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");