Version:  2.0.40 2.2.26 2.4.37 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 3.19

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 __virtio_test_bit(portdev->vdev, 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 = cpu_to_virtio32(portdev->vdev, port_id);
570         cpkt.event = cpu_to_virtio16(portdev->vdev, event);
571         cpkt.value = cpu_to_virtio16(portdev->vdev, 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 __user *out_buf,
673                             size_t out_count, 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((__force char *)out_buf, buf->buf + buf->offset,
692                        out_count);
693         }
694 
695         buf->offset += out_count;
696 
697         if (buf->offset == buf->len) {
698                 /*
699                  * We're done using all the data in this buffer.
700                  * Re-queue so that the Host can send us more data.
701                  */
702                 spin_lock_irqsave(&port->inbuf_lock, flags);
703                 port->inbuf = NULL;
704 
705                 if (add_inbuf(port->in_vq, buf) < 0)
706                         dev_warn(port->dev, "failed add_buf\n");
707 
708                 spin_unlock_irqrestore(&port->inbuf_lock, flags);
709         }
710         /* Return the number of bytes actually copied */
711         return out_count;
712 }
713 
714 /* The condition that must be true for polling to end */
715 static bool will_read_block(struct port *port)
716 {
717         if (!port->guest_connected) {
718                 /* Port got hot-unplugged. Let's exit. */
719                 return false;
720         }
721         return !port_has_data(port) && port->host_connected;
722 }
723 
724 static bool will_write_block(struct port *port)
725 {
726         bool ret;
727 
728         if (!port->guest_connected) {
729                 /* Port got hot-unplugged. Let's exit. */
730                 return false;
731         }
732         if (!port->host_connected)
733                 return true;
734 
735         spin_lock_irq(&port->outvq_lock);
736         /*
737          * Check if the Host has consumed any buffers since we last
738          * sent data (this is only applicable for nonblocking ports).
739          */
740         reclaim_consumed_buffers(port);
741         ret = port->outvq_full;
742         spin_unlock_irq(&port->outvq_lock);
743 
744         return ret;
745 }
746 
747 static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
748                               size_t count, loff_t *offp)
749 {
750         struct port *port;
751         ssize_t ret;
752 
753         port = filp->private_data;
754 
755         /* Port is hot-unplugged. */
756         if (!port->guest_connected)
757                 return -ENODEV;
758 
759         if (!port_has_data(port)) {
760                 /*
761                  * If nothing's connected on the host just return 0 in
762                  * case of list_empty; this tells the userspace app
763                  * that there's no connection
764                  */
765                 if (!port->host_connected)
766                         return 0;
767                 if (filp->f_flags & O_NONBLOCK)
768                         return -EAGAIN;
769 
770                 ret = wait_event_freezable(port->waitqueue,
771                                            !will_read_block(port));
772                 if (ret < 0)
773                         return ret;
774         }
775         /* Port got hot-unplugged while we were waiting above. */
776         if (!port->guest_connected)
777                 return -ENODEV;
778         /*
779          * We could've received a disconnection message while we were
780          * waiting for more data.
781          *
782          * This check is not clubbed in the if() statement above as we
783          * might receive some data as well as the host could get
784          * disconnected after we got woken up from our wait.  So we
785          * really want to give off whatever data we have and only then
786          * check for host_connected.
787          */
788         if (!port_has_data(port) && !port->host_connected)
789                 return 0;
790 
791         return fill_readbuf(port, ubuf, count, true);
792 }
793 
794 static int wait_port_writable(struct port *port, bool nonblock)
795 {
796         int ret;
797 
798         if (will_write_block(port)) {
799                 if (nonblock)
800                         return -EAGAIN;
801 
802                 ret = wait_event_freezable(port->waitqueue,
803                                            !will_write_block(port));
804                 if (ret < 0)
805                         return ret;
806         }
807         /* Port got hot-unplugged. */
808         if (!port->guest_connected)
809                 return -ENODEV;
810 
811         return 0;
812 }
813 
814 static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
815                                size_t count, loff_t *offp)
816 {
817         struct port *port;
818         struct port_buffer *buf;
819         ssize_t ret;
820         bool nonblock;
821         struct scatterlist sg[1];
822 
823         /* Userspace could be out to fool us */
824         if (!count)
825                 return 0;
826 
827         port = filp->private_data;
828 
829         nonblock = filp->f_flags & O_NONBLOCK;
830 
831         ret = wait_port_writable(port, nonblock);
832         if (ret < 0)
833                 return ret;
834 
835         count = min((size_t)(32 * 1024), count);
836 
837         buf = alloc_buf(port->out_vq, count, 0);
838         if (!buf)
839                 return -ENOMEM;
840 
841         ret = copy_from_user(buf->buf, ubuf, count);
842         if (ret) {
843                 ret = -EFAULT;
844                 goto free_buf;
845         }
846 
847         /*
848          * We now ask send_buf() to not spin for generic ports -- we
849          * can re-use the same code path that non-blocking file
850          * descriptors take for blocking file descriptors since the
851          * wait is already done and we're certain the write will go
852          * through to the host.
853          */
854         nonblock = true;
855         sg_init_one(sg, buf->buf, count);
856         ret = __send_to_port(port, sg, 1, count, buf, nonblock);
857 
858         if (nonblock && ret > 0)
859                 goto out;
860 
861 free_buf:
862         free_buf(buf, true);
863 out:
864         return ret;
865 }
866 
867 struct sg_list {
868         unsigned int n;
869         unsigned int size;
870         size_t len;
871         struct scatterlist *sg;
872 };
873 
874 static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
875                         struct splice_desc *sd)
876 {
877         struct sg_list *sgl = sd->u.data;
878         unsigned int offset, len;
879 
880         if (sgl->n == sgl->size)
881                 return 0;
882 
883         /* Try lock this page */
884         if (buf->ops->steal(pipe, buf) == 0) {
885                 /* Get reference and unlock page for moving */
886                 get_page(buf->page);
887                 unlock_page(buf->page);
888 
889                 len = min(buf->len, sd->len);
890                 sg_set_page(&(sgl->sg[sgl->n]), buf->page, len, buf->offset);
891         } else {
892                 /* Failback to copying a page */
893                 struct page *page = alloc_page(GFP_KERNEL);
894                 char *src;
895 
896                 if (!page)
897                         return -ENOMEM;
898 
899                 offset = sd->pos & ~PAGE_MASK;
900 
901                 len = sd->len;
902                 if (len + offset > PAGE_SIZE)
903                         len = PAGE_SIZE - offset;
904 
905                 src = kmap_atomic(buf->page);
906                 memcpy(page_address(page) + offset, src + buf->offset, len);
907                 kunmap_atomic(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 */
918 static 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 
976 error_out:
977         pipe_unlock(pipe);
978         return ret;
979 }
980 
981 static 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 
1004 static void remove_port(struct kref *kref);
1005 
1006 static 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 
1040 static 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;
1089 out:
1090         kref_put(&port->kref, remove_port);
1091         return ret;
1092 }
1093 
1094 static 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  */
1108 static 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  */
1128 static 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  */
1151 static 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, (__force char __user *)buf, count, false);
1167 }
1168 
1169 static 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 */
1186 static 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 
1200 static void notifier_del_vio(struct hvc_struct *hp, int data)
1201 {
1202         hp->irq_requested = 0;
1203 }
1204 
1205 /* The operations for console ports. */
1206 static 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  */
1223 int __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 
1229 static 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 
1279 static 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 
1289 static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
1290 
1291 static struct attribute *port_sysfs_entries[] = {
1292         &dev_attr_name.attr,
1293         NULL
1294 };
1295 
1296 static struct attribute_group port_attribute_group = {
1297         .name = NULL,           /* put in device directory */
1298         .attrs = port_sysfs_entries,
1299 };
1300 
1301 static 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 
1342 static const struct file_operations port_debugfs_ops = {
1343         .owner = THIS_MODULE,
1344         .open  = simple_open,
1345         .read  = debugfs_read,
1346 };
1347 
1348 static 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 
1357 static 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 
1383 static 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 
1389 static 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 
1503 free_inbufs:
1504         while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1505                 free_buf(buf, true);
1506 free_device:
1507         device_destroy(pdrvdata.class, port->dev->devt);
1508 free_cdev:
1509         cdev_del(port->cdev);
1510 free_port:
1511         kfree(port);
1512 fail:
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. */
1519 static 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 
1528 static void remove_port_data(struct port *port)
1529 {
1530         struct port_buffer *buf;
1531 
1532         spin_lock_irq(&port->inbuf_lock);
1533         /* Remove unused data this port might have received. */
1534         discard_port_data(port);
1535 
1536         /* Remove buffers we queued up for the Host to send us data in. */
1537         while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1538                 free_buf(buf, true);
1539         spin_unlock_irq(&port->inbuf_lock);
1540 
1541         spin_lock_irq(&port->outvq_lock);
1542         reclaim_consumed_buffers(port);
1543 
1544         /* Free pending buffers from the out-queue. */
1545         while ((buf = virtqueue_detach_unused_buf(port->out_vq)))
1546                 free_buf(buf, true);
1547         spin_unlock_irq(&port->outvq_lock);
1548 }
1549 
1550 /*
1551  * Port got unplugged.  Remove port from portdev's list and drop the
1552  * kref reference.  If no userspace has this port opened, it will
1553  * result in immediate removal the port.
1554  */
1555 static void unplug_port(struct port *port)
1556 {
1557         spin_lock_irq(&port->portdev->ports_lock);
1558         list_del(&port->list);
1559         spin_unlock_irq(&port->portdev->ports_lock);
1560 
1561         spin_lock_irq(&port->inbuf_lock);
1562         if (port->guest_connected) {
1563                 /* Let the app know the port is going down. */
1564                 send_sigio_to_port(port);
1565 
1566                 /* Do this after sigio is actually sent */
1567                 port->guest_connected = false;
1568                 port->host_connected = false;
1569 
1570                 wake_up_interruptible(&port->waitqueue);
1571         }
1572         spin_unlock_irq(&port->inbuf_lock);
1573 
1574         if (is_console_port(port)) {
1575                 spin_lock_irq(&pdrvdata_lock);
1576                 list_del(&port->cons.list);
1577                 spin_unlock_irq(&pdrvdata_lock);
1578                 hvc_remove(port->cons.hvc);
1579         }
1580 
1581         remove_port_data(port);
1582 
1583         /*
1584          * We should just assume the device itself has gone off --
1585          * else a close on an open port later will try to send out a
1586          * control message.
1587          */
1588         port->portdev = NULL;
1589 
1590         sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1591         device_destroy(pdrvdata.class, port->dev->devt);
1592         cdev_del(port->cdev);
1593 
1594         debugfs_remove(port->debugfs_file);
1595         kfree(port->name);
1596 
1597         /*
1598          * Locks around here are not necessary - a port can't be
1599          * opened after we removed the port struct from ports_list
1600          * above.
1601          */
1602         kref_put(&port->kref, remove_port);
1603 }
1604 
1605 /* Any private messages that the Host and Guest want to share */
1606 static void handle_control_message(struct virtio_device *vdev,
1607                                    struct ports_device *portdev,
1608                                    struct port_buffer *buf)
1609 {
1610         struct virtio_console_control *cpkt;
1611         struct port *port;
1612         size_t name_size;
1613         int err;
1614 
1615         cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1616 
1617         port = find_port_by_id(portdev, virtio32_to_cpu(vdev, cpkt->id));
1618         if (!port &&
1619             cpkt->event != cpu_to_virtio16(vdev, VIRTIO_CONSOLE_PORT_ADD)) {
1620                 /* No valid header at start of buffer.  Drop it. */
1621                 dev_dbg(&portdev->vdev->dev,
1622                         "Invalid index %u in control packet\n", cpkt->id);
1623                 return;
1624         }
1625 
1626         switch (virtio16_to_cpu(vdev, cpkt->event)) {
1627         case VIRTIO_CONSOLE_PORT_ADD:
1628                 if (port) {
1629                         dev_dbg(&portdev->vdev->dev,
1630                                 "Port %u already added\n", port->id);
1631                         send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1632                         break;
1633                 }
1634                 if (virtio32_to_cpu(vdev, cpkt->id) >=
1635                     portdev->config.max_nr_ports) {
1636                         dev_warn(&portdev->vdev->dev,
1637                                 "Request for adding port with "
1638                                 "out-of-bound id %u, max. supported id: %u\n",
1639                                 cpkt->id, portdev->config.max_nr_ports - 1);
1640                         break;
1641                 }
1642                 add_port(portdev, virtio32_to_cpu(vdev, cpkt->id));
1643                 break;
1644         case VIRTIO_CONSOLE_PORT_REMOVE:
1645                 unplug_port(port);
1646                 break;
1647         case VIRTIO_CONSOLE_CONSOLE_PORT:
1648                 if (!cpkt->value)
1649                         break;
1650                 if (is_console_port(port))
1651                         break;
1652 
1653                 init_port_console(port);
1654                 complete(&early_console_added);
1655                 /*
1656                  * Could remove the port here in case init fails - but
1657                  * have to notify the host first.
1658                  */
1659                 break;
1660         case VIRTIO_CONSOLE_RESIZE: {
1661                 struct {
1662                         __u16 rows;
1663                         __u16 cols;
1664                 } size;
1665 
1666                 if (!is_console_port(port))
1667                         break;
1668 
1669                 memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1670                        sizeof(size));
1671                 set_console_size(port, size.rows, size.cols);
1672 
1673                 port->cons.hvc->irq_requested = 1;
1674                 resize_console(port);
1675                 break;
1676         }
1677         case VIRTIO_CONSOLE_PORT_OPEN:
1678                 port->host_connected = virtio16_to_cpu(vdev, cpkt->value);
1679                 wake_up_interruptible(&port->waitqueue);
1680                 /*
1681                  * If the host port got closed and the host had any
1682                  * unconsumed buffers, we'll be able to reclaim them
1683                  * now.
1684                  */
1685                 spin_lock_irq(&port->outvq_lock);
1686                 reclaim_consumed_buffers(port);
1687                 spin_unlock_irq(&port->outvq_lock);
1688 
1689                 /*
1690                  * If the guest is connected, it'll be interested in
1691                  * knowing the host connection state changed.
1692                  */
1693                 spin_lock_irq(&port->inbuf_lock);
1694                 send_sigio_to_port(port);
1695                 spin_unlock_irq(&port->inbuf_lock);
1696                 break;
1697         case VIRTIO_CONSOLE_PORT_NAME:
1698                 /*
1699                  * If we woke up after hibernation, we can get this
1700                  * again.  Skip it in that case.
1701                  */
1702                 if (port->name)
1703                         break;
1704 
1705                 /*
1706                  * Skip the size of the header and the cpkt to get the size
1707                  * of the name that was sent
1708                  */
1709                 name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1710 
1711                 port->name = kmalloc(name_size, GFP_KERNEL);
1712                 if (!port->name) {
1713                         dev_err(port->dev,
1714                                 "Not enough space to store port name\n");
1715                         break;
1716                 }
1717                 strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1718                         name_size - 1);
1719                 port->name[name_size - 1] = 0;
1720 
1721                 /*
1722                  * Since we only have one sysfs attribute, 'name',
1723                  * create it only if we have a name for the port.
1724                  */
1725                 err = sysfs_create_group(&port->dev->kobj,
1726                                          &port_attribute_group);
1727                 if (err) {
1728                         dev_err(port->dev,
1729                                 "Error %d creating sysfs device attributes\n",
1730                                 err);
1731                 } else {
1732                         /*
1733                          * Generate a udev event so that appropriate
1734                          * symlinks can be created based on udev
1735                          * rules.
1736                          */
1737                         kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1738                 }
1739                 break;
1740         }
1741 }
1742 
1743 static void control_work_handler(struct work_struct *work)
1744 {
1745         struct ports_device *portdev;
1746         struct virtqueue *vq;
1747         struct port_buffer *buf;
1748         unsigned int len;
1749 
1750         portdev = container_of(work, struct ports_device, control_work);
1751         vq = portdev->c_ivq;
1752 
1753         spin_lock(&portdev->c_ivq_lock);
1754         while ((buf = virtqueue_get_buf(vq, &len))) {
1755                 spin_unlock(&portdev->c_ivq_lock);
1756 
1757                 buf->len = len;
1758                 buf->offset = 0;
1759 
1760                 handle_control_message(vq->vdev, portdev, buf);
1761 
1762                 spin_lock(&portdev->c_ivq_lock);
1763                 if (add_inbuf(portdev->c_ivq, buf) < 0) {
1764                         dev_warn(&portdev->vdev->dev,
1765                                  "Error adding buffer to queue\n");
1766                         free_buf(buf, false);
1767                 }
1768         }
1769         spin_unlock(&portdev->c_ivq_lock);
1770 }
1771 
1772 static void out_intr(struct virtqueue *vq)
1773 {
1774         struct port *port;
1775 
1776         port = find_port_by_vq(vq->vdev->priv, vq);
1777         if (!port)
1778                 return;
1779 
1780         wake_up_interruptible(&port->waitqueue);
1781 }
1782 
1783 static void in_intr(struct virtqueue *vq)
1784 {
1785         struct port *port;
1786         unsigned long flags;
1787 
1788         port = find_port_by_vq(vq->vdev->priv, vq);
1789         if (!port)
1790                 return;
1791 
1792         spin_lock_irqsave(&port->inbuf_lock, flags);
1793         port->inbuf = get_inbuf(port);
1794 
1795         /*
1796          * Normally the port should not accept data when the port is
1797          * closed. For generic serial ports, the host won't (shouldn't)
1798          * send data till the guest is connected. But this condition
1799          * can be reached when a console port is not yet connected (no
1800          * tty is spawned) and the other side sends out data over the
1801          * vring, or when a remote devices start sending data before
1802          * the ports are opened.
1803          *
1804          * A generic serial port will discard data if not connected,
1805          * while console ports and rproc-serial ports accepts data at
1806          * any time. rproc-serial is initiated with guest_connected to
1807          * false because port_fops_open expects this. Console ports are
1808          * hooked up with an HVC console and is initialized with
1809          * guest_connected to true.
1810          */
1811 
1812         if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
1813                 discard_port_data(port);
1814 
1815         /* Send a SIGIO indicating new data in case the process asked for it */
1816         send_sigio_to_port(port);
1817 
1818         spin_unlock_irqrestore(&port->inbuf_lock, flags);
1819 
1820         wake_up_interruptible(&port->waitqueue);
1821 
1822         if (is_console_port(port) && hvc_poll(port->cons.hvc))
1823                 hvc_kick();
1824 }
1825 
1826 static void control_intr(struct virtqueue *vq)
1827 {
1828         struct ports_device *portdev;
1829 
1830         portdev = vq->vdev->priv;
1831         schedule_work(&portdev->control_work);
1832 }
1833 
1834 static void config_intr(struct virtio_device *vdev)
1835 {
1836         struct ports_device *portdev;
1837 
1838         portdev = vdev->priv;
1839 
1840         if (!use_multiport(portdev)) {
1841                 struct port *port;
1842                 u16 rows, cols;
1843 
1844                 virtio_cread(vdev, struct virtio_console_config, cols, &cols);
1845                 virtio_cread(vdev, struct virtio_console_config, rows, &rows);
1846 
1847                 port = find_port_by_id(portdev, 0);
1848                 set_console_size(port, rows, cols);
1849 
1850                 /*
1851                  * We'll use this way of resizing only for legacy
1852                  * support.  For newer userspace
1853                  * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1854                  * to indicate console size changes so that it can be
1855                  * done per-port.
1856                  */
1857                 resize_console(port);
1858         }
1859 }
1860 
1861 static int init_vqs(struct ports_device *portdev)
1862 {
1863         vq_callback_t **io_callbacks;
1864         char **io_names;
1865         struct virtqueue **vqs;
1866         u32 i, j, nr_ports, nr_queues;
1867         int err;
1868 
1869         nr_ports = portdev->config.max_nr_ports;
1870         nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1871 
1872         vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
1873         io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
1874         io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
1875         portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1876                                   GFP_KERNEL);
1877         portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1878                                    GFP_KERNEL);
1879         if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
1880             !portdev->out_vqs) {
1881                 err = -ENOMEM;
1882                 goto free;
1883         }
1884 
1885         /*
1886          * For backward compat (newer host but older guest), the host
1887          * spawns a console port first and also inits the vqs for port
1888          * 0 before others.
1889          */
1890         j = 0;
1891         io_callbacks[j] = in_intr;
1892         io_callbacks[j + 1] = out_intr;
1893         io_names[j] = "input";
1894         io_names[j + 1] = "output";
1895         j += 2;
1896 
1897         if (use_multiport(portdev)) {
1898                 io_callbacks[j] = control_intr;
1899                 io_callbacks[j + 1] = NULL;
1900                 io_names[j] = "control-i";
1901                 io_names[j + 1] = "control-o";
1902 
1903                 for (i = 1; i < nr_ports; i++) {
1904                         j += 2;
1905                         io_callbacks[j] = in_intr;
1906                         io_callbacks[j + 1] = out_intr;
1907                         io_names[j] = "input";
1908                         io_names[j + 1] = "output";
1909                 }
1910         }
1911         /* Find the queues. */
1912         err = portdev->vdev->config->find_vqs(portdev->vdev, nr_queues, vqs,
1913                                               io_callbacks,
1914                                               (const char **)io_names);
1915         if (err)
1916                 goto free;
1917 
1918         j = 0;
1919         portdev->in_vqs[0] = vqs[0];
1920         portdev->out_vqs[0] = vqs[1];
1921         j += 2;
1922         if (use_multiport(portdev)) {
1923                 portdev->c_ivq = vqs[j];
1924                 portdev->c_ovq = vqs[j + 1];
1925 
1926                 for (i = 1; i < nr_ports; i++) {
1927                         j += 2;
1928                         portdev->in_vqs[i] = vqs[j];
1929                         portdev->out_vqs[i] = vqs[j + 1];
1930                 }
1931         }
1932         kfree(io_names);
1933         kfree(io_callbacks);
1934         kfree(vqs);
1935 
1936         return 0;
1937 
1938 free:
1939         kfree(portdev->out_vqs);
1940         kfree(portdev->in_vqs);
1941         kfree(io_names);
1942         kfree(io_callbacks);
1943         kfree(vqs);
1944 
1945         return err;
1946 }
1947 
1948 static const struct file_operations portdev_fops = {
1949         .owner = THIS_MODULE,
1950 };
1951 
1952 static void remove_vqs(struct ports_device *portdev)
1953 {
1954         portdev->vdev->config->del_vqs(portdev->vdev);
1955         kfree(portdev->in_vqs);
1956         kfree(portdev->out_vqs);
1957 }
1958 
1959 static void remove_controlq_data(struct ports_device *portdev)
1960 {
1961         struct port_buffer *buf;
1962         unsigned int len;
1963 
1964         if (!use_multiport(portdev))
1965                 return;
1966 
1967         while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
1968                 free_buf(buf, true);
1969 
1970         while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
1971                 free_buf(buf, true);
1972 }
1973 
1974 /*
1975  * Once we're further in boot, we get probed like any other virtio
1976  * device.
1977  *
1978  * If the host also supports multiple console ports, we check the
1979  * config space to see how many ports the host has spawned.  We
1980  * initialize each port found.
1981  */
1982 static int virtcons_probe(struct virtio_device *vdev)
1983 {
1984         struct ports_device *portdev;
1985         int err;
1986         bool multiport;
1987         bool early = early_put_chars != NULL;
1988 
1989         /* Ensure to read early_put_chars now */
1990         barrier();
1991 
1992         portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
1993         if (!portdev) {
1994                 err = -ENOMEM;
1995                 goto fail;
1996         }
1997 
1998         /* Attach this portdev to this virtio_device, and vice-versa. */
1999         portdev->vdev = vdev;
2000         vdev->priv = portdev;
2001 
2002         portdev->chr_major = register_chrdev(0, "virtio-portsdev",
2003                                              &portdev_fops);
2004         if (portdev->chr_major < 0) {
2005                 dev_err(&vdev->dev,
2006                         "Error %d registering chrdev for device %u\n",
2007                         portdev->chr_major, vdev->index);
2008                 err = portdev->chr_major;
2009                 goto free;
2010         }
2011 
2012         multiport = false;
2013         portdev->config.max_nr_ports = 1;
2014 
2015         /* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
2016         if (!is_rproc_serial(vdev) &&
2017             virtio_cread_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
2018                                  struct virtio_console_config, max_nr_ports,
2019                                  &portdev->config.max_nr_ports) == 0) {
2020                 multiport = true;
2021         }
2022 
2023         err = init_vqs(portdev);
2024         if (err < 0) {
2025                 dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
2026                 goto free_chrdev;
2027         }
2028 
2029         spin_lock_init(&portdev->ports_lock);
2030         INIT_LIST_HEAD(&portdev->ports);
2031 
2032         virtio_device_ready(portdev->vdev);
2033 
2034         if (multiport) {
2035                 unsigned int nr_added_bufs;
2036 
2037                 spin_lock_init(&portdev->c_ivq_lock);
2038                 spin_lock_init(&portdev->c_ovq_lock);
2039                 INIT_WORK(&portdev->control_work, &control_work_handler);
2040 
2041                 nr_added_bufs = fill_queue(portdev->c_ivq,
2042                                            &portdev->c_ivq_lock);
2043                 if (!nr_added_bufs) {
2044                         dev_err(&vdev->dev,
2045                                 "Error allocating buffers for control queue\n");
2046                         err = -ENOMEM;
2047                         goto free_vqs;
2048                 }
2049         } else {
2050                 /*
2051                  * For backward compatibility: Create a console port
2052                  * if we're running on older host.
2053                  */
2054                 add_port(portdev, 0);
2055         }
2056 
2057         spin_lock_irq(&pdrvdata_lock);
2058         list_add_tail(&portdev->list, &pdrvdata.portdevs);
2059         spin_unlock_irq(&pdrvdata_lock);
2060 
2061         __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2062                            VIRTIO_CONSOLE_DEVICE_READY, 1);
2063 
2064         /*
2065          * If there was an early virtio console, assume that there are no
2066          * other consoles. We need to wait until the hvc_alloc matches the
2067          * hvc_instantiate, otherwise tty_open will complain, resulting in
2068          * a "Warning: unable to open an initial console" boot failure.
2069          * Without multiport this is done in add_port above. With multiport
2070          * this might take some host<->guest communication - thus we have to
2071          * wait.
2072          */
2073         if (multiport && early)
2074                 wait_for_completion(&early_console_added);
2075 
2076         return 0;
2077 
2078 free_vqs:
2079         /* The host might want to notify mgmt sw about device add failure */
2080         __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2081                            VIRTIO_CONSOLE_DEVICE_READY, 0);
2082         remove_vqs(portdev);
2083 free_chrdev:
2084         unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2085 free:
2086         kfree(portdev);
2087 fail:
2088         return err;
2089 }
2090 
2091 static void virtcons_remove(struct virtio_device *vdev)
2092 {
2093         struct ports_device *portdev;
2094         struct port *port, *port2;
2095 
2096         portdev = vdev->priv;
2097 
2098         spin_lock_irq(&pdrvdata_lock);
2099         list_del(&portdev->list);
2100         spin_unlock_irq(&pdrvdata_lock);
2101 
2102         /* Disable interrupts for vqs */
2103         vdev->config->reset(vdev);
2104         /* Finish up work that's lined up */
2105         if (use_multiport(portdev))
2106                 cancel_work_sync(&portdev->control_work);
2107 
2108         list_for_each_entry_safe(port, port2, &portdev->ports, list)
2109                 unplug_port(port);
2110 
2111         unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2112 
2113         /*
2114          * When yanking out a device, we immediately lose the
2115          * (device-side) queues.  So there's no point in keeping the
2116          * guest side around till we drop our final reference.  This
2117          * also means that any ports which are in an open state will
2118          * have to just stop using the port, as the vqs are going
2119          * away.
2120          */
2121         remove_controlq_data(portdev);
2122         remove_vqs(portdev);
2123         kfree(portdev);
2124 }
2125 
2126 static struct virtio_device_id id_table[] = {
2127         { VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
2128         { 0 },
2129 };
2130 
2131 static unsigned int features[] = {
2132         VIRTIO_CONSOLE_F_SIZE,
2133         VIRTIO_CONSOLE_F_MULTIPORT,
2134 };
2135 
2136 static struct virtio_device_id rproc_serial_id_table[] = {
2137 #if IS_ENABLED(CONFIG_REMOTEPROC)
2138         { VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
2139 #endif
2140         { 0 },
2141 };
2142 
2143 static unsigned int rproc_serial_features[] = {
2144 };
2145 
2146 #ifdef CONFIG_PM_SLEEP
2147 static int virtcons_freeze(struct virtio_device *vdev)
2148 {
2149         struct ports_device *portdev;
2150         struct port *port;
2151 
2152         portdev = vdev->priv;
2153 
2154         vdev->config->reset(vdev);
2155 
2156         virtqueue_disable_cb(portdev->c_ivq);
2157         cancel_work_sync(&portdev->control_work);
2158         /*
2159          * Once more: if control_work_handler() was running, it would
2160          * enable the cb as the last step.
2161          */
2162         virtqueue_disable_cb(portdev->c_ivq);
2163         remove_controlq_data(portdev);
2164 
2165         list_for_each_entry(port, &portdev->ports, list) {
2166                 virtqueue_disable_cb(port->in_vq);
2167                 virtqueue_disable_cb(port->out_vq);
2168                 /*
2169                  * We'll ask the host later if the new invocation has
2170                  * the port opened or closed.
2171                  */
2172                 port->host_connected = false;
2173                 remove_port_data(port);
2174         }
2175         remove_vqs(portdev);
2176 
2177         return 0;
2178 }
2179 
2180 static int virtcons_restore(struct virtio_device *vdev)
2181 {
2182         struct ports_device *portdev;
2183         struct port *port;
2184         int ret;
2185 
2186         portdev = vdev->priv;
2187 
2188         ret = init_vqs(portdev);
2189         if (ret)
2190                 return ret;
2191 
2192         virtio_device_ready(portdev->vdev);
2193 
2194         if (use_multiport(portdev))
2195                 fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2196 
2197         list_for_each_entry(port, &portdev->ports, list) {
2198                 port->in_vq = portdev->in_vqs[port->id];
2199                 port->out_vq = portdev->out_vqs[port->id];
2200 
2201                 fill_queue(port->in_vq, &port->inbuf_lock);
2202 
2203                 /* Get port open/close status on the host */
2204                 send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
2205 
2206                 /*
2207                  * If a port was open at the time of suspending, we
2208                  * have to let the host know that it's still open.
2209                  */
2210                 if (port->guest_connected)
2211                         send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
2212         }
2213         return 0;
2214 }
2215 #endif
2216 
2217 static struct virtio_driver virtio_console = {
2218         .feature_table = features,
2219         .feature_table_size = ARRAY_SIZE(features),
2220         .driver.name =  KBUILD_MODNAME,
2221         .driver.owner = THIS_MODULE,
2222         .id_table =     id_table,
2223         .probe =        virtcons_probe,
2224         .remove =       virtcons_remove,
2225         .config_changed = config_intr,
2226 #ifdef CONFIG_PM_SLEEP
2227         .freeze =       virtcons_freeze,
2228         .restore =      virtcons_restore,
2229 #endif
2230 };
2231 
2232 static struct virtio_driver virtio_rproc_serial = {
2233         .feature_table = rproc_serial_features,
2234         .feature_table_size = ARRAY_SIZE(rproc_serial_features),
2235         .driver.name =  "virtio_rproc_serial",
2236         .driver.owner = THIS_MODULE,
2237         .id_table =     rproc_serial_id_table,
2238         .probe =        virtcons_probe,
2239         .remove =       virtcons_remove,
2240 };
2241 
2242 static int __init init(void)
2243 {
2244         int err;
2245 
2246         pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
2247         if (IS_ERR(pdrvdata.class)) {
2248                 err = PTR_ERR(pdrvdata.class);
2249                 pr_err("Error %d creating virtio-ports class\n", err);
2250                 return err;
2251         }
2252 
2253         pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
2254         if (!pdrvdata.debugfs_dir)
2255                 pr_warning("Error creating debugfs dir for virtio-ports\n");
2256         INIT_LIST_HEAD(&pdrvdata.consoles);
2257         INIT_LIST_HEAD(&pdrvdata.portdevs);
2258 
2259         err = register_virtio_driver(&virtio_console);
2260         if (err < 0) {
2261                 pr_err("Error %d registering virtio driver\n", err);
2262                 goto free;
2263         }
2264         err = register_virtio_driver(&virtio_rproc_serial);
2265         if (err < 0) {
2266                 pr_err("Error %d registering virtio rproc serial driver\n",
2267                        err);
2268                 goto unregister;
2269         }
2270         return 0;
2271 unregister:
2272         unregister_virtio_driver(&virtio_console);
2273 free:
2274         debugfs_remove_recursive(pdrvdata.debugfs_dir);
2275         class_destroy(pdrvdata.class);
2276         return err;
2277 }
2278 
2279 static void __exit fini(void)
2280 {
2281         reclaim_dma_bufs();
2282 
2283         unregister_virtio_driver(&virtio_console);
2284         unregister_virtio_driver(&virtio_rproc_serial);
2285 
2286         class_destroy(pdrvdata.class);
2287         debugfs_remove_recursive(pdrvdata.debugfs_dir);
2288 }
2289 module_init(init);
2290 module_exit(fini);
2291 
2292 MODULE_DEVICE_TABLE(virtio, id_table);
2293 MODULE_DESCRIPTION("Virtio console driver");
2294 MODULE_LICENSE("GPL");
2295 

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