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
  81static DEFINE_SPINLOCK(pdrvdata_lock);
  82static DECLARE_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                        kref_get(&port->kref);
 278                        goto out;
 279                }
 280        }
 281        port = NULL;
 282out:
 283        spin_unlock_irqrestore(&portdev->ports_lock, flags);
 284
 285        return port;
 286}
 287
 288static struct port *find_port_by_devt(dev_t dev)
 289{
 290        struct ports_device *portdev;
 291        struct port *port;
 292        unsigned long flags;
 293
 294        spin_lock_irqsave(&pdrvdata_lock, flags);
 295        list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
 296                port = find_port_by_devt_in_portdev(portdev, dev);
 297                if (port)
 298                        goto out;
 299        }
 300        port = NULL;
 301out:
 302        spin_unlock_irqrestore(&pdrvdata_lock, flags);
 303        return port;
 304}
 305
 306static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
 307{
 308        struct port *port;
 309        unsigned long flags;
 310
 311        spin_lock_irqsave(&portdev->ports_lock, flags);
 312        list_for_each_entry(port, &portdev->ports, list)
 313                if (port->id == id)
 314                        goto out;
 315        port = NULL;
 316out:
 317        spin_unlock_irqrestore(&portdev->ports_lock, flags);
 318
 319        return port;
 320}
 321
 322static struct port *find_port_by_vq(struct ports_device *portdev,
 323                                    struct virtqueue *vq)
 324{
 325        struct port *port;
 326        unsigned long flags;
 327
 328        spin_lock_irqsave(&portdev->ports_lock, flags);
 329        list_for_each_entry(port, &portdev->ports, list)
 330                if (port->in_vq == vq || port->out_vq == vq)
 331                        goto out;
 332        port = NULL;
 333out:
 334        spin_unlock_irqrestore(&portdev->ports_lock, flags);
 335        return port;
 336}
 337
 338static bool is_console_port(struct port *port)
 339{
 340        if (port->cons.hvc)
 341                return true;
 342        return false;
 343}
 344
 345static bool is_rproc_serial(const struct virtio_device *vdev)
 346{
 347        return is_rproc_enabled && vdev->id.device == VIRTIO_ID_RPROC_SERIAL;
 348}
 349
 350static inline bool use_multiport(struct ports_device *portdev)
 351{
 352        /*
 353         * This condition can be true when put_chars is called from
 354         * early_init
 355         */
 356        if (!portdev->vdev)
 357                return 0;
 358        return portdev->vdev->features[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 359}
 360
 361static DEFINE_SPINLOCK(dma_bufs_lock);
 362static LIST_HEAD(pending_free_dma_bufs);
 363
 364static void free_buf(struct port_buffer *buf, bool can_sleep)
 365{
 366        unsigned int i;
 367
 368        for (i = 0; i < buf->sgpages; i++) {
 369                struct page *page = sg_page(&buf->sg[i]);
 370                if (!page)
 371                        break;
 372                put_page(page);
 373        }
 374
 375        if (!buf->dev) {
 376                kfree(buf->buf);
 377        } else if (is_rproc_enabled) {
 378                unsigned long flags;
 379
 380                /* dma_free_coherent requires interrupts to be enabled. */
 381                if (!can_sleep) {
 382                        /* queue up dma-buffers to be freed later */
 383                        spin_lock_irqsave(&dma_bufs_lock, flags);
 384                        list_add_tail(&buf->list, &pending_free_dma_bufs);
 385                        spin_unlock_irqrestore(&dma_bufs_lock, flags);
 386                        return;
 387                }
 388                dma_free_coherent(buf->dev, buf->size, buf->buf, buf->dma);
 389
 390                /* Release device refcnt and allow it to be freed */
 391                put_device(buf->dev);
 392        }
 393
 394        kfree(buf);
 395}
 396
 397static void reclaim_dma_bufs(void)
 398{
 399        unsigned long flags;
 400        struct port_buffer *buf, *tmp;
 401        LIST_HEAD(tmp_list);
 402
 403        if (list_empty(&pending_free_dma_bufs))
 404                return;
 405
 406        /* Create a copy of the pending_free_dma_bufs while holding the lock */
 407        spin_lock_irqsave(&dma_bufs_lock, flags);
 408        list_cut_position(&tmp_list, &pending_free_dma_bufs,
 409                          pending_free_dma_bufs.prev);
 410        spin_unlock_irqrestore(&dma_bufs_lock, flags);
 411
 412        /* Release the dma buffers, without irqs enabled */
 413        list_for_each_entry_safe(buf, tmp, &tmp_list, list) {
 414                list_del(&buf->list);
 415                free_buf(buf, true);
 416        }
 417}
 418
 419static struct port_buffer *alloc_buf(struct virtqueue *vq, size_t buf_size,
 420                                     int pages)
 421{
 422        struct port_buffer *buf;
 423
 424        reclaim_dma_bufs();
 425
 426        /*
 427         * Allocate buffer and the sg list. The sg list array is allocated
 428         * directly after the port_buffer struct.
 429         */
 430        buf = kmalloc(sizeof(*buf) + sizeof(struct scatterlist) * pages,
 431                      GFP_KERNEL);
 432        if (!buf)
 433                goto fail;
 434
 435        buf->sgpages = pages;
 436        if (pages > 0) {
 437                buf->dev = NULL;
 438                buf->buf = NULL;
 439                return buf;
 440        }
 441
 442        if (is_rproc_serial(vq->vdev)) {
 443                /*
 444                 * Allocate DMA memory from ancestor. When a virtio
 445                 * device is created by remoteproc, the DMA memory is
 446                 * associated with the grandparent device:
 447                 * vdev => rproc => platform-dev.
 448                 * The code here would have been less quirky if
 449                 * DMA_MEMORY_INCLUDES_CHILDREN had been supported
 450                 * in dma-coherent.c
 451                 */
 452                if (!vq->vdev->dev.parent || !vq->vdev->dev.parent->parent)
 453                        goto free_buf;
 454                buf->dev = vq->vdev->dev.parent->parent;
 455
 456                /* Increase device refcnt to avoid freeing it */
 457                get_device(buf->dev);
 458                buf->buf = dma_alloc_coherent(buf->dev, buf_size, &buf->dma,
 459                                              GFP_KERNEL);
 460        } else {
 461                buf->dev = NULL;
 462                buf->buf = kmalloc(buf_size, GFP_KERNEL);
 463        }
 464
 465        if (!buf->buf)
 466                goto free_buf;
 467        buf->len = 0;
 468        buf->offset = 0;
 469        buf->size = buf_size;
 470        return buf;
 471
 472free_buf:
 473        kfree(buf);
 474fail:
 475        return NULL;
 476}
 477
 478/* Callers should take appropriate locks */
 479static struct port_buffer *get_inbuf(struct port *port)
 480{
 481        struct port_buffer *buf;
 482        unsigned int len;
 483
 484        if (port->inbuf)
 485                return port->inbuf;
 486
 487        buf = virtqueue_get_buf(port->in_vq, &len);
 488        if (buf) {
 489                buf->len = len;
 490                buf->offset = 0;
 491                port->stats.bytes_received += len;
 492        }
 493        return buf;
 494}
 495
 496/*
 497 * Create a scatter-gather list representing our input buffer and put
 498 * it in the queue.
 499 *
 500 * Callers should take appropriate locks.
 501 */
 502static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
 503{
 504        struct scatterlist sg[1];
 505        int ret;
 506
 507        sg_init_one(sg, buf->buf, buf->size);
 508
 509        ret = virtqueue_add_inbuf(vq, sg, 1, buf, GFP_ATOMIC);
 510        virtqueue_kick(vq);
 511        if (!ret)
 512                ret = vq->num_free;
 513        return ret;
 514}
 515
 516/* Discard any unread data this port has. Callers lockers. */
 517static void discard_port_data(struct port *port)
 518{
 519        struct port_buffer *buf;
 520        unsigned int err;
 521
 522        if (!port->portdev) {
 523                /* Device has been unplugged.  vqs are already gone. */
 524                return;
 525        }
 526        buf = get_inbuf(port);
 527
 528        err = 0;
 529        while (buf) {
 530                port->stats.bytes_discarded += buf->len - buf->offset;
 531                if (add_inbuf(port->in_vq, buf) < 0) {
 532                        err++;
 533                        free_buf(buf, false);
 534                }
 535                port->inbuf = NULL;
 536                buf = get_inbuf(port);
 537        }
 538        if (err)
 539                dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
 540                         err);
 541}
 542
 543static bool port_has_data(struct port *port)
 544{
 545        unsigned long flags;
 546        bool ret;
 547
 548        ret = false;
 549        spin_lock_irqsave(&port->inbuf_lock, flags);
 550        port->inbuf = get_inbuf(port);
 551        if (port->inbuf)
 552                ret = true;
 553
 554        spin_unlock_irqrestore(&port->inbuf_lock, flags);
 555        return ret;
 556}
 557
 558static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
 559                                  unsigned int event, unsigned int value)
 560{
 561        struct scatterlist sg[1];
 562        struct virtio_console_control cpkt;
 563        struct virtqueue *vq;
 564        unsigned int len;
 565
 566        if (!use_multiport(portdev))
 567                return 0;
 568
 569        cpkt.id = port_id;
 570        cpkt.event = event;
 571        cpkt.value = value;
 572
 573        vq = portdev->c_ovq;
 574
 575        sg_init_one(sg, &cpkt, sizeof(cpkt));
 576
 577        spin_lock(&portdev->c_ovq_lock);
 578        if (virtqueue_add_outbuf(vq, sg, 1, &cpkt, GFP_ATOMIC) == 0) {
 579                virtqueue_kick(vq);
 580                while (!virtqueue_get_buf(vq, &len))
 581                        cpu_relax();
 582        }
 583        spin_unlock(&portdev->c_ovq_lock);
 584        return 0;
 585}
 586
 587static ssize_t send_control_msg(struct port *port, unsigned int event,
 588                                unsigned int value)
 589{
 590        /* Did the port get unplugged before userspace closed it? */
 591        if (port->portdev)
 592                return __send_control_msg(port->portdev, port->id, event, value);
 593        return 0;
 594}
 595
 596
 597/* Callers must take the port->outvq_lock */
 598static void reclaim_consumed_buffers(struct port *port)
 599{
 600        struct port_buffer *buf;
 601        unsigned int len;
 602
 603        if (!port->portdev) {
 604                /* Device has been unplugged.  vqs are already gone. */
 605                return;
 606        }
 607        while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
 608                free_buf(buf, false);
 609                port->outvq_full = false;
 610        }
 611}
 612
 613static ssize_t __send_to_port(struct port *port, struct scatterlist *sg,
 614                              int nents, size_t in_count,
 615                              void *data, bool nonblock)
 616{
 617        struct virtqueue *out_vq;
 618        int err;
 619        unsigned long flags;
 620        unsigned int len;
 621
 622        out_vq = port->out_vq;
 623
 624        spin_lock_irqsave(&port->outvq_lock, flags);
 625
 626        reclaim_consumed_buffers(port);
 627
 628        err = virtqueue_add_outbuf(out_vq, sg, nents, data, GFP_ATOMIC);
 629
 630        /* Tell Host to go! */
 631        virtqueue_kick(out_vq);
 632
 633        if (err) {
 634                in_count = 0;
 635                goto done;
 636        }
 637
 638        if (out_vq->num_free == 0)
 639                port->outvq_full = true;
 640
 641        if (nonblock)
 642                goto done;
 643
 644        /*
 645         * Wait till the host acknowledges it pushed out the data we
 646         * sent.  This is done for data from the hvc_console; the tty
 647         * operations are performed with spinlocks held so we can't
 648         * sleep here.  An alternative would be to copy the data to a
 649         * buffer and relax the spinning requirement.  The downside is
 650         * we need to kmalloc a GFP_ATOMIC buffer each time the
 651         * console driver writes something out.
 652         */
 653        while (!virtqueue_get_buf(out_vq, &len))
 654                cpu_relax();
 655done:
 656        spin_unlock_irqrestore(&port->outvq_lock, flags);
 657
 658        port->stats.bytes_sent += in_count;
 659        /*
 660         * We're expected to return the amount of data we wrote -- all
 661         * of it
 662         */
 663        return in_count;
 664}
 665
 666/*
 667 * Give out the data that's requested from the buffer that we have
 668 * queued up.
 669 */
 670static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count,
 671                            bool to_user)
 672{
 673        struct port_buffer *buf;
 674        unsigned long flags;
 675
 676        if (!out_count || !port_has_data(port))
 677                return 0;
 678
 679        buf = port->inbuf;
 680        out_count = min(out_count, buf->len - buf->offset);
 681
 682        if (to_user) {
 683                ssize_t ret;
 684
 685                ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
 686                if (ret)
 687                        return -EFAULT;
 688        } else {
 689                memcpy(out_buf, buf->buf + buf->offset, out_count);
 690        }
 691
 692        buf->offset += out_count;
 693
 694        if (buf->offset == buf->len) {
 695                /*
 696                 * We're done using all the data in this buffer.
 697                 * Re-queue so that the Host can send us more data.
 698                 */
 699                spin_lock_irqsave(&port->inbuf_lock, flags);
 700                port->inbuf = NULL;
 701
 702                if (add_inbuf(port->in_vq, buf) < 0)
 703                        dev_warn(port->dev, "failed add_buf\n");
 704
 705                spin_unlock_irqrestore(&port->inbuf_lock, flags);
 706        }
 707        /* Return the number of bytes actually copied */
 708        return out_count;
 709}
 710
 711/* The condition that must be true for polling to end */
 712static bool will_read_block(struct port *port)
 713{
 714        if (!port->guest_connected) {
 715                /* Port got hot-unplugged. Let's exit. */
 716                return false;
 717        }
 718        return !port_has_data(port) && port->host_connected;
 719}
 720
 721static bool will_write_block(struct port *port)
 722{
 723        bool ret;
 724
 725        if (!port->guest_connected) {
 726                /* Port got hot-unplugged. Let's exit. */
 727                return false;
 728        }
 729        if (!port->host_connected)
 730                return true;
 731
 732        spin_lock_irq(&port->outvq_lock);
 733        /*
 734         * Check if the Host has consumed any buffers since we last
 735         * sent data (this is only applicable for nonblocking ports).
 736         */
 737        reclaim_consumed_buffers(port);
 738        ret = port->outvq_full;
 739        spin_unlock_irq(&port->outvq_lock);
 740
 741        return ret;
 742}
 743
 744static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
 745                              size_t count, loff_t *offp)
 746{
 747        struct port *port;
 748        ssize_t ret;
 749
 750        port = filp->private_data;
 751
 752        /* Port is hot-unplugged. */
 753        if (!port->guest_connected)
 754                return -ENODEV;
 755
 756        if (!port_has_data(port)) {
 757                /*
 758                 * If nothing's connected on the host just return 0 in
 759                 * case of list_empty; this tells the userspace app
 760                 * that there's no connection
 761                 */
 762                if (!port->host_connected)
 763                        return 0;
 764                if (filp->f_flags & O_NONBLOCK)
 765                        return -EAGAIN;
 766
 767                ret = wait_event_freezable(port->waitqueue,
 768                                           !will_read_block(port));
 769                if (ret < 0)
 770                        return ret;
 771        }
 772        /* Port got hot-unplugged while we were waiting above. */
 773        if (!port->guest_connected)
 774                return -ENODEV;
 775        /*
 776         * We could've received a disconnection message while we were
 777         * waiting for more data.
 778         *
 779         * This check is not clubbed in the if() statement above as we
 780         * might receive some data as well as the host could get
 781         * disconnected after we got woken up from our wait.  So we
 782         * really want to give off whatever data we have and only then
 783         * check for host_connected.
 784         */
 785        if (!port_has_data(port) && !port->host_connected)
 786                return 0;
 787
 788        return fill_readbuf(port, ubuf, count, true);
 789}
 790
 791static int wait_port_writable(struct port *port, bool nonblock)
 792{
 793        int ret;
 794
 795        if (will_write_block(port)) {
 796                if (nonblock)
 797                        return -EAGAIN;
 798
 799                ret = wait_event_freezable(port->waitqueue,
 800                                           !will_write_block(port));
 801                if (ret < 0)
 802                        return ret;
 803        }
 804        /* Port got hot-unplugged. */
 805        if (!port->guest_connected)
 806                return -ENODEV;
 807
 808        return 0;
 809}
 810
 811static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
 812                               size_t count, loff_t *offp)
 813{
 814        struct port *port;
 815        struct port_buffer *buf;
 816        ssize_t ret;
 817        bool nonblock;
 818        struct scatterlist sg[1];
 819
 820        /* Userspace could be out to fool us */
 821        if (!count)
 822                return 0;
 823
 824        port = filp->private_data;
 825
 826        nonblock = filp->f_flags & O_NONBLOCK;
 827
 828        ret = wait_port_writable(port, nonblock);
 829        if (ret < 0)
 830                return ret;
 831
 832        count = min((size_t)(32 * 1024), count);
 833
 834        buf = alloc_buf(port->out_vq, count, 0);
 835        if (!buf)
 836                return -ENOMEM;
 837
 838        ret = copy_from_user(buf->buf, ubuf, count);
 839        if (ret) {
 840                ret = -EFAULT;
 841                goto free_buf;
 842        }
 843
 844        /*
 845         * We now ask send_buf() to not spin for generic ports -- we
 846         * can re-use the same code path that non-blocking file
 847         * descriptors take for blocking file descriptors since the
 848         * wait is already done and we're certain the write will go
 849         * through to the host.
 850         */
 851        nonblock = true;
 852        sg_init_one(sg, buf->buf, count);
 853        ret = __send_to_port(port, sg, 1, count, buf, nonblock);
 854
 855        if (nonblock && ret > 0)
 856                goto out;
 857
 858free_buf:
 859        free_buf(buf, true);
 860out:
 861        return ret;
 862}
 863
 864struct sg_list {
 865        unsigned int n;
 866        unsigned int size;
 867        size_t len;
 868        struct scatterlist *sg;
 869};
 870
 871static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 872                        struct splice_desc *sd)
 873{
 874        struct sg_list *sgl = sd->u.data;
 875        unsigned int offset, len;
 876
 877        if (sgl->n == sgl->size)
 878                return 0;
 879
 880        /* Try lock this page */
 881        if (buf->ops->steal(pipe, buf) == 0) {
 882                /* Get reference and unlock page for moving */
 883                get_page(buf->page);
 884                unlock_page(buf->page);
 885
 886                len = min(buf->len, sd->len);
 887                sg_set_page(&(sgl->sg[sgl->n]), buf->page, len, buf->offset);
 888        } else {
 889                /* Failback to copying a page */
 890                struct page *page = alloc_page(GFP_KERNEL);
 891                char *src = buf->ops->map(pipe, buf, 1);
 892                char *dst;
 893
 894                if (!page)
 895                        return -ENOMEM;
 896                dst = kmap(page);
 897
 898                offset = sd->pos & ~PAGE_MASK;
 899
 900                len = sd->len;
 901                if (len + offset > PAGE_SIZE)
 902                        len = PAGE_SIZE - offset;
 903
 904                memcpy(dst + offset, src + buf->offset, len);
 905
 906                kunmap(page);
 907                buf->ops->unmap(pipe, buf, src);
 908
 909                sg_set_page(&(sgl->sg[sgl->n]), page, len, offset);
 910        }
 911        sgl->n++;
 912        sgl->len += len;
 913
 914        return len;
 915}
 916
 917/* Faster zero-copy write by splicing */
 918static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
 919                                      struct file *filp, loff_t *ppos,
 920                                      size_t len, unsigned int flags)
 921{
 922        struct port *port = filp->private_data;
 923        struct sg_list sgl;
 924        ssize_t ret;
 925        struct port_buffer *buf;
 926        struct splice_desc sd = {
 927                .total_len = len,
 928                .flags = flags,
 929                .pos = *ppos,
 930                .u.data = &sgl,
 931        };
 932
 933        /*
 934         * Rproc_serial does not yet support splice. To support splice
 935         * pipe_to_sg() must allocate dma-buffers and copy content from
 936         * regular pages to dma pages. And alloc_buf and free_buf must
 937         * support allocating and freeing such a list of dma-buffers.
 938         */
 939        if (is_rproc_serial(port->out_vq->vdev))
 940                return -EINVAL;
 941
 942        /*
 943         * pipe->nrbufs == 0 means there are no data to transfer,
 944         * so this returns just 0 for no data.
 945         */
 946        pipe_lock(pipe);
 947        if (!pipe->nrbufs) {
 948                ret = 0;
 949                goto error_out;
 950        }
 951
 952        ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK);
 953        if (ret < 0)
 954                goto error_out;
 955
 956        buf = alloc_buf(port->out_vq, 0, pipe->nrbufs);
 957        if (!buf) {
 958                ret = -ENOMEM;
 959                goto error_out;
 960        }
 961
 962        sgl.n = 0;
 963        sgl.len = 0;
 964        sgl.size = pipe->nrbufs;
 965        sgl.sg = buf->sg;
 966        sg_init_table(sgl.sg, sgl.size);
 967        ret = __splice_from_pipe(pipe, &sd, pipe_to_sg);
 968        pipe_unlock(pipe);
 969        if (likely(ret > 0))
 970                ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true);
 971
 972        if (unlikely(ret <= 0))
 973                free_buf(buf, true);
 974        return ret;
 975
 976error_out:
 977        pipe_unlock(pipe);
 978        return ret;
 979}
 980
 981static unsigned int port_fops_poll(struct file *filp, poll_table *wait)
 982{
 983        struct port *port;
 984        unsigned int ret;
 985
 986        port = filp->private_data;
 987        poll_wait(filp, &port->waitqueue, wait);
 988
 989        if (!port->guest_connected) {
 990                /* Port got unplugged */
 991                return POLLHUP;
 992        }
 993        ret = 0;
 994        if (!will_read_block(port))
 995                ret |= POLLIN | POLLRDNORM;
 996        if (!will_write_block(port))
 997                ret |= POLLOUT;
 998        if (!port->host_connected)
 999                ret |= POLLHUP;
1000
1001        return ret;
1002}
1003
1004static void remove_port(struct kref *kref);
1005
1006static int port_fops_release(struct inode *inode, struct file *filp)
1007{
1008        struct port *port;
1009
1010        port = filp->private_data;
1011
1012        /* Notify host of port being closed */
1013        send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
1014
1015        spin_lock_irq(&port->inbuf_lock);
1016        port->guest_connected = false;
1017
1018        discard_port_data(port);
1019
1020        spin_unlock_irq(&port->inbuf_lock);
1021
1022        spin_lock_irq(&port->outvq_lock);
1023        reclaim_consumed_buffers(port);
1024        spin_unlock_irq(&port->outvq_lock);
1025
1026        reclaim_dma_bufs();
1027        /*
1028         * Locks aren't necessary here as a port can't be opened after
1029         * unplug, and if a port isn't unplugged, a kref would already
1030         * exist for the port.  Plus, taking ports_lock here would
1031         * create a dependency on other locks taken by functions
1032         * inside remove_port if we're the last holder of the port,
1033         * creating many problems.
1034         */
1035        kref_put(&port->kref, remove_port);
1036
1037        return 0;
1038}
1039
1040static int port_fops_open(struct inode *inode, struct file *filp)
1041{
1042        struct cdev *cdev = inode->i_cdev;
1043        struct port *port;
1044        int ret;
1045
1046        /* We get the port with a kref here */
1047        port = find_port_by_devt(cdev->dev);
1048        if (!port) {
1049                /* Port was unplugged before we could proceed */
1050                return -ENXIO;
1051        }
1052        filp->private_data = port;
1053
1054        /*
1055         * Don't allow opening of console port devices -- that's done
1056         * via /dev/hvc
1057         */
1058        if (is_console_port(port)) {
1059                ret = -ENXIO;
1060                goto out;
1061        }
1062
1063        /* Allow only one process to open a particular port at a time */
1064        spin_lock_irq(&port->inbuf_lock);
1065        if (port->guest_connected) {
1066                spin_unlock_irq(&port->inbuf_lock);
1067                ret = -EBUSY;
1068                goto out;
1069        }
1070
1071        port->guest_connected = true;
1072        spin_unlock_irq(&port->inbuf_lock);
1073
1074        spin_lock_irq(&port->outvq_lock);
1075        /*
1076         * There might be a chance that we missed reclaiming a few
1077         * buffers in the window of the port getting previously closed
1078         * and opening now.
1079         */
1080        reclaim_consumed_buffers(port);
1081        spin_unlock_irq(&port->outvq_lock);
1082
1083        nonseekable_open(inode, filp);
1084
1085        /* Notify host of port being opened */
1086        send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
1087
1088        return 0;
1089out:
1090        kref_put(&port->kref, remove_port);
1091        return ret;
1092}
1093
1094static int port_fops_fasync(int fd, struct file *filp, int mode)
1095{
1096        struct port *port;
1097
1098        port = filp->private_data;
1099        return fasync_helper(fd, filp, mode, &port->async_queue);
1100}
1101
1102/*
1103 * The file operations that we support: programs in the guest can open
1104 * a console device, read from it, write to it, poll for data and
1105 * close it.  The devices are at
1106 *   /dev/vport<device number>p<port number>
1107 */
1108static const struct file_operations port_fops = {
1109        .owner = THIS_MODULE,
1110        .open  = port_fops_open,
1111        .read  = port_fops_read,
1112        .write = port_fops_write,
1113        .splice_write = port_fops_splice_write,
1114        .poll  = port_fops_poll,
1115        .release = port_fops_release,
1116        .fasync = port_fops_fasync,
1117        .llseek = no_llseek,
1118};
1119
1120/*
1121 * The put_chars() callback is pretty straightforward.
1122 *
1123 * We turn the characters into a scatter-gather list, add it to the
1124 * output queue and then kick the Host.  Then we sit here waiting for
1125 * it to finish: inefficient in theory, but in practice
1126 * implementations will do it immediately (lguest's Launcher does).
1127 */
1128static int put_chars(u32 vtermno, const char *buf, int count)
1129{
1130        struct port *port;
1131        struct scatterlist sg[1];
1132
1133        if (unlikely(early_put_chars))
1134                return early_put_chars(vtermno, buf, count);
1135
1136        port = find_port_by_vtermno(vtermno);
1137        if (!port)
1138                return -EPIPE;
1139
1140        sg_init_one(sg, buf, count);
1141        return __send_to_port(port, sg, 1, count, (void *)buf, false);
1142}
1143
1144/*
1145 * get_chars() is the callback from the hvc_console infrastructure
1146 * when an interrupt is received.
1147 *
1148 * We call out to fill_readbuf that gets us the required data from the
1149 * buffers that are queued up.
1150 */
1151static int get_chars(u32 vtermno, char *buf, int count)
1152{
1153        struct port *port;
1154
1155        /* If we've not set up the port yet, we have no input to give. */
1156        if (unlikely(early_put_chars))
1157                return 0;
1158
1159        port = find_port_by_vtermno(vtermno);
1160        if (!port)
1161                return -EPIPE;
1162
1163        /* If we don't have an input queue yet, we can't get input. */
1164        BUG_ON(!port->in_vq);
1165
1166        return fill_readbuf(port, buf, count, false);
1167}
1168
1169static void resize_console(struct port *port)
1170{
1171        struct virtio_device *vdev;
1172
1173        /* The port could have been hot-unplugged */
1174        if (!port || !is_console_port(port))
1175                return;
1176
1177        vdev = port->portdev->vdev;
1178
1179        /* Don't test F_SIZE at all if we're rproc: not a valid feature! */
1180        if (!is_rproc_serial(vdev) &&
1181            virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
1182                hvc_resize(port->cons.hvc, port->cons.ws);
1183}
1184
1185/* We set the configuration at this point, since we now have a tty */
1186static int notifier_add_vio(struct hvc_struct *hp, int data)
1187{
1188        struct port *port;
1189
1190        port = find_port_by_vtermno(hp->vtermno);
1191        if (!port)
1192                return -EINVAL;
1193
1194        hp->irq_requested = 1;
1195        resize_console(port);
1196
1197        return 0;
1198}
1199
1200static void notifier_del_vio(struct hvc_struct *hp, int data)
1201{
1202        hp->irq_requested = 0;
1203}
1204
1205/* The operations for console ports. */
1206static const struct hv_ops hv_ops = {
1207        .get_chars = get_chars,
1208        .put_chars = put_chars,
1209        .notifier_add = notifier_add_vio,
1210        .notifier_del = notifier_del_vio,
1211        .notifier_hangup = notifier_del_vio,
1212};
1213
1214/*
1215 * Console drivers are initialized very early so boot messages can go
1216 * out, so we do things slightly differently from the generic virtio
1217 * initialization of the net and block drivers.
1218 *
1219 * At this stage, the console is output-only.  It's too early to set
1220 * up a virtqueue, so we let the drivers do some boutique early-output
1221 * thing.
1222 */
1223int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
1224{
1225        early_put_chars = put_chars;
1226        return hvc_instantiate(0, 0, &hv_ops);
1227}
1228
1229static int init_port_console(struct port *port)
1230{
1231        int ret;
1232
1233        /*
1234         * The Host's telling us this port is a console port.  Hook it
1235         * up with an hvc console.
1236         *
1237         * To set up and manage our virtual console, we call
1238         * hvc_alloc().
1239         *
1240         * The first argument of hvc_alloc() is the virtual console
1241         * number.  The second argument is the parameter for the
1242         * notification mechanism (like irq number).  We currently
1243         * leave this as zero, virtqueues have implicit notifications.
1244         *
1245         * The third argument is a "struct hv_ops" containing the
1246         * put_chars() get_chars(), notifier_add() and notifier_del()
1247         * pointers.  The final argument is the output buffer size: we
1248         * can do any size, so we put PAGE_SIZE here.
1249         */
1250        port->cons.vtermno = pdrvdata.next_vtermno;
1251
1252        port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
1253        if (IS_ERR(port->cons.hvc)) {
1254                ret = PTR_ERR(port->cons.hvc);
1255                dev_err(port->dev,
1256                        "error %d allocating hvc for port\n", ret);
1257                port->cons.hvc = NULL;
1258                return ret;
1259        }
1260        spin_lock_irq(&pdrvdata_lock);
1261        pdrvdata.next_vtermno++;
1262        list_add_tail(&port->cons.list, &pdrvdata.consoles);
1263        spin_unlock_irq(&pdrvdata_lock);
1264        port->guest_connected = true;
1265
1266        /*
1267         * Start using the new console output if this is the first
1268         * console to come up.
1269         */
1270        if (early_put_chars)
1271                early_put_chars = NULL;
1272
1273        /* Notify host of port being opened */
1274        send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1275
1276        return 0;
1277}
1278
1279static ssize_t show_port_name(struct device *dev,
1280                              struct device_attribute *attr, char *buffer)
1281{
1282        struct port *port;
1283
1284        port = dev_get_drvdata(dev);
1285
1286        return sprintf(buffer, "%s\n", port->name);
1287}
1288
1289static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
1290
1291static struct attribute *port_sysfs_entries[] = {
1292        &dev_attr_name.attr,
1293        NULL
1294};
1295
1296static struct attribute_group port_attribute_group = {
1297        .name = NULL,           /* put in device directory */
1298        .attrs = port_sysfs_entries,
1299};
1300
1301static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
1302                            size_t count, loff_t *offp)
1303{
1304        struct port *port;
1305        char *buf;
1306        ssize_t ret, out_offset, out_count;
1307
1308        out_count = 1024;
1309        buf = kmalloc(out_count, GFP_KERNEL);
1310        if (!buf)
1311                return -ENOMEM;
1312
1313        port = filp->private_data;
1314        out_offset = 0;
1315        out_offset += snprintf(buf + out_offset, out_count,
1316                               "name: %s\n", port->name ? port->name : "");
1317        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1318                               "guest_connected: %d\n", port->guest_connected);
1319        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1320                               "host_connected: %d\n", port->host_connected);
1321        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1322                               "outvq_full: %d\n", port->outvq_full);
1323        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1324                               "bytes_sent: %lu\n", port->stats.bytes_sent);
1325        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1326                               "bytes_received: %lu\n",
1327                               port->stats.bytes_received);
1328        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1329                               "bytes_discarded: %lu\n",
1330                               port->stats.bytes_discarded);
1331        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1332                               "is_console: %s\n",
1333                               is_console_port(port) ? "yes" : "no");
1334        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1335                               "console_vtermno: %u\n", port->cons.vtermno);
1336
1337        ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
1338        kfree(buf);
1339        return ret;
1340}
1341
1342static const struct file_operations port_debugfs_ops = {
1343        .owner = THIS_MODULE,
1344        .open  = simple_open,
1345        .read  = debugfs_read,
1346};
1347
1348static void set_console_size(struct port *port, u16 rows, u16 cols)
1349{
1350        if (!port || !is_console_port(port))
1351                return;
1352
1353        port->cons.ws.ws_row = rows;
1354        port->cons.ws.ws_col = cols;
1355}
1356
1357static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
1358{
1359        struct port_buffer *buf;
1360        unsigned int nr_added_bufs;
1361        int ret;
1362
1363        nr_added_bufs = 0;
1364        do {
1365                buf = alloc_buf(vq, PAGE_SIZE, 0);
1366                if (!buf)
1367                        break;
1368
1369                spin_lock_irq(lock);
1370                ret = add_inbuf(vq, buf);
1371                if (ret < 0) {
1372                        spin_unlock_irq(lock);
1373                        free_buf(buf, true);
1374                        break;
1375                }
1376                nr_added_bufs++;
1377                spin_unlock_irq(lock);
1378        } while (ret > 0);
1379
1380        return nr_added_bufs;
1381}
1382
1383static void send_sigio_to_port(struct port *port)
1384{
1385        if (port->async_queue && port->guest_connected)
1386                kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
1387}
1388
1389static int add_port(struct ports_device *portdev, u32 id)
1390{
1391        char debugfs_name[16];
1392        struct port *port;
1393        struct port_buffer *buf;
1394        dev_t devt;
1395        unsigned int nr_added_bufs;
1396        int err;
1397
1398        port = kmalloc(sizeof(*port), GFP_KERNEL);
1399        if (!port) {
1400                err = -ENOMEM;
1401                goto fail;
1402        }
1403        kref_init(&port->kref);
1404
1405        port->portdev = portdev;
1406        port->id = id;
1407
1408        port->name = NULL;
1409        port->inbuf = NULL;
1410        port->cons.hvc = NULL;
1411        port->async_queue = NULL;
1412
1413        port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
1414
1415        port->host_connected = port->guest_connected = false;
1416        port->stats = (struct port_stats) { 0 };
1417
1418        port->outvq_full = false;
1419
1420        port->in_vq = portdev->in_vqs[port->id];
1421        port->out_vq = portdev->out_vqs[port->id];
1422
1423        port->cdev = cdev_alloc();
1424        if (!port->cdev) {
1425                dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
1426                err = -ENOMEM;
1427                goto free_port;
1428        }
1429        port->cdev->ops = &port_fops;
1430
1431        devt = MKDEV(portdev->chr_major, id);
1432        err = cdev_add(port->cdev, devt, 1);
1433        if (err < 0) {
1434                dev_err(&port->portdev->vdev->dev,
1435                        "Error %d adding cdev for port %u\n", err, id);
1436                goto free_cdev;
1437        }
1438        port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
1439                                  devt, port, "vport%up%u",
1440                                  port->portdev->vdev->index, id);
1441        if (IS_ERR(port->dev)) {
1442                err = PTR_ERR(port->dev);
1443                dev_err(&port->portdev->vdev->dev,
1444                        "Error %d creating device for port %u\n",
1445                        err, id);
1446                goto free_cdev;
1447        }
1448
1449        spin_lock_init(&port->inbuf_lock);
1450        spin_lock_init(&port->outvq_lock);
1451        init_waitqueue_head(&port->waitqueue);
1452
1453        /* Fill the in_vq with buffers so the host can send us data. */
1454        nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
1455        if (!nr_added_bufs) {
1456                dev_err(port->dev, "Error allocating inbufs\n");
1457                err = -ENOMEM;
1458                goto free_device;
1459        }
1460
1461        if (is_rproc_serial(port->portdev->vdev))
1462                /*
1463                 * For rproc_serial assume remote processor is connected.
1464                 * rproc_serial does not want the console port, only
1465                 * the generic port implementation.
1466                 */
1467                port->host_connected = true;
1468        else if (!use_multiport(port->portdev)) {
1469                /*
1470                 * If we're not using multiport support,
1471                 * this has to be a console port.
1472                 */
1473                err = init_port_console(port);
1474                if (err)
1475                        goto free_inbufs;
1476        }
1477
1478        spin_lock_irq(&portdev->ports_lock);
1479        list_add_tail(&port->list, &port->portdev->ports);
1480        spin_unlock_irq(&portdev->ports_lock);
1481
1482        /*
1483         * Tell the Host we're set so that it can send us various
1484         * configuration parameters for this port (eg, port name,
1485         * caching, whether this is a console port, etc.)
1486         */
1487        send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1488
1489        if (pdrvdata.debugfs_dir) {
1490                /*
1491                 * Finally, create the debugfs file that we can use to
1492                 * inspect a port's state at any time
1493                 */
1494                sprintf(debugfs_name, "vport%up%u",
1495                        port->portdev->vdev->index, id);
1496                port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
1497                                                         pdrvdata.debugfs_dir,
1498                                                         port,
1499                                                         &port_debugfs_ops);
1500        }
1501        return 0;
1502
1503free_inbufs:
1504        while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1505                free_buf(buf, true);
1506free_device:
1507        device_destroy(pdrvdata.class, port->dev->devt);
1508free_cdev:
1509        cdev_del(port->cdev);
1510free_port:
1511        kfree(port);
1512fail:
1513        /* The host might want to notify management sw about port add failure */
1514        __send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
1515        return err;
1516}
1517
1518/* No users remain, remove all port-specific data. */
1519static void remove_port(struct kref *kref)
1520{
1521        struct port *port;
1522
1523        port = container_of(kref, struct port, kref);
1524
1525        kfree(port);
1526}
1527
1528static void remove_port_data(struct port *port)
1529{
1530        struct port_buffer *buf;
1531
1532        /* Remove unused data this port might have received. */
1533        discard_port_data(port);
1534
1535        reclaim_consumed_buffers(port);
1536
1537        /* Remove buffers we queued up for the Host to send us data in. */
1538        while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1539                free_buf(buf, true);
1540
1541        /* Free pending buffers from the out-queue. */
1542        while ((buf = virtqueue_detach_unused_buf(port->out_vq)))
1543                free_buf(buf, true);
1544}
1545
1546/*
1547 * Port got unplugged.  Remove port from portdev's list and drop the
1548 * kref reference.  If no userspace has this port opened, it will
1549 * result in immediate removal the port.
1550 */
1551static void unplug_port(struct port *port)
1552{
1553        spin_lock_irq(&port->portdev->ports_lock);
1554        list_del(&port->list);
1555        spin_unlock_irq(&port->portdev->ports_lock);
1556
1557        if (port->guest_connected) {
1558                /* Let the app know the port is going down. */
1559                send_sigio_to_port(port);
1560
1561                /* Do this after sigio is actually sent */
1562                port->guest_connected = false;
1563                port->host_connected = false;
1564
1565                wake_up_interruptible(&port->waitqueue);
1566        }
1567
1568        if (is_console_port(port)) {
1569                spin_lock_irq(&pdrvdata_lock);
1570                list_del(&port->cons.list);
1571                spin_unlock_irq(&pdrvdata_lock);
1572                hvc_remove(port->cons.hvc);
1573        }
1574
1575        remove_port_data(port);
1576
1577        /*
1578         * We should just assume the device itself has gone off --
1579         * else a close on an open port later will try to send out a
1580         * control message.
1581         */
1582        port->portdev = NULL;
1583
1584        sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1585        device_destroy(pdrvdata.class, port->dev->devt);
1586        cdev_del(port->cdev);
1587
1588        kfree(port->name);
1589
1590        debugfs_remove(port->debugfs_file);
1591
1592        /*
1593         * Locks around here are not necessary - a port can't be
1594         * opened after we removed the port struct from ports_list
1595         * above.
1596         */
1597        kref_put(&port->kref, remove_port);
1598}
1599
1600/* Any private messages that the Host and Guest want to share */
1601static void handle_control_message(struct ports_device *portdev,
1602                                   struct port_buffer *buf)
1603{
1604        struct virtio_console_control *cpkt;
1605        struct port *port;
1606        size_t name_size;
1607        int err;
1608
1609        cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1610
1611        port = find_port_by_id(portdev, cpkt->id);
1612        if (!port && cpkt->event != VIRTIO_CONSOLE_PORT_ADD) {
1613                /* No valid header at start of buffer.  Drop it. */
1614                dev_dbg(&portdev->vdev->dev,
1615                        "Invalid index %u in control packet\n", cpkt->id);
1616                return;
1617        }
1618
1619        switch (cpkt->event) {
1620        case VIRTIO_CONSOLE_PORT_ADD:
1621                if (port) {
1622                        dev_dbg(&portdev->vdev->dev,
1623                                "Port %u already added\n", port->id);
1624                        send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1625                        break;
1626                }
1627                if (cpkt->id >= portdev->config.max_nr_ports) {
1628                        dev_warn(&portdev->vdev->dev,
1629                                "Request for adding port with out-of-bound id %u, max. supported id: %u\n",
1630                                cpkt->id, portdev->config.max_nr_ports - 1);
1631                        break;
1632                }
1633                add_port(portdev, cpkt->id);
1634                break;
1635        case VIRTIO_CONSOLE_PORT_REMOVE:
1636                unplug_port(port);
1637                break;
1638        case VIRTIO_CONSOLE_CONSOLE_PORT:
1639                if (!cpkt->value)
1640                        break;
1641                if (is_console_port(port))
1642                        break;
1643
1644                init_port_console(port);
1645                complete(&early_console_added);
1646                /*
1647                 * Could remove the port here in case init fails - but
1648                 * have to notify the host first.
1649                 */
1650                break;
1651        case VIRTIO_CONSOLE_RESIZE: {
1652                struct {
1653                        __u16 rows;
1654                        __u16 cols;
1655                } size;
1656
1657                if (!is_console_port(port))
1658                        break;
1659
1660                memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1661                       sizeof(size));
1662                set_console_size(port, size.rows, size.cols);
1663
1664                port->cons.hvc->irq_requested = 1;
1665                resize_console(port);
1666                break;
1667        }
1668        case VIRTIO_CONSOLE_PORT_OPEN:
1669                port->host_connected = cpkt->value;
1670                wake_up_interruptible(&port->waitqueue);
1671                /*
1672                 * If the host port got closed and the host had any
1673                 * unconsumed buffers, we'll be able to reclaim them
1674                 * now.
1675                 */
1676                spin_lock_irq(&port->outvq_lock);
1677                reclaim_consumed_buffers(port);
1678                spin_unlock_irq(&port->outvq_lock);
1679
1680                /*
1681                 * If the guest is connected, it'll be interested in
1682                 * knowing the host connection state changed.
1683                 */
1684                send_sigio_to_port(port);
1685                break;
1686        case VIRTIO_CONSOLE_PORT_NAME:
1687                /*
1688                 * If we woke up after hibernation, we can get this
1689                 * again.  Skip it in that case.
1690                 */
1691                if (port->name)
1692                        break;
1693
1694                /*
1695                 * Skip the size of the header and the cpkt to get the size
1696                 * of the name that was sent
1697                 */
1698                name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1699
1700                port->name = kmalloc(name_size, GFP_KERNEL);
1701                if (!port->name) {
1702                        dev_err(port->dev,
1703                                "Not enough space to store port name\n");
1704                        break;
1705                }
1706                strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1707                        name_size - 1);
1708                port->name[name_size - 1] = 0;
1709
1710                /*
1711                 * Since we only have one sysfs attribute, 'name',
1712                 * create it only if we have a name for the port.
1713                 */
1714                err = sysfs_create_group(&port->dev->kobj,
1715                                         &port_attribute_group);
1716                if (err) {
1717                        dev_err(port->dev,
1718                                "Error %d creating sysfs device attributes\n",
1719                                err);
1720                } else {
1721                        /*
1722                         * Generate a udev event so that appropriate
1723                         * symlinks can be created based on udev
1724                         * rules.
1725                         */
1726                        kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1727                }
1728                break;
1729        }
1730}
1731
1732static void control_work_handler(struct work_struct *work)
1733{
1734        struct ports_device *portdev;
1735        struct virtqueue *vq;
1736        struct port_buffer *buf;
1737        unsigned int len;
1738
1739        portdev = container_of(work, struct ports_device, control_work);
1740        vq = portdev->c_ivq;
1741
1742        spin_lock(&portdev->c_ivq_lock);
1743        while ((buf = virtqueue_get_buf(vq, &len))) {
1744                spin_unlock(&portdev->c_ivq_lock);
1745
1746                buf->len = len;
1747                buf->offset = 0;
1748
1749                handle_control_message(portdev, buf);
1750
1751                spin_lock(&portdev->c_ivq_lock);
1752                if (add_inbuf(portdev->c_ivq, buf) < 0) {
1753                        dev_warn(&portdev->vdev->dev,
1754                                 "Error adding buffer to queue\n");
1755                        free_buf(buf, false);
1756                }
1757        }
1758        spin_unlock(&portdev->c_ivq_lock);
1759}
1760
1761static void out_intr(struct virtqueue *vq)
1762{
1763        struct port *port;
1764
1765        port = find_port_by_vq(vq->vdev->priv, vq);
1766        if (!port)
1767                return;
1768
1769        wake_up_interruptible(&port->waitqueue);
1770}
1771
1772static void in_intr(struct virtqueue *vq)
1773{
1774        struct port *port;
1775        unsigned long flags;
1776
1777        port = find_port_by_vq(vq->vdev->priv, vq);
1778        if (!port)
1779                return;
1780
1781        spin_lock_irqsave(&port->inbuf_lock, flags);
1782        port->inbuf = get_inbuf(port);
1783
1784        /*
1785         * Normally the port should not accept data when the port is
1786         * closed. For generic serial ports, the host won't (shouldn't)
1787         * send data till the guest is connected. But this condition
1788         * can be reached when a console port is not yet connected (no
1789         * tty is spawned) and the other side sends out data over the
1790         * vring, or when a remote devices start sending data before
1791         * the ports are opened.
1792         *
1793         * A generic serial port will discard data if not connected,
1794         * while console ports and rproc-serial ports accepts data at
1795         * any time. rproc-serial is initiated with guest_connected to
1796         * false because port_fops_open expects this. Console ports are
1797         * hooked up with an HVC console and is initialized with
1798         * guest_connected to true.
1799         */
1800
1801        if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
1802                discard_port_data(port);
1803
1804        spin_unlock_irqrestore(&port->inbuf_lock, flags);
1805
1806        wake_up_interruptible(&port->waitqueue);
1807
1808        /* Send a SIGIO indicating new data in case the process asked for it */
1809        send_sigio_to_port(port);
1810
1811        if (is_console_port(port) && hvc_poll(port->cons.hvc))
1812                hvc_kick();
1813}
1814
1815static void control_intr(struct virtqueue *vq)
1816{
1817        struct ports_device *portdev;
1818
1819        portdev = vq->vdev->priv;
1820        schedule_work(&portdev->control_work);
1821}
1822
1823static void config_intr(struct virtio_device *vdev)
1824{
1825        struct ports_device *portdev;
1826
1827        portdev = vdev->priv;
1828
1829        if (!use_multiport(portdev)) {
1830                struct port *port;
1831                u16 rows, cols;
1832
1833                vdev->config->get(vdev,
1834                                  offsetof(struct virtio_console_config, cols),
1835                                  &cols, sizeof(u16));
1836                vdev->config->get(vdev,
1837                                  offsetof(struct virtio_console_config, rows),
1838                                  &rows, sizeof(u16));
1839
1840                port = find_port_by_id(portdev, 0);
1841                set_console_size(port, rows, cols);
1842
1843                /*
1844                 * We'll use this way of resizing only for legacy
1845                 * support.  For newer userspace
1846                 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1847                 * to indicate console size changes so that it can be
1848                 * done per-port.
1849                 */
1850                resize_console(port);
1851        }
1852}
1853
1854static int init_vqs(struct ports_device *portdev)
1855{
1856        vq_callback_t **io_callbacks;
1857        char **io_names;
1858        struct virtqueue **vqs;
1859        u32 i, j, nr_ports, nr_queues;
1860        int err;
1861
1862        nr_ports = portdev->config.max_nr_ports;
1863        nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1864
1865        vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
1866        io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
1867        io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
1868        portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1869                                  GFP_KERNEL);
1870        portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1871                                   GFP_KERNEL);
1872        if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
1873            !portdev->out_vqs) {
1874                err = -ENOMEM;
1875                goto free;
1876        }
1877
1878        /*
1879         * For backward compat (newer host but older guest), the host
1880         * spawns a console port first and also inits the vqs for port
1881         * 0 before others.
1882         */
1883        j = 0;
1884        io_callbacks[j] = in_intr;
1885        io_callbacks[j + 1] = out_intr;
1886        io_names[j] = "input";
1887        io_names[j + 1] = "output";
1888        j += 2;
1889
1890        if (use_multiport(portdev)) {
1891                io_callbacks[j] = control_intr;
1892                io_callbacks[j + 1] = NULL;
1893                io_names[j] = "control-i";
1894                io_names[j + 1] = "control-o";
1895
1896                for (i = 1; i < nr_ports; i++) {
1897                        j += 2;
1898                        io_callbacks[j] = in_intr;
1899                        io_callbacks[j + 1] = out_intr;
1900                        io_names[j] = "input";
1901                        io_names[j + 1] = "output";
1902                }
1903        }
1904        /* Find the queues. */
1905        err = portdev->vdev->config->find_vqs(portdev->vdev, nr_queues, vqs,
1906                                              io_callbacks,
1907                                              (const char **)io_names);
1908        if (err)
1909                goto free;
1910
1911        j = 0;
1912        portdev->in_vqs[0] = vqs[0];
1913        portdev->out_vqs[0] = vqs[1];
1914        j += 2;
1915        if (use_multiport(portdev)) {
1916                portdev->c_ivq = vqs[j];
1917                portdev->c_ovq = vqs[j + 1];
1918
1919                for (i = 1; i < nr_ports; i++) {
1920                        j += 2;
1921                        portdev->in_vqs[i] = vqs[j];
1922                        portdev->out_vqs[i] = vqs[j + 1];
1923                }
1924        }
1925        kfree(io_names);
1926        kfree(io_callbacks);
1927        kfree(vqs);
1928
1929        return 0;
1930
1931free:
1932        kfree(portdev->out_vqs);
1933        kfree(portdev->in_vqs);
1934        kfree(io_names);
1935        kfree(io_callbacks);
1936        kfree(vqs);
1937
1938        return err;
1939}
1940
1941static const struct file_operations portdev_fops = {
1942        .owner = THIS_MODULE,
1943};
1944
1945static void remove_vqs(struct ports_device *portdev)
1946{
1947        portdev->vdev->config->del_vqs(portdev->vdev);
1948        kfree(portdev->in_vqs);
1949        kfree(portdev->out_vqs);
1950}
1951
1952static void remove_controlq_data(struct ports_device *portdev)
1953{
1954        struct port_buffer *buf;
1955        unsigned int len;
1956
1957        if (!use_multiport(portdev))
1958                return;
1959
1960        while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
1961                free_buf(buf, true);
1962
1963        while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
1964                free_buf(buf, true);
1965}
1966
1967/*
1968 * Once we're further in boot, we get probed like any other virtio
1969 * device.
1970 *
1971 * If the host also supports multiple console ports, we check the
1972 * config space to see how many ports the host has spawned.  We
1973 * initialize each port found.
1974 */
1975static int virtcons_probe(struct virtio_device *vdev)
1976{
1977        struct ports_device *portdev;
1978        int err;
1979        bool multiport;
1980        bool early = early_put_chars != NULL;
1981
1982        /* Ensure to read early_put_chars now */
1983        barrier();
1984
1985        portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
1986        if (!portdev) {
1987                err = -ENOMEM;
1988                goto fail;
1989        }
1990
1991        /* Attach this portdev to this virtio_device, and vice-versa. */
1992        portdev->vdev = vdev;
1993        vdev->priv = portdev;
1994
1995        portdev->chr_major = register_chrdev(0, "virtio-portsdev",
1996                                             &portdev_fops);
1997        if (portdev->chr_major < 0) {
1998                dev_err(&vdev->dev,
1999                        "Error %d registering chrdev for device %u\n",
2000                        portdev->chr_major, vdev->index);
2001                err = portdev->chr_major;
2002                goto free;
2003        }
2004
2005        multiport = false;
2006        portdev->config.max_nr_ports = 1;
2007
2008        /* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
2009        if (!is_rproc_serial(vdev) &&
2010            virtio_config_val(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
2011                                  offsetof(struct virtio_console_config,
2012                                           max_nr_ports),
2013                                  &portdev->config.max_nr_ports) == 0) {
2014                multiport = true;
2015        }
2016
2017        err = init_vqs(portdev);
2018        if (err < 0) {
2019                dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
2020                goto free_chrdev;
2021        }
2022
2023        spin_lock_init(&portdev->ports_lock);
2024        INIT_LIST_HEAD(&portdev->ports);
2025
2026        if (multiport) {
2027                unsigned int nr_added_bufs;
2028
2029                spin_lock_init(&portdev->c_ivq_lock);
2030                spin_lock_init(&portdev->c_ovq_lock);
2031                INIT_WORK(&portdev->control_work, &control_work_handler);
2032
2033                nr_added_bufs = fill_queue(portdev->c_ivq,
2034                                           &portdev->c_ivq_lock);
2035                if (!nr_added_bufs) {
2036                        dev_err(&vdev->dev,
2037                                "Error allocating buffers for control queue\n");
2038                        err = -ENOMEM;
2039                        goto free_vqs;
2040                }
2041        } else {
2042                /*
2043                 * For backward compatibility: Create a console port
2044                 * if we're running on older host.
2045                 */
2046                add_port(portdev, 0);
2047        }
2048
2049        spin_lock_irq(&pdrvdata_lock);
2050        list_add_tail(&portdev->list, &pdrvdata.portdevs);
2051        spin_unlock_irq(&pdrvdata_lock);
2052
2053        __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2054                           VIRTIO_CONSOLE_DEVICE_READY, 1);
2055
2056        /*
2057         * If there was an early virtio console, assume that there are no
2058         * other consoles. We need to wait until the hvc_alloc matches the
2059         * hvc_instantiate, otherwise tty_open will complain, resulting in
2060         * a "Warning: unable to open an initial console" boot failure.
2061         * Without multiport this is done in add_port above. With multiport
2062         * this might take some host<->guest communication - thus we have to
2063         * wait.
2064         */
2065        if (multiport && early)
2066                wait_for_completion(&early_console_added);
2067
2068        return 0;
2069
2070free_vqs:
2071        /* The host might want to notify mgmt sw about device add failure */
2072        __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2073                           VIRTIO_CONSOLE_DEVICE_READY, 0);
2074        remove_vqs(portdev);
2075free_chrdev:
2076        unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2077free:
2078        kfree(portdev);
2079fail:
2080        return err;
2081}
2082
2083static void virtcons_remove(struct virtio_device *vdev)
2084{
2085        struct ports_device *portdev;
2086        struct port *port, *port2;
2087
2088        portdev = vdev->priv;
2089
2090        spin_lock_irq(&pdrvdata_lock);
2091        list_del(&portdev->list);
2092        spin_unlock_irq(&pdrvdata_lock);
2093
2094        /* Disable interrupts for vqs */
2095        vdev->config->reset(vdev);
2096        /* Finish up work that's lined up */
2097        if (use_multiport(portdev))
2098                cancel_work_sync(&portdev->control_work);
2099
2100        list_for_each_entry_safe(port, port2, &portdev->ports, list)
2101                unplug_port(port);
2102
2103        unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2104
2105        /*
2106         * When yanking out a device, we immediately lose the
2107         * (device-side) queues.  So there's no point in keeping the
2108         * guest side around till we drop our final reference.  This
2109         * also means that any ports which are in an open state will
2110         * have to just stop using the port, as the vqs are going
2111         * away.
2112         */
2113        remove_controlq_data(portdev);
2114        remove_vqs(portdev);
2115        kfree(portdev);
2116}
2117
2118static struct virtio_device_id id_table[] = {
2119        { VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
2120        { 0 },
2121};
2122
2123static unsigned int features[] = {
2124        VIRTIO_CONSOLE_F_SIZE,
2125        VIRTIO_CONSOLE_F_MULTIPORT,
2126};
2127
2128static struct virtio_device_id rproc_serial_id_table[] = {
2129#if IS_ENABLED(CONFIG_REMOTEPROC)
2130        { VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
2131#endif
2132        { 0 },
2133};
2134
2135static unsigned int rproc_serial_features[] = {
2136};
2137
2138#ifdef CONFIG_PM
2139static int virtcons_freeze(struct virtio_device *vdev)
2140{
2141        struct ports_device *portdev;
2142        struct port *port;
2143
2144        portdev = vdev->priv;
2145
2146        vdev->config->reset(vdev);
2147
2148        virtqueue_disable_cb(portdev->c_ivq);
2149        cancel_work_sync(&portdev->control_work);
2150        /*
2151         * Once more: if control_work_handler() was running, it would
2152         * enable the cb as the last step.
2153         */
2154        virtqueue_disable_cb(portdev->c_ivq);
2155        remove_controlq_data(portdev);
2156
2157        list_for_each_entry(port, &portdev->ports, list) {
2158                virtqueue_disable_cb(port->in_vq);
2159                virtqueue_disable_cb(port->out_vq);
2160                /*
2161                 * We'll ask the host later if the new invocation has
2162                 * the port opened or closed.
2163                 */
2164                port->host_connected = false;
2165                remove_port_data(port);
2166        }
2167        remove_vqs(portdev);
2168
2169        return 0;
2170}
2171
2172static int virtcons_restore(struct virtio_device *vdev)
2173{
2174        struct ports_device *portdev;
2175        struct port *port;
2176        int ret;
2177
2178        portdev = vdev->priv;
2179
2180        ret = init_vqs(portdev);
2181        if (ret)
2182                return ret;
2183
2184        if (use_multiport(portdev))
2185                fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2186
2187        list_for_each_entry(port, &portdev->ports, list) {
2188                port->in_vq = portdev->in_vqs[port->id];
2189                port->out_vq = portdev->out_vqs[port->id];
2190
2191                fill_queue(port->in_vq, &port->inbuf_lock);
2192
2193                /* Get port open/close status on the host */
2194                send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
2195
2196                /*
2197                 * If a port was open at the time of suspending, we
2198                 * have to let the host know that it's still open.
2199                 */
2200                if (port->guest_connected)
2201                        send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
2202        }
2203        return 0;
2204}
2205#endif
2206
2207static struct virtio_driver virtio_console = {
2208        .feature_table = features,
2209        .feature_table_size = ARRAY_SIZE(features),
2210        .driver.name =  KBUILD_MODNAME,
2211        .driver.owner = THIS_MODULE,
2212        .id_table =     id_table,
2213        .probe =        virtcons_probe,
2214        .remove =       virtcons_remove,
2215        .config_changed = config_intr,
2216#ifdef CONFIG_PM
2217        .freeze =       virtcons_freeze,
2218        .restore =      virtcons_restore,
2219#endif
2220};
2221
2222static struct virtio_driver virtio_rproc_serial = {
2223        .feature_table = rproc_serial_features,
2224        .feature_table_size = ARRAY_SIZE(rproc_serial_features),
2225        .driver.name =  "virtio_rproc_serial",
2226        .driver.owner = THIS_MODULE,
2227        .id_table =     rproc_serial_id_table,
2228        .probe =        virtcons_probe,
2229        .remove =       virtcons_remove,
2230};
2231
2232static int __init init(void)
2233{
2234        int err;
2235
2236        pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
2237        if (IS_ERR(pdrvdata.class)) {
2238                err = PTR_ERR(pdrvdata.class);
2239                pr_err("Error %d creating virtio-ports class\n", err);
2240                return err;
2241        }
2242
2243        pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
2244        if (!pdrvdata.debugfs_dir) {
2245                pr_warning("Error %ld creating debugfs dir for virtio-ports\n",
2246                           PTR_ERR(pdrvdata.debugfs_dir));
2247        }
2248        INIT_LIST_HEAD(&pdrvdata.consoles);
2249        INIT_LIST_HEAD(&pdrvdata.portdevs);
2250
2251        err = register_virtio_driver(&virtio_console);
2252        if (err < 0) {
2253                pr_err("Error %d registering virtio driver\n", err);
2254                goto free;
2255        }
2256        err = register_virtio_driver(&virtio_rproc_serial);
2257        if (err < 0) {
2258                pr_err("Error %d registering virtio rproc serial driver\n",
2259                       err);
2260                goto unregister;
2261        }
2262        return 0;
2263unregister:
2264        unregister_virtio_driver(&virtio_console);
2265free:
2266        if (pdrvdata.debugfs_dir)
2267                debugfs_remove_recursive(pdrvdata.debugfs_dir);
2268        class_destroy(pdrvdata.class);
2269        return err;
2270}
2271
2272static 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        if (pdrvdata.debugfs_dir)
2281                debugfs_remove_recursive(pdrvdata.debugfs_dir);
2282}
2283module_init(init);
2284module_exit(fini);
2285
2286MODULE_DEVICE_TABLE(virtio, id_table);
2287MODULE_DESCRIPTION("Virtio console driver");
2288MODULE_LICENSE("GPL");
2289
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