev;
1154
1155        /* Don't test F_SIZE at all if we're rproc: not a valid feature! */
1156        if (!is_rproc_serial(vdev) &&
1157            virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
1158                hvc_resize(port->cons.hvc, port->cons.ws);
1159}
1160
1161/* We set the configuration at this point, since we now have a tty */
1162static int notifier_add_vio(struct hvc_struct *hp, int data)
1163{
1164        struct port *port;
1165
1166        port = find_port_by_vtermno(hp->vtermno);
1167        if (!port)
1168                return -EINVAL;
1169
1170        hp->irq_requested = 1;
1171        resize_console(port);
1172
1173        return 0;
1174}
1175
1176static void notifier_del_vio(struct hvc_struct *hp, int data)
1177{
1178        hp->irq_requested = 0;
1179}
1180
1181/* The operations for console ports. */
1182static const struct hv_ops hv_ops = {
1183        .get_chars = get_chars,
1184        .put_chars = put_chars,
1185        .notifier_add = notifier_add_vio,
1186        .notifier_del = notifier_del_vio,
1187        .notifier_hangup = notifier_del_vio,
1188};
1189
1190/*
1191 * Console drivers are initialized very early so boot messages can go
1192 * out, so we do things slightly differently from the generic virtio
1193 * initialization of the net and block drivers.
1194 *
1195 * At this stage, the console is output-only.  It's too early to set
1196 * up a virtqueue, so we let the drivers do some boutique early-output
1197 * thing.
1198 */
1199int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
1200{
1201        early_put_chars = put_chars;
1202        return hvc_instantiate(0, 0, &hv_ops);
1203}
1204
1205int init_port_console(struct port *port)
1206{
1207        int ret;
1208
1209        /*
1210         * The Host's telling us this port is a console port.  Hook it
1211         * up with an hvc console.
1212         *
1213         * To set up and manage our virtual console, we call
1214         * hvc_alloc().
1215         *
1216         * The first argument of hvc_alloc() is the virtual console
1217         * number.  The second argument is the parameter for the
1218         * notification mechanism (like irq number).  We currently
1219         * leave this as zero, virtqueues have implicit notifications.
1220         *
1221         * The third argument is a "struct hv_ops" containing the
1222         * put_chars() get_chars(), notifier_add() and notifier_del()
1223         * pointers.  The final argument is the output buffer size: we
1224         * can do any size, so we put PAGE_SIZE here.
1225         */
1226        port->cons.vtermno = pdrvdata.next_vtermno;
1227
1228        port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
1229        if (IS_ERR(port->cons.hvc)) {
1230                ret = PTR_ERR(port->cons.hvc);
1231                dev_err(port->dev,
1232                        "error %d allocating hvc for port\n", ret);
1233                port->cons.hvc = NULL;
1234                return ret;
1235        }
1236        spin_lock_irq(&pdrvdata_lock);
1237        pdrvdata.next_vtermno++;
1238        list_add_tail(&port->cons.list, &pdrvdata.consoles);
1239        spin_unlock_irq(&pdrvdata_lock);
1240        port->guest_connected = true;
1241
1242        /*
1243         * Start using the new console output if this is the first
1244         * console to come up.
1245         */
1246        if (early_put_chars)
1247                early_put_chars = NULL;
1248
1249        /* Notify host of port being opened */
1250        send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1251
1252        return 0;
1253}
1254
1255static ssize_t show_port_name(struct device *dev,
1256                              struct device_attribute *attr, char *buffer)
1257{
1258        struct port *port;
1259
1260        port = dev_get_drvdata(dev);
1261
1262        return sprintf(buffer, "%s\n", port->name);
1263}
1264
1265static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
1266
1267static struct attribute *port_sysfs_entries[] = {
1268        &dev_attr_name.attr,
1269        NULL
1270};
1271
1272static struct attribute_group port_attribute_group = {
1273        .name = NULL,           /* put in device directory */
1274        .attrs = port_sysfs_entries,
1275};
1276
1277static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
1278                            size_t count, loff_t *offp)
1279{
1280        struct port *port;
1281        char *buf;
1282        ssize_t ret, out_offset, out_count;
1283
1284        out_count = 1024;
1285        buf = kmalloc(out_count, GFP_KERNEL);
1286        if (!buf)
1287                return -ENOMEM;
1288
1289        port = filp->private_data;
1290        out_offset = 0;
1291        out_offset += snprintf(buf + out_offset, out_count,
1292                               "name: %s\n", port->name ? port->name : "");
1293        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1294                               "guest_connected: %d\n", port->guest_connected);
1295        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1296                               "host_connected: %d\n", port->host_connected);
1297        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1298                               "outvq_full: %d\n", port->outvq_full);
1299        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1300                               "bytes_sent: %lu\n", port->stats.bytes_sent);
1301        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1302                               "bytes_received: %lu\n",
1303                               port->stats.bytes_received);
1304        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1305                               "bytes_discarded: %lu\n",
1306                               port->stats.bytes_discarded);
1307        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1308                               "is_console: %s\n",
1309                               is_console_port(port) ? "yes" : "no");
1310        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1311                               "console_vtermno: %u\n", port->cons.vtermno);
1312
1313        ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
1314        kfree(buf);
1315        return ret;
1316}
1317
1318static const struct file_operations port_debugfs_ops = {
1319        .owner = THIS_MODULE,
1320        .open  = simple_open,
1321        .read  = debugfs_read,
1322};
1323
1324static void set_console_size(struct port *port, u16 rows, u16 cols)
1325{
1326        if (!port || !is_console_port(port))
1327                return;
1328
1329        port->cons.ws.ws_row = rows;
1330        port->cons.ws.ws_col = cols;
1331}
1332
1333static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
1334{
1335        struct port_buffer *buf;
1336        unsigned int nr_added_bufs;
1337        int ret;
1338
1339        nr_added_bufs = 0;
1340        do {
1341                buf = alloc_buf(vq, PAGE_SIZE, 0);
1342                if (!buf)
1343                        break;
1344
1345                spin_lock_irq(lock);
1346                ret = add_inbuf(vq, buf);
1347                if (ret < 0) {
1348                        spin_unlock_irq(lock);
1349                        free_buf(buf, true);
1350                        break;
1351                }
1352                nr_added_bufs++;
1353                spin_unlock_irq(lock);
1354        } while (ret > 0);
1355
1356        return nr_added_bufs;
1357}
1358
1359static void send_sigio_to_port(struct port *port)
1360{
1361        if (port->async_queue && port->guest_connected)
1362                kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
1363}
1364
1365static int add_port(struct ports_device *portdev, u32 id)
1366{
1367        char debugfs_name[16];
1368        struct port *port;
1369        struct port_buffer *buf;
1370        dev_t devt;
1371        unsigned int nr_added_bufs;
1372        int err;
1373
1374        port = kmalloc(sizeof(*port), GFP_KERNEL);
1375        if (!port) {
1376                err = -ENOMEM;
1377                goto fail;
1378        }
1379        kref_init(&port->kref);
1380
1381        port->portdev = portdev;
1382        port->id = id;
1383
1384        port->name = NULL;
1385        port->inbuf = NULL;
1386        port->cons.hvc = NULL;
1387        port->async_queue = NULL;
1388
1389        port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
1390
1391        port->host_connected = port->guest_connected = false;
1392        port->stats = (struct port_stats) { 0 };
1393
1394        port->outvq_full = false;
1395
1396        port->in_vq = portdev->in_vqs[port->id];
1397        port->out_vq = portdev->out_vqs[port->id];
1398
1399        port->cdev = cdev_alloc();
1400        if (!port->cdev) {
1401                dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
1402                err = -ENOMEM;
1403                goto free_port;
1404        }
1405        port->cdev->ops = &port_fops;
1406
1407        devt = MKDEV(portdev->chr_major, id);
1408        err = cdev_add(port->cdev, devt, 1);
1409        if (err < 0) {
1410                dev_err(&port->portdev->vdev->dev,
1411                        "Error %d adding cdev for port %u\n", err, id);
1412                goto free_cdev;
1413        }
1414        port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
1415                                  devt, port, "vport%up%u",
1416                                  port->portdev->vdev->index, id);
1417        if (IS_ERR(port->dev)) {
1418                err = PTR_ERR(port->dev);
1419                dev_err(&port->portdev->vdev->dev,
1420                        "Error %d creating device for port %u\n",
1421                        err, id);
1422                goto free_cdev;
1423        }
1424
1425        spin_lock_init(&port->inbuf_lock);
1426        spin_lock_init(&port->outvq_lock);
1427        init_waitqueue_head(&port->waitqueue);
1428
1429        /* Fill the in_vq with buffers so the host can send us data. */
1430        nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
1431        if (!nr_added_bufs) {
1432                dev_err(port->dev, "Error allocating inbufs\n");
1433                err = -ENOMEM;
1434                goto free_device;
1435        }
1436
1437        if (is_rproc_serial(port->portdev->vdev))
1438                /*
1439                 * For rproc_serial assume remote processor is connected.
1440                 * rproc_serial does not want the console port, only
1441                 * the generic port implementation.
1442                 */
1443                port->host_connected = true;
1444        else if (!use_multiport(port->portdev)) {
1445                /*
1446                 * If we're not using multiport support,
1447                 * this has to be a console port.
1448                 */
1449                err = init_port_console(port);
1450                if (err)
1451                        goto free_inbufs;
1452        }
1453
1454        spin_lock_irq(&portdev->ports_lock);
1455        list_add_tail(&port->list, &port->portdev->ports);
1456        spin_unlock_irq(&portdev->ports_lock);
1457
1458        /*
1459         * Tell the Host we're set so that it can send us various
1460         * configuration parameters for this port (eg, port name,
1461         * caching, whether this is a console port, etc.)
1462         */
1463        send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1464
1465        if (pdrvdata.debugfs_dir) {
1466                /*
1467                 * Finally, create the debugfs file that we can use to
1468                 * inspect a port's state at any time
1469                 */
1470                sprintf(debugfs_name, "vport%up%u",
1471                        port->portdev->vdev->index, id);
1472                port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
1473                                                         pdrvdata.debugfs_dir,
1474                                                         port,
1475                                                         &port_debugfs_ops);
1476        }
1477        return 0;
1478
1479free_inbufs:
1480        while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1481                free_buf(buf, true);
1482free_device:
1483        device_destroy(pdrvdata.class, port->dev->devt);
1484free_cdev:
1485        cdev_del(port->cdev);
1486free_port:
1487        kfree(port);
1488fail:
1489        /* The host might want to notify management sw about port add failure */
1490        __send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
1491        return err;
1492}
1493
1494/* No users remain, remove all port-specific data. */
1495static void remove_port(struct kref *kref)
1496{
1497        struct port *port;
1498
1499        port = container_of(kref, struct port, kref);
1500
1501        sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1502        device_destroy(pdrvdata.class, port->dev->devt);
1503        cdev_del(port->cdev);
1504
1505        kfree(port->name);
1506
1507        debugfs_remove(port->debugfs_file);
1508
1509        kfree(port);
1510}
1511
1512static void remove_port_data(struct port *port)
1513{
1514        struct port_buffer *buf;
1515
1516        /* Remove unused data this port might have received. */
1517        discard_port_data(port);
1518
1519        reclaim_consumed_buffers(port);
1520
1521        /* Remove buffers we queued up for the Host to send us data in. */
1522        while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1523                free_buf(buf, true);
1524
1525        /* Free pending buffers from the out-queue. */
1526        while ((buf = virtqueue_detach_unused_buf(port->out_vq)))
1527                free_buf(buf, true);
1528}
1529
1530/*
1531 * Port got unplugged.  Remove port from portdev's list and drop the
1532 * kref reference.  If no userspace has this port opened, it will
1533 * result in immediate removal the port.
1534 */
1535static void unplug_port(struct port *port)
1536{
1537        spin_lock_irq(&port->portdev->ports_lock);
1538        list_del(&port->list);
1539        spin_unlock_irq(&port->portdev->ports_lock);
1540
1541        if (port->guest_connected) {
1542                port->guest_connected = false;
1543                port->host_connected = false;
1544                wake_up_interruptible(&port->waitqueue);
1545
1546                /* Let the app know the port is going down. */
1547                send_sigio_to_port(port);
1548        }
1549
1550        if (is_console_port(port)) {
1551                spin_lock_irq(&pdrvdata_lock);
1552                list_del(&port->cons.list);
1553                spin_unlock_irq(&pdrvdata_lock);
1554                hvc_remove(port->cons.hvc);
1555        }
1556
1557        remove_port_data(port);
1558
1559        /*
1560         * We should just assume the device itself has gone off --
1561         * else a close on an open port later will try to send out a
1562         * control message.
1563         */
1564        port->portdev = NULL;
1565
1566        /*
1567         * Locks around here are not necessary - a port can't be
1568         * opened after we removed the port struct from ports_list
1569         * above.
1570         */
1571        kref_put(&port->kref, remove_port);
1572}
1573
1574/* Any private messages that the Host and Guest want to share */
1575static void handle_control_message(struct ports_device *portdev,
1576                                   struct port_buffer *buf)
1577{
1578        struct virtio_console_control *cpkt;
1579        struct port *port;
1580        size_t name_size;
1581        int err;
1582
1583        cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1584
1585        port = find_port_by_id(portdev, cpkt->id);
1586        if (!port && cpkt->event != VIRTIO_CONSOLE_PORT_ADD) {
1587                /* No valid header at start of buffer.  Drop it. */
1588                dev_dbg(&portdev->vdev->dev,
1589                        "Invalid index %u in control packet\n", cpkt->id);
1590                return;
1591        }
1592
1593        switch (cpkt->event) {
1594        case VIRTIO_CONSOLE_PORT_ADD:
1595                if (port) {
1596                        dev_dbg(&portdev->vdev->dev,
1597                                "Port %u already added\n", port->id);
1598                        send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1599                        break;
1600                }
1601                if (cpkt->id >= portdev->config.max_nr_ports) {
1602                        dev_warn(&portdev->vdev->dev,
1603                                "Request for adding port with out-of-bound id %u, max. supported id: %u\n",
1604                                cpkt->id, portdev->config.max_nr_ports - 1);
1605                        break;
1606                }
1607                add_port(portdev, cpkt->id);
1608                break;
1609        case VIRTIO_CONSOLE_PORT_REMOVE:
1610                unplug_port(port);
1611                break;
1612        case VIRTIO_CONSOLE_CONSOLE_PORT:
1613                if (!cpkt->value)
1614                        break;
1615                if (is_console_port(port))
1616                        break;
1617
1618                init_port_console(port);
1619                complete(&early_console_added);
1620                /*
1621                 * Could remove the port here in case init fails - but
1622                 * have to notify the host first.
1623                 */
1624                break;
1625        case VIRTIO_CONSOLE_RESIZE: {
1626                struct {
1627                        __u16 rows;
1628                        __u16 cols;
1629                } size;
1630
1631                if (!is_console_port(port))
1632                        break;
1633
1634                memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1635                       sizeof(size));
1636                set_console_size(port, size.rows, size.cols);
1637
1638                port->cons.hvc->irq_requested = 1;
1639                resize_console(port);
1640                break;
1641        }
1642        case VIRTIO_CONSOLE_PORT_OPEN:
1643                port->host_connected = cpkt->value;
1644                wake_up_interruptible(&port->waitqueue);
1645                /*
1646                 * If the host port got closed and the host had any
1647                 * unconsumed buffers, we'll be able to reclaim them
1648                 * now.
1649                 */
1650                spin_lock_irq(&port->outvq_lock);
1651                reclaim_consumed_buffers(port);
1652                spin_unlock_irq(&port->outvq_lock);
1653
1654                /*
1655                 * If the guest is connected, it'll be interested in
1656                 * knowing the host connection state changed.
1657                 */
1658                send_sigio_to_port(port);
1659                break;
1660        case VIRTIO_CONSOLE_PORT_NAME:
1661                /*
1662                 * If we woke up after hibernation, we can get this
1663                 * again.  Skip it in that case.
1664                 */
1665                if (port->name)
1666                        break;
1667
1668                /*
1669                 * Skip the size of the header and the cpkt to get the size
1670                 * of the name that was sent
1671                 */
1672                name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1673
1674                port->name = kmalloc(name_size, GFP_KERNEL);
1675                if (!port->name) {
1676                        dev_err(port->dev,
1677                                "Not enough space to store port name\n");
1678                        break;
1679                }
1680                strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1681                        name_size - 1);
1682                port->name[name_size - 1] = 0;
1683
1684                /*
1685                 * Since we only have one sysfs attribute, 'name',
1686                 * create it only if we have a name for the port.
1687                 */
1688                err = sysfs_create_group(&port->dev->kobj,
1689                                         &port_attribute_group);
1690                if (err) {
1691                        dev_err(port->dev,
1692                                "Error %d creating sysfs device attributes\n",
1693                                err);
1694                } else {
1695                        /*
1696                         * Generate a udev event so that appropriate
1697                         * symlinks can be created based on udev
1698                         * rules.
1699                         */
1700                        kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1701                }
1702                break;
1703        }
1704}
1705
1706static void control_work_handler(struct work_struct *work)
1707{
1708        struct ports_device *portdev;
1709        struct virtqueue *vq;
1710        struct port_buffer *buf;
1711        unsigned int len;
1712
1713        portdev = container_of(work, struct ports_device, control_work);
1714        vq = portdev->c_ivq;
1715
1716        spin_lock(&portdev->c_ivq_lock);
1717        while ((buf = virtqueue_get_buf(vq, &len))) {
1718                spin_unlock(&portdev->c_ivq_lock);
1719
1720                buf->len = len;
1721                buf->offset = 0;
1722
1723                handle_control_message(portdev, buf);
1724
1725                spin_lock(&portdev->c_ivq_lock);
1726                if (add_inbuf(portdev->c_ivq, buf) < 0) {
1727                        dev_warn(&portdev->vdev->dev,
1728                                 "Error adding buffer to queue\n");
1729                        free_buf(buf, false);
1730                }
1731        }
1732        spin_unlock(&portdev->c_ivq_lock);
1733}
1734
1735static void out_intr(struct virtqueue *vq)
1736{
1737        struct port *port;
1738
1739        port = find_port_by_vq(vq->vdev->priv, vq);
1740        if (!port)
1741                return;
1742
1743        wake_up_interruptible(&port->waitqueue);
1744}
1745
1746static void in_intr(struct virtqueue *vq)
1747{
1748        struct port *port;
1749        unsigned long flags;
1750
1751        port = find_port_by_vq(vq->vdev->priv, vq);
1752        if (!port)
1753                return;
1754
1755        spin_lock_irqsave(&port->inbuf_lock, flags);
1756        port->inbuf = get_inbuf(port);
1757
1758        /*
1759         * Normally the port should not accept data when the port is
1760         * closed. For generic serial ports, the host won't (shouldn't)
1761         * send data till the guest is connected. But this condition
1762         * can be reached when a console port is not yet connected (no
1763         * tty is spawned) and the other side sends out data over the
1764         * vring, or when a remote devices start sending data before
1765         * the ports are opened.
1766         *
1767         * A generic serial port will discard data if not connected,
1768         * while console ports and rproc-serial ports accepts data at
1769         * any time. rproc-serial is initiated with guest_connected to
1770         * false because port_fops_open expects this. Console ports are
1771         * hooked up with an HVC console and is initialized with
1772         * guest_connected to true.
1773         */
1774
1775        if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
1776                discard_port_data(port);
1777
1778        spin_unlock_irqrestore(&port->inbuf_lock, flags);
1779
1780        wake_up_interruptible(&port->waitqueue);
1781
1782        /* Send a SIGIO indicating new data in case the process asked for it */
1783        send_sigio_to_port(port);
1784
1785        if (is_console_port(port) && hvc_poll(port->cons.hvc))
1786                hvc_kick();
1787}
1788
1789static void control_intr(struct virtqueue *vq)
1790{
1791        struct ports_device *portdev;
1792
1793        portdev = vq->vdev->priv;
1794        schedule_work(&portdev->control_work);
1795}
1796
1797static void config_intr(struct virtio_device *vdev)
1798{
1799        struct ports_device *portdev;
1800
1801        portdev = vdev->priv;
1802
1803        if (!use_multiport(portdev)) {
1804                struct port *port;
1805                u16 rows, cols;
1806
1807                vdev->config->get(vdev,
1808                                  offsetof(struct virtio_console_config, cols),
1809                                  &cols, sizeof(u16));
1810                vdev->config->get(vdev,
1811                                  offsetof(struct virtio_console_config, rows),
1812                                  &rows, sizeof(u16));
1813
1814                port = find_port_by_id(portdev, 0);
1815                set_console_size(port, rows, cols);
1816
1817                /*
1818                 * We'll use this way of resizing only for legacy
1819                 * support.  For newer userspace
1820                 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1821                 * to indicate console size changes so that it can be
1822                 * done per-port.
1823                 */
1824                resize_console(port);
1825        }
1826}
1827
1828static int init_vqs(struct ports_device *portdev)
1829{
1830        vq_callback_t **io_callbacks;
1831        char **io_names;
1832        struct virtqueue **vqs;
1833        u32 i, j, nr_ports, nr_queues;
1834        int err;
1835
1836        nr_ports = portdev->config.max_nr_ports;
1837        nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1838
1839        vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
1840        io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
1841        io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
1842        portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1843                                  GFP_KERNEL);
1844        portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1845                                   GFP_KERNEL);
1846        if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
1847            !portdev->out_vqs) {
1848                err = -ENOMEM;
1849                goto free;
1850        }
1851
1852        /*
1853         * For backward compat (newer host but older guest), the host
1854         * spawns a console port first and also inits the vqs for port
1855         * 0 before others.
1856         */
1857        j = 0;
1858        io_callbacks[j] = in_intr;
1859        io_callbacks[j + 1] = out_intr;
1860        io_names[j] = "input";
1861        io_names[j + 1] = "output";
1862        j += 2;
1863
1864        if (use_multiport(portdev)) {
1865                io_callbacks[j] = control_intr;
1866                io_callbacks[j + 1] = NULL;
1867                io_names[j] = "control-i";
1868                io_names[j + 1] = "control-o";
1869
1870                for (i = 1; i < nr_ports; i++) {
1871                        j += 2;
1872                        io_callbacks[j] = in_intr;
1873                        io_callbacks[j + 1] = out_intr;
1874                        io_names[j] = "input";
1875                        io_names[j + 1] = "output";
1876                }
1877        }
1878        /* Find the queues. */
1879        err = portdev->vdev->config->find_vqs(portdev->vdev, nr_queues, vqs,
1880                                              io_callbacks,
1881                                              (const char **)io_names);
1882        if (err)
1883                goto free;
1884
1885        j = 0;
1886        portdev->in_vqs[0] = vqs[0];
1887        portdev->out_vqs[0] = vqs[1];
1888        j += 2;
1889        if (use_multiport(portdev)) {
1890                portdev->c_ivq = vqs[j];
1891                portdev->c_ovq = vqs[j + 1];
1892
1893                for (i = 1; i < nr_ports; i++) {
1894                        j += 2;
1895                        portdev->in_vqs[i] = vqs[j];
1896                        portdev->out_vqs[i] = vqs[j + 1];
1897                }
1898        }
1899        kfree(io_names);
1900        kfree(io_callbacks);
1901        kfree(vqs);
1902
1903        return 0;
1904
1905free:
1906        kfree(portdev->out_vqs);
1907        kfree(portdev->in_vqs);
1908        kfree(io_names);
1909        kfree(io_callbacks);
1910        kfree(vqs);
1911
1912        return err;
1913}
1914
1915static const struct file_operations portdev_fops = {
1916        .owner = THIS_MODULE,
1917};
1918
1919static void remove_vqs(struct ports_device *portdev)
1920{
1921        portdev->vdev->config->del_vqs(portdev->vdev);
1922        kfree(portdev->in_vqs);
1923        kfree(portdev->out_vqs);
1924}
1925
1926static void remove_controlq_data(struct ports_device *portdev)
1927{
1928        struct port_buffer *buf;
1929        unsigned int len;
1930
1931        if (!use_multiport(portdev))
1932                return;
1933
1934        while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
1935                free_buf(buf, true);
1936
1937        while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
1938                free_buf(buf, true);
1939}
1940
1941/*
1942 * Once we're further in boot, we get probed like any other virtio
1943 * device.
1944 *
1945 * If the host also supports multiple console ports, we check the
1946 * config space to see how many ports the host has spawned.  We
1947 * initialize each port found.
1948 */
1949static int virtcons_probe(struct virtio_device *vdev)
1950{
1951        struct ports_device *portdev;
1952        int err;
1953        bool multiport;
1954        bool early = early_put_chars != NULL;
1955
1956        /* Ensure to read early_put_chars now */
1957        barrier();
1958
1959        portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
1960        if (!portdev) {
1961                err = -ENOMEM;
1962                goto fail;
1963        }
1964
1965        /* Attach this portdev to this virtio_device, and vice-versa. */
1966        portdev->vdev = vdev;
1967        vdev->priv = portdev;
1968
1969        portdev->chr_major = register_chrdev(0, "virtio-portsdev",
1970                                             &portdev_fops);
1971        if (portdev->chr_major < 0) {
1972                dev_err(&vdev->dev,
1973                        "Error %d registering chrdev for device %u\n",
1974                        portdev->chr_major, vdev->index);
1975                err = portdev->chr_major;
1976                goto free;
1977        }
1978
1979        multiport = false;
1980        portdev->config.max_nr_ports = 1;
1981
1982        /* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
1983        if (!is_rproc_serial(vdev) &&
1984            virtio_config_val(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
1985                                  offsetof(struct virtio_console_config,
1986                                           max_nr_ports),
1987                                  &portdev->config.max_nr_ports) == 0) {
1988                multiport = true;
1989        }
1990
1991        err = init_vqs(portdev);
1992        if (err < 0) {
1993                dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
1994                goto free_chrdev;
1995        }
1996
1997        spin_lock_init(&portdev->ports_lock);
1998        INIT_LIST_HEAD(&portdev->ports);
1999
2000        if (multiport) {
2001                unsigned int nr_added_bufs;
2002
2003                spin_lock_init(&portdev->c_ivq_lock);
2004                spin_lock_init(&portdev->c_ovq_lock);
2005                INIT_WORK(&portdev->control_work, &control_work_handler);
2006
2007                nr_added_bufs = fill_queue(portdev->c_ivq,
2008                                           &portdev->c_ivq_lock);
2009                if (!nr_added_bufs) {
2010                        dev_err(&vdev->dev,
2011                                "Error allocating buffers for control queue\n");
2012                        err = -ENOMEM;
2013                        goto free_vqs;
2014                }
2015        } else {
2016                /*
2017                 * For backward compatibility: Create a console port
2018                 * if we're running on older host.
2019                 */
2020                add_port(portdev, 0);
2021        }
2022
2023        spin_lock_irq(&pdrvdata_lock);
2024        list_add_tail(&portdev->list, &pdrvdata.portdevs);
2025        spin_unlock_irq(&pdrvdata_lock);
2026
2027        __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2028                           VIRTIO_CONSOLE_DEVICE_READY, 1);
2029
2030        /*
2031         * If there was an early virtio console, assume that there are no
2032         * other consoles. We need to wait until the hvc_alloc matches the
2033         * hvc_instantiate, otherwise tty_open will complain, resulting in
2034         * a "Warning: unable to open an initial console" boot failure.
2035         * Without multiport this is done in add_port above. With multiport
2036         * this might take some host<->guest communication - thus we have to
2037         * wait.
2038         */
2039        if (multiport && early)
2040                wait_for_completion(&early_console_added);
2041
2042        return 0;
2043
2044free_vqs:
2045        /* The host might want to notify mgmt sw about device add failure */
2046        __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2047                           VIRTIO_CONSOLE_DEVICE_READY, 0);
2048        remove_vqs(portdev);
2049free_chrdev:
2050        unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2051free:
2052        kfree(portdev);
2053fail:
2054        return err;
2055}
2056
2057static void virtcons_remove(struct virtio_device *vdev)
2058{
2059        struct ports_device *portdev;
2060        struct port *port, *port2;
2061
2062        portdev = vdev->priv;
2063
2064        spin_lock_irq(&pdrvdata_lock);
2065        list_del(&portdev->list);
2066        spin_unlock_irq(&pdrvdata_lock);
2067
2068        /* Disable interrupts for vqs */
2069        vdev->config->reset(vdev);
2070        /* Finish up work that's lined up */
2071        if (use_multiport(portdev))
2072                cancel_work_sync(&portdev->control_work);
2073
2074        list_for_each_entry_safe(port, port2, &portdev->ports, list)
2075                unplug_port(port);
2076
2077        unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2078
2079        /*
2080         * When yanking out a device, we immediately lose the
2081         * (device-side) queues.  So there's no point in keeping the
2082         * guest side around till we drop our final reference.  This
2083         * also means that any ports which are in an open state will
2084         * have to just stop using the port, as the vqs are going
2085         * away.
2086         */
2087        remove_controlq_data(portdev);
2088        remove_vqs(portdev);
2089        kfree(portdev);
2090}
2091
2092static struct virtio_device_id id_table[] = {
2093        { VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
2094        { 0 },
2095};
2096
2097static unsigned int features[] = {
2098        VIRTIO_CONSOLE_F_SIZE,
2099        VIRTIO_CONSOLE_F_MULTIPORT,
2100};
2101
2102static struct virtio_device_id rproc_serial_id_table[] = {
2103#if IS_ENABLED(CONFIG_REMOTEPROC)
2104        { VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
2105#endif
2106        { 0 },
2107};
2108
2109static unsigned int rproc_serial_features[] = {
2110};
2111
2112#ifdef CONFIG_PM
2113static int virtcons_freeze(struct virtio_device *vdev)
2114{
2115        struct ports_device *portdev;
2116        struct port *port;
2117
2118        portdev = vdev->priv;
2119
2120        vdev->config->reset(vdev);
2121
2122        virtqueue_disable_cb(portdev->c_ivq);
2123        cancel_work_sync(&portdev->control_work);
2124        /*
2125         * Once more: if control_work_handler() was running, it would
2126         * enable the cb as the last step.
2127         */
2128        virtqueue_disable_cb(portdev->c_ivq);
2129        remove_controlq_data(portdev);
2130
2131        list_for_each_entry(port, &portdev->ports, list) {
2132                virtqueue_disable_cb(port->in_vq);
2133                virtqueue_disable_cb(port->out_vq);
2134                /*
2135                 * We'll ask the host later if the new invocation has
2136                 * the port opened or closed.
2137                 */
2138                port->host_connected = false;
2139                remove_port_data(port);
2140        }
2141        remove_vqs(portdev);
2142
2143        return 0;
2144}
2145
2146static int virtcons_restore(struct virtio_device *vdev)
2147{
2148        struct ports_device *portdev;
2149        struct port *port;
2150        int ret;
2151
2152        portdev = vdev->priv;
2153
2154        ret = init_vqs(portdev);
2155        if (ret)
2156                return ret;
2157
2158        if (use_multiport(portdev))
2159                fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2160
2161        list_for_each_entry(port, &portdev->ports, list) {
2162                port->in_vq = portdev->in_vqs[port->id];
2163                port->out_vq = portdev->out_vqs[port->id];
2164
2165                fill_queue(port->in_vq, &port->inbuf_lock);
2166
2167                /* Get port open/close status on the host */
2168                send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
2169
2170                /*
2171                 * If a port was open at the time of suspending, we
2172                 * have to let the host know that it's still open.
2173                 */
2174                if (port->guest_connected)
2175                        send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
2176        }
2177        return 0;
2178}
2179#endif
2180
2181static struct virtio_driver virtio_console = {
2182        .feature_table = features,
2183        .feature_table_size = ARRAY_SIZE(features),
2184        .driver.name =  KBUILD_MODNAME,
2185        .driver.owner = THIS_MODULE,
2186        .id_table =     id_table,
2187        .probe =        virtcons_probe,
2188        .remove =       virtcons_remove,
2189        .config_changed = config_intr,
2190#ifdef CONFIG_PM
2191        .freeze =       virtcons_freeze,
2192        .restore =      virtcons_restore,
2193#endif
2194};
2195
2196static struct virtio_driver virtio_rproc_serial = {
2197        .feature_table = rproc_serial_features,
2198        .feature_table_size = ARRAY_SIZE(rproc_serial_features),
2199        .driver.name =  "virtio_rproc_serial",
2200        .driver.owner = THIS_MODULE,
2201        .id_table =     rproc_serial_id_table,
2202        .probe =        virtcons_probe,
2203        .remove =       virtcons_remove,
2204};
2205
2206static int __init init(void)
2207{
2208        int err;
2209
2210        pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
2211        if (IS_ERR(pdrvdata.class)) {
2212                err = PTR_ERR(pdrvdata.class);
2213                pr_err("Error %d creating virtio-ports class\n", err);
2214                return err;
2215        }
2216
2217        pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
2218        if (!pdrvdata.debugfs_dir) {
2219                pr_warning("Error %ld creating debugfs dir for virtio-ports\n",
2220                           PTR_ERR(pdrvdata.debugfs_dir));
2221        }
2222        INIT_LIST_HEAD(&pdrvdata.consoles);
2223        INIT_LIST_HEAD(&pdrvdata.portdevs);
2224
2225        err = register_virtio_driver(&virtio_console);
2226        if (err < 0) {
2227                pr_err("Error %d registering virtio driver\n", err);
2228                goto free;
2229        }
2230        err = register_virtio_driver(&virtio_rproc_serial);
2231        if (err < 0) {
2232                pr_err("Error %d registering virtio rproc serial driver\n",
2233                       err);
2234                goto unregister;
2235        }
2236        return 0;
2237unregister:
2238        unregister_virtio_driver(&virtio_console);
2239free:
2240        if (pdrvdata.debugfs_dir)
2241                debugfs_remove_recursive(pdrvdata.debugfs_dir);
2242        class_destroy(pdrvdata.class);
2243        return err;
2244}
2245
2246static void __exit fini(void)
2247{
2248        reclaim_dma_bufs();
2249
2250        unregister_virtio_driver(&virtio_console);
2251        unregister_virtio_driver(&virtio_rproc_serial);
2252
2253        class_destroy(pdrvdata.class);
2254        if (pdrvdata.debugfs_dir)
2255                debugfs_remove_recursive(pdrvdata.debugfs_dir);
2256}
2257module_init(init);
2258module_exit(fini);
2259
2260MODULE_DEVICE_TABLE(virtio, id_table);
2261MODULE_DESCRIPTION("Virtio console driver");
2262MODULE_LICENSE("GPL");
2263
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