xref: /openbmc/qemu/hw/char/sclpconsole-lm.c (revision a9ded601) 
1 /*
2  * SCLP event types
3  *    Operations Command - Line Mode input
4  *    Message            - Line Mode output
5  *
6  * Copyright IBM, Corp. 2013
7  *
8  * Authors:
9  *  Heinz Graalfs <graalfs@linux.vnet.ibm.com>
10  *
11  * This work is licensed under the terms of the GNU GPL, version 2 or (at your
12  * option) any later version.  See the COPYING file in the top-level directory.
13  *
14  */
15 
16 #include "qemu/osdep.h"
17 #include "hw/qdev.h"
18 #include "qemu/thread.h"
19 #include "qemu/error-report.h"
20 #include "chardev/char-fe.h"
21 
22 #include "hw/s390x/sclp.h"
23 #include "hw/s390x/event-facility.h"
24 #include "hw/s390x/ebcdic.h"
25 
26 #define SIZE_BUFFER 4096
27 #define NEWLINE     "\n"
28 
29 typedef struct OprtnsCommand {
30     EventBufferHeader header;
31     MDMSU message_unit;
32     char data[0];
33 } QEMU_PACKED OprtnsCommand;
34 
35 /* max size for line-mode data in 4K SCCB page */
36 #define SIZE_CONSOLE_BUFFER (SCCB_DATA_LEN - sizeof(OprtnsCommand))
37 
38 typedef struct SCLPConsoleLM {
39     SCLPEvent event;
40     CharBackend chr;
41     bool echo;                  /* immediate echo of input if true        */
42     uint32_t write_errors;      /* errors writing to char layer           */
43     uint32_t length;            /* length of byte stream in buffer        */
44     uint8_t buf[SIZE_CONSOLE_BUFFER];
45 } SCLPConsoleLM;
46 
47 #define TYPE_SCLPLM_CONSOLE "sclplmconsole"
48 #define SCLPLM_CONSOLE(obj) \
49     OBJECT_CHECK(SCLPConsoleLM, (obj), TYPE_SCLPLM_CONSOLE)
50 
51 /*
52 *  Character layer call-back functions
53  *
54  * Allow 1 character at a time
55  *
56  * Accumulate bytes from character layer in console buffer,
57  * event_pending is set when a newline character is encountered
58  *
59  * The maximum command line length is limited by the maximum
60  * space available in an SCCB. Line mode console input is sent
61  * truncated to the guest in case it doesn't fit into the SCCB.
62  */
63 
64 static int chr_can_read(void *opaque)
65 {
66     SCLPConsoleLM *scon = opaque;
67 
68     if (scon->event.event_pending) {
69         return 0;
70     }
71     return 1;
72 }
73 
74 static void chr_read(void *opaque, const uint8_t *buf, int size)
75 {
76     SCLPConsoleLM *scon = opaque;
77 
78     assert(size == 1);
79 
80     if (*buf == '\r' || *buf == '\n') {
81         scon->event.event_pending = true;
82         sclp_service_interrupt(0);
83         return;
84     }
85     if (scon->length == SIZE_CONSOLE_BUFFER) {
86         /* Eat the character, but still process CR and LF.  */
87         return;
88     }
89     scon->buf[scon->length] = *buf;
90     scon->length += 1;
91     if (scon->echo) {
92         /* XXX this blocks entire thread. Rewrite to use
93          * qemu_chr_fe_write and background I/O callbacks */
94         qemu_chr_fe_write_all(&scon->chr, buf, size);
95     }
96 }
97 
98 /* functions to be called by event facility */
99 
100 static bool can_handle_event(uint8_t type)
101 {
102     return type == SCLP_EVENT_MESSAGE || type == SCLP_EVENT_PMSGCMD;
103 }
104 
105 static unsigned int send_mask(void)
106 {
107     return SCLP_EVENT_MASK_OP_CMD | SCLP_EVENT_MASK_PMSGCMD;
108 }
109 
110 static unsigned int receive_mask(void)
111 {
112     return SCLP_EVENT_MASK_MSG | SCLP_EVENT_MASK_PMSGCMD;
113 }
114 
115 /*
116  * Triggered by SCLP's read_event_data
117  * - convert ASCII byte stream to EBCDIC and
118  * - copy converted data into provided (SCLP) buffer
119  */
120 static int get_console_data(SCLPEvent *event, uint8_t *buf, size_t *size,
121                             int avail)
122 {
123     int len;
124 
125     SCLPConsoleLM *cons = SCLPLM_CONSOLE(event);
126 
127     len = cons->length;
128     /* data need to fit into provided SCLP buffer */
129     if (len > avail) {
130         return 1;
131     }
132 
133     ebcdic_put(buf, (char *)&cons->buf, len);
134     *size = len;
135     cons->length = 0;
136     /* data provided and no more data pending */
137     event->event_pending = false;
138     qemu_notify_event();
139     return 0;
140 }
141 
142 static int read_event_data(SCLPEvent *event, EventBufferHeader *evt_buf_hdr,
143                            int *slen)
144 {
145     int avail, rc;
146     size_t src_len;
147     uint8_t *to;
148     OprtnsCommand *oc = (OprtnsCommand *) evt_buf_hdr;
149 
150     if (!event->event_pending) {
151         /* no data pending */
152         return 0;
153     }
154 
155     to = (uint8_t *)&oc->data;
156     avail = *slen - sizeof(OprtnsCommand);
157     rc = get_console_data(event, to, &src_len, avail);
158     if (rc) {
159         /* data didn't fit, try next SCCB */
160         return 1;
161     }
162 
163     oc->message_unit.mdmsu.gds_id = GDS_ID_MDSMU;
164     oc->message_unit.mdmsu.length = cpu_to_be16(sizeof(struct MDMSU));
165 
166     oc->message_unit.cpmsu.gds_id = GDS_ID_CPMSU;
167     oc->message_unit.cpmsu.length =
168         cpu_to_be16(sizeof(struct MDMSU) - sizeof(GdsVector));
169 
170     oc->message_unit.text_command.gds_id = GDS_ID_TEXTCMD;
171     oc->message_unit.text_command.length =
172         cpu_to_be16(sizeof(struct MDMSU) - (2 * sizeof(GdsVector)));
173 
174     oc->message_unit.self_def_text_message.key = GDS_KEY_SELFDEFTEXTMSG;
175     oc->message_unit.self_def_text_message.length =
176         cpu_to_be16(sizeof(struct MDMSU) - (3 * sizeof(GdsVector)));
177 
178     oc->message_unit.text_message.key = GDS_KEY_TEXTMSG;
179     oc->message_unit.text_message.length =
180         cpu_to_be16(sizeof(GdsSubvector) + src_len);
181 
182     oc->header.length = cpu_to_be16(sizeof(OprtnsCommand) + src_len);
183     oc->header.type = SCLP_EVENT_OPRTNS_COMMAND;
184     *slen = avail - src_len;
185 
186     return 1;
187 }
188 
189 /*
190  * Triggered by SCLP's write_event_data
191  *  - write console data to character layer
192  *  returns < 0 if an error occurred
193  */
194 static int write_console_data(SCLPEvent *event, const uint8_t *buf, int len)
195 {
196     SCLPConsoleLM *scon = SCLPLM_CONSOLE(event);
197 
198     if (!qemu_chr_fe_get_driver(&scon->chr)) {
199         /* If there's no backend, we can just say we consumed all data. */
200         return len;
201     }
202 
203     /* XXX this blocks entire thread. Rewrite to use
204      * qemu_chr_fe_write and background I/O callbacks */
205     return qemu_chr_fe_write_all(&scon->chr, buf, len);
206 }
207 
208 static int process_mdb(SCLPEvent *event, MDBO *mdbo)
209 {
210     int rc;
211     int len;
212     uint8_t buffer[SIZE_BUFFER];
213 
214     len = be16_to_cpu(mdbo->length);
215     len -= sizeof(mdbo->length) + sizeof(mdbo->type)
216             + sizeof(mdbo->mto.line_type_flags)
217             + sizeof(mdbo->mto.alarm_control)
218             + sizeof(mdbo->mto._reserved);
219 
220     assert(len <= SIZE_BUFFER);
221 
222     /* convert EBCDIC SCLP contents to ASCII console message */
223     ascii_put(buffer, mdbo->mto.message, len);
224     rc = write_console_data(event, (uint8_t *)NEWLINE, 1);
225     if (rc < 0) {
226         return rc;
227     }
228     return write_console_data(event, buffer, len);
229 }
230 
231 static int write_event_data(SCLPEvent *event, EventBufferHeader *ebh)
232 {
233     int len;
234     int written;
235     int errors = 0;
236     MDBO *mdbo;
237     SclpMsg *data = (SclpMsg *) ebh;
238     SCLPConsoleLM *scon = SCLPLM_CONSOLE(event);
239 
240     len = be16_to_cpu(data->mdb.header.length);
241     if (len < sizeof(data->mdb.header)) {
242         return SCLP_RC_INCONSISTENT_LENGTHS;
243     }
244     len -= sizeof(data->mdb.header);
245 
246     /* first check message buffers */
247     mdbo = data->mdb.mdbo;
248     while (len > 0) {
249         if (be16_to_cpu(mdbo->length) > len
250                 || be16_to_cpu(mdbo->length) == 0) {
251             return SCLP_RC_INCONSISTENT_LENGTHS;
252         }
253         len -= be16_to_cpu(mdbo->length);
254         mdbo = (void *) mdbo + be16_to_cpu(mdbo->length);
255     }
256 
257     /* then execute */
258     len = be16_to_cpu(data->mdb.header.length) - sizeof(data->mdb.header);
259     mdbo = data->mdb.mdbo;
260     while (len > 0) {
261         switch (be16_to_cpu(mdbo->type)) {
262         case MESSAGE_TEXT:
263             /* message text object */
264             written = process_mdb(event, mdbo);
265             if (written < 0) {
266                 /* character layer error */
267                 errors++;
268             }
269             break;
270         default: /* ignore */
271             break;
272         }
273         len -= be16_to_cpu(mdbo->length);
274         mdbo = (void *) mdbo + be16_to_cpu(mdbo->length);
275     }
276     if (errors) {
277         scon->write_errors += errors;
278     }
279     data->header.flags = SCLP_EVENT_BUFFER_ACCEPTED;
280 
281     return SCLP_RC_NORMAL_COMPLETION;
282 }
283 
284 /* functions for live migration */
285 
286 static const VMStateDescription vmstate_sclplmconsole = {
287     .name = "sclplmconsole",
288     .version_id = 0,
289     .minimum_version_id = 0,
290     .fields = (VMStateField[]) {
291         VMSTATE_BOOL(event.event_pending, SCLPConsoleLM),
292         VMSTATE_UINT32(write_errors, SCLPConsoleLM),
293         VMSTATE_UINT32(length, SCLPConsoleLM),
294         VMSTATE_UINT8_ARRAY(buf, SCLPConsoleLM, SIZE_CONSOLE_BUFFER),
295         VMSTATE_END_OF_LIST()
296      }
297 };
298 
299 /* qemu object creation and initialization functions */
300 
301 /* tell character layer our call-back functions */
302 
303 static int console_init(SCLPEvent *event)
304 {
305     static bool console_available;
306 
307     SCLPConsoleLM *scon = SCLPLM_CONSOLE(event);
308 
309     if (console_available) {
310         error_report("Multiple line-mode operator consoles are not supported");
311         return -1;
312     }
313     console_available = true;
314 
315     qemu_chr_fe_set_handlers(&scon->chr, chr_can_read,
316                              chr_read, NULL, scon, NULL, true);
317 
318     return 0;
319 }
320 
321 static int console_exit(SCLPEvent *event)
322 {
323     return 0;
324 }
325 
326 static void console_reset(DeviceState *dev)
327 {
328    SCLPEvent *event = SCLP_EVENT(dev);
329    SCLPConsoleLM *scon = SCLPLM_CONSOLE(event);
330 
331    event->event_pending = false;
332    scon->length = 0;
333    scon->write_errors = 0;
334 }
335 
336 static Property console_properties[] = {
337     DEFINE_PROP_CHR("chardev", SCLPConsoleLM, chr),
338     DEFINE_PROP_UINT32("write_errors", SCLPConsoleLM, write_errors, 0),
339     DEFINE_PROP_BOOL("echo", SCLPConsoleLM, echo, true),
340     DEFINE_PROP_END_OF_LIST(),
341 };
342 
343 static void console_class_init(ObjectClass *klass, void *data)
344 {
345     DeviceClass *dc = DEVICE_CLASS(klass);
346     SCLPEventClass *ec = SCLP_EVENT_CLASS(klass);
347 
348     dc->props = console_properties;
349     dc->reset = console_reset;
350     dc->vmsd = &vmstate_sclplmconsole;
351     ec->init = console_init;
352     ec->exit = console_exit;
353     ec->get_send_mask = send_mask;
354     ec->get_receive_mask = receive_mask;
355     ec->can_handle_event = can_handle_event;
356     ec->read_event_data = read_event_data;
357     ec->write_event_data = write_event_data;
358     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
359 }
360 
361 static const TypeInfo sclp_console_info = {
362     .name          = "sclplmconsole",
363     .parent        = TYPE_SCLP_EVENT,
364     .instance_size = sizeof(SCLPConsoleLM),
365     .class_init    = console_class_init,
366     .class_size    = sizeof(SCLPEventClass),
367 };
368 
369 static void register_types(void)
370 {
371     type_register_static(&sclp_console_info);
372 }
373 
374 type_init(register_types)
375