source: src/linux/universal/linux-4.9/drivers/char/virtio_console.c @ 31885

Last change on this file since 31885 was 31885, checked in by brainslayer, 3 months ago

update

File size: 56.6 KB
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1/*
2 * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
3 * Copyright (C) 2009, 2010, 2011 Red Hat, Inc.
4 * Copyright (C) 2009, 2010, 2011 Amit Shah <amit.shah@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19 */
20#include <linux/cdev.h>
21#include <linux/debugfs.h>
22#include <linux/completion.h>
23#include <linux/device.h>
24#include <linux/err.h>
25#include <linux/freezer.h>
26#include <linux/fs.h>
27#include <linux/splice.h>
28#include <linux/pagemap.h>
29#include <linux/init.h>
30#include <linux/list.h>
31#include <linux/poll.h>
32#include <linux/sched.h>
33#include <linux/slab.h>
34#include <linux/spinlock.h>
35#include <linux/virtio.h>
36#include <linux/virtio_console.h>
37#include <linux/wait.h>
38#include <linux/workqueue.h>
39#include <linux/module.h>
40#include <linux/dma-mapping.h>
41#include "../tty/hvc/hvc_console.h"
42
43#define is_rproc_enabled IS_ENABLED(CONFIG_REMOTEPROC)
44
45/*
46 * This is a global struct for storing common data for all the devices
47 * this driver handles.
48 *
49 * Mainly, it has a linked list for all the consoles in one place so
50 * that callbacks from hvc for get_chars(), put_chars() work properly
51 * across multiple devices and multiple ports per device.
52 */
53struct ports_driver_data {
54        /* Used for registering chardevs */
55        struct class *class;
56
57        /* Used for exporting per-port information to debugfs */
58        struct dentry *debugfs_dir;
59
60        /* List of all the devices we're handling */
61        struct list_head portdevs;
62
63        /*
64         * This is used to keep track of the number of hvc consoles
65         * spawned by this driver.  This number is given as the first
66         * argument to hvc_alloc().  To correctly map an initial
67         * console spawned via hvc_instantiate to the console being
68         * hooked up via hvc_alloc, we need to pass the same vtermno.
69         *
70         * We also just assume the first console being initialised was
71         * the first one that got used as the initial console.
72         */
73        unsigned int next_vtermno;
74
75        /* All the console devices handled by this driver */
76        struct list_head consoles;
77};
78static struct ports_driver_data pdrvdata;
79
80static DEFINE_SPINLOCK(pdrvdata_lock);
81static DECLARE_COMPLETION(early_console_added);
82
83/* This struct holds information that's relevant only for console ports */
84struct console {
85        /* We'll place all consoles in a list in the pdrvdata struct */
86        struct list_head list;
87
88        /* The hvc device associated with this console port */
89        struct hvc_struct *hvc;
90
91        /* The size of the console */
92        struct winsize ws;
93
94        /*
95         * This number identifies the number that we used to register
96         * with hvc in hvc_instantiate() and hvc_alloc(); this is the
97         * number passed on by the hvc callbacks to us to
98         * differentiate between the other console ports handled by
99         * this driver
100         */
101        u32 vtermno;
102};
103
104struct port_buffer {
105        char *buf;
106
107        /* size of the buffer in *buf above */
108        size_t size;
109
110        /* used length of the buffer */
111        size_t len;
112        /* offset in the buf from which to consume data */
113        size_t offset;
114
115        /* DMA address of buffer */
116        dma_addr_t dma;
117
118        /* Device we got DMA memory from */
119        struct device *dev;
120
121        /* List of pending dma buffers to free */
122        struct list_head list;
123
124        /* If sgpages == 0 then buf is used */
125        unsigned int sgpages;
126
127        /* sg is used if spages > 0. sg must be the last in is struct */
128        struct scatterlist sg[0];
129};
130
131/*
132 * This is a per-device struct that stores data common to all the
133 * ports for that device (vdev->priv).
134 */
135struct ports_device {
136        /* Next portdev in the list, head is in the pdrvdata struct */
137        struct list_head list;
138
139        /*
140         * Workqueue handlers where we process deferred work after
141         * notification
142         */
143        struct work_struct control_work;
144        struct work_struct config_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        /*
168         * A control packet buffer for guest->host requests, protected
169         * by c_ovq_lock.
170         */
171        struct virtio_console_control cpkt;
172
173        /* Array of per-port IO virtqueues */
174        struct virtqueue **in_vqs, **out_vqs;
175
176        /* Major number for this device.  Ports will be created as minors. */
177        int chr_major;
178};
179
180struct port_stats {
181        unsigned long bytes_sent, bytes_received, bytes_discarded;
182};
183
184/* This struct holds the per-port data */
185struct port {
186        /* Next port in the list, head is in the ports_device */
187        struct list_head list;
188
189        /* Pointer to the parent virtio_console device */
190        struct ports_device *portdev;
191
192        /* The current buffer from which data has to be fed to readers */
193        struct port_buffer *inbuf;
194
195        /*
196         * To protect the operations on the in_vq associated with this
197         * port.  Has to be a spinlock because it can be called from
198         * interrupt context (get_char()).
199         */
200        spinlock_t inbuf_lock;
201
202        /* Protect the operations on the out_vq. */
203        spinlock_t outvq_lock;
204
205        /* The IO vqs for this port */
206        struct virtqueue *in_vq, *out_vq;
207
208        /* File in the debugfs directory that exposes this port's information */
209        struct dentry *debugfs_file;
210
211        /*
212         * Keep count of the bytes sent, received and discarded for
213         * this port for accounting and debugging purposes.  These
214         * counts are not reset across port open / close events.
215         */
216        struct port_stats stats;
217
218        /*
219         * The entries in this struct will be valid if this port is
220         * hooked up to an hvc console
221         */
222        struct console cons;
223
224        /* Each port associates with a separate char device */
225        struct cdev *cdev;
226        struct device *dev;
227
228        /* Reference-counting to handle port hot-unplugs and file operations */
229        struct kref kref;
230
231        /* A waitqueue for poll() or blocking read operations */
232        wait_queue_head_t waitqueue;
233
234        /* The 'name' of the port that we expose via sysfs properties */
235        char *name;
236
237        /* We can notify apps of host connect / disconnect events via SIGIO */
238        struct fasync_struct *async_queue;
239
240        /* The 'id' to identify the port with the Host */
241        u32 id;
242
243        bool outvq_full;
244
245        /* Is the host device open */
246        bool host_connected;
247
248        /* We should allow only one process to open a port */
249        bool guest_connected;
250};
251
252/* This is the very early arch-specified put chars function. */
253static int (*early_put_chars)(u32, const char *, int);
254
255static struct port *find_port_by_vtermno(u32 vtermno)
256{
257        struct port *port;
258        struct console *cons;
259        unsigned long flags;
260
261        spin_lock_irqsave(&pdrvdata_lock, flags);
262        list_for_each_entry(cons, &pdrvdata.consoles, list) {
263                if (cons->vtermno == vtermno) {
264                        port = container_of(cons, struct port, cons);
265                        goto out;
266                }
267        }
268        port = NULL;
269out:
270        spin_unlock_irqrestore(&pdrvdata_lock, flags);
271        return port;
272}
273
274static struct port *find_port_by_devt_in_portdev(struct ports_device *portdev,
275                                                 dev_t dev)
276{
277        struct port *port;
278        unsigned long flags;
279
280        spin_lock_irqsave(&portdev->ports_lock, flags);
281        list_for_each_entry(port, &portdev->ports, list) {
282                if (port->cdev->dev == dev) {
283                        kref_get(&port->kref);
284                        goto out;
285                }
286        }
287        port = NULL;
288out:
289        spin_unlock_irqrestore(&portdev->ports_lock, flags);
290
291        return port;
292}
293
294static struct port *find_port_by_devt(dev_t dev)
295{
296        struct ports_device *portdev;
297        struct port *port;
298        unsigned long flags;
299
300        spin_lock_irqsave(&pdrvdata_lock, flags);
301        list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
302                port = find_port_by_devt_in_portdev(portdev, dev);
303                if (port)
304                        goto out;
305        }
306        port = NULL;
307out:
308        spin_unlock_irqrestore(&pdrvdata_lock, flags);
309        return port;
310}
311
312static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
313{
314        struct port *port;
315        unsigned long flags;
316
317        spin_lock_irqsave(&portdev->ports_lock, flags);
318        list_for_each_entry(port, &portdev->ports, list)
319                if (port->id == id)
320                        goto out;
321        port = NULL;
322out:
323        spin_unlock_irqrestore(&portdev->ports_lock, flags);
324
325        return port;
326}
327
328static struct port *find_port_by_vq(struct ports_device *portdev,
329                                    struct virtqueue *vq)
330{
331        struct port *port;
332        unsigned long flags;
333
334        spin_lock_irqsave(&portdev->ports_lock, flags);
335        list_for_each_entry(port, &portdev->ports, list)
336                if (port->in_vq == vq || port->out_vq == vq)
337                        goto out;
338        port = NULL;
339out:
340        spin_unlock_irqrestore(&portdev->ports_lock, flags);
341        return port;
342}
343
344static bool is_console_port(struct port *port)
345{
346        if (port->cons.hvc)
347                return true;
348        return false;
349}
350
351static bool is_rproc_serial(const struct virtio_device *vdev)
352{
353        return is_rproc_enabled && vdev->id.device == VIRTIO_ID_RPROC_SERIAL;
354}
355
356static inline bool use_multiport(struct ports_device *portdev)
357{
358        /*
359         * This condition can be true when put_chars is called from
360         * early_init
361         */
362        if (!portdev->vdev)
363                return false;
364        return __virtio_test_bit(portdev->vdev, VIRTIO_CONSOLE_F_MULTIPORT);
365}
366
367static DEFINE_SPINLOCK(dma_bufs_lock);
368static LIST_HEAD(pending_free_dma_bufs);
369
370static void free_buf(struct port_buffer *buf, bool can_sleep)
371{
372        unsigned int i;
373
374        for (i = 0; i < buf->sgpages; i++) {
375                struct page *page = sg_page(&buf->sg[i]);
376                if (!page)
377                        break;
378                put_page(page);
379        }
380
381        if (!buf->dev) {
382                kfree(buf->buf);
383        } else if (is_rproc_enabled) {
384                unsigned long flags;
385
386                /* dma_free_coherent requires interrupts to be enabled. */
387                if (!can_sleep) {
388                        /* queue up dma-buffers to be freed later */
389                        spin_lock_irqsave(&dma_bufs_lock, flags);
390                        list_add_tail(&buf->list, &pending_free_dma_bufs);
391                        spin_unlock_irqrestore(&dma_bufs_lock, flags);
392                        return;
393                }
394                dma_free_coherent(buf->dev, buf->size, buf->buf, buf->dma);
395
396                /* Release device refcnt and allow it to be freed */
397                put_device(buf->dev);
398        }
399
400        kfree(buf);
401}
402
403static void reclaim_dma_bufs(void)
404{
405        unsigned long flags;
406        struct port_buffer *buf, *tmp;
407        LIST_HEAD(tmp_list);
408
409        if (list_empty(&pending_free_dma_bufs))
410                return;
411
412        /* Create a copy of the pending_free_dma_bufs while holding the lock */
413        spin_lock_irqsave(&dma_bufs_lock, flags);
414        list_cut_position(&tmp_list, &pending_free_dma_bufs,
415                          pending_free_dma_bufs.prev);
416        spin_unlock_irqrestore(&dma_bufs_lock, flags);
417
418        /* Release the dma buffers, without irqs enabled */
419        list_for_each_entry_safe(buf, tmp, &tmp_list, list) {
420                list_del(&buf->list);
421                free_buf(buf, true);
422        }
423}
424
425static struct port_buffer *alloc_buf(struct virtqueue *vq, size_t buf_size,
426                                     int pages)
427{
428        struct port_buffer *buf;
429
430        reclaim_dma_bufs();
431
432        /*
433         * Allocate buffer and the sg list. The sg list array is allocated
434         * directly after the port_buffer struct.
435         */
436        buf = kmalloc(sizeof(*buf) + sizeof(struct scatterlist) * pages,
437                      GFP_KERNEL);
438        if (!buf)
439                goto fail;
440
441        buf->sgpages = pages;
442        if (pages > 0) {
443                buf->dev = NULL;
444                buf->buf = NULL;
445                return buf;
446        }
447
448        if (is_rproc_serial(vq->vdev)) {
449                /*
450                 * Allocate DMA memory from ancestor. When a virtio
451                 * device is created by remoteproc, the DMA memory is
452                 * associated with the grandparent device:
453                 * vdev => rproc => platform-dev.
454                 * The code here would have been less quirky if
455                 * DMA_MEMORY_INCLUDES_CHILDREN had been supported
456                 * in dma-coherent.c
457                 */
458                if (!vq->vdev->dev.parent || !vq->vdev->dev.parent->parent)
459                        goto free_buf;
460                buf->dev = vq->vdev->dev.parent->parent;
461
462                /* Increase device refcnt to avoid freeing it */
463                get_device(buf->dev);
464                buf->buf = dma_alloc_coherent(buf->dev, buf_size, &buf->dma,
465                                              GFP_KERNEL);
466        } else {
467                buf->dev = NULL;
468                buf->buf = kmalloc(buf_size, GFP_KERNEL);
469        }
470
471        if (!buf->buf)
472                goto free_buf;
473        buf->len = 0;
474        buf->offset = 0;
475        buf->size = buf_size;
476        return buf;
477
478free_buf:
479        kfree(buf);
480fail:
481        return NULL;
482}
483
484/* Callers should take appropriate locks */
485static struct port_buffer *get_inbuf(struct port *port)
486{
487        struct port_buffer *buf;
488        unsigned int len;
489
490        if (port->inbuf)
491                return port->inbuf;
492
493        buf = virtqueue_get_buf(port->in_vq, &len);
494        if (buf) {
495                buf->len = len;
496                buf->offset = 0;
497                port->stats.bytes_received += len;
498        }
499        return buf;
500}
501
502/*
503 * Create a scatter-gather list representing our input buffer and put
504 * it in the queue.
505 *
506 * Callers should take appropriate locks.
507 */
508static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
509{
510        struct scatterlist sg[1];
511        int ret;
512
513        sg_init_one(sg, buf->buf, buf->size);
514
515        ret = virtqueue_add_inbuf(vq, sg, 1, buf, GFP_ATOMIC);
516        virtqueue_kick(vq);
517        if (!ret)
518                ret = vq->num_free;
519        return ret;
520}
521
522/* Discard any unread data this port has. Callers lockers. */
523static void discard_port_data(struct port *port)
524{
525        struct port_buffer *buf;
526        unsigned int err;
527
528        if (!port->portdev) {
529                /* Device has been unplugged.  vqs are already gone. */
530                return;
531        }
532        buf = get_inbuf(port);
533
534        err = 0;
535        while (buf) {
536                port->stats.bytes_discarded += buf->len - buf->offset;
537                if (add_inbuf(port->in_vq, buf) < 0) {
538                        err++;
539                        free_buf(buf, false);
540                }
541                port->inbuf = NULL;
542                buf = get_inbuf(port);
543        }
544        if (err)
545                dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
546                         err);
547}
548
549static bool port_has_data(struct port *port)
550{
551        unsigned long flags;
552        bool ret;
553
554        ret = false;
555        spin_lock_irqsave(&port->inbuf_lock, flags);
556        port->inbuf = get_inbuf(port);
557        if (port->inbuf)
558                ret = true;
559
560        spin_unlock_irqrestore(&port->inbuf_lock, flags);
561        return ret;
562}
563
564static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
565                                  unsigned int event, unsigned int value)
566{
567        struct scatterlist sg[1];
568        struct virtqueue *vq;
569        unsigned int len;
570
571        if (!use_multiport(portdev))
572                return 0;
573
574        vq = portdev->c_ovq;
575
576        spin_lock(&portdev->c_ovq_lock);
577
578        portdev->cpkt.id = cpu_to_virtio32(portdev->vdev, port_id);
579        portdev->cpkt.event = cpu_to_virtio16(portdev->vdev, event);
580        portdev->cpkt.value = cpu_to_virtio16(portdev->vdev, value);
581
582        sg_init_one(sg, &portdev->cpkt, sizeof(struct virtio_console_control));
583
584        if (virtqueue_add_outbuf(vq, sg, 1, &portdev->cpkt, GFP_ATOMIC) == 0) {
585                virtqueue_kick(vq);
586                while (!virtqueue_get_buf(vq, &len)
587                        && !virtqueue_is_broken(vq))
588                        cpu_relax();
589        }
590
591        spin_unlock(&portdev->c_ovq_lock);
592        return 0;
593}
594
595static ssize_t send_control_msg(struct port *port, unsigned int event,
596                                unsigned int value)
597{
598        /* Did the port get unplugged before userspace closed it? */
599        if (port->portdev)
600                return __send_control_msg(port->portdev, port->id, event, value);
601        return 0;
602}
603
604
605/* Callers must take the port->outvq_lock */
606static void reclaim_consumed_buffers(struct port *port)
607{
608        struct port_buffer *buf;
609        unsigned int len;
610
611        if (!port->portdev) {
612                /* Device has been unplugged.  vqs are already gone. */
613                return;
614        }
615        while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
616                free_buf(buf, false);
617                port->outvq_full = false;
618        }
619}
620
621static ssize_t __send_to_port(struct port *port, struct scatterlist *sg,
622                              int nents, size_t in_count,
623                              void *data, bool nonblock)
624{
625        struct virtqueue *out_vq;
626        int err;
627        unsigned long flags;
628        unsigned int len;
629
630        out_vq = port->out_vq;
631
632        spin_lock_irqsave(&port->outvq_lock, flags);
633
634        reclaim_consumed_buffers(port);
635
636        err = virtqueue_add_outbuf(out_vq, sg, nents, data, GFP_ATOMIC);
637
638        /* Tell Host to go! */
639        virtqueue_kick(out_vq);
640
641        if (err) {
642                in_count = 0;
643                goto done;
644        }
645
646        if (out_vq->num_free == 0)
647                port->outvq_full = true;
648
649        if (nonblock)
650                goto done;
651
652        /*
653         * Wait till the host acknowledges it pushed out the data we
654         * sent.  This is done for data from the hvc_console; the tty
655         * operations are performed with spinlocks held so we can't
656         * sleep here.  An alternative would be to copy the data to a
657         * buffer and relax the spinning requirement.  The downside is
658         * we need to kmalloc a GFP_ATOMIC buffer each time the
659         * console driver writes something out.
660         */
661        while (!virtqueue_get_buf(out_vq, &len)
662                && !virtqueue_is_broken(out_vq))
663                cpu_relax();
664done:
665        spin_unlock_irqrestore(&port->outvq_lock, flags);
666
667        port->stats.bytes_sent += in_count;
668        /*
669         * We're expected to return the amount of data we wrote -- all
670         * of it
671         */
672        return in_count;
673}
674
675/*
676 * Give out the data that's requested from the buffer that we have
677 * queued up.
678 */
679static ssize_t fill_readbuf(struct port *port, char __user *out_buf,
680                            size_t out_count, bool to_user)
681{
682        struct port_buffer *buf;
683        unsigned long flags;
684
685        if (!out_count || !port_has_data(port))
686                return 0;
687
688        buf = port->inbuf;
689        out_count = min(out_count, buf->len - buf->offset);
690
691        if (to_user) {
692                ssize_t ret;
693
694                ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
695                if (ret)
696                        return -EFAULT;
697        } else {
698                memcpy((__force char *)out_buf, buf->buf + buf->offset,
699                       out_count);
700        }
701
702        buf->offset += out_count;
703
704        if (buf->offset == buf->len) {
705                /*
706                 * We're done using all the data in this buffer.
707                 * Re-queue so that the Host can send us more data.
708                 */
709                spin_lock_irqsave(&port->inbuf_lock, flags);
710                port->inbuf = NULL;
711
712                if (add_inbuf(port->in_vq, buf) < 0)
713                        dev_warn(port->dev, "failed add_buf\n");
714
715                spin_unlock_irqrestore(&port->inbuf_lock, flags);
716        }
717        /* Return the number of bytes actually copied */
718        return out_count;
719}
720
721/* The condition that must be true for polling to end */
722static bool will_read_block(struct port *port)
723{
724        if (!port->guest_connected) {
725                /* Port got hot-unplugged. Let's exit. */
726                return false;
727        }
728        return !port_has_data(port) && port->host_connected;
729}
730
731static bool will_write_block(struct port *port)
732{
733        bool ret;
734
735        if (!port->guest_connected) {
736                /* Port got hot-unplugged. Let's exit. */
737                return false;
738        }
739        if (!port->host_connected)
740                return true;
741
742        spin_lock_irq(&port->outvq_lock);
743        /*
744         * Check if the Host has consumed any buffers since we last
745         * sent data (this is only applicable for nonblocking ports).
746         */
747        reclaim_consumed_buffers(port);
748        ret = port->outvq_full;
749        spin_unlock_irq(&port->outvq_lock);
750
751        return ret;
752}
753
754static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
755                              size_t count, loff_t *offp)
756{
757        struct port *port;
758        ssize_t ret;
759
760        port = filp->private_data;
761
762        /* Port is hot-unplugged. */
763        if (!port->guest_connected)
764                return -ENODEV;
765
766        if (!port_has_data(port)) {
767                /*
768                 * If nothing's connected on the host just return 0 in
769                 * case of list_empty; this tells the userspace app
770                 * that there's no connection
771                 */
772                if (!port->host_connected)
773                        return 0;
774                if (filp->f_flags & O_NONBLOCK)
775                        return -EAGAIN;
776
777                ret = wait_event_freezable(port->waitqueue,
778                                           !will_read_block(port));
779                if (ret < 0)
780                        return ret;
781        }
782        /* Port got hot-unplugged while we were waiting above. */
783        if (!port->guest_connected)
784                return -ENODEV;
785        /*
786         * We could've received a disconnection message while we were
787         * waiting for more data.
788         *
789         * This check is not clubbed in the if() statement above as we
790         * might receive some data as well as the host could get
791         * disconnected after we got woken up from our wait.  So we
792         * really want to give off whatever data we have and only then
793         * check for host_connected.
794         */
795        if (!port_has_data(port) && !port->host_connected)
796                return 0;
797
798        return fill_readbuf(port, ubuf, count, true);
799}
800
801static int wait_port_writable(struct port *port, bool nonblock)
802{
803        int ret;
804
805        if (will_write_block(port)) {
806                if (nonblock)
807                        return -EAGAIN;
808
809                ret = wait_event_freezable(port->waitqueue,
810                                           !will_write_block(port));
811                if (ret < 0)
812                        return ret;
813        }
814        /* Port got hot-unplugged. */
815        if (!port->guest_connected)
816                return -ENODEV;
817
818        return 0;
819}
820
821static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
822                               size_t count, loff_t *offp)
823{
824        struct port *port;
825        struct port_buffer *buf;
826        ssize_t ret;
827        bool nonblock;
828        struct scatterlist sg[1];
829
830        /* Userspace could be out to fool us */
831        if (!count)
832                return 0;
833
834        port = filp->private_data;
835
836        nonblock = filp->f_flags & O_NONBLOCK;
837
838        ret = wait_port_writable(port, nonblock);
839        if (ret < 0)
840                return ret;
841
842        count = min((size_t)(32 * 1024), count);
843
844        buf = alloc_buf(port->out_vq, count, 0);
845        if (!buf)
846                return -ENOMEM;
847
848        ret = copy_from_user(buf->buf, ubuf, count);
849        if (ret) {
850                ret = -EFAULT;
851                goto free_buf;
852        }
853
854        /*
855         * We now ask send_buf() to not spin for generic ports -- we
856         * can re-use the same code path that non-blocking file
857         * descriptors take for blocking file descriptors since the
858         * wait is already done and we're certain the write will go
859         * through to the host.
860         */
861        nonblock = true;
862        sg_init_one(sg, buf->buf, count);
863        ret = __send_to_port(port, sg, 1, count, buf, nonblock);
864
865        if (nonblock && ret > 0)
866                goto out;
867
868free_buf:
869        free_buf(buf, true);
870out:
871        return ret;
872}
873
874struct sg_list {
875        unsigned int n;
876        unsigned int size;
877        size_t len;
878        struct scatterlist *sg;
879};
880
881static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
882                        struct splice_desc *sd)
883{
884        struct sg_list *sgl = sd->u.data;
885        unsigned int offset, len;
886
887        if (sgl->n == sgl->size)
888                return 0;
889
890        /* Try lock this page */
891        if (pipe_buf_steal(pipe, buf) == 0) {
892                /* Get reference and unlock page for moving */
893                get_page(buf->page);
894                unlock_page(buf->page);
895
896                len = min(buf->len, sd->len);
897                sg_set_page(&(sgl->sg[sgl->n]), buf->page, len, buf->offset);
898        } else {
899                /* Failback to copying a page */
900                struct page *page = alloc_page(GFP_KERNEL);
901                char *src;
902
903                if (!page)
904                        return -ENOMEM;
905
906                offset = sd->pos & ~PAGE_MASK;
907
908                len = sd->len;
909                if (len + offset > PAGE_SIZE)
910                        len = PAGE_SIZE - offset;
911
912                src = kmap_atomic(buf->page);
913                memcpy(page_address(page) + offset, src + buf->offset, len);
914                kunmap_atomic(src);
915
916                sg_set_page(&(sgl->sg[sgl->n]), page, len, offset);
917        }
918        sgl->n++;
919        sgl->len += len;
920
921        return len;
922}
923
924/* Faster zero-copy write by splicing */
925static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
926                                      struct file *filp, loff_t *ppos,
927                                      size_t len, unsigned int flags)
928{
929        struct port *port = filp->private_data;
930        struct sg_list sgl;
931        ssize_t ret;
932        struct port_buffer *buf;
933        struct splice_desc sd = {
934                .total_len = len,
935                .flags = flags,
936                .pos = *ppos,
937                .u.data = &sgl,
938        };
939
940        /*
941         * Rproc_serial does not yet support splice. To support splice
942         * pipe_to_sg() must allocate dma-buffers and copy content from
943         * regular pages to dma pages. And alloc_buf and free_buf must
944         * support allocating and freeing such a list of dma-buffers.
945         */
946        if (is_rproc_serial(port->out_vq->vdev))
947                return -EINVAL;
948
949        /*
950         * pipe->nrbufs == 0 means there are no data to transfer,
951         * so this returns just 0 for no data.
952         */
953        pipe_lock(pipe);
954        if (!pipe->nrbufs) {
955                ret = 0;
956                goto error_out;
957        }
958
959        ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK);
960        if (ret < 0)
961                goto error_out;
962
963        buf = alloc_buf(port->out_vq, 0, pipe->nrbufs);
964        if (!buf) {
965                ret = -ENOMEM;
966                goto error_out;
967        }
968
969        sgl.n = 0;
970        sgl.len = 0;
971        sgl.size = pipe->nrbufs;
972        sgl.sg = buf->sg;
973        sg_init_table(sgl.sg, sgl.size);
974        ret = __splice_from_pipe(pipe, &sd, pipe_to_sg);
975        pipe_unlock(pipe);
976        if (likely(ret > 0))
977                ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true);
978
979        if (unlikely(ret <= 0))
980                free_buf(buf, true);
981        return ret;
982
983error_out:
984        pipe_unlock(pipe);
985        return ret;
986}
987
988static unsigned int port_fops_poll(struct file *filp, poll_table *wait)
989{
990        struct port *port;
991        unsigned int ret;
992
993        port = filp->private_data;
994        poll_wait(filp, &port->waitqueue, wait);
995
996        if (!port->guest_connected) {
997                /* Port got unplugged */
998                return POLLHUP;
999        }
1000        ret = 0;
1001        if (!will_read_block(port))
1002                ret |= POLLIN | POLLRDNORM;
1003        if (!will_write_block(port))
1004                ret |= POLLOUT;
1005        if (!port->host_connected)
1006                ret |= POLLHUP;
1007
1008        return ret;
1009}
1010
1011static void remove_port(struct kref *kref);
1012
1013static int port_fops_release(struct inode *inode, struct file *filp)
1014{
1015        struct port *port;
1016
1017        port = filp->private_data;
1018
1019        /* Notify host of port being closed */
1020        send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
1021
1022        spin_lock_irq(&port->inbuf_lock);
1023        port->guest_connected = false;
1024
1025        discard_port_data(port);
1026
1027        spin_unlock_irq(&port->inbuf_lock);
1028
1029        spin_lock_irq(&port->outvq_lock);
1030        reclaim_consumed_buffers(port);
1031        spin_unlock_irq(&port->outvq_lock);
1032
1033        reclaim_dma_bufs();
1034        /*
1035         * Locks aren't necessary here as a port can't be opened after
1036         * unplug, and if a port isn't unplugged, a kref would already
1037         * exist for the port.  Plus, taking ports_lock here would
1038         * create a dependency on other locks taken by functions
1039         * inside remove_port if we're the last holder of the port,
1040         * creating many problems.
1041         */
1042        kref_put(&port->kref, remove_port);
1043
1044        return 0;
1045}
1046
1047static int port_fops_open(struct inode *inode, struct file *filp)
1048{
1049        struct cdev *cdev = inode->i_cdev;
1050        struct port *port;
1051        int ret;
1052
1053        /* We get the port with a kref here */
1054        port = find_port_by_devt(cdev->dev);
1055        if (!port) {
1056                /* Port was unplugged before we could proceed */
1057                return -ENXIO;
1058        }
1059        filp->private_data = port;
1060
1061        /*
1062         * Don't allow opening of console port devices -- that's done
1063         * via /dev/hvc
1064         */
1065        if (is_console_port(port)) {
1066                ret = -ENXIO;
1067                goto out;
1068        }
1069
1070        /* Allow only one process to open a particular port at a time */
1071        spin_lock_irq(&port->inbuf_lock);
1072        if (port->guest_connected) {
1073                spin_unlock_irq(&port->inbuf_lock);
1074                ret = -EBUSY;
1075                goto out;
1076        }
1077
1078        port->guest_connected = true;
1079        spin_unlock_irq(&port->inbuf_lock);
1080
1081        spin_lock_irq(&port->outvq_lock);
1082        /*
1083         * There might be a chance that we missed reclaiming a few
1084         * buffers in the window of the port getting previously closed
1085         * and opening now.
1086         */
1087        reclaim_consumed_buffers(port);
1088        spin_unlock_irq(&port->outvq_lock);
1089
1090        nonseekable_open(inode, filp);
1091
1092        /* Notify host of port being opened */
1093        send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
1094
1095        return 0;
1096out:
1097        kref_put(&port->kref, remove_port);
1098        return ret;
1099}
1100
1101static int port_fops_fasync(int fd, struct file *filp, int mode)
1102{
1103        struct port *port;
1104
1105        port = filp->private_data;
1106        return fasync_helper(fd, filp, mode, &port->async_queue);
1107}
1108
1109/*
1110 * The file operations that we support: programs in the guest can open
1111 * a console device, read from it, write to it, poll for data and
1112 * close it.  The devices are at
1113 *   /dev/vport<device number>p<port number>
1114 */
1115static const struct file_operations port_fops = {
1116        .owner = THIS_MODULE,
1117        .open  = port_fops_open,
1118        .read  = port_fops_read,
1119        .write = port_fops_write,
1120        .splice_write = port_fops_splice_write,
1121        .poll  = port_fops_poll,
1122        .release = port_fops_release,
1123        .fasync = port_fops_fasync,
1124        .llseek = no_llseek,
1125};
1126
1127/*
1128 * The put_chars() callback is pretty straightforward.
1129 *
1130 * We turn the characters into a scatter-gather list, add it to the
1131 * output queue and then kick the Host.  Then we sit here waiting for
1132 * it to finish: inefficient in theory, but in practice
1133 * implementations will do it immediately (lguest's Launcher does).
1134 */
1135static int put_chars(u32 vtermno, const char *buf, int count)
1136{
1137        struct port *port;
1138        struct scatterlist sg[1];
1139        void *data;
1140        int ret;
1141
1142        if (unlikely(early_put_chars))
1143                return early_put_chars(vtermno, buf, count);
1144
1145        port = find_port_by_vtermno(vtermno);
1146        if (!port)
1147                return -EPIPE;
1148
1149        data = kmemdup(buf, count, GFP_ATOMIC);
1150        if (!data)
1151                return -ENOMEM;
1152
1153        sg_init_one(sg, data, count);
1154        ret = __send_to_port(port, sg, 1, count, data, false);
1155        kfree(data);
1156        return ret;
1157}
1158
1159/*
1160 * get_chars() is the callback from the hvc_console infrastructure
1161 * when an interrupt is received.
1162 *
1163 * We call out to fill_readbuf that gets us the required data from the
1164 * buffers that are queued up.
1165 */
1166static int get_chars(u32 vtermno, char *buf, int count)
1167{
1168        struct port *port;
1169
1170        /* If we've not set up the port yet, we have no input to give. */
1171        if (unlikely(early_put_chars))
1172                return 0;
1173
1174        port = find_port_by_vtermno(vtermno);
1175        if (!port)
1176                return -EPIPE;
1177
1178        /* If we don't have an input queue yet, we can't get input. */
1179        BUG_ON(!port->in_vq);
1180
1181        return fill_readbuf(port, (__force char __user *)buf, count, false);
1182}
1183
1184static void resize_console(struct port *port)
1185{
1186        struct virtio_device *vdev;
1187
1188        /* The port could have been hot-unplugged */
1189        if (!port || !is_console_port(port))
1190                return;
1191
1192        vdev = port->portdev->vdev;
1193
1194        /* Don't test F_SIZE at all if we're rproc: not a valid feature! */
1195        if (!is_rproc_serial(vdev) &&
1196            virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
1197                hvc_resize(port->cons.hvc, port->cons.ws);
1198}
1199
1200/* We set the configuration at this point, since we now have a tty */
1201static int notifier_add_vio(struct hvc_struct *hp, int data)
1202{
1203        struct port *port;
1204
1205        port = find_port_by_vtermno(hp->vtermno);
1206        if (!port)
1207                return -EINVAL;
1208
1209        hp->irq_requested = 1;
1210        resize_console(port);
1211
1212        return 0;
1213}
1214
1215static void notifier_del_vio(struct hvc_struct *hp, int data)
1216{
1217        hp->irq_requested = 0;
1218}
1219
1220/* The operations for console ports. */
1221static const struct hv_ops hv_ops = {
1222        .get_chars = get_chars,
1223        .put_chars = put_chars,
1224        .notifier_add = notifier_add_vio,
1225        .notifier_del = notifier_del_vio,
1226        .notifier_hangup = notifier_del_vio,
1227};
1228
1229/*
1230 * Console drivers are initialized very early so boot messages can go
1231 * out, so we do things slightly differently from the generic virtio
1232 * initialization of the net and block drivers.
1233 *
1234 * At this stage, the console is output-only.  It's too early to set
1235 * up a virtqueue, so we let the drivers do some boutique early-output
1236 * thing.
1237 */
1238int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
1239{
1240        early_put_chars = put_chars;
1241        return hvc_instantiate(0, 0, &hv_ops);
1242}
1243
1244static int init_port_console(struct port *port)
1245{
1246        int ret;
1247
1248        /*
1249         * The Host's telling us this port is a console port.  Hook it
1250         * up with an hvc console.
1251         *
1252         * To set up and manage our virtual console, we call
1253         * hvc_alloc().
1254         *
1255         * The first argument of hvc_alloc() is the virtual console
1256         * number.  The second argument is the parameter for the
1257         * notification mechanism (like irq number).  We currently
1258         * leave this as zero, virtqueues have implicit notifications.
1259         *
1260         * The third argument is a "struct hv_ops" containing the
1261         * put_chars() get_chars(), notifier_add() and notifier_del()
1262         * pointers.  The final argument is the output buffer size: we
1263         * can do any size, so we put PAGE_SIZE here.
1264         */
1265        port->cons.vtermno = pdrvdata.next_vtermno;
1266
1267        port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
1268        if (IS_ERR(port->cons.hvc)) {
1269                ret = PTR_ERR(port->cons.hvc);
1270                dev_err(port->dev,
1271                        "error %d allocating hvc for port\n", ret);
1272                port->cons.hvc = NULL;
1273                return ret;
1274        }
1275        spin_lock_irq(&pdrvdata_lock);
1276        pdrvdata.next_vtermno++;
1277        list_add_tail(&port->cons.list, &pdrvdata.consoles);
1278        spin_unlock_irq(&pdrvdata_lock);
1279        port->guest_connected = true;
1280
1281        /*
1282         * Start using the new console output if this is the first
1283         * console to come up.
1284         */
1285        if (early_put_chars)
1286                early_put_chars = NULL;
1287
1288        /* Notify host of port being opened */
1289        send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1290
1291        return 0;
1292}
1293
1294static ssize_t show_port_name(struct device *dev,
1295                              struct device_attribute *attr, char *buffer)
1296{
1297        struct port *port;
1298
1299        port = dev_get_drvdata(dev);
1300
1301        return sprintf(buffer, "%s\n", port->name);
1302}
1303
1304static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
1305
1306static struct attribute *port_sysfs_entries[] = {
1307        &dev_attr_name.attr,
1308        NULL
1309};
1310
1311static struct attribute_group port_attribute_group = {
1312        .name = NULL,           /* put in device directory */
1313        .attrs = port_sysfs_entries,
1314};
1315
1316static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
1317                            size_t count, loff_t *offp)
1318{
1319        struct port *port;
1320        char *buf;
1321        ssize_t ret, out_offset, out_count;
1322
1323        out_count = 1024;
1324        buf = kmalloc(out_count, GFP_KERNEL);
1325        if (!buf)
1326                return -ENOMEM;
1327
1328        port = filp->private_data;
1329        out_offset = 0;
1330        out_offset += snprintf(buf + out_offset, out_count,
1331                               "name: %s\n", port->name ? port->name : "");
1332        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1333                               "guest_connected: %d\n", port->guest_connected);
1334        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1335                               "host_connected: %d\n", port->host_connected);
1336        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1337                               "outvq_full: %d\n", port->outvq_full);
1338        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1339                               "bytes_sent: %lu\n", port->stats.bytes_sent);
1340        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1341                               "bytes_received: %lu\n",
1342                               port->stats.bytes_received);
1343        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1344                               "bytes_discarded: %lu\n",
1345                               port->stats.bytes_discarded);
1346        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1347                               "is_console: %s\n",
1348                               is_console_port(port) ? "yes" : "no");
1349        out_offset += snprintf(buf + out_offset, out_count - out_offset,
1350                               "console_vtermno: %u\n", port->cons.vtermno);
1351
1352        ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
1353        kfree(buf);
1354        return ret;
1355}
1356
1357static const struct file_operations port_debugfs_ops = {
1358        .owner = THIS_MODULE,
1359        .open  = simple_open,
1360        .read  = debugfs_read,
1361};
1362
1363static void set_console_size(struct port *port, u16 rows, u16 cols)
1364{
1365        if (!port || !is_console_port(port))
1366                return;
1367
1368        port->cons.ws.ws_row = rows;
1369        port->cons.ws.ws_col = cols;
1370}
1371
1372static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
1373{
1374        struct port_buffer *buf;
1375        unsigned int nr_added_bufs;
1376        int ret;
1377
1378        nr_added_bufs = 0;
1379        do {
1380                buf = alloc_buf(vq, PAGE_SIZE, 0);
1381                if (!buf)
1382                        break;
1383
1384                spin_lock_irq(lock);
1385                ret = add_inbuf(vq, buf);
1386                if (ret < 0) {
1387                        spin_unlock_irq(lock);
1388                        free_buf(buf, true);
1389                        break;
1390                }
1391                nr_added_bufs++;
1392                spin_unlock_irq(lock);
1393        } while (ret > 0);
1394
1395        return nr_added_bufs;
1396}
1397
1398static void send_sigio_to_port(struct port *port)
1399{
1400        if (port->async_queue && port->guest_connected)
1401                kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
1402}
1403
1404static int add_port(struct ports_device *portdev, u32 id)
1405{
1406        char debugfs_name[16];
1407        struct port *port;
1408        struct port_buffer *buf;
1409        dev_t devt;
1410        unsigned int nr_added_bufs;
1411        int err;
1412
1413        port = kmalloc(sizeof(*port), GFP_KERNEL);
1414        if (!port) {
1415                err = -ENOMEM;
1416                goto fail;
1417        }
1418        kref_init(&port->kref);
1419
1420        port->portdev = portdev;
1421        port->id = id;
1422
1423        port->name = NULL;
1424        port->inbuf = NULL;
1425        port->cons.hvc = NULL;
1426        port->async_queue = NULL;
1427
1428        port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
1429
1430        port->host_connected = port->guest_connected = false;
1431        port->stats = (struct port_stats) { 0 };
1432
1433        port->outvq_full = false;
1434
1435        port->in_vq = portdev->in_vqs[port->id];
1436        port->out_vq = portdev->out_vqs[port->id];
1437
1438        port->cdev = cdev_alloc();
1439        if (!port->cdev) {
1440                dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
1441                err = -ENOMEM;
1442                goto free_port;
1443        }
1444        port->cdev->ops = &port_fops;
1445
1446        devt = MKDEV(portdev->chr_major, id);
1447        err = cdev_add(port->cdev, devt, 1);
1448        if (err < 0) {
1449                dev_err(&port->portdev->vdev->dev,
1450                        "Error %d adding cdev for port %u\n", err, id);
1451                goto free_cdev;
1452        }
1453        port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
1454                                  devt, port, "vport%up%u",
1455                                  port->portdev->vdev->index, id);
1456        if (IS_ERR(port->dev)) {
1457                err = PTR_ERR(port->dev);
1458                dev_err(&port->portdev->vdev->dev,
1459                        "Error %d creating device for port %u\n",
1460                        err, id);
1461                goto free_cdev;
1462        }
1463
1464        spin_lock_init(&port->inbuf_lock);
1465        spin_lock_init(&port->outvq_lock);
1466        init_waitqueue_head(&port->waitqueue);
1467
1468        /* Fill the in_vq with buffers so the host can send us data. */
1469        nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
1470        if (!nr_added_bufs) {
1471                dev_err(port->dev, "Error allocating inbufs\n");
1472                err = -ENOMEM;
1473                goto free_device;
1474        }
1475
1476        if (is_rproc_serial(port->portdev->vdev))
1477                /*
1478                 * For rproc_serial assume remote processor is connected.
1479                 * rproc_serial does not want the console port, only
1480                 * the generic port implementation.
1481                 */
1482                port->host_connected = true;
1483        else if (!use_multiport(port->portdev)) {
1484                /*
1485                 * If we're not using multiport support,
1486                 * this has to be a console port.
1487                 */
1488                err = init_port_console(port);
1489                if (err)
1490                        goto free_inbufs;
1491        }
1492
1493        spin_lock_irq(&portdev->ports_lock);
1494        list_add_tail(&port->list, &port->portdev->ports);
1495        spin_unlock_irq(&portdev->ports_lock);
1496
1497        /*
1498         * Tell the Host we're set so that it can send us various
1499         * configuration parameters for this port (eg, port name,
1500         * caching, whether this is a console port, etc.)
1501         */
1502        send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1503
1504        if (pdrvdata.debugfs_dir) {
1505                /*
1506                 * Finally, create the debugfs file that we can use to
1507                 * inspect a port's state at any time
1508                 */
1509                snprintf(debugfs_name, sizeof(debugfs_name), "vport%up%u",
1510                         port->portdev->vdev->index, id);
1511                port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
1512                                                         pdrvdata.debugfs_dir,
1513                                                         port,
1514                                                         &port_debugfs_ops);
1515        }
1516        return 0;
1517
1518free_inbufs:
1519        while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1520                free_buf(buf, true);
1521free_device:
1522        device_destroy(pdrvdata.class, port->dev->devt);
1523free_cdev:
1524        cdev_del(port->cdev);
1525free_port:
1526        kfree(port);
1527fail:
1528        /* The host might want to notify management sw about port add failure */
1529        __send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
1530        return err;
1531}
1532
1533/* No users remain, remove all port-specific data. */
1534static void remove_port(struct kref *kref)
1535{
1536        struct port *port;
1537
1538        port = container_of(kref, struct port, kref);
1539
1540        kfree(port);
1541}
1542
1543static void remove_port_data(struct port *port)
1544{
1545        struct port_buffer *buf;
1546
1547        spin_lock_irq(&port->inbuf_lock);
1548        /* Remove unused data this port might have received. */
1549        discard_port_data(port);
1550        spin_unlock_irq(&port->inbuf_lock);
1551
1552        /* Remove buffers we queued up for the Host to send us data in. */
1553        do {
1554                spin_lock_irq(&port->inbuf_lock);
1555                buf = virtqueue_detach_unused_buf(port->in_vq);
1556                spin_unlock_irq(&port->inbuf_lock);
1557                if (buf)
1558                        free_buf(buf, true);
1559        } while (buf);
1560
1561        spin_lock_irq(&port->outvq_lock);
1562        reclaim_consumed_buffers(port);
1563        spin_unlock_irq(&port->outvq_lock);
1564
1565        /* Free pending buffers from the out-queue. */
1566        do {
1567                spin_lock_irq(&port->outvq_lock);
1568                buf = virtqueue_detach_unused_buf(port->out_vq);
1569                spin_unlock_irq(&port->outvq_lock);
1570                if (buf)
1571                        free_buf(buf, true);
1572        } while (buf);
1573}
1574
1575/*
1576 * Port got unplugged.  Remove port from portdev's list and drop the
1577 * kref reference.  If no userspace has this port opened, it will
1578 * result in immediate removal the port.
1579 */
1580static void unplug_port(struct port *port)
1581{
1582        spin_lock_irq(&port->portdev->ports_lock);
1583        list_del(&port->list);
1584        spin_unlock_irq(&port->portdev->ports_lock);
1585
1586        spin_lock_irq(&port->inbuf_lock);
1587        if (port->guest_connected) {
1588                /* Let the app know the port is going down. */
1589                send_sigio_to_port(port);
1590
1591                /* Do this after sigio is actually sent */
1592                port->guest_connected = false;
1593                port->host_connected = false;
1594
1595                wake_up_interruptible(&port->waitqueue);
1596        }
1597        spin_unlock_irq(&port->inbuf_lock);
1598
1599        if (is_console_port(port)) {
1600                spin_lock_irq(&pdrvdata_lock);
1601                list_del(&port->cons.list);
1602                spin_unlock_irq(&pdrvdata_lock);
1603                hvc_remove(port->cons.hvc);
1604        }
1605
1606        remove_port_data(port);
1607
1608        /*
1609         * We should just assume the device itself has gone off --
1610         * else a close on an open port later will try to send out a
1611         * control message.
1612         */
1613        port->portdev = NULL;
1614
1615        sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1616        device_destroy(pdrvdata.class, port->dev->devt);
1617        cdev_del(port->cdev);
1618
1619        debugfs_remove(port->debugfs_file);
1620        kfree(port->name);
1621
1622        /*
1623         * Locks around here are not necessary - a port can't be
1624         * opened after we removed the port struct from ports_list
1625         * above.
1626         */
1627        kref_put(&port->kref, remove_port);
1628}
1629
1630/* Any private messages that the Host and Guest want to share */
1631static void handle_control_message(struct virtio_device *vdev,
1632                                   struct ports_device *portdev,
1633                                   struct port_buffer *buf)
1634{
1635        struct virtio_console_control *cpkt;
1636        struct port *port;
1637        size_t name_size;
1638        int err;
1639
1640        cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1641
1642        port = find_port_by_id(portdev, virtio32_to_cpu(vdev, cpkt->id));
1643        if (!port &&
1644            cpkt->event != cpu_to_virtio16(vdev, VIRTIO_CONSOLE_PORT_ADD)) {
1645                /* No valid header at start of buffer.  Drop it. */
1646                dev_dbg(&portdev->vdev->dev,
1647                        "Invalid index %u in control packet\n", cpkt->id);
1648                return;
1649        }
1650
1651        switch (virtio16_to_cpu(vdev, cpkt->event)) {
1652        case VIRTIO_CONSOLE_PORT_ADD:
1653                if (port) {
1654                        dev_dbg(&portdev->vdev->dev,
1655                                "Port %u already added\n", port->id);
1656                        send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1657                        break;
1658                }
1659                if (virtio32_to_cpu(vdev, cpkt->id) >=
1660                    portdev->config.max_nr_ports) {
1661                        dev_warn(&portdev->vdev->dev,
1662                                "Request for adding port with "
1663                                "out-of-bound id %u, max. supported id: %u\n",
1664                                cpkt->id, portdev->config.max_nr_ports - 1);
1665                        break;
1666                }
1667                add_port(portdev, virtio32_to_cpu(vdev, cpkt->id));
1668                break;
1669        case VIRTIO_CONSOLE_PORT_REMOVE:
1670                unplug_port(port);
1671                break;
1672        case VIRTIO_CONSOLE_CONSOLE_PORT:
1673                if (!cpkt->value)
1674                        break;
1675                if (is_console_port(port))
1676                        break;
1677
1678                init_port_console(port);
1679                complete(&early_console_added);
1680                /*
1681                 * Could remove the port here in case init fails - but
1682                 * have to notify the host first.
1683                 */
1684                break;
1685        case VIRTIO_CONSOLE_RESIZE: {
1686                struct {
1687                        __u16 rows;
1688                        __u16 cols;
1689                } size;
1690
1691                if (!is_console_port(port))
1692                        break;
1693
1694                memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1695                       sizeof(size));
1696                set_console_size(port, size.rows, size.cols);
1697
1698                port->cons.hvc->irq_requested = 1;
1699                resize_console(port);
1700                break;
1701        }
1702        case VIRTIO_CONSOLE_PORT_OPEN:
1703                port->host_connected = virtio16_to_cpu(vdev, cpkt->value);
1704                wake_up_interruptible(&port->waitqueue);
1705                /*
1706                 * If the host port got closed and the host had any
1707                 * unconsumed buffers, we'll be able to reclaim them
1708                 * now.
1709                 */
1710                spin_lock_irq(&port->outvq_lock);
1711                reclaim_consumed_buffers(port);
1712                spin_unlock_irq(&port->outvq_lock);
1713
1714                /*
1715                 * If the guest is connected, it'll be interested in
1716                 * knowing the host connection state changed.
1717                 */
1718                spin_lock_irq(&port->inbuf_lock);
1719                send_sigio_to_port(port);
1720                spin_unlock_irq(&port->inbuf_lock);
1721                break;
1722        case VIRTIO_CONSOLE_PORT_NAME:
1723                /*
1724                 * If we woke up after hibernation, we can get this
1725                 * again.  Skip it in that case.
1726                 */
1727                if (port->name)
1728                        break;
1729
1730                /*
1731                 * Skip the size of the header and the cpkt to get the size
1732                 * of the name that was sent
1733                 */
1734                name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1735
1736                port->name = kmalloc(name_size, GFP_KERNEL);
1737                if (!port->name) {
1738                        dev_err(port->dev,
1739                                "Not enough space to store port name\n");
1740                        break;
1741                }
1742                strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1743                        name_size - 1);
1744                port->name[name_size - 1] = 0;
1745
1746                /*
1747                 * Since we only have one sysfs attribute, 'name',
1748                 * create it only if we have a name for the port.
1749                 */
1750                err = sysfs_create_group(&port->dev->kobj,
1751                                         &port_attribute_group);
1752                if (err) {
1753                        dev_err(port->dev,
1754                                "Error %d creating sysfs device attributes\n",
1755                                err);
1756                } else {
1757                        /*
1758                         * Generate a udev event so that appropriate
1759                         * symlinks can be created based on udev
1760                         * rules.
1761                         */
1762                        kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1763                }
1764                break;
1765        }
1766}
1767
1768static void control_work_handler(struct work_struct *work)
1769{
1770        struct ports_device *portdev;
1771        struct virtqueue *vq;
1772        struct port_buffer *buf;
1773        unsigned int len;
1774
1775        portdev = container_of(work, struct ports_device, control_work);
1776        vq = portdev->c_ivq;
1777
1778        spin_lock(&portdev->c_ivq_lock);
1779        while ((buf = virtqueue_get_buf(vq, &len))) {
1780                spin_unlock(&portdev->c_ivq_lock);
1781
1782                buf->len = len;
1783                buf->offset = 0;
1784
1785                handle_control_message(vq->vdev, portdev, buf);
1786
1787                spin_lock(&portdev->c_ivq_lock);
1788                if (add_inbuf(portdev->c_ivq, buf) < 0) {
1789                        dev_warn(&portdev->vdev->dev,
1790                                 "Error adding buffer to queue\n");
1791                        free_buf(buf, false);
1792                }
1793        }
1794        spin_unlock(&portdev->c_ivq_lock);
1795}
1796
1797static void out_intr(struct virtqueue *vq)
1798{
1799        struct port *port;
1800
1801        port = find_port_by_vq(vq->vdev->priv, vq);
1802        if (!port)
1803                return;
1804
1805        wake_up_interruptible(&port->waitqueue);
1806}
1807
1808static void in_intr(struct virtqueue *vq)
1809{
1810        struct port *port;
1811        unsigned long flags;
1812
1813        port = find_port_by_vq(vq->vdev->priv, vq);
1814        if (!port)
1815                return;
1816
1817        spin_lock_irqsave(&port->inbuf_lock, flags);
1818        port->inbuf = get_inbuf(port);
1819
1820        /*
1821         * Normally the port should not accept data when the port is
1822         * closed. For generic serial ports, the host won't (shouldn't)
1823         * send data till the guest is connected. But this condition
1824         * can be reached when a console port is not yet connected (no
1825         * tty is spawned) and the other side sends out data over the
1826         * vring, or when a remote devices start sending data before
1827         * the ports are opened.
1828         *
1829         * A generic serial port will discard data if not connected,
1830         * while console ports and rproc-serial ports accepts data at
1831         * any time. rproc-serial is initiated with guest_connected to
1832         * false because port_fops_open expects this. Console ports are
1833         * hooked up with an HVC console and is initialized with
1834         * guest_connected to true.
1835         */
1836
1837        if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
1838                discard_port_data(port);
1839
1840        /* Send a SIGIO indicating new data in case the process asked for it */
1841        send_sigio_to_port(port);
1842
1843        spin_unlock_irqrestore(&port->inbuf_lock, flags);
1844
1845        wake_up_interruptible(&port->waitqueue);
1846
1847        if (is_console_port(port) && hvc_poll(port->cons.hvc))
1848                hvc_kick();
1849}
1850
1851static void control_intr(struct virtqueue *vq)
1852{
1853        struct ports_device *portdev;
1854
1855        portdev = vq->vdev->priv;
1856        schedule_work(&portdev->control_work);
1857}
1858
1859static void config_intr(struct virtio_device *vdev)
1860{
1861        struct ports_device *portdev;
1862
1863        portdev = vdev->priv;
1864
1865        if (!use_multiport(portdev))
1866                schedule_work(&portdev->config_work);
1867}
1868
1869static void config_work_handler(struct work_struct *work)
1870{
1871        struct ports_device *portdev;
1872
1873        portdev = container_of(work, struct ports_device, control_work);
1874        if (!use_multiport(portdev)) {
1875                struct virtio_device *vdev;
1876                struct port *port;
1877                u16 rows, cols;
1878
1879                vdev = portdev->vdev;
1880                virtio_cread(vdev, struct virtio_console_config, cols, &cols);
1881                virtio_cread(vdev, struct virtio_console_config, rows, &rows);
1882
1883                port = find_port_by_id(portdev, 0);
1884                set_console_size(port, rows, cols);
1885
1886                /*
1887                 * We'll use this way of resizing only for legacy
1888                 * support.  For newer userspace
1889                 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1890                 * to indicate console size changes so that it can be
1891                 * done per-port.
1892                 */
1893                resize_console(port);
1894        }
1895}
1896
1897static int init_vqs(struct ports_device *portdev)
1898{
1899        vq_callback_t **io_callbacks;
1900        char **io_names;
1901        struct virtqueue **vqs;
1902        u32 i, j, nr_ports, nr_queues;
1903        int err;
1904
1905        nr_ports = portdev->config.max_nr_ports;
1906        nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1907
1908        vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
1909        io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
1910        io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
1911        portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1912                                  GFP_KERNEL);
1913        portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1914                                   GFP_KERNEL);
1915        if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
1916            !portdev->out_vqs) {
1917                err = -ENOMEM;
1918                goto free;
1919        }
1920
1921        /*
1922         * For backward compat (newer host but older guest), the host
1923         * spawns a console port first and also inits the vqs for port
1924         * 0 before others.
1925         */
1926        j = 0;
1927        io_callbacks[j] = in_intr;
1928        io_callbacks[j + 1] = out_intr;
1929        io_names[j] = "input";
1930        io_names[j + 1] = "output";
1931        j += 2;
1932
1933        if (use_multiport(portdev)) {
1934                io_callbacks[j] = control_intr;
1935                io_callbacks[j + 1] = NULL;
1936                io_names[j] = "control-i";
1937                io_names[j + 1] = "control-o";
1938
1939                for (i = 1; i < nr_ports; i++) {
1940                        j += 2;
1941                        io_callbacks[j] = in_intr;
1942                        io_callbacks[j + 1] = out_intr;
1943                        io_names[j] = "input";
1944                        io_names[j + 1] = "output";
1945                }
1946        }
1947        /* Find the queues. */
1948        err = portdev->vdev->config->find_vqs(portdev->vdev, nr_queues, vqs,
1949                                              io_callbacks,
1950                                              (const char **)io_names);
1951        if (err)
1952                goto free;
1953
1954        j = 0;
1955        portdev->in_vqs[0] = vqs[0];
1956        portdev->out_vqs[0] = vqs[1];
1957        j += 2;
1958        if (use_multiport(portdev)) {
1959                portdev->c_ivq = vqs[j];
1960                portdev->c_ovq = vqs[j + 1];
1961
1962                for (i = 1; i < nr_ports; i++) {
1963                        j += 2;
1964                        portdev->in_vqs[i] = vqs[j];
1965                        portdev->out_vqs[i] = vqs[j + 1];
1966                }
1967        }
1968        kfree(io_names);
1969        kfree(io_callbacks);
1970        kfree(vqs);
1971
1972        return 0;
1973
1974free:
1975        kfree(portdev->out_vqs);
1976        kfree(portdev->in_vqs);
1977        kfree(io_names);
1978        kfree(io_callbacks);
1979        kfree(vqs);
1980
1981        return err;
1982}
1983
1984static const struct file_operations portdev_fops = {
1985        .owner = THIS_MODULE,
1986};
1987
1988static void remove_vqs(struct ports_device *portdev)
1989{
1990        portdev->vdev->config->del_vqs(portdev->vdev);
1991        kfree(portdev->in_vqs);
1992        kfree(portdev->out_vqs);
1993}
1994
1995static void remove_controlq_data(struct ports_device *portdev)
1996{
1997        struct port_buffer *buf;
1998        unsigned int len;
1999
2000        if (!use_multiport(portdev))
2001                return;
2002
2003        while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
2004                free_buf(buf, true);
2005
2006        while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
2007                free_buf(buf, true);
2008}
2009
2010/*
2011 * Once we're further in boot, we get probed like any other virtio
2012 * device.
2013 *
2014 * If the host also supports multiple console ports, we check the
2015 * config space to see how many ports the host has spawned.  We
2016 * initialize each port found.
2017 */
2018static int virtcons_probe(struct virtio_device *vdev)
2019{
2020        struct ports_device *portdev;
2021        int err;
2022        bool multiport;
2023        bool early = early_put_chars != NULL;
2024
2025        /* We only need a config space if features are offered */
2026        if (!vdev->config->get &&
2027            (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)
2028             || virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT))) {
2029                dev_err(&vdev->dev, "%s failure: config access disabled\n",
2030                        __func__);
2031                return -EINVAL;
2032        }
2033
2034        /* Ensure to read early_put_chars now */
2035        barrier();
2036
2037        portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
2038        if (!portdev) {
2039                err = -ENOMEM;
2040                goto fail;
2041        }
2042
2043        /* Attach this portdev to this virtio_device, and vice-versa. */
2044        portdev->vdev = vdev;
2045        vdev->priv = portdev;
2046
2047        portdev->chr_major = register_chrdev(0, "virtio-portsdev",
2048                                             &portdev_fops);
2049        if (portdev->chr_major < 0) {
2050                dev_err(&vdev->dev,
2051                        "Error %d registering chrdev for device %u\n",
2052                        portdev->chr_major, vdev->index);
2053                err = portdev->chr_major;
2054                goto free;
2055        }
2056
2057        multiport = false;
2058        portdev->config.max_nr_ports = 1;
2059
2060        /* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
2061        if (!is_rproc_serial(vdev) &&
2062            virtio_cread_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
2063                                 struct virtio_console_config, max_nr_ports,
2064                                 &portdev->config.max_nr_ports) == 0) {
2065                multiport = true;
2066        }
2067
2068        err = init_vqs(portdev);
2069        if (err < 0) {
2070                dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
2071                goto free_chrdev;
2072        }
2073
2074        spin_lock_init(&portdev->ports_lock);
2075        INIT_LIST_HEAD(&portdev->ports);
2076
2077        virtio_device_ready(portdev->vdev);
2078
2079        INIT_WORK(&portdev->config_work, &config_work_handler);
2080        INIT_WORK(&portdev->control_work, &control_work_handler);
2081
2082        if (multiport) {
2083                unsigned int nr_added_bufs;
2084
2085                spin_lock_init(&portdev->c_ivq_lock);
2086                spin_lock_init(&portdev->c_ovq_lock);
2087
2088                nr_added_bufs = fill_queue(portdev->c_ivq,
2089                                           &portdev->c_ivq_lock);
2090                if (!nr_added_bufs) {
2091                        dev_err(&vdev->dev,
2092                                "Error allocating buffers for control queue\n");
2093                        err = -ENOMEM;
2094                        goto free_vqs;
2095                }
2096        } else {
2097                /*
2098                 * For backward compatibility: Create a console port
2099                 * if we're running on older host.
2100                 */
2101                add_port(portdev, 0);
2102        }
2103
2104        spin_lock_irq(&pdrvdata_lock);
2105        list_add_tail(&portdev->list, &pdrvdata.portdevs);
2106        spin_unlock_irq(&pdrvdata_lock);
2107
2108        __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2109                           VIRTIO_CONSOLE_DEVICE_READY, 1);
2110
2111        /*
2112         * If there was an early virtio console, assume that there are no
2113         * other consoles. We need to wait until the hvc_alloc matches the
2114         * hvc_instantiate, otherwise tty_open will complain, resulting in
2115         * a "Warning: unable to open an initial console" boot failure.
2116         * Without multiport this is done in add_port above. With multiport
2117         * this might take some host<->guest communication - thus we have to
2118         * wait.
2119         */
2120        if (multiport && early)
2121                wait_for_completion(&early_console_added);
2122
2123        return 0;
2124
2125free_vqs:
2126        /* The host might want to notify mgmt sw about device add failure */
2127        __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2128                           VIRTIO_CONSOLE_DEVICE_READY, 0);
2129        remove_vqs(portdev);
2130free_chrdev:
2131        unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2132free:
2133        kfree(portdev);
2134fail:
2135        return err;
2136}
2137
2138static void virtcons_remove(struct virtio_device *vdev)
2139{
2140        struct ports_device *portdev;
2141        struct port *port, *port2;
2142
2143        portdev = vdev->priv;
2144
2145        spin_lock_irq(&pdrvdata_lock);
2146        list_del(&portdev->list);
2147        spin_unlock_irq(&pdrvdata_lock);
2148
2149        /* Disable interrupts for vqs */
2150        vdev->config->reset(vdev);
2151        /* Finish up work that's lined up */
2152        if (use_multiport(portdev))
2153                cancel_work_sync(&portdev->control_work);
2154        else
2155                cancel_work_sync(&portdev->config_work);
2156
2157        list_for_each_entry_safe(port, port2, &portdev->ports, list)
2158                unplug_port(port);
2159
2160        unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2161
2162        /*
2163         * When yanking out a device, we immediately lose the
2164         * (device-side) queues.  So there's no point in keeping the
2165         * guest side around till we drop our final reference.  This
2166         * also means that any ports which are in an open state will
2167         * have to just stop using the port, as the vqs are going
2168         * away.
2169         */
2170        remove_controlq_data(portdev);
2171        remove_vqs(portdev);
2172        kfree(portdev);
2173}
2174
2175static struct virtio_device_id id_table[] = {
2176        { VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
2177        { 0 },
2178};
2179
2180static unsigned int features[] = {
2181        VIRTIO_CONSOLE_F_SIZE,
2182        VIRTIO_CONSOLE_F_MULTIPORT,
2183};
2184
2185static struct virtio_device_id rproc_serial_id_table[] = {
2186#if IS_ENABLED(CONFIG_REMOTEPROC)
2187        { VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
2188#endif
2189        { 0 },
2190};
2191
2192static unsigned int rproc_serial_features[] = {
2193};
2194
2195#ifdef CONFIG_PM_SLEEP
2196static int virtcons_freeze(struct virtio_device *vdev)
2197{
2198        struct ports_device *portdev;
2199        struct port *port;
2200
2201        portdev = vdev->priv;
2202
2203        vdev->config->reset(vdev);
2204
2205        virtqueue_disable_cb(portdev->c_ivq);
2206        cancel_work_sync(&portdev->control_work);
2207        cancel_work_sync(&portdev->config_work);
2208        /*
2209         * Once more: if control_work_handler() was running, it would
2210         * enable the cb as the last step.
2211         */
2212        virtqueue_disable_cb(portdev->c_ivq);
2213        remove_controlq_data(portdev);
2214
2215        list_for_each_entry(port, &portdev->ports, list) {
2216                virtqueue_disable_cb(port->in_vq);
2217                virtqueue_disable_cb(port->out_vq);
2218                /*
2219                 * We'll ask the host later if the new invocation has
2220                 * the port opened or closed.
2221                 */
2222                port->host_connected = false;
2223                remove_port_data(port);
2224        }
2225        remove_vqs(portdev);
2226
2227        return 0;
2228}
2229
2230static int virtcons_restore(struct virtio_device *vdev)
2231{
2232        struct ports_device *portdev;
2233        struct port *port;
2234        int ret;
2235
2236        portdev = vdev->priv;
2237
2238        ret = init_vqs(portdev);
2239        if (ret)
2240                return ret;
2241
2242        virtio_device_ready(portdev->vdev);
2243
2244        if (use_multiport(portdev))
2245                fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2246
2247        list_for_each_entry(port, &portdev->ports, list) {
2248                port->in_vq = portdev->in_vqs[port->id];
2249                port->out_vq = portdev->out_vqs[port->id];
2250
2251                fill_queue(port->in_vq, &port->inbuf_lock);
2252
2253                /* Get port open/close status on the host */
2254                send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
2255
2256                /*
2257                 * If a port was open at the time of suspending, we
2258                 * have to let the host know that it's still open.
2259                 */
2260                if (port->guest_connected)
2261                        send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
2262        }
2263        return 0;
2264}
2265#endif
2266
2267static struct virtio_driver virtio_console = {
2268        .feature_table = features,
2269        .feature_table_size = ARRAY_SIZE(features),
2270        .driver.name =  KBUILD_MODNAME,
2271        .driver.owner = THIS_MODULE,
2272        .id_table =     id_table,
2273        .probe =        virtcons_probe,
2274        .remove =       virtcons_remove,
2275        .config_changed = config_intr,
2276#ifdef CONFIG_PM_SLEEP
2277        .freeze =       virtcons_freeze,
2278        .restore =      virtcons_restore,
2279#endif
2280};
2281
2282static struct virtio_driver virtio_rproc_serial = {
2283        .feature_table = rproc_serial_features,
2284        .feature_table_size = ARRAY_SIZE(rproc_serial_features),
2285        .driver.name =  "virtio_rproc_serial",
2286        .driver.owner = THIS_MODULE,
2287        .id_table =     rproc_serial_id_table,
2288        .probe =        virtcons_probe,
2289        .remove =       virtcons_remove,
2290};
2291
2292static int __init init(void)
2293{
2294        int err;
2295
2296        pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
2297        if (IS_ERR(pdrvdata.class)) {
2298                err = PTR_ERR(pdrvdata.class);
2299                pr_err("Error %d creating virtio-ports class\n", err);
2300                return err;
2301        }
2302
2303        pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
2304        if (!pdrvdata.debugfs_dir)
2305                pr_warning("Error creating debugfs dir for virtio-ports\n");
2306        INIT_LIST_HEAD(&pdrvdata.consoles);
2307        INIT_LIST_HEAD(&pdrvdata.portdevs);
2308
2309        err = register_virtio_driver(&virtio_console);
2310        if (err < 0) {
2311                pr_err("Error %d registering virtio driver\n", err);
2312                goto free;
2313        }
2314        err = register_virtio_driver(&virtio_rproc_serial);
2315        if (err < 0) {
2316                pr_err("Error %d registering virtio rproc serial driver\n",
2317                       err);
2318                goto unregister;
2319        }
2320        return 0;
2321unregister:
2322        unregister_virtio_driver(&virtio_console);
2323free:
2324        debugfs_remove_recursive(pdrvdata.debugfs_dir);
2325        class_destroy(pdrvdata.class);
2326        return err;
2327}
2328
2329static void __exit fini(void)
2330{
2331        reclaim_dma_bufs();
2332
2333        unregister_virtio_driver(&virtio_console);
2334        unregister_virtio_driver(&virtio_rproc_serial);
2335
2336        class_destroy(pdrvdata.class);
2337        debugfs_remove_recursive(pdrvdata.debugfs_dir);
2338}
2339module_init(init);
2340module_exit(fini);
2341
2342MODULE_DEVICE_TABLE(virtio, id_table);
2343MODULE_DESCRIPTION("Virtio console driver");
2344MODULE_LICENSE("GPL");
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