Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/drivers/char/virtio_console.c

  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  */
 54 struct 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 };
 79 static struct ports_driver_data pdrvdata;
 80 
 81 static DEFINE_SPINLOCK(pdrvdata_lock);
 82 static DECLARE_COMPLETION(early_console_added);
 83 
 84 /* This struct holds information that's relevant only for console ports */
 85 struct 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 
105 struct 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  */
136 struct 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 
174 struct port_stats {
175         unsigned long bytes_sent, bytes_received, bytes_discarded;
176 };
177 
178 /* This struct holds the per-port data */
179 struct 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. */
247 static int (*early_put_chars)(u32, const char *, int);
248 
249 static 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;
263 out:
264         spin_unlock_irqrestore(&pdrvdata_lock, flags);
265         return port;
266 }
267 
268 static 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;
282 out:
283         spin_unlock_irqrestore(&portdev->ports_lock, flags);
284 
285         return port;
286 }
287 
288 static 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;
301 out:
302         spin_unlock_irqrestore(&pdrvdata_lock, flags);
303         return port;
304 }
305 
306 static 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;
316 out:
317         spin_unlock_irqrestore(&portdev->ports_lock, flags);
318 
319         return port;
320 }
321 
322 static 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;
333 out:
334         spin_unlock_irqrestore(&portdev->ports_lock, flags);
335         return port;
336 }
337 
338 static bool is_console_port(struct port *port)
339 {
340         if (port->cons.hvc)
341                 return true;
342         return false;
343 }
344 
345 static bool is_rproc_serial(const struct virtio_device *vdev)
346 {
347         return is_rproc_enabled && vdev->id.device == VIRTIO_ID_RPROC_SERIAL;
348 }
349 
350 static 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 
361 static DEFINE_SPINLOCK(dma_bufs_lock);
362 static LIST_HEAD(pending_free_dma_bufs);
363 
364 static 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 
397 static 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 
419 static 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 
472 free_buf:
473         kfree(buf);
474 fail:
475         return NULL;
476 }
477 
478 /* Callers should take appropriate locks */
479 static 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  */
502 static 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. */
517 static 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 
543 static 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 
558 static 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                         && !virtqueue_is_broken(vq))
582                         cpu_relax();
583         }
584         spin_unlock(&portdev->c_ovq_lock);
585         return 0;
586 }
587 
588 static ssize_t send_control_msg(struct port *port, unsigned int event,
589                                 unsigned int value)
590 {
591         /* Did the port get unplugged before userspace closed it? */
592         if (port->portdev)
593                 return __send_control_msg(port->portdev, port->id, event, value);
594         return 0;
595 }
596 
597 
598 /* Callers must take the port->outvq_lock */
599 static void reclaim_consumed_buffers(struct port *port)
600 {
601         struct port_buffer *buf;
602         unsigned int len;
603 
604         if (!port->portdev) {
605                 /* Device has been unplugged.  vqs are already gone. */
606                 return;
607         }
608         while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
609                 free_buf(buf, false);
610                 port->outvq_full = false;
611         }
612 }
613 
614 static ssize_t __send_to_port(struct port *port, struct scatterlist *sg,
615                               int nents, size_t in_count,
616                               void *data, bool nonblock)
617 {
618         struct virtqueue *out_vq;
619         int err;
620         unsigned long flags;
621         unsigned int len;
622 
623         out_vq = port->out_vq;
624 
625         spin_lock_irqsave(&port->outvq_lock, flags);
626 
627         reclaim_consumed_buffers(port);
628 
629         err = virtqueue_add_outbuf(out_vq, sg, nents, data, GFP_ATOMIC);
630 
631         /* Tell Host to go! */
632         virtqueue_kick(out_vq);
633 
634         if (err) {
635                 in_count = 0;
636                 goto done;
637         }
638 
639         if (out_vq->num_free == 0)
640                 port->outvq_full = true;
641 
642         if (nonblock)
643                 goto done;
644 
645         /*
646          * Wait till the host acknowledges it pushed out the data we
647          * sent.  This is done for data from the hvc_console; the tty
648          * operations are performed with spinlocks held so we can't
649          * sleep here.  An alternative would be to copy the data to a
650          * buffer and relax the spinning requirement.  The downside is
651          * we need to kmalloc a GFP_ATOMIC buffer each time the
652          * console driver writes something out.
653          */
654         while (!virtqueue_get_buf(out_vq, &len)
655                 && !virtqueue_is_broken(out_vq))
656                 cpu_relax();
657 done:
658         spin_unlock_irqrestore(&port->outvq_lock, flags);
659 
660         port->stats.bytes_sent += in_count;
661         /*
662          * We're expected to return the amount of data we wrote -- all
663          * of it
664          */
665         return in_count;
666 }
667 
668 /*
669  * Give out the data that's requested from the buffer that we have
670  * queued up.
671  */
672 static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count,
673                             bool to_user)
674 {
675         struct port_buffer *buf;
676         unsigned long flags;
677 
678         if (!out_count || !port_has_data(port))
679                 return 0;
680 
681         buf = port->inbuf;
682         out_count = min(out_count, buf->len - buf->offset);
683 
684         if (to_user) {
685                 ssize_t ret;
686 
687                 ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
688                 if (ret)
689                         return -EFAULT;
690         } else {
691                 memcpy(out_buf, buf->buf + buf->offset, out_count);
692         }
693 
694         buf->offset += out_count;
695 
696         if (buf->offset == buf->len) {
697                 /*
698                  * We're done using all the data in this buffer.
699                  * Re-queue so that the Host can send us more data.
700                  */
701                 spin_lock_irqsave(&port->inbuf_lock, flags);
702                 port->inbuf = NULL;
703 
704                 if (add_inbuf(port->in_vq, buf) < 0)
705                         dev_warn(port->dev, "failed add_buf\n");
706 
707                 spin_unlock_irqrestore(&port->inbuf_lock, flags);
708         }
709         /* Return the number of bytes actually copied */
710         return out_count;
711 }
712 
713 /* The condition that must be true for polling to end */
714 static bool will_read_block(struct port *port)
715 {
716         if (!port->guest_connected) {
717                 /* Port got hot-unplugged. Let's exit. */
718                 return false;
719         }
720         return !port_has_data(port) && port->host_connected;
721 }
722 
723 static bool will_write_block(struct port *port)
724 {
725         bool ret;
726 
727         if (!port->guest_connected) {
728                 /* Port got hot-unplugged. Let's exit. */
729                 return false;
730         }
731         if (!port->host_connected)
732                 return true;
733 
734         spin_lock_irq(&port->outvq_lock);
735         /*
736          * Check if the Host has consumed any buffers since we last
737          * sent data (this is only applicable for nonblocking ports).
738          */
739         reclaim_consumed_buffers(port);
740         ret = port->outvq_full;
741         spin_unlock_irq(&port->outvq_lock);
742 
743         return ret;
744 }
745 
746 static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
747                               size_t count, loff_t *offp)
748 {
749         struct port *port;
750         ssize_t ret;
751 
752         port = filp->private_data;
753 
754         /* Port is hot-unplugged. */
755         if (!port->guest_connected)
756                 return -ENODEV;
757 
758         if (!port_has_data(port)) {
759                 /*
760                  * If nothing's connected on the host just return 0 in
761                  * case of list_empty; this tells the userspace app
762                  * that there's no connection
763                  */
764                 if (!port->host_connected)
765                         return 0;
766                 if (filp->f_flags & O_NONBLOCK)
767                         return -EAGAIN;
768 
769                 ret = wait_event_freezable(port->waitqueue,
770                                            !will_read_block(port));
771                 if (ret < 0)
772                         return ret;
773         }
774         /* Port got hot-unplugged while we were waiting above. */
775         if (!port->guest_connected)
776                 return -ENODEV;
777         /*
778          * We could've received a disconnection message while we were
779          * waiting for more data.
780          *
781          * This check is not clubbed in the if() statement above as we
782          * might receive some data as well as the host could get
783          * disconnected after we got woken up from our wait.  So we
784          * really want to give off whatever data we have and only then
785          * check for host_connected.
786          */
787         if (!port_has_data(port) && !port->host_connected)
788                 return 0;
789 
790         return fill_readbuf(port, ubuf, count, true);
791 }
792 
793 static int wait_port_writable(struct port *port, bool nonblock)
794 {
795         int ret;
796 
797         if (will_write_block(port)) {
798                 if (nonblock)
799                         return -EAGAIN;
800 
801                 ret = wait_event_freezable(port->waitqueue,
802                                            !will_write_block(port));
803                 if (ret < 0)
804                         return ret;
805         }
806         /* Port got hot-unplugged. */
807         if (!port->guest_connected)
808                 return -ENODEV;
809 
810         return 0;
811 }
812 
813 static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
814                                size_t count, loff_t *offp)
815 {
816         struct port *port;
817         struct port_buffer *buf;
818         ssize_t ret;
819         bool nonblock;
820         struct scatterlist sg[1];
821 
822         /* Userspace could be out to fool us */
823         if (!count)
824                 return 0;
825 
826         port = filp->private_data;
827 
828         nonblock = filp->f_flags & O_NONBLOCK;
829 
830         ret = wait_port_writable(port, nonblock);
831         if (ret < 0)
832                 return ret;
833 
834         count = min((size_t)(32 * 1024), count);
835 
836         buf = alloc_buf(port->out_vq, count, 0);
837         if (!buf)
838                 return -ENOMEM;
839 
840         ret = copy_from_user(buf->buf, ubuf, count);
841         if (ret) {
842                 ret = -EFAULT;
843                 goto free_buf;
844         }
845 
846         /*
847          * We now ask send_buf() to not spin for generic ports -- we
848          * can re-use the same code path that non-blocking file
849          * descriptors take for blocking file descriptors since the
850          * wait is already done and we're certain the write will go
851          * through to the host.
852          */
853         nonblock = true;
854         sg_init_one(sg, buf->buf, count);
855         ret = __send_to_port(port, sg, 1, count, buf, nonblock);
856 
857         if (nonblock && ret > 0)
858                 goto out;
859 
860 free_buf:
861         free_buf(buf, true);
862 out:
863         return ret;
864 }
865 
866 struct sg_list {
867         unsigned int n;
868         unsigned int size;
869         size_t len;
870         struct scatterlist *sg;
871 };
872 
873 static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
874                         struct splice_desc *sd)
875 {
876         struct sg_list *sgl = sd->u.data;
877         unsigned int offset, len;
878 
879         if (sgl->n == sgl->size)
880                 return 0;
881 
882         /* Try lock this page */
883         if (buf->ops->steal(pipe, buf) == 0) {
884                 /* Get reference and unlock page for moving */
885                 get_page(buf->page);
886                 unlock_page(buf->page);
887 
888                 len = min(buf->len, sd->len);
889                 sg_set_page(&(sgl->sg[sgl->n]), buf->page, len, buf->offset);
890         } else {
891                 /* Failback to copying a page */
892                 struct page *page = alloc_page(GFP_KERNEL);
893                 char *src;
894 
895                 if (!page)
896                         return -ENOMEM;
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                 src = kmap_atomic(buf->page);
905                 memcpy(page_address(page) + offset, src + buf->offset, len);
906                 kunmap_atomic(src);
907 
908                 sg_set_page(&(sgl->sg[sgl->n]), page, len, offset);
909         }
910         sgl->n++;
911         sgl->len += len;
912 
913         return len;
914 }
915 
916 /* Faster zero-copy write by splicing */
917 static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
918                                       struct file *filp, loff_t *ppos,
919                                       size_t len, unsigned int flags)
920 {
921         struct port *port = filp->private_data;
922         struct sg_list sgl;
923         ssize_t ret;
924         struct port_buffer *buf;
925         struct splice_desc sd = {
926                 .total_len = len,
927                 .flags = flags,
928                 .pos = *ppos,
929                 .u.data = &sgl,
930         };
931 
932         /*
933          * Rproc_serial does not yet support splice. To support splice
934          * pipe_to_sg() must allocate dma-buffers and copy content from
935          * regular pages to dma pages. And alloc_buf and free_buf must
936          * support allocating and freeing such a list of dma-buffers.
937          */
938         if (is_rproc_serial(port->out_vq->vdev))
939                 return -EINVAL;
940 
941         /*
942          * pipe->nrbufs == 0 means there are no data to transfer,
943          * so this returns just 0 for no data.
944          */
945         pipe_lock(pipe);
946         if (!pipe->nrbufs) {
947                 ret = 0;
948                 goto error_out;
949         }
950 
951         ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK);
952         if (ret < 0)
953                 goto error_out;
954 
955         buf = alloc_buf(port->out_vq, 0, pipe->nrbufs);
956         if (!buf) {
957                 ret = -ENOMEM;
958                 goto error_out;
959         }
960 
961         sgl.n = 0;
962         sgl.len = 0;
963         sgl.size = pipe->nrbufs;
964         sgl.sg = buf->sg;
965         sg_init_table(sgl.sg, sgl.size);
966         ret = __splice_from_pipe(pipe, &sd, pipe_to_sg);
967         pipe_unlock(pipe);
968         if (likely(ret > 0))
969                 ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true);
970 
971         if (unlikely(ret <= 0))
972                 free_buf(buf, true);
973         return ret;
974 
975 error_out:
976         pipe_unlock(pipe);
977         return ret;
978 }
979 
980 static unsigned int port_fops_poll(struct file *filp, poll_table *wait)
981 {
982         struct port *port;
983         unsigned int ret;
984 
985         port = filp->private_data;
986         poll_wait(filp, &port->waitqueue, wait);
987 
988         if (!port->guest_connected) {
989                 /* Port got unplugged */
990                 return POLLHUP;
991         }
992         ret = 0;
993         if (!will_read_block(port))
994                 ret |= POLLIN | POLLRDNORM;
995         if (!will_write_block(port))
996                 ret |= POLLOUT;
997         if (!port->host_connected)
998                 ret |= POLLHUP;
999 
1000         return ret;
1001 }
1002 
1003 static void remove_port(struct kref *kref);
1004 
1005 static int port_fops_release(struct inode *inode, struct file *filp)
1006 {
1007         struct port *port;
1008 
1009         port = filp->private_data;
1010 
1011         /* Notify host of port being closed */
1012         send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
1013 
1014         spin_lock_irq(&port->inbuf_lock);
1015         port->guest_connected = false;
1016 
1017         discard_port_data(port);
1018 
1019         spin_unlock_irq(&port->inbuf_lock);
1020 
1021         spin_lock_irq(&port->outvq_lock);
1022         reclaim_consumed_buffers(port);
1023         spin_unlock_irq(&port->outvq_lock);
1024 
1025         reclaim_dma_bufs();
1026         /*
1027          * Locks aren't necessary here as a port can't be opened after
1028          * unplug, and if a port isn't unplugged, a kref would already
1029          * exist for the port.  Plus, taking ports_lock here would
1030          * create a dependency on other locks taken by functions
1031          * inside remove_port if we're the last holder of the port,
1032          * creating many problems.
1033          */
1034         kref_put(&port->kref, remove_port);
1035 
1036         return 0;
1037 }
1038 
1039 static int port_fops_open(struct inode *inode, struct file *filp)
1040 {
1041         struct cdev *cdev = inode->i_cdev;
1042         struct port *port;
1043         int ret;
1044 
1045         /* We get the port with a kref here */
1046         port = find_port_by_devt(cdev->dev);
1047         if (!port) {
1048                 /* Port was unplugged before we could proceed */
1049                 return -ENXIO;
1050         }
1051         filp->private_data = port;
1052 
1053         /*
1054          * Don't allow opening of console port devices -- that's done
1055          * via /dev/hvc
1056          */
1057         if (is_console_port(port)) {
1058                 ret = -ENXIO;
1059                 goto out;
1060         }
1061 
1062         /* Allow only one process to open a particular port at a time */
1063         spin_lock_irq(&port->inbuf_lock);
1064         if (port->guest_connected) {
1065                 spin_unlock_irq(&port->inbuf_lock);
1066                 ret = -EBUSY;
1067                 goto out;
1068         }
1069 
1070         port->guest_connected = true;
1071         spin_unlock_irq(&port->inbuf_lock);
1072 
1073         spin_lock_irq(&port->outvq_lock);
1074         /*
1075          * There might be a chance that we missed reclaiming a few
1076          * buffers in the window of the port getting previously closed
1077          * and opening now.
1078          */
1079         reclaim_consumed_buffers(port);
1080         spin_unlock_irq(&port->outvq_lock);
1081 
1082         nonseekable_open(inode, filp);
1083 
1084         /* Notify host of port being opened */
1085         send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
1086 
1087         return 0;
1088 out:
1089         kref_put(&port->kref, remove_port);
1090         return ret;
1091 }
1092 
1093 static int port_fops_fasync(int fd, struct file *filp, int mode)
1094 {
1095         struct port *port;
1096 
1097         port = filp->private_data;
1098         return fasync_helper(fd, filp, mode, &port->async_queue);
1099 }
1100 
1101 /*
1102  * The file operations that we support: programs in the guest can open
1103  * a console device, read from it, write to it, poll for data and
1104  * close it.  The devices are at
1105  *   /dev/vport<device number>p<port number>
1106  */
1107 static const struct file_operations port_fops = {
1108         .owner = THIS_MODULE,
1109         .open  = port_fops_open,
1110         .read  = port_fops_read,
1111         .write = port_fops_write,
1112         .splice_write = port_fops_splice_write,
1113         .poll  = port_fops_poll,
1114         .release = port_fops_release,
1115         .fasync = port_fops_fasync,
1116         .llseek = no_llseek,
1117 };
1118 
1119 /*
1120  * The put_chars() callback is pretty straightforward.
1121  *
1122  * We turn the characters into a scatter-gather list, add it to the
1123  * output queue and then kick the Host.  Then we sit here waiting for
1124  * it to finish: inefficient in theory, but in practice
1125  * implementations will do it immediately (lguest's Launcher does).
1126  */
1127 static int put_chars(u32 vtermno, const char *buf, int count)
1128 {
1129         struct port *port;
1130         struct scatterlist sg[1];
1131 
1132         if (unlikely(early_put_chars))
1133                 return early_put_chars(vtermno, buf, count);
1134 
1135         port = find_port_by_vtermno(vtermno);
1136         if (!port)
1137                 return -EPIPE;
1138 
1139         sg_init_one(sg, buf, count);
1140         return __send_to_port(port, sg, 1, count, (void *)buf, false);
1141 }
1142 
1143 /*
1144  * get_chars() is the callback from the hvc_console infrastructure
1145  * when an interrupt is received.
1146  *
1147  * We call out to fill_readbuf that gets us the required data from the
1148  * buffers that are queued up.
1149  */
1150 static int get_chars(u32 vtermno, char *buf, int count)
1151 {
1152         struct port *port;
1153 
1154         /* If we've not set up the port yet, we have no input to give. */
1155         if (unlikely(early_put_chars))
1156                 return 0;
1157 
1158         port = find_port_by_vtermno(vtermno);
1159         if (!port)
1160                 return -EPIPE;
1161 
1162         /* If we don't have an input queue yet, we can't get input. */
1163         BUG_ON(!port->in_vq);
1164 
1165         return fill_readbuf(port, buf, count, false);
1166 }
1167 
1168 static void resize_console(struct port *port)
1169 {
1170         struct virtio_device *vdev;
1171 
1172         /* The port could have been hot-unplugged */
1173         if (!port || !is_console_port(port))
1174                 return;
1175 
1176         vdev = port->portdev->vdev;
1177 
1178         /* Don't test F_SIZE at all if we're rproc: not a valid feature! */
1179         if (!is_rproc_serial(vdev) &&
1180             virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
1181                 hvc_resize(port->cons.hvc, port->cons.ws);
1182 }
1183 
1184 /* We set the configuration at this point, since we now have a tty */
1185 static int notifier_add_vio(struct hvc_struct *hp, int data)
1186 {
1187         struct port *port;
1188 
1189         port = find_port_by_vtermno(hp->vtermno);
1190         if (!port)
1191                 return -EINVAL;
1192 
1193         hp->irq_requested = 1;
1194         resize_console(port);
1195 
1196         return 0;
1197 }
1198 
1199 static void notifier_del_vio(struct hvc_struct *hp, int data)
1200 {
1201         hp->irq_requested = 0;
1202 }
1203 
1204 /* The operations for console ports. */
1205 static const struct hv_ops hv_ops = {
1206         .get_chars = get_chars,
1207         .put_chars = put_chars,
1208         .notifier_add = notifier_add_vio,
1209         .notifier_del = notifier_del_vio,
1210         .notifier_hangup = notifier_del_vio,
1211 };
1212 
1213 /*
1214  * Console drivers are initialized very early so boot messages can go
1215  * out, so we do things slightly differently from the generic virtio
1216  * initialization of the net and block drivers.
1217  *
1218  * At this stage, the console is output-only.  It's too early to set
1219  * up a virtqueue, so we let the drivers do some boutique early-output
1220  * thing.
1221  */
1222 int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
1223 {
1224         early_put_chars = put_chars;
1225         return hvc_instantiate(0, 0, &hv_ops);
1226 }
1227 
1228 static int init_port_console(struct port *port)
1229 {
1230         int ret;
1231 
1232         /*
1233          * The Host's telling us this port is a console port.  Hook it
1234          * up with an hvc console.
1235          *
1236          * To set up and manage our virtual console, we call
1237          * hvc_alloc().
1238          *
1239          * The first argument of hvc_alloc() is the virtual console
1240          * number.  The second argument is the parameter for the
1241          * notification mechanism (like irq number).  We currently
1242          * leave this as zero, virtqueues have implicit notifications.
1243          *
1244          * The third argument is a "struct hv_ops" containing the
1245          * put_chars() get_chars(), notifier_add() and notifier_del()
1246          * pointers.  The final argument is the output buffer size: we
1247          * can do any size, so we put PAGE_SIZE here.
1248          */
1249         port->cons.vtermno = pdrvdata.next_vtermno;
1250 
1251         port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
1252         if (IS_ERR(port->cons.hvc)) {
1253                 ret = PTR_ERR(port->cons.hvc);
1254                 dev_err(port->dev,
1255                         "error %d allocating hvc for port\n", ret);
1256                 port->cons.hvc = NULL;
1257                 return ret;
1258         }
1259         spin_lock_irq(&pdrvdata_lock);
1260         pdrvdata.next_vtermno++;
1261         list_add_tail(&port->cons.list, &pdrvdata.consoles);
1262         spin_unlock_irq(&pdrvdata_lock);
1263         port->guest_connected = true;
1264 
1265         /*
1266          * Start using the new console output if this is the first
1267          * console to come up.
1268          */
1269         if (early_put_chars)
1270                 early_put_chars = NULL;
1271 
1272         /* Notify host of port being opened */
1273         send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1274 
1275         return 0;
1276 }
1277 
1278 static ssize_t show_port_name(struct device *dev,
1279                               struct device_attribute *attr, char *buffer)
1280 {
1281         struct port *port;
1282 
1283         port = dev_get_drvdata(dev);
1284 
1285         return sprintf(buffer, "%s\n", port->name);
1286 }
1287 
1288 static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
1289 
1290 static struct attribute *port_sysfs_entries[] = {
1291         &dev_attr_name.attr,
1292         NULL
1293 };
1294 
1295 static struct attribute_group port_attribute_group = {
1296         .name = NULL,           /* put in device directory */
1297         .attrs = port_sysfs_entries,
1298 };
1299 
1300 static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
1301                             size_t count, loff_t *offp)
1302 {
1303         struct port *port;
1304         char *buf;
1305         ssize_t ret, out_offset, out_count;
1306 
1307         out_count = 1024;
1308         buf = kmalloc(out_count, GFP_KERNEL);
1309         if (!buf)
1310                 return -ENOMEM;
1311 
1312         port = filp->private_data;
1313         out_offset = 0;
1314         out_offset += snprintf(buf + out_offset, out_count,
1315                                "name: %s\n", port->name ? port->name : "");
1316         out_offset += snprintf(buf + out_offset, out_count - out_offset,
1317                                "guest_connected: %d\n", port->guest_connected);
1318         out_offset += snprintf(buf + out_offset, out_count - out_offset,
1319                                "host_connected: %d\n", port->host_connected);
1320         out_offset += snprintf(buf + out_offset, out_count - out_offset,
1321                                "outvq_full: %d\n", port->outvq_full);
1322         out_offset += snprintf(buf + out_offset, out_count - out_offset,
1323                                "bytes_sent: %lu\n", port->stats.bytes_sent);
1324         out_offset += snprintf(buf + out_offset, out_count - out_offset,
1325                                "bytes_received: %lu\n",
1326                                port->stats.bytes_received);
1327         out_offset += snprintf(buf + out_offset, out_count - out_offset,
1328                                "bytes_discarded: %lu\n",
1329                                port->stats.bytes_discarded);
1330         out_offset += snprintf(buf + out_offset, out_count - out_offset,
1331                                "is_console: %s\n",
1332                                is_console_port(port) ? "yes" : "no");
1333         out_offset += snprintf(buf + out_offset, out_count - out_offset,
1334                                "console_vtermno: %u\n", port->cons.vtermno);
1335 
1336         ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
1337         kfree(buf);
1338         return ret;
1339 }
1340 
1341 static const struct file_operations port_debugfs_ops = {
1342         .owner = THIS_MODULE,
1343         .open  = simple_open,
1344         .read  = debugfs_read,
1345 };
1346 
1347 static void set_console_size(struct port *port, u16 rows, u16 cols)
1348 {
1349         if (!port || !is_console_port(port))
1350                 return;
1351 
1352         port->cons.ws.ws_row = rows;
1353         port->cons.ws.ws_col = cols;
1354 }
1355 
1356 static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
1357 {
1358         struct port_buffer *buf;
1359         unsigned int nr_added_bufs;
1360         int ret;
1361 
1362         nr_added_bufs = 0;
1363         do {
1364                 buf = alloc_buf(vq, PAGE_SIZE, 0);
1365                 if (!buf)
1366                         break;
1367 
1368                 spin_lock_irq(lock);
1369                 ret = add_inbuf(vq, buf);
1370                 if (ret < 0) {
1371                         spin_unlock_irq(lock);
1372                         free_buf(buf, true);
1373                         break;
1374                 }
1375                 nr_added_bufs++;
1376                 spin_unlock_irq(lock);
1377         } while (ret > 0);
1378 
1379         return nr_added_bufs;
1380 }
1381 
1382 static void send_sigio_to_port(struct port *port)
1383 {
1384         if (port->async_queue && port->guest_connected)
1385                 kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
1386 }
1387 
1388 static int add_port(struct ports_device *portdev, u32 id)
1389 {
1390         char debugfs_name[16];
1391         struct port *port;
1392         struct port_buffer *buf;
1393         dev_t devt;
1394         unsigned int nr_added_bufs;
1395         int err;
1396 
1397         port = kmalloc(sizeof(*port), GFP_KERNEL);
1398         if (!port) {
1399                 err = -ENOMEM;
1400                 goto fail;
1401         }
1402         kref_init(&port->kref);
1403 
1404         port->portdev = portdev;
1405         port->id = id;
1406 
1407         port->name = NULL;
1408         port->inbuf = NULL;
1409         port->cons.hvc = NULL;
1410         port->async_queue = NULL;
1411 
1412         port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
1413 
1414         port->host_connected = port->guest_connected = false;
1415         port->stats = (struct port_stats) { 0 };
1416 
1417         port->outvq_full = false;
1418 
1419         port->in_vq = portdev->in_vqs[port->id];
1420         port->out_vq = portdev->out_vqs[port->id];
1421 
1422         port->cdev = cdev_alloc();
1423         if (!port->cdev) {
1424                 dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
1425                 err = -ENOMEM;
1426                 goto free_port;
1427         }
1428         port->cdev->ops = &port_fops;
1429 
1430         devt = MKDEV(portdev->chr_major, id);
1431         err = cdev_add(port->cdev, devt, 1);
1432         if (err < 0) {
1433                 dev_err(&port->portdev->vdev->dev,
1434                         "Error %d adding cdev for port %u\n", err, id);
1435                 goto free_cdev;
1436         }
1437         port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
1438                                   devt, port, "vport%up%u",
1439                                   port->portdev->vdev->index, id);
1440         if (IS_ERR(port->dev)) {
1441                 err = PTR_ERR(port->dev);
1442                 dev_err(&port->portdev->vdev->dev,
1443                         "Error %d creating device for port %u\n",
1444                         err, id);
1445                 goto free_cdev;
1446         }
1447 
1448         spin_lock_init(&port->inbuf_lock);
1449         spin_lock_init(&port->outvq_lock);
1450         init_waitqueue_head(&port->waitqueue);
1451 
1452         /* Fill the in_vq with buffers so the host can send us data. */
1453         nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
1454         if (!nr_added_bufs) {
1455                 dev_err(port->dev, "Error allocating inbufs\n");
1456                 err = -ENOMEM;
1457                 goto free_device;
1458         }
1459 
1460         if (is_rproc_serial(port->portdev->vdev))
1461                 /*
1462                  * For rproc_serial assume remote processor is connected.
1463                  * rproc_serial does not want the console port, only
1464                  * the generic port implementation.
1465                  */
1466                 port->host_connected = true;
1467         else if (!use_multiport(port->portdev)) {
1468                 /*
1469                  * If we're not using multiport support,
1470                  * this has to be a console port.
1471                  */
1472                 err = init_port_console(port);
1473                 if (err)
1474                         goto free_inbufs;
1475         }
1476 
1477         spin_lock_irq(&portdev->ports_lock);
1478         list_add_tail(&port->list, &port->portdev->ports);
1479         spin_unlock_irq(&portdev->ports_lock);
1480 
1481         /*
1482          * Tell the Host we're set so that it can send us various
1483          * configuration parameters for this port (eg, port name,
1484          * caching, whether this is a console port, etc.)
1485          */
1486         send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1487 
1488         if (pdrvdata.debugfs_dir) {
1489                 /*
1490                  * Finally, create the debugfs file that we can use to
1491                  * inspect a port's state at any time
1492                  */
1493                 sprintf(debugfs_name, "vport%up%u",
1494                         port->portdev->vdev->index, id);
1495                 port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
1496                                                          pdrvdata.debugfs_dir,
1497                                                          port,
1498                                                          &port_debugfs_ops);
1499         }
1500         return 0;
1501 
1502 free_inbufs:
1503         while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1504                 free_buf(buf, true);
1505 free_device:
1506         device_destroy(pdrvdata.class, port->dev->devt);
1507 free_cdev:
1508         cdev_del(port->cdev);
1509 free_port:
1510         kfree(port);
1511 fail:
1512         /* The host might want to notify management sw about port add failure */
1513         __send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
1514         return err;
1515 }
1516 
1517 /* No users remain, remove all port-specific data. */
1518 static void remove_port(struct kref *kref)
1519 {
1520         struct port *port;
1521 
1522         port = container_of(kref, struct port, kref);
1523 
1524         kfree(port);
1525 }
1526 
1527 static void remove_port_data(struct port *port)
1528 {
1529         struct port_buffer *buf;
1530 
1531         spin_lock_irq(&port->inbuf_lock);
1532         /* Remove unused data this port might have received. */
1533         discard_port_data(port);
1534 
1535         /* Remove buffers we queued up for the Host to send us data in. */
1536         while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1537                 free_buf(buf, true);
1538         spin_unlock_irq(&port->inbuf_lock);
1539 
1540         spin_lock_irq(&port->outvq_lock);
1541         reclaim_consumed_buffers(port);
1542 
1543         /* Free pending buffers from the out-queue. */
1544         while ((buf = virtqueue_detach_unused_buf(port->out_vq)))
1545                 free_buf(buf, true);
1546         spin_unlock_irq(&port->outvq_lock);
1547 }
1548 
1549 /*
1550  * Port got unplugged.  Remove port from portdev's list and drop the
1551  * kref reference.  If no userspace has this port opened, it will
1552  * result in immediate removal the port.
1553  */
1554 static void unplug_port(struct port *port)
1555 {
1556         spin_lock_irq(&port->portdev->ports_lock);
1557         list_del(&port->list);
1558         spin_unlock_irq(&port->portdev->ports_lock);
1559 
1560         spin_lock_irq(&port->inbuf_lock);
1561         if (port->guest_connected) {
1562                 /* Let the app know the port is going down. */
1563                 send_sigio_to_port(port);
1564 
1565                 /* Do this after sigio is actually sent */
1566                 port->guest_connected = false;
1567                 port->host_connected = false;
1568 
1569                 wake_up_interruptible(&port->waitqueue);
1570         }
1571         spin_unlock_irq(&port->inbuf_lock);
1572 
1573         if (is_console_port(port)) {
1574                 spin_lock_irq(&pdrvdata_lock);
1575                 list_del(&port->cons.list);
1576                 spin_unlock_irq(&pdrvdata_lock);
1577                 hvc_remove(port->cons.hvc);
1578         }
1579 
1580         remove_port_data(port);
1581 
1582         /*
1583          * We should just assume the device itself has gone off --
1584          * else a close on an open port later will try to send out a
1585          * control message.
1586          */
1587         port->portdev = NULL;
1588 
1589         sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1590         device_destroy(pdrvdata.class, port->dev->devt);
1591         cdev_del(port->cdev);
1592 
1593         debugfs_remove(port->debugfs_file);
1594         kfree(port->name);
1595 
1596         /*
1597          * Locks around here are not necessary - a port can't be
1598          * opened after we removed the port struct from ports_list
1599          * above.
1600          */
1601         kref_put(&port->kref, remove_port);
1602 }
1603 
1604 /* Any private messages that the Host and Guest want to share */
1605 static void handle_control_message(struct ports_device *portdev,
1606                                    struct port_buffer *buf)
1607 {
1608         struct virtio_console_control *cpkt;
1609         struct port *port;
1610         size_t name_size;
1611         int err;
1612 
1613         cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1614 
1615         port = find_port_by_id(portdev, cpkt->id);
1616         if (!port && cpkt->event != VIRTIO_CONSOLE_PORT_ADD) {
1617                 /* No valid header at start of buffer.  Drop it. */
1618                 dev_dbg(&portdev->vdev->dev,
1619                         "Invalid index %u in control packet\n", cpkt->id);
1620                 return;
1621         }
1622 
1623         switch (cpkt->event) {
1624         case VIRTIO_CONSOLE_PORT_ADD:
1625                 if (port) {
1626                         dev_dbg(&portdev->vdev->dev,
1627                                 "Port %u already added\n", port->id);
1628                         send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1629                         break;
1630                 }
1631                 if (cpkt->id >= portdev->config.max_nr_ports) {
1632                         dev_warn(&portdev->vdev->dev,
1633                                 "Request for adding port with out-of-bound id %u, max. supported id: %u\n",
1634                                 cpkt->id, portdev->config.max_nr_ports - 1);
1635                         break;
1636                 }
1637                 add_port(portdev, cpkt->id);
1638                 break;
1639         case VIRTIO_CONSOLE_PORT_REMOVE:
1640                 unplug_port(port);
1641                 break;
1642         case VIRTIO_CONSOLE_CONSOLE_PORT:
1643                 if (!cpkt->value)
1644                         break;
1645                 if (is_console_port(port))
1646                         break;
1647 
1648                 init_port_console(port);
1649                 complete(&early_console_added);
1650                 /*
1651                  * Could remove the port here in case init fails - but
1652                  * have to notify the host first.
1653                  */
1654                 break;
1655         case VIRTIO_CONSOLE_RESIZE: {
1656                 struct {
1657                         __u16 rows;
1658                         __u16 cols;
1659                 } size;
1660 
1661                 if (!is_console_port(port))
1662                         break;
1663 
1664                 memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1665                        sizeof(size));
1666                 set_console_size(port, size.rows, size.cols);
1667 
1668                 port->cons.hvc->irq_requested = 1;
1669                 resize_console(port);
1670                 break;
1671         }
1672         case VIRTIO_CONSOLE_PORT_OPEN:
1673                 port->host_connected = cpkt->value;
1674                 wake_up_interruptible(&port->waitqueue);
1675                 /*
1676                  * If the host port got closed and the host had any
1677                  * unconsumed buffers, we'll be able to reclaim them
1678                  * now.
1679                  */
1680                 spin_lock_irq(&port->outvq_lock);
1681                 reclaim_consumed_buffers(port);
1682                 spin_unlock_irq(&port->outvq_lock);
1683 
1684                 /*
1685                  * If the guest is connected, it'll be interested in
1686                  * knowing the host connection state changed.
1687                  */
1688                 spin_lock_irq(&port->inbuf_lock);
1689                 send_sigio_to_port(port);
1690                 spin_unlock_irq(&port->inbuf_lock);
1691                 break;
1692         case VIRTIO_CONSOLE_PORT_NAME:
1693                 /*
1694                  * If we woke up after hibernation, we can get this
1695                  * again.  Skip it in that case.
1696                  */
1697                 if (port->name)
1698                         break;
1699 
1700                 /*
1701                  * Skip the size of the header and the cpkt to get the size
1702                  * of the name that was sent
1703                  */
1704                 name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1705 
1706                 port->name = kmalloc(name_size, GFP_KERNEL);
1707                 if (!port->name) {
1708                         dev_err(port->dev,
1709                                 "Not enough space to store port name\n");
1710                         break;
1711                 }
1712                 strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1713                         name_size - 1);
1714                 port->name[name_size - 1] = 0;
1715 
1716                 /*
1717                  * Since we only have one sysfs attribute, 'name',
1718                  * create it only if we have a name for the port.
1719                  */
1720                 err = sysfs_create_group(&port->dev->kobj,
1721                                          &port_attribute_group);
1722                 if (err) {
1723                         dev_err(port->dev,
1724                                 "Error %d creating sysfs device attributes\n",
1725                                 err);
1726                 } else {
1727                         /*
1728                          * Generate a udev event so that appropriate
1729                          * symlinks can be created based on udev
1730                          * rules.
1731                          */
1732                         kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1733                 }
1734                 break;
1735         }
1736 }
1737 
1738 static void control_work_handler(struct work_struct *work)
1739 {
1740         struct ports_device *portdev;
1741         struct virtqueue *vq;
1742         struct port_buffer *buf;
1743         unsigned int len;
1744 
1745         portdev = container_of(work, struct ports_device, control_work);
1746         vq = portdev->c_ivq;
1747 
1748         spin_lock(&portdev->c_ivq_lock);
1749         while ((buf = virtqueue_get_buf(vq, &len))) {
1750                 spin_unlock(&portdev->c_ivq_lock);
1751 
1752                 buf->len = len;
1753                 buf->offset = 0;
1754 
1755                 handle_control_message(portdev, buf);
1756 
1757                 spin_lock(&portdev->c_ivq_lock);
1758                 if (add_inbuf(portdev->c_ivq, buf) < 0) {
1759                         dev_warn(&portdev->vdev->dev,
1760                                  "Error adding buffer to queue\n");
1761                         free_buf(buf, false);
1762                 }
1763         }
1764         spin_unlock(&portdev->c_ivq_lock);
1765 }
1766 
1767 static void out_intr(struct virtqueue *vq)
1768 {
1769         struct port *port;
1770 
1771         port = find_port_by_vq(vq->vdev->priv, vq);
1772         if (!port)
1773                 return;
1774 
1775         wake_up_interruptible(&port->waitqueue);
1776 }
1777 
1778 static void in_intr(struct virtqueue *vq)
1779 {
1780         struct port *port;
1781         unsigned long flags;
1782 
1783         port = find_port_by_vq(vq->vdev->priv, vq);
1784         if (!port)
1785                 return;
1786 
1787         spin_lock_irqsave(&port->inbuf_lock, flags);
1788         port->inbuf = get_inbuf(port);
1789 
1790         /*
1791          * Normally the port should not accept data when the port is
1792          * closed. For generic serial ports, the host won't (shouldn't)
1793          * send data till the guest is connected. But this condition
1794          * can be reached when a console port is not yet connected (no
1795          * tty is spawned) and the other side sends out data over the
1796          * vring, or when a remote devices start sending data before
1797          * the ports are opened.
1798          *
1799          * A generic serial port will discard data if not connected,
1800          * while console ports and rproc-serial ports accepts data at
1801          * any time. rproc-serial is initiated with guest_connected to
1802          * false because port_fops_open expects this. Console ports are
1803          * hooked up with an HVC console and is initialized with
1804          * guest_connected to true.
1805          */
1806 
1807         if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
1808                 discard_port_data(port);
1809 
1810         /* Send a SIGIO indicating new data in case the process asked for it */
1811         send_sigio_to_port(port);
1812 
1813         spin_unlock_irqrestore(&port->inbuf_lock, flags);
1814 
1815         wake_up_interruptible(&port->waitqueue);
1816 
1817         if (is_console_port(port) && hvc_poll(port->cons.hvc))
1818                 hvc_kick();
1819 }
1820 
1821 static void control_intr(struct virtqueue *vq)
1822 {
1823         struct ports_device *portdev;
1824 
1825         portdev = vq->vdev->priv;
1826         schedule_work(&portdev->control_work);
1827 }
1828 
1829 static void config_intr(struct virtio_device *vdev)
1830 {
1831         struct ports_device *portdev;
1832 
1833         portdev = vdev->priv;
1834 
1835         if (!use_multiport(portdev)) {
1836                 struct port *port;
1837                 u16 rows, cols;
1838 
1839                 virtio_cread(vdev, struct virtio_console_config, cols, &cols);
1840                 virtio_cread(vdev, struct virtio_console_config, rows, &rows);
1841 
1842                 port = find_port_by_id(portdev, 0);
1843                 set_console_size(port, rows, cols);
1844 
1845                 /*
1846                  * We'll use this way of resizing only for legacy
1847                  * support.  For newer userspace
1848                  * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1849                  * to indicate console size changes so that it can be
1850                  * done per-port.
1851                  */
1852                 resize_console(port);
1853         }
1854 }
1855 
1856 static int init_vqs(struct ports_device *portdev)
1857 {
1858         vq_callback_t **io_callbacks;
1859         char **io_names;
1860         struct virtqueue **vqs;
1861         u32 i, j, nr_ports, nr_queues;
1862         int err;
1863 
1864         nr_ports = portdev->config.max_nr_ports;
1865         nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1866 
1867         vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
1868         io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
1869         io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
1870         portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1871                                   GFP_KERNEL);
1872         portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1873                                    GFP_KERNEL);
1874         if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
1875             !portdev->out_vqs) {
1876                 err = -ENOMEM;
1877                 goto free;
1878         }
1879 
1880         /*
1881          * For backward compat (newer host but older guest), the host
1882          * spawns a console port first and also inits the vqs for port
1883          * 0 before others.
1884          */
1885         j = 0;
1886         io_callbacks[j] = in_intr;
1887         io_callbacks[j + 1] = out_intr;
1888         io_names[j] = "input";
1889         io_names[j + 1] = "output";
1890         j += 2;
1891 
1892         if (use_multiport(portdev)) {
1893                 io_callbacks[j] = control_intr;
1894                 io_callbacks[j + 1] = NULL;
1895                 io_names[j] = "control-i";
1896                 io_names[j + 1] = "control-o";
1897 
1898                 for (i = 1; i < nr_ports; i++) {
1899                         j += 2;
1900                         io_callbacks[j] = in_intr;
1901                         io_callbacks[j + 1] = out_intr;
1902                         io_names[j] = "input";
1903                         io_names[j + 1] = "output";
1904                 }
1905         }
1906         /* Find the queues. */
1907         err = portdev->vdev->config->find_vqs(portdev->vdev, nr_queues, vqs,
1908                                               io_callbacks,
1909                                               (const char **)io_names);
1910         if (err)
1911                 goto free;
1912 
1913         j = 0;
1914         portdev->in_vqs[0] = vqs[0];
1915         portdev->out_vqs[0] = vqs[1];
1916         j += 2;
1917         if (use_multiport(portdev)) {
1918                 portdev->c_ivq = vqs[j];
1919                 portdev->c_ovq = vqs[j + 1];
1920 
1921                 for (i = 1; i < nr_ports; i++) {
1922                         j += 2;
1923                         portdev->in_vqs[i] = vqs[j];
1924                         portdev->out_vqs[i] = vqs[j + 1];
1925                 }
1926         }
1927         kfree(io_names);
1928         kfree(io_callbacks);
1929         kfree(vqs);
1930 
1931         return 0;
1932 
1933 free:
1934         kfree(portdev->out_vqs);
1935         kfree(portdev->in_vqs);
1936         kfree(io_names);
1937         kfree(io_callbacks);
1938         kfree(vqs);
1939 
1940         return err;
1941 }
1942 
1943 static const struct file_operations portdev_fops = {
1944         .owner = THIS_MODULE,
1945 };
1946 
1947 static void remove_vqs(struct ports_device *portdev)
1948 {
1949         portdev->vdev->config->del_vqs(portdev->vdev);
1950         kfree(portdev->in_vqs);
1951         kfree(portdev->out_vqs);
1952 }
1953 
1954 static void remove_controlq_data(struct ports_device *portdev)
1955 {
1956         struct port_buffer *buf;
1957         unsigned int len;
1958 
1959         if (!use_multiport(portdev))
1960                 return;
1961 
1962         while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
1963                 free_buf(buf, true);
1964 
1965         while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
1966                 free_buf(buf, true);
1967 }
1968 
1969 /*
1970  * Once we're further in boot, we get probed like any other virtio
1971  * device.
1972  *
1973  * If the host also supports multiple console ports, we check the
1974  * config space to see how many ports the host has spawned.  We
1975  * initialize each port found.
1976  */
1977 static int virtcons_probe(struct virtio_device *vdev)
1978 {
1979         struct ports_device *portdev;
1980         int err;
1981         bool multiport;
1982         bool early = early_put_chars != NULL;
1983 
1984         /* Ensure to read early_put_chars now */
1985         barrier();
1986 
1987         portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
1988         if (!portdev) {
1989                 err = -ENOMEM;
1990                 goto fail;
1991         }
1992 
1993         /* Attach this portdev to this virtio_device, and vice-versa. */
1994         portdev->vdev = vdev;
1995         vdev->priv = portdev;
1996 
1997         portdev->chr_major = register_chrdev(0, "virtio-portsdev",
1998                                              &portdev_fops);
1999         if (portdev->chr_major < 0) {
2000                 dev_err(&vdev->dev,
2001                         "Error %d registering chrdev for device %u\n",
2002                         portdev->chr_major, vdev->index);
2003                 err = portdev->chr_major;
2004                 goto free;
2005         }
2006 
2007         multiport = false;
2008         portdev->config.max_nr_ports = 1;
2009 
2010         /* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
2011         if (!is_rproc_serial(vdev) &&
2012             virtio_cread_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
2013                                  struct virtio_console_config, max_nr_ports,
2014                                  &portdev->config.max_nr_ports) == 0) {
2015                 multiport = true;
2016         }
2017 
2018         err = init_vqs(portdev);
2019         if (err < 0) {
2020                 dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
2021                 goto free_chrdev;
2022         }
2023 
2024         spin_lock_init(&portdev->ports_lock);
2025         INIT_LIST_HEAD(&portdev->ports);
2026 
2027         virtio_device_ready(portdev->vdev);
2028 
2029         if (multiport) {
2030                 unsigned int nr_added_bufs;
2031 
2032                 spin_lock_init(&portdev->c_ivq_lock);
2033                 spin_lock_init(&portdev->c_ovq_lock);
2034                 INIT_WORK(&portdev->control_work, &control_work_handler);
2035 
2036                 nr_added_bufs = fill_queue(portdev->c_ivq,
2037                                            &portdev->c_ivq_lock);
2038                 if (!nr_added_bufs) {
2039                         dev_err(&vdev->dev,
2040                                 "Error allocating buffers for control queue\n");
2041                         err = -ENOMEM;
2042                         goto free_vqs;
2043                 }
2044         } else {
2045                 /*
2046                  * For backward compatibility: Create a console port
2047                  * if we're running on older host.
2048                  */
2049                 add_port(portdev, 0);
2050         }
2051 
2052         spin_lock_irq(&pdrvdata_lock);
2053         list_add_tail(&portdev->list, &pdrvdata.portdevs);
2054         spin_unlock_irq(&pdrvdata_lock);
2055 
2056         __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2057                            VIRTIO_CONSOLE_DEVICE_READY, 1);
2058 
2059         /*
2060          * If there was an early virtio console, assume that there are no
2061          * other consoles. We need to wait until the hvc_alloc matches the
2062          * hvc_instantiate, otherwise tty_open will complain, resulting in
2063          * a "Warning: unable to open an initial console" boot failure.
2064          * Without multiport this is done in add_port above. With multiport
2065          * this might take some host<->guest communication - thus we have to
2066          * wait.
2067          */
2068         if (multiport && early)
2069                 wait_for_completion(&early_console_added);
2070 
2071         return 0;
2072 
2073 free_vqs:
2074         /* The host might want to notify mgmt sw about device add failure */
2075         __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2076                            VIRTIO_CONSOLE_DEVICE_READY, 0);
2077         remove_vqs(portdev);
2078 free_chrdev:
2079         unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2080 free:
2081         kfree(portdev);
2082 fail:
2083         return err;
2084 }
2085 
2086 static void virtcons_remove(struct virtio_device *vdev)
2087 {
2088         struct ports_device *portdev;
2089         struct port *port, *port2;
2090 
2091         portdev = vdev->priv;
2092 
2093         spin_lock_irq(&pdrvdata_lock);
2094         list_del(&portdev->list);
2095         spin_unlock_irq(&pdrvdata_lock);
2096 
2097         /* Disable interrupts for vqs */
2098         vdev->config->reset(vdev);
2099         /* Finish up work that's lined up */
2100         if (use_multiport(portdev))
2101                 cancel_work_sync(&portdev->control_work);
2102 
2103         list_for_each_entry_safe(port, port2, &portdev->ports, list)
2104                 unplug_port(port);
2105 
2106         unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2107 
2108         /*
2109          * When yanking out a device, we immediately lose the
2110          * (device-side) queues.  So there's no point in keeping the
2111          * guest side around till we drop our final reference.  This
2112          * also means that any ports which are in an open state will
2113          * have to just stop using the port, as the vqs are going
2114          * away.
2115          */
2116         remove_controlq_data(portdev);
2117         remove_vqs(portdev);
2118         kfree(portdev);
2119 }
2120 
2121 static struct virtio_device_id id_table[] = {
2122         { VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
2123         { 0 },
2124 };
2125 
2126 static unsigned int features[] = {
2127         VIRTIO_CONSOLE_F_SIZE,
2128         VIRTIO_CONSOLE_F_MULTIPORT,
2129 };
2130 
2131 static struct virtio_device_id rproc_serial_id_table[] = {
2132 #if IS_ENABLED(CONFIG_REMOTEPROC)
2133         { VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
2134 #endif
2135         { 0 },
2136 };
2137 
2138 static unsigned int rproc_serial_features[] = {
2139 };
2140 
2141 #ifdef CONFIG_PM_SLEEP
2142 static int virtcons_freeze(struct virtio_device *vdev)
2143 {
2144         struct ports_device *portdev;
2145         struct port *port;
2146 
2147         portdev = vdev->priv;
2148 
2149         vdev->config->reset(vdev);
2150 
2151         virtqueue_disable_cb(portdev->c_ivq);
2152         cancel_work_sync(&portdev->control_work);
2153         /*
2154          * Once more: if control_work_handler() was running, it would
2155          * enable the cb as the last step.
2156          */
2157         virtqueue_disable_cb(portdev->c_ivq);
2158         remove_controlq_data(portdev);
2159 
2160         list_for_each_entry(port, &portdev->ports, list) {
2161                 virtqueue_disable_cb(port->in_vq);
2162                 virtqueue_disable_cb(port->out_vq);
2163                 /*
2164                  * We'll ask the host later if the new invocation has
2165                  * the port opened or closed.
2166                  */
2167                 port->host_connected = false;
2168                 remove_port_data(port);
2169         }
2170         remove_vqs(portdev);
2171 
2172         return 0;
2173 }
2174 
2175 static int virtcons_restore(struct virtio_device *vdev)
2176 {
2177         struct ports_device *portdev;
2178         struct port *port;
2179         int ret;
2180 
2181         portdev = vdev->priv;
2182 
2183         ret = init_vqs(portdev);
2184         if (ret)
2185                 return ret;
2186 
2187         virtio_device_ready(portdev->vdev);
2188 
2189         if (use_multiport(portdev))
2190                 fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2191 
2192         list_for_each_entry(port, &portdev->ports, list) {
2193                 port->in_vq = portdev->in_vqs[port->id];
2194                 port->out_vq = portdev->out_vqs[port->id];
2195 
2196                 fill_queue(port->in_vq, &port->inbuf_lock);
2197 
2198                 /* Get port open/close status on the host */
2199                 send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
2200 
2201                 /*
2202                  * If a port was open at the time of suspending, we
2203                  * have to let the host know that it's still open.
2204                  */
2205                 if (port->guest_connected)
2206                         send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
2207         }
2208         return 0;
2209 }
2210 #endif
2211 
2212 static struct virtio_driver virtio_console = {
2213         .feature_table = features,
2214         .feature_table_size = ARRAY_SIZE(features),
2215         .driver.name =  KBUILD_MODNAME,
2216         .driver.owner = THIS_MODULE,
2217         .id_table =     id_table,
2218         .probe =        virtcons_probe,
2219         .remove =       virtcons_remove,
2220         .config_changed = config_intr,
2221 #ifdef CONFIG_PM_SLEEP
2222         .freeze =       virtcons_freeze,
2223         .restore =      virtcons_restore,
2224 #endif
2225 };
2226 
2227 static struct virtio_driver virtio_rproc_serial = {
2228         .feature_table = rproc_serial_features,
2229         .feature_table_size = ARRAY_SIZE(rproc_serial_features),
2230         .driver.name =  "virtio_rproc_serial",
2231         .driver.owner = THIS_MODULE,
2232         .id_table =     rproc_serial_id_table,
2233         .probe =        virtcons_probe,
2234         .remove =       virtcons_remove,
2235 };
2236 
2237 static int __init init(void)
2238 {
2239         int err;
2240 
2241         pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
2242         if (IS_ERR(pdrvdata.class)) {
2243                 err = PTR_ERR(pdrvdata.class);
2244                 pr_err("Error %d creating virtio-ports class\n", err);
2245                 return err;
2246         }
2247 
2248         pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
2249         if (!pdrvdata.debugfs_dir)
2250                 pr_warning("Error creating debugfs dir for virtio-ports\n");
2251         INIT_LIST_HEAD(&pdrvdata.consoles);
2252         INIT_LIST_HEAD(&pdrvdata.portdevs);
2253 
2254         err = register_virtio_driver(&virtio_console);
2255         if (err < 0) {
2256                 pr_err("Error %d registering virtio driver\n", err);
2257                 goto free;
2258         }
2259         err = register_virtio_driver(&virtio_rproc_serial);
2260         if (err < 0) {
2261                 pr_err("Error %d registering virtio rproc serial driver\n",
2262                        err);
2263                 goto unregister;
2264         }
2265         return 0;
2266 unregister:
2267         unregister_virtio_driver(&virtio_console);
2268 free:
2269         debugfs_remove_recursive(pdrvdata.debugfs_dir);
2270         class_destroy(pdrvdata.class);
2271         return err;
2272 }
2273 
2274 static void __exit fini(void)
2275 {
2276         reclaim_dma_bufs();
2277 
2278         unregister_virtio_driver(&virtio_console);
2279         unregister_virtio_driver(&virtio_rproc_serial);
2280 
2281         class_destroy(pdrvdata.class);
2282         debugfs_remove_recursive(pdrvdata.debugfs_dir);
2283 }
2284 module_init(init);
2285 module_exit(fini);
2286 
2287 MODULE_DEVICE_TABLE(virtio, id_table);
2288 MODULE_DESCRIPTION("Virtio console driver");
2289 MODULE_LICENSE("GPL");
2290 

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