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a23ea924 RR |
1 | /* |
2 | * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation | |
31610434 RR |
3 | * |
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. | |
8 | * | |
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. | |
13 | * | |
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 | |
17 | */ | |
18 | #include <linux/err.h> | |
19 | #include <linux/init.h> | |
20 | #include <linux/virtio.h> | |
21 | #include <linux/virtio_console.h> | |
22 | #include "hvc_console.h" | |
23 | ||
fdb9a054 AS |
24 | struct port_buffer { |
25 | char *buf; | |
26 | ||
27 | /* size of the buffer in *buf above */ | |
28 | size_t size; | |
29 | ||
30 | /* used length of the buffer */ | |
31 | size_t len; | |
32 | /* offset in the buf from which to consume data */ | |
33 | size_t offset; | |
34 | }; | |
35 | ||
21206ede RR |
36 | struct port { |
37 | struct virtqueue *in_vq, *out_vq; | |
38 | struct virtio_device *vdev; | |
fdb9a054 AS |
39 | |
40 | /* The current buffer from which data has to be fed to readers */ | |
41 | struct port_buffer *inbuf; | |
21206ede RR |
42 | |
43 | /* The hvc device */ | |
44 | struct hvc_struct *hvc; | |
45 | }; | |
31610434 | 46 | |
21206ede RR |
47 | /* We have one port ready to go immediately, for a console. */ |
48 | static struct port console; | |
91fcad19 | 49 | |
971f3390 RR |
50 | /* This is the very early arch-specified put chars function. */ |
51 | static int (*early_put_chars)(u32, const char *, int); | |
52 | ||
fdb9a054 AS |
53 | static void free_buf(struct port_buffer *buf) |
54 | { | |
55 | kfree(buf->buf); | |
56 | kfree(buf); | |
57 | } | |
58 | ||
59 | static struct port_buffer *alloc_buf(size_t buf_size) | |
60 | { | |
61 | struct port_buffer *buf; | |
62 | ||
63 | buf = kmalloc(sizeof(*buf), GFP_KERNEL); | |
64 | if (!buf) | |
65 | goto fail; | |
66 | buf->buf = kzalloc(buf_size, GFP_KERNEL); | |
67 | if (!buf->buf) | |
68 | goto free_buf; | |
69 | buf->len = 0; | |
70 | buf->offset = 0; | |
71 | buf->size = buf_size; | |
72 | return buf; | |
73 | ||
74 | free_buf: | |
75 | kfree(buf); | |
76 | fail: | |
77 | return NULL; | |
78 | } | |
79 | ||
e27b5198 AS |
80 | /* |
81 | * Create a scatter-gather list representing our input buffer and put | |
82 | * it in the queue. | |
83 | * | |
84 | * Callers should take appropriate locks. | |
85 | */ | |
86 | static void add_inbuf(struct virtqueue *vq, struct port_buffer *buf) | |
87 | { | |
88 | struct scatterlist sg[1]; | |
89 | sg_init_one(sg, buf->buf, buf->size); | |
90 | ||
91 | if (vq->vq_ops->add_buf(vq, sg, 0, 1, buf) < 0) | |
92 | BUG(); | |
93 | vq->vq_ops->kick(vq); | |
94 | } | |
95 | ||
a23ea924 RR |
96 | /* |
97 | * The put_chars() callback is pretty straightforward. | |
31610434 | 98 | * |
a23ea924 RR |
99 | * We turn the characters into a scatter-gather list, add it to the |
100 | * output queue and then kick the Host. Then we sit here waiting for | |
101 | * it to finish: inefficient in theory, but in practice | |
102 | * implementations will do it immediately (lguest's Launcher does). | |
103 | */ | |
31610434 RR |
104 | static int put_chars(u32 vtermno, const char *buf, int count) |
105 | { | |
106 | struct scatterlist sg[1]; | |
107 | unsigned int len; | |
21206ede | 108 | struct port *port; |
31610434 | 109 | |
971f3390 RR |
110 | if (unlikely(early_put_chars)) |
111 | return early_put_chars(vtermno, buf, count); | |
112 | ||
21206ede RR |
113 | port = &console; |
114 | ||
31610434 RR |
115 | /* This is a convenient routine to initialize a single-elem sg list */ |
116 | sg_init_one(sg, buf, count); | |
117 | ||
21206ede RR |
118 | /* This shouldn't fail: if it does, we lose chars. */ |
119 | if (port->out_vq->vq_ops->add_buf(port->out_vq, sg, 1, 0, port) >= 0) { | |
31610434 | 120 | /* Tell Host to go! */ |
21206ede RR |
121 | port->out_vq->vq_ops->kick(port->out_vq); |
122 | while (!port->out_vq->vq_ops->get_buf(port->out_vq, &len)) | |
31610434 RR |
123 | cpu_relax(); |
124 | } | |
125 | ||
126 | /* We're expected to return the amount of data we wrote: all of it. */ | |
127 | return count; | |
128 | } | |
129 | ||
a23ea924 RR |
130 | /* |
131 | * get_chars() is the callback from the hvc_console infrastructure | |
132 | * when an interrupt is received. | |
31610434 | 133 | * |
a23ea924 RR |
134 | * Most of the code deals with the fact that the hvc_console() |
135 | * infrastructure only asks us for 16 bytes at a time. We keep | |
136 | * in_offset and in_used fields for partially-filled buffers. | |
137 | */ | |
31610434 RR |
138 | static int get_chars(u32 vtermno, char *buf, int count) |
139 | { | |
21206ede | 140 | struct port *port; |
fdb9a054 | 141 | unsigned int len; |
21206ede RR |
142 | |
143 | port = &console; | |
144 | ||
31610434 | 145 | /* If we don't have an input queue yet, we can't get input. */ |
21206ede | 146 | BUG_ON(!port->in_vq); |
31610434 | 147 | |
21206ede | 148 | /* No more in buffer? See if they've (re)used it. */ |
fdb9a054 AS |
149 | if (port->inbuf->offset == port->inbuf->len) { |
150 | if (!port->in_vq->vq_ops->get_buf(port->in_vq, &len)) | |
31610434 | 151 | return 0; |
fdb9a054 AS |
152 | port->inbuf->offset = 0; |
153 | port->inbuf->len = len; | |
31610434 RR |
154 | } |
155 | ||
156 | /* You want more than we have to give? Well, try wanting less! */ | |
fdb9a054 AS |
157 | if (port->inbuf->offset + count > port->inbuf->len) |
158 | count = port->inbuf->len - port->inbuf->offset; | |
31610434 RR |
159 | |
160 | /* Copy across to their buffer and increment offset. */ | |
fdb9a054 AS |
161 | memcpy(buf, port->inbuf->buf + port->inbuf->offset, count); |
162 | port->inbuf->offset += count; | |
31610434 RR |
163 | |
164 | /* Finished? Re-register buffer so Host will use it again. */ | |
fdb9a054 | 165 | if (port->inbuf->offset == port->inbuf->len) |
e27b5198 | 166 | add_inbuf(port->in_vq, port->inbuf); |
31610434 RR |
167 | |
168 | return count; | |
169 | } | |
31610434 | 170 | |
c2983458 CB |
171 | /* |
172 | * virtio console configuration. This supports: | |
173 | * - console resize | |
174 | */ | |
175 | static void virtcons_apply_config(struct virtio_device *dev) | |
176 | { | |
177 | struct winsize ws; | |
178 | ||
179 | if (virtio_has_feature(dev, VIRTIO_CONSOLE_F_SIZE)) { | |
180 | dev->config->get(dev, | |
181 | offsetof(struct virtio_console_config, cols), | |
182 | &ws.ws_col, sizeof(u16)); | |
183 | dev->config->get(dev, | |
184 | offsetof(struct virtio_console_config, rows), | |
185 | &ws.ws_row, sizeof(u16)); | |
21206ede | 186 | hvc_resize(console.hvc, ws); |
c2983458 CB |
187 | } |
188 | } | |
189 | ||
91fcad19 | 190 | /* |
a23ea924 RR |
191 | * we support only one console, the hvc struct is a global var We set |
192 | * the configuration at this point, since we now have a tty | |
91fcad19 CB |
193 | */ |
194 | static int notifier_add_vio(struct hvc_struct *hp, int data) | |
195 | { | |
196 | hp->irq_requested = 1; | |
21206ede | 197 | virtcons_apply_config(console.vdev); |
c2983458 | 198 | |
91fcad19 CB |
199 | return 0; |
200 | } | |
201 | ||
202 | static void notifier_del_vio(struct hvc_struct *hp, int data) | |
203 | { | |
204 | hp->irq_requested = 0; | |
205 | } | |
206 | ||
207 | static void hvc_handle_input(struct virtqueue *vq) | |
208 | { | |
21206ede | 209 | if (hvc_poll(console.hvc)) |
91fcad19 CB |
210 | hvc_kick(); |
211 | } | |
212 | ||
971f3390 | 213 | /* The operations for the console. */ |
1dff3996 | 214 | static const struct hv_ops hv_ops = { |
971f3390 RR |
215 | .get_chars = get_chars, |
216 | .put_chars = put_chars, | |
217 | .notifier_add = notifier_add_vio, | |
218 | .notifier_del = notifier_del_vio, | |
219 | .notifier_hangup = notifier_del_vio, | |
220 | }; | |
221 | ||
222 | /* | |
223 | * Console drivers are initialized very early so boot messages can go | |
224 | * out, so we do things slightly differently from the generic virtio | |
225 | * initialization of the net and block drivers. | |
226 | * | |
227 | * At this stage, the console is output-only. It's too early to set | |
228 | * up a virtqueue, so we let the drivers do some boutique early-output | |
229 | * thing. | |
230 | */ | |
231 | int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int)) | |
232 | { | |
233 | early_put_chars = put_chars; | |
234 | return hvc_instantiate(0, 0, &hv_ops); | |
235 | } | |
236 | ||
a23ea924 RR |
237 | /* |
238 | * Once we're further in boot, we get probed like any other virtio | |
239 | * device. At this stage we set up the output virtqueue. | |
31610434 | 240 | * |
a23ea924 RR |
241 | * To set up and manage our virtual console, we call hvc_alloc(). |
242 | * Since we never remove the console device we never need this pointer | |
243 | * again. | |
31610434 | 244 | * |
a23ea924 RR |
245 | * Finally we put our input buffer in the input queue, ready to |
246 | * receive. | |
247 | */ | |
21206ede | 248 | static int __devinit virtcons_probe(struct virtio_device *vdev) |
31610434 | 249 | { |
d2a7ddda MT |
250 | vq_callback_t *callbacks[] = { hvc_handle_input, NULL}; |
251 | const char *names[] = { "input", "output" }; | |
252 | struct virtqueue *vqs[2]; | |
21206ede | 253 | struct port *port; |
31610434 | 254 | int err; |
31610434 | 255 | |
21206ede RR |
256 | port = &console; |
257 | if (port->vdev) { | |
258 | dev_warn(&port->vdev->dev, | |
f550804a AS |
259 | "Multiple virtio-console devices not supported yet\n"); |
260 | return -EEXIST; | |
261 | } | |
21206ede | 262 | port->vdev = vdev; |
31610434 RR |
263 | |
264 | /* This is the scratch page we use to receive console input */ | |
fdb9a054 | 265 | port->inbuf = alloc_buf(PAGE_SIZE); |
21206ede | 266 | if (!port->inbuf) { |
31610434 RR |
267 | err = -ENOMEM; |
268 | goto fail; | |
269 | } | |
270 | ||
d2a7ddda | 271 | /* Find the queues. */ |
d2a7ddda MT |
272 | err = vdev->config->find_vqs(vdev, 2, vqs, callbacks, names); |
273 | if (err) | |
31610434 | 274 | goto free; |
31610434 | 275 | |
21206ede RR |
276 | port->in_vq = vqs[0]; |
277 | port->out_vq = vqs[1]; | |
31610434 | 278 | |
a23ea924 RR |
279 | /* |
280 | * The first argument of hvc_alloc() is the virtual console | |
281 | * number, so we use zero. The second argument is the | |
282 | * parameter for the notification mechanism (like irq | |
283 | * number). We currently leave this as zero, virtqueues have | |
284 | * implicit notifications. | |
31610434 | 285 | * |
a23ea924 RR |
286 | * The third argument is a "struct hv_ops" containing the |
287 | * put_chars(), get_chars(), notifier_add() and notifier_del() | |
288 | * pointers. The final argument is the output buffer size: we | |
289 | * can do any size, so we put PAGE_SIZE here. | |
290 | */ | |
21206ede RR |
291 | port->hvc = hvc_alloc(0, 0, &hv_ops, PAGE_SIZE); |
292 | if (IS_ERR(port->hvc)) { | |
293 | err = PTR_ERR(port->hvc); | |
d2a7ddda | 294 | goto free_vqs; |
31610434 RR |
295 | } |
296 | ||
297 | /* Register the input buffer the first time. */ | |
e27b5198 | 298 | add_inbuf(port->in_vq, port->inbuf); |
971f3390 RR |
299 | |
300 | /* Start using the new console output. */ | |
301 | early_put_chars = NULL; | |
31610434 RR |
302 | return 0; |
303 | ||
d2a7ddda MT |
304 | free_vqs: |
305 | vdev->config->del_vqs(vdev); | |
31610434 | 306 | free: |
fdb9a054 | 307 | free_buf(port->inbuf); |
31610434 RR |
308 | fail: |
309 | return err; | |
310 | } | |
311 | ||
312 | static struct virtio_device_id id_table[] = { | |
313 | { VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID }, | |
314 | { 0 }, | |
315 | }; | |
316 | ||
c2983458 CB |
317 | static unsigned int features[] = { |
318 | VIRTIO_CONSOLE_F_SIZE, | |
319 | }; | |
320 | ||
31610434 | 321 | static struct virtio_driver virtio_console = { |
c2983458 CB |
322 | .feature_table = features, |
323 | .feature_table_size = ARRAY_SIZE(features), | |
31610434 RR |
324 | .driver.name = KBUILD_MODNAME, |
325 | .driver.owner = THIS_MODULE, | |
326 | .id_table = id_table, | |
327 | .probe = virtcons_probe, | |
c2983458 | 328 | .config_changed = virtcons_apply_config, |
31610434 RR |
329 | }; |
330 | ||
331 | static int __init init(void) | |
332 | { | |
333 | return register_virtio_driver(&virtio_console); | |
334 | } | |
335 | module_init(init); | |
336 | ||
337 | MODULE_DEVICE_TABLE(virtio, id_table); | |
338 | MODULE_DESCRIPTION("Virtio console driver"); | |
339 | MODULE_LICENSE("GPL"); |