2 * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 #include <linux/err.h>
19 #include <linux/init.h>
20 #include <linux/list.h>
21 #include <linux/spinlock.h>
22 #include <linux/virtio.h>
23 #include <linux/virtio_console.h>
24 #include "hvc_console.h"
27 * This is a global struct for storing common data for all the devices
28 * this driver handles.
30 * Mainly, it has a linked list for all the consoles in one place so
31 * that callbacks from hvc for get_chars(), put_chars() work properly
32 * across multiple devices and multiple ports per device.
34 struct ports_driver_data
{
36 * This is used to keep track of the number of hvc consoles
37 * spawned by this driver. This number is given as the first
38 * argument to hvc_alloc(). To correctly map an initial
39 * console spawned via hvc_instantiate to the console being
40 * hooked up via hvc_alloc, we need to pass the same vtermno.
42 * We also just assume the first console being initialised was
43 * the first one that got used as the initial console.
45 unsigned int next_vtermno
;
47 /* All the console devices handled by this driver */
48 struct list_head consoles
;
50 static struct ports_driver_data pdrvdata
;
52 DEFINE_SPINLOCK(pdrvdata_lock
);
54 /* This struct holds information that's relevant only for console ports */
56 /* We'll place all consoles in a list in the pdrvdata struct */
57 struct list_head list
;
59 /* The hvc device associated with this console port */
60 struct hvc_struct
*hvc
;
63 * This number identifies the number that we used to register
64 * with hvc in hvc_instantiate() and hvc_alloc(); this is the
65 * number passed on by the hvc callbacks to us to
66 * differentiate between the other console ports handled by
73 * This is a per-device struct that stores data common to all the
74 * ports for that device (vdev->priv).
77 /* Array of per-port IO virtqueues */
78 struct virtqueue
**in_vqs
, **out_vqs
;
80 struct virtio_device
*vdev
;
86 /* size of the buffer in *buf above */
89 /* used length of the buffer */
91 /* offset in the buf from which to consume data */
95 /* This struct holds the per-port data */
97 /* Pointer to the parent virtio_console device */
98 struct ports_device
*portdev
;
100 /* The current buffer from which data has to be fed to readers */
101 struct port_buffer
*inbuf
;
103 /* The IO vqs for this port */
104 struct virtqueue
*in_vq
, *out_vq
;
107 * The entries in this struct will be valid if this port is
108 * hooked up to an hvc console
113 /* This is the very early arch-specified put chars function. */
114 static int (*early_put_chars
)(u32
, const char *, int);
116 static struct port
*find_port_by_vtermno(u32 vtermno
)
119 struct console
*cons
;
122 spin_lock_irqsave(&pdrvdata_lock
, flags
);
123 list_for_each_entry(cons
, &pdrvdata
.consoles
, list
) {
124 if (cons
->vtermno
== vtermno
) {
125 port
= container_of(cons
, struct port
, cons
);
131 spin_unlock_irqrestore(&pdrvdata_lock
, flags
);
135 static void free_buf(struct port_buffer
*buf
)
141 static struct port_buffer
*alloc_buf(size_t buf_size
)
143 struct port_buffer
*buf
;
145 buf
= kmalloc(sizeof(*buf
), GFP_KERNEL
);
148 buf
->buf
= kzalloc(buf_size
, GFP_KERNEL
);
153 buf
->size
= buf_size
;
162 /* Callers should take appropriate locks */
163 static void *get_inbuf(struct port
*port
)
165 struct port_buffer
*buf
;
166 struct virtqueue
*vq
;
170 buf
= vq
->vq_ops
->get_buf(vq
, &len
);
179 * Create a scatter-gather list representing our input buffer and put
182 * Callers should take appropriate locks.
184 static void add_inbuf(struct virtqueue
*vq
, struct port_buffer
*buf
)
186 struct scatterlist sg
[1];
188 sg_init_one(sg
, buf
->buf
, buf
->size
);
190 if (vq
->vq_ops
->add_buf(vq
, sg
, 0, 1, buf
) < 0)
192 vq
->vq_ops
->kick(vq
);
196 * The put_chars() callback is pretty straightforward.
198 * We turn the characters into a scatter-gather list, add it to the
199 * output queue and then kick the Host. Then we sit here waiting for
200 * it to finish: inefficient in theory, but in practice
201 * implementations will do it immediately (lguest's Launcher does).
203 static int put_chars(u32 vtermno
, const char *buf
, int count
)
205 struct scatterlist sg
[1];
207 struct virtqueue
*out_vq
;
210 port
= find_port_by_vtermno(vtermno
);
214 if (unlikely(early_put_chars
))
215 return early_put_chars(vtermno
, buf
, count
);
217 out_vq
= port
->out_vq
;
218 /* This is a convenient routine to initialize a single-elem sg list */
219 sg_init_one(sg
, buf
, count
);
221 /* This shouldn't fail: if it does, we lose chars. */
222 if (out_vq
->vq_ops
->add_buf(out_vq
, sg
, 1, 0, port
) >= 0) {
223 /* Tell Host to go! */
224 out_vq
->vq_ops
->kick(out_vq
);
225 while (!out_vq
->vq_ops
->get_buf(out_vq
, &len
))
229 /* We're expected to return the amount of data we wrote: all of it. */
234 * get_chars() is the callback from the hvc_console infrastructure
235 * when an interrupt is received.
237 * Most of the code deals with the fact that the hvc_console()
238 * infrastructure only asks us for 16 bytes at a time. We keep
239 * in_offset and in_used fields for partially-filled buffers.
241 static int get_chars(u32 vtermno
, char *buf
, int count
)
245 port
= find_port_by_vtermno(vtermno
);
249 /* If we don't have an input queue yet, we can't get input. */
250 BUG_ON(!port
->in_vq
);
252 /* No more in buffer? See if they've (re)used it. */
253 if (port
->inbuf
->offset
== port
->inbuf
->len
) {
254 if (!get_inbuf(port
))
258 /* You want more than we have to give? Well, try wanting less! */
259 if (port
->inbuf
->offset
+ count
> port
->inbuf
->len
)
260 count
= port
->inbuf
->len
- port
->inbuf
->offset
;
262 /* Copy across to their buffer and increment offset. */
263 memcpy(buf
, port
->inbuf
->buf
+ port
->inbuf
->offset
, count
);
264 port
->inbuf
->offset
+= count
;
266 /* Finished? Re-register buffer so Host will use it again. */
267 if (port
->inbuf
->offset
== port
->inbuf
->len
)
268 add_inbuf(port
->in_vq
, port
->inbuf
);
273 static void resize_console(struct port
*port
)
275 struct virtio_device
*vdev
;
278 vdev
= port
->portdev
->vdev
;
279 if (virtio_has_feature(vdev
, VIRTIO_CONSOLE_F_SIZE
)) {
280 vdev
->config
->get(vdev
,
281 offsetof(struct virtio_console_config
, cols
),
282 &ws
.ws_col
, sizeof(u16
));
283 vdev
->config
->get(vdev
,
284 offsetof(struct virtio_console_config
, rows
),
285 &ws
.ws_row
, sizeof(u16
));
286 hvc_resize(port
->cons
.hvc
, ws
);
290 static void virtcons_apply_config(struct virtio_device
*vdev
)
292 resize_console(find_port_by_vtermno(0));
295 /* We set the configuration at this point, since we now have a tty */
296 static int notifier_add_vio(struct hvc_struct
*hp
, int data
)
300 port
= find_port_by_vtermno(hp
->vtermno
);
304 hp
->irq_requested
= 1;
305 resize_console(port
);
310 static void notifier_del_vio(struct hvc_struct
*hp
, int data
)
312 hp
->irq_requested
= 0;
315 static void hvc_handle_input(struct virtqueue
*vq
)
317 struct console
*cons
;
318 bool activity
= false;
320 list_for_each_entry(cons
, &pdrvdata
.consoles
, list
)
321 activity
|= hvc_poll(cons
->hvc
);
327 /* The operations for the console. */
328 static const struct hv_ops hv_ops
= {
329 .get_chars
= get_chars
,
330 .put_chars
= put_chars
,
331 .notifier_add
= notifier_add_vio
,
332 .notifier_del
= notifier_del_vio
,
333 .notifier_hangup
= notifier_del_vio
,
337 * Console drivers are initialized very early so boot messages can go
338 * out, so we do things slightly differently from the generic virtio
339 * initialization of the net and block drivers.
341 * At this stage, the console is output-only. It's too early to set
342 * up a virtqueue, so we let the drivers do some boutique early-output
345 int __init
virtio_cons_early_init(int (*put_chars
)(u32
, const char *, int))
347 early_put_chars
= put_chars
;
348 return hvc_instantiate(0, 0, &hv_ops
);
351 int __devinit
init_port_console(struct port
*port
)
356 * The Host's telling us this port is a console port. Hook it
357 * up with an hvc console.
359 * To set up and manage our virtual console, we call
362 * The first argument of hvc_alloc() is the virtual console
363 * number. The second argument is the parameter for the
364 * notification mechanism (like irq number). We currently
365 * leave this as zero, virtqueues have implicit notifications.
367 * The third argument is a "struct hv_ops" containing the
368 * put_chars() get_chars(), notifier_add() and notifier_del()
369 * pointers. The final argument is the output buffer size: we
370 * can do any size, so we put PAGE_SIZE here.
372 port
->cons
.vtermno
= pdrvdata
.next_vtermno
;
374 port
->cons
.hvc
= hvc_alloc(port
->cons
.vtermno
, 0, &hv_ops
, PAGE_SIZE
);
375 if (IS_ERR(port
->cons
.hvc
)) {
376 ret
= PTR_ERR(port
->cons
.hvc
);
377 port
->cons
.hvc
= NULL
;
380 spin_lock_irq(&pdrvdata_lock
);
381 pdrvdata
.next_vtermno
++;
382 list_add_tail(&port
->cons
.list
, &pdrvdata
.consoles
);
383 spin_unlock_irq(&pdrvdata_lock
);
388 static int __devinit
add_port(struct ports_device
*portdev
)
393 port
= kmalloc(sizeof(*port
), GFP_KERNEL
);
399 port
->portdev
= portdev
;
400 port
->in_vq
= portdev
->in_vqs
[0];
401 port
->out_vq
= portdev
->out_vqs
[0];
403 port
->inbuf
= alloc_buf(PAGE_SIZE
);
409 err
= init_port_console(port
);
413 /* Register the input buffer the first time. */
414 add_inbuf(port
->in_vq
, port
->inbuf
);
419 free_buf(port
->inbuf
);
426 static int init_vqs(struct ports_device
*portdev
)
428 vq_callback_t
**io_callbacks
;
430 struct virtqueue
**vqs
;
431 u32 nr_ports
, nr_queues
;
434 /* We currently only have one port and two queues for that port */
438 vqs
= kmalloc(nr_queues
* sizeof(struct virtqueue
*), GFP_KERNEL
);
443 io_callbacks
= kmalloc(nr_queues
* sizeof(vq_callback_t
*), GFP_KERNEL
);
448 io_names
= kmalloc(nr_queues
* sizeof(char *), GFP_KERNEL
);
453 portdev
->in_vqs
= kmalloc(nr_ports
* sizeof(struct virtqueue
*),
455 if (!portdev
->in_vqs
) {
459 portdev
->out_vqs
= kmalloc(nr_ports
* sizeof(struct virtqueue
*),
461 if (!portdev
->out_vqs
) {
466 io_callbacks
[0] = hvc_handle_input
;
467 io_callbacks
[1] = NULL
;
468 io_names
[0] = "input";
469 io_names
[1] = "output";
471 /* Find the queues. */
472 err
= portdev
->vdev
->config
->find_vqs(portdev
->vdev
, nr_queues
, vqs
,
474 (const char **)io_names
);
478 portdev
->in_vqs
[0] = vqs
[0];
479 portdev
->out_vqs
[0] = vqs
[1];
492 kfree(portdev
->out_vqs
);
494 kfree(portdev
->in_vqs
);
502 * Once we're further in boot, we get probed like any other virtio
505 static int __devinit
virtcons_probe(struct virtio_device
*vdev
)
507 struct ports_device
*portdev
;
510 portdev
= kmalloc(sizeof(*portdev
), GFP_KERNEL
);
516 /* Attach this portdev to this virtio_device, and vice-versa. */
517 portdev
->vdev
= vdev
;
518 vdev
->priv
= portdev
;
520 err
= init_vqs(portdev
);
522 dev_err(&vdev
->dev
, "Error %d initializing vqs\n", err
);
526 /* We only have one port. */
527 err
= add_port(portdev
);
531 /* Start using the new console output. */
532 early_put_chars
= NULL
;
536 vdev
->config
->del_vqs(vdev
);
537 kfree(portdev
->in_vqs
);
538 kfree(portdev
->out_vqs
);
545 static struct virtio_device_id id_table
[] = {
546 { VIRTIO_ID_CONSOLE
, VIRTIO_DEV_ANY_ID
},
550 static unsigned int features
[] = {
551 VIRTIO_CONSOLE_F_SIZE
,
554 static struct virtio_driver virtio_console
= {
555 .feature_table
= features
,
556 .feature_table_size
= ARRAY_SIZE(features
),
557 .driver
.name
= KBUILD_MODNAME
,
558 .driver
.owner
= THIS_MODULE
,
559 .id_table
= id_table
,
560 .probe
= virtcons_probe
,
561 .config_changed
= virtcons_apply_config
,
564 static int __init
init(void)
566 INIT_LIST_HEAD(&pdrvdata
.consoles
);
568 return register_virtio_driver(&virtio_console
);
572 MODULE_DEVICE_TABLE(virtio
, id_table
);
573 MODULE_DESCRIPTION("Virtio console driver");
574 MODULE_LICENSE("GPL");