1 #include <linux/types.h>
2 #include <linux/init.h>
3 #include <linux/delay.h>
4 #include <linux/slab.h>
5 #include <linux/console.h>
6 #include <asm/hvsi.h>
7
8 #include "hvc_console.h"
9
hvsi_send_packet(struct hvsi_priv * pv,struct hvsi_header * packet)10 static int hvsi_send_packet(struct hvsi_priv *pv, struct hvsi_header *packet)
11 {
12 packet->seqno = atomic_inc_return(&pv->seqno);
13
14 /* Assumes that always succeeds, works in practice */
15 return pv->put_chars(pv->termno, (char *)packet, packet->len);
16 }
17
hvsi_start_handshake(struct hvsi_priv * pv)18 static void hvsi_start_handshake(struct hvsi_priv *pv)
19 {
20 struct hvsi_query q;
21
22 /* Reset state */
23 pv->established = 0;
24 atomic_set(&pv->seqno, 0);
25
26 pr_devel("HVSI@%x: Handshaking started\n", pv->termno);
27
28 /* Send version query */
29 q.hdr.type = VS_QUERY_PACKET_HEADER;
30 q.hdr.len = sizeof(struct hvsi_query);
31 q.verb = VSV_SEND_VERSION_NUMBER;
32 hvsi_send_packet(pv, &q.hdr);
33 }
34
hvsi_send_close(struct hvsi_priv * pv)35 static int hvsi_send_close(struct hvsi_priv *pv)
36 {
37 struct hvsi_control ctrl;
38
39 pv->established = 0;
40
41 ctrl.hdr.type = VS_CONTROL_PACKET_HEADER;
42 ctrl.hdr.len = sizeof(struct hvsi_control);
43 ctrl.verb = VSV_CLOSE_PROTOCOL;
44 return hvsi_send_packet(pv, &ctrl.hdr);
45 }
46
hvsi_cd_change(struct hvsi_priv * pv,int cd)47 static void hvsi_cd_change(struct hvsi_priv *pv, int cd)
48 {
49 if (cd)
50 pv->mctrl |= TIOCM_CD;
51 else {
52 pv->mctrl &= ~TIOCM_CD;
53
54 /* We copy the existing hvsi driver semantics
55 * here which are to trigger a hangup when
56 * we get a carrier loss.
57 * Closing our connection to the server will
58 * do just that.
59 */
60 if (!pv->is_console && pv->opened) {
61 pr_devel("HVSI@%x Carrier lost, hanging up !\n",
62 pv->termno);
63 hvsi_send_close(pv);
64 }
65 }
66 }
67
hvsi_got_control(struct hvsi_priv * pv)68 static void hvsi_got_control(struct hvsi_priv *pv)
69 {
70 struct hvsi_control *pkt = (struct hvsi_control *)pv->inbuf;
71
72 switch (pkt->verb) {
73 case VSV_CLOSE_PROTOCOL:
74 /* We restart the handshaking */
75 hvsi_start_handshake(pv);
76 break;
77 case VSV_MODEM_CTL_UPDATE:
78 /* Transition of carrier detect */
79 hvsi_cd_change(pv, pkt->word & HVSI_TSCD);
80 break;
81 }
82 }
83
hvsi_got_query(struct hvsi_priv * pv)84 static void hvsi_got_query(struct hvsi_priv *pv)
85 {
86 struct hvsi_query *pkt = (struct hvsi_query *)pv->inbuf;
87 struct hvsi_query_response r;
88
89 /* We only handle version queries */
90 if (pkt->verb != VSV_SEND_VERSION_NUMBER)
91 return;
92
93 pr_devel("HVSI@%x: Got version query, sending response...\n",
94 pv->termno);
95
96 /* Send version response */
97 r.hdr.type = VS_QUERY_RESPONSE_PACKET_HEADER;
98 r.hdr.len = sizeof(struct hvsi_query_response);
99 r.verb = VSV_SEND_VERSION_NUMBER;
100 r.u.version = HVSI_VERSION;
101 r.query_seqno = pkt->hdr.seqno;
102 hvsi_send_packet(pv, &r.hdr);
103
104 /* Assume protocol is open now */
105 pv->established = 1;
106 }
107
hvsi_got_response(struct hvsi_priv * pv)108 static void hvsi_got_response(struct hvsi_priv *pv)
109 {
110 struct hvsi_query_response *r =
111 (struct hvsi_query_response *)pv->inbuf;
112
113 switch(r->verb) {
114 case VSV_SEND_MODEM_CTL_STATUS:
115 hvsi_cd_change(pv, r->u.mctrl_word & HVSI_TSCD);
116 pv->mctrl_update = 1;
117 break;
118 }
119 }
120
hvsi_check_packet(struct hvsi_priv * pv)121 static int hvsi_check_packet(struct hvsi_priv *pv)
122 {
123 u8 len, type;
124
125 /* Check header validity. If it's invalid, we ditch
126 * the whole buffer and hope we eventually resync
127 */
128 if (pv->inbuf[0] < 0xfc) {
129 pv->inbuf_len = pv->inbuf_pktlen = 0;
130 return 0;
131 }
132 type = pv->inbuf[0];
133 len = pv->inbuf[1];
134
135 /* Packet incomplete ? */
136 if (pv->inbuf_len < len)
137 return 0;
138
139 pr_devel("HVSI@%x: Got packet type %x len %d bytes:\n",
140 pv->termno, type, len);
141
142 /* We have a packet, yay ! Handle it */
143 switch(type) {
144 case VS_DATA_PACKET_HEADER:
145 pv->inbuf_pktlen = len - 4;
146 pv->inbuf_cur = 4;
147 return 1;
148 case VS_CONTROL_PACKET_HEADER:
149 hvsi_got_control(pv);
150 break;
151 case VS_QUERY_PACKET_HEADER:
152 hvsi_got_query(pv);
153 break;
154 case VS_QUERY_RESPONSE_PACKET_HEADER:
155 hvsi_got_response(pv);
156 break;
157 }
158
159 /* Swallow packet and retry */
160 pv->inbuf_len -= len;
161 memmove(pv->inbuf, &pv->inbuf[len], pv->inbuf_len);
162 return 1;
163 }
164
hvsi_get_packet(struct hvsi_priv * pv)165 static int hvsi_get_packet(struct hvsi_priv *pv)
166 {
167 /* If we have room in the buffer, ask HV for more */
168 if (pv->inbuf_len < HVSI_INBUF_SIZE)
169 pv->inbuf_len += pv->get_chars(pv->termno,
170 &pv->inbuf[pv->inbuf_len],
171 HVSI_INBUF_SIZE - pv->inbuf_len);
172 /*
173 * If we have at least 4 bytes in the buffer, check for
174 * a full packet and retry
175 */
176 if (pv->inbuf_len >= 4)
177 return hvsi_check_packet(pv);
178 return 0;
179 }
180
hvsilib_get_chars(struct hvsi_priv * pv,char * buf,int count)181 int hvsilib_get_chars(struct hvsi_priv *pv, char *buf, int count)
182 {
183 unsigned int tries, read = 0;
184
185 if (WARN_ON(!pv))
186 return -ENXIO;
187
188 /* If we aren't open, don't do anything in order to avoid races
189 * with connection establishment. The hvc core will call this
190 * before we have returned from notifier_add(), and we need to
191 * avoid multiple users playing with the receive buffer
192 */
193 if (!pv->opened)
194 return 0;
195
196 /* We try twice, once with what data we have and once more
197 * after we try to fetch some more from the hypervisor
198 */
199 for (tries = 1; count && tries < 2; tries++) {
200 /* Consume existing data packet */
201 if (pv->inbuf_pktlen) {
202 unsigned int l = min(count, (int)pv->inbuf_pktlen);
203 memcpy(&buf[read], &pv->inbuf[pv->inbuf_cur], l);
204 pv->inbuf_cur += l;
205 pv->inbuf_pktlen -= l;
206 count -= l;
207 read += l;
208 }
209 if (count == 0)
210 break;
211
212 /* Data packet fully consumed, move down remaning data */
213 if (pv->inbuf_cur) {
214 pv->inbuf_len -= pv->inbuf_cur;
215 memmove(pv->inbuf, &pv->inbuf[pv->inbuf_cur],
216 pv->inbuf_len);
217 pv->inbuf_cur = 0;
218 }
219
220 /* Try to get another packet */
221 if (hvsi_get_packet(pv))
222 tries--;
223 }
224 if (!pv->established) {
225 pr_devel("HVSI@%x: returning -EPIPE\n", pv->termno);
226 return -EPIPE;
227 }
228 return read;
229 }
230
hvsilib_put_chars(struct hvsi_priv * pv,const char * buf,int count)231 int hvsilib_put_chars(struct hvsi_priv *pv, const char *buf, int count)
232 {
233 struct hvsi_data dp;
234 int rc, adjcount = min(count, HVSI_MAX_OUTGOING_DATA);
235
236 if (WARN_ON(!pv))
237 return -ENODEV;
238
239 dp.hdr.type = VS_DATA_PACKET_HEADER;
240 dp.hdr.len = adjcount + sizeof(struct hvsi_header);
241 memcpy(dp.data, buf, adjcount);
242 rc = hvsi_send_packet(pv, &dp.hdr);
243 if (rc <= 0)
244 return rc;
245 return adjcount;
246 }
247
maybe_msleep(unsigned long ms)248 static void maybe_msleep(unsigned long ms)
249 {
250 /* During early boot, IRQs are disabled, use mdelay */
251 if (irqs_disabled())
252 mdelay(ms);
253 else
254 msleep(ms);
255 }
256
hvsilib_read_mctrl(struct hvsi_priv * pv)257 int hvsilib_read_mctrl(struct hvsi_priv *pv)
258 {
259 struct hvsi_query q;
260 int rc, timeout;
261
262 pr_devel("HVSI@%x: Querying modem control status...\n",
263 pv->termno);
264
265 pv->mctrl_update = 0;
266 q.hdr.type = VS_QUERY_PACKET_HEADER;
267 q.hdr.len = sizeof(struct hvsi_query);
268 q.hdr.seqno = atomic_inc_return(&pv->seqno);
269 q.verb = VSV_SEND_MODEM_CTL_STATUS;
270 rc = hvsi_send_packet(pv, &q.hdr);
271 if (rc <= 0) {
272 pr_devel("HVSI@%x: Error %d...\n", pv->termno, rc);
273 return rc;
274 }
275
276 /* Try for up to 200ms */
277 for (timeout = 0; timeout < 20; timeout++) {
278 if (!pv->established)
279 return -ENXIO;
280 if (pv->mctrl_update)
281 return 0;
282 if (!hvsi_get_packet(pv))
283 maybe_msleep(10);
284 }
285 return -EIO;
286 }
287
hvsilib_write_mctrl(struct hvsi_priv * pv,int dtr)288 int hvsilib_write_mctrl(struct hvsi_priv *pv, int dtr)
289 {
290 struct hvsi_control ctrl;
291 unsigned short mctrl;
292
293 mctrl = pv->mctrl;
294 if (dtr)
295 mctrl |= TIOCM_DTR;
296 else
297 mctrl &= ~TIOCM_DTR;
298 if (mctrl == pv->mctrl)
299 return 0;
300 pv->mctrl = mctrl;
301
302 pr_devel("HVSI@%x: %s DTR...\n", pv->termno,
303 dtr ? "Setting" : "Clearing");
304
305 ctrl.hdr.type = VS_CONTROL_PACKET_HEADER,
306 ctrl.hdr.len = sizeof(struct hvsi_control);
307 ctrl.verb = VSV_SET_MODEM_CTL;
308 ctrl.mask = HVSI_TSDTR;
309 ctrl.word = dtr ? HVSI_TSDTR : 0;
310 return hvsi_send_packet(pv, &ctrl.hdr);
311 }
312
hvsilib_establish(struct hvsi_priv * pv)313 void hvsilib_establish(struct hvsi_priv *pv)
314 {
315 int timeout;
316
317 pr_devel("HVSI@%x: Establishing...\n", pv->termno);
318
319 /* Try for up to 200ms, there can be a packet to
320 * start the process waiting for us...
321 */
322 for (timeout = 0; timeout < 20; timeout++) {
323 if (pv->established)
324 goto established;
325 if (!hvsi_get_packet(pv))
326 maybe_msleep(10);
327 }
328
329 /* Failed, send a close connection packet just
330 * in case
331 */
332 pr_devel("HVSI@%x: ... sending close\n", pv->termno);
333
334 hvsi_send_close(pv);
335
336 /* Then restart handshake */
337
338 pr_devel("HVSI@%x: ... restarting handshake\n", pv->termno);
339
340 hvsi_start_handshake(pv);
341
342 pr_devel("HVSI@%x: ... waiting handshake\n", pv->termno);
343
344 /* Try for up to 400ms */
345 for (timeout = 0; timeout < 40; timeout++) {
346 if (pv->established)
347 goto established;
348 if (!hvsi_get_packet(pv))
349 maybe_msleep(10);
350 }
351
352 if (!pv->established) {
353 pr_devel("HVSI@%x: Timeout handshaking, giving up !\n",
354 pv->termno);
355 return;
356 }
357 established:
358 /* Query modem control lines */
359
360 pr_devel("HVSI@%x: ... established, reading mctrl\n", pv->termno);
361
362 hvsilib_read_mctrl(pv);
363
364 /* Set our own DTR */
365
366 pr_devel("HVSI@%x: ... setting mctrl\n", pv->termno);
367
368 hvsilib_write_mctrl(pv, 1);
369
370 /* Set the opened flag so reads are allowed */
371 wmb();
372 pv->opened = 1;
373 }
374
hvsilib_open(struct hvsi_priv * pv,struct hvc_struct * hp)375 int hvsilib_open(struct hvsi_priv *pv, struct hvc_struct *hp)
376 {
377 pr_devel("HVSI@%x: open !\n", pv->termno);
378
379 /* Keep track of the tty data structure */
380 pv->tty = tty_kref_get(hp->tty);
381
382 hvsilib_establish(pv);
383
384 return 0;
385 }
386
hvsilib_close(struct hvsi_priv * pv,struct hvc_struct * hp)387 void hvsilib_close(struct hvsi_priv *pv, struct hvc_struct *hp)
388 {
389 unsigned long flags;
390
391 pr_devel("HVSI@%x: close !\n", pv->termno);
392
393 if (!pv->is_console) {
394 pr_devel("HVSI@%x: Not a console, tearing down\n",
395 pv->termno);
396
397 /* Clear opened, synchronize with khvcd */
398 spin_lock_irqsave(&hp->lock, flags);
399 pv->opened = 0;
400 spin_unlock_irqrestore(&hp->lock, flags);
401
402 /* Clear our own DTR */
403 if (!pv->tty || (pv->tty->termios->c_cflag & HUPCL))
404 hvsilib_write_mctrl(pv, 0);
405
406 /* Tear down the connection */
407 hvsi_send_close(pv);
408 }
409
410 if (pv->tty)
411 tty_kref_put(pv->tty);
412 pv->tty = NULL;
413 }
414
hvsilib_init(struct hvsi_priv * pv,int (* get_chars)(uint32_t termno,char * buf,int count),int (* put_chars)(uint32_t termno,const char * buf,int count),int termno,int is_console)415 void hvsilib_init(struct hvsi_priv *pv,
416 int (*get_chars)(uint32_t termno, char *buf, int count),
417 int (*put_chars)(uint32_t termno, const char *buf,
418 int count),
419 int termno, int is_console)
420 {
421 memset(pv, 0, sizeof(*pv));
422 pv->get_chars = get_chars;
423 pv->put_chars = put_chars;
424 pv->termno = termno;
425 pv->is_console = is_console;
426 }
427