xref: /openbmc/qemu/hw/char/sclpconsole.c (revision 9884abee)
1 /*
2  * SCLP event type
3  *    Ascii Console Data (VT220 Console)
4  *
5  * Copyright IBM, Corp. 2012
6  *
7  * Authors:
8  *  Heinz Graalfs <graalfs@de.ibm.com>
9  *
10  * This work is licensed under the terms of the GNU GPL, version 2 or (at your
11  * option) any later version.  See the COPYING file in the top-level directory.
12  *
13  */
14 
15 #include "qemu/osdep.h"
16 #include <hw/qdev.h>
17 #include "qemu/thread.h"
18 #include "qemu/error-report.h"
19 
20 #include "hw/s390x/sclp.h"
21 #include "hw/s390x/event-facility.h"
22 #include "sysemu/char.h"
23 
24 typedef struct ASCIIConsoleData {
25     EventBufferHeader ebh;
26     char data[0];
27 } QEMU_PACKED ASCIIConsoleData;
28 
29 /* max size for ASCII data in 4K SCCB page */
30 #define SIZE_BUFFER_VT220 4080
31 
32 typedef struct SCLPConsole {
33     SCLPEvent event;
34     CharDriverState *chr;
35     uint8_t iov[SIZE_BUFFER_VT220];
36     uint32_t iov_sclp;      /* offset in buf for SCLP read operation       */
37     uint32_t iov_bs;        /* offset in buf for char layer read operation */
38     uint32_t iov_data_len;  /* length of byte stream in buffer             */
39     uint32_t iov_sclp_rest; /* length of byte stream not read via SCLP     */
40     bool notify;            /* qemu_notify_event() req'd if true           */
41 } SCLPConsole;
42 
43 /* character layer call-back functions */
44 
45 /* Return number of bytes that fit into iov buffer */
46 static int chr_can_read(void *opaque)
47 {
48     SCLPConsole *scon = opaque;
49     int avail = SIZE_BUFFER_VT220 - scon->iov_data_len;
50 
51     if (avail == 0) {
52         scon->notify = true;
53     }
54     return avail;
55 }
56 
57 /* Send data from a char device over to the guest */
58 static void chr_read(void *opaque, const uint8_t *buf, int size)
59 {
60     SCLPConsole *scon = opaque;
61 
62     assert(scon);
63     /* read data must fit into current buffer */
64     assert(size <= SIZE_BUFFER_VT220 - scon->iov_data_len);
65 
66     /* put byte-stream from character layer into buffer */
67     memcpy(&scon->iov[scon->iov_bs], buf, size);
68     scon->iov_data_len += size;
69     scon->iov_sclp_rest += size;
70     scon->iov_bs += size;
71     scon->event.event_pending = true;
72     sclp_service_interrupt(0);
73 }
74 
75 /* functions to be called by event facility */
76 
77 static bool can_handle_event(uint8_t type)
78 {
79     return type == SCLP_EVENT_ASCII_CONSOLE_DATA;
80 }
81 
82 static unsigned int send_mask(void)
83 {
84     return SCLP_EVENT_MASK_MSG_ASCII;
85 }
86 
87 static unsigned int receive_mask(void)
88 {
89     return SCLP_EVENT_MASK_MSG_ASCII;
90 }
91 
92 /* triggered by SCLP's read_event_data -
93  * copy console data byte-stream into provided (SCLP) buffer
94  */
95 static void get_console_data(SCLPEvent *event, uint8_t *buf, size_t *size,
96                              int avail)
97 {
98     SCLPConsole *cons = DO_UPCAST(SCLPConsole, event, event);
99 
100     /* first byte is hex 0 saying an ascii string follows */
101     *buf++ = '\0';
102     avail--;
103     /* if all data fit into provided SCLP buffer */
104     if (avail >= cons->iov_sclp_rest) {
105         /* copy character byte-stream to SCLP buffer */
106         memcpy(buf, &cons->iov[cons->iov_sclp], cons->iov_sclp_rest);
107         *size = cons->iov_sclp_rest + 1;
108         cons->iov_sclp = 0;
109         cons->iov_bs = 0;
110         cons->iov_data_len = 0;
111         cons->iov_sclp_rest = 0;
112         event->event_pending = false;
113         /* data provided and no more data pending */
114     } else {
115         /* if provided buffer is too small, just copy part */
116         memcpy(buf, &cons->iov[cons->iov_sclp], avail);
117         *size = avail + 1;
118         cons->iov_sclp_rest -= avail;
119         cons->iov_sclp += avail;
120         /* more data pending */
121     }
122     if (cons->notify) {
123         cons->notify = false;
124         qemu_notify_event();
125     }
126 }
127 
128 static int read_event_data(SCLPEvent *event, EventBufferHeader *evt_buf_hdr,
129                            int *slen)
130 {
131     int avail;
132     size_t src_len;
133     uint8_t *to;
134     ASCIIConsoleData *acd = (ASCIIConsoleData *) evt_buf_hdr;
135 
136     if (!event->event_pending) {
137         /* no data pending */
138         return 0;
139     }
140 
141     to = (uint8_t *)&acd->data;
142     avail = *slen - sizeof(ASCIIConsoleData);
143     get_console_data(event, to, &src_len, avail);
144 
145     acd->ebh.length = cpu_to_be16(sizeof(ASCIIConsoleData) + src_len);
146     acd->ebh.type = SCLP_EVENT_ASCII_CONSOLE_DATA;
147     acd->ebh.flags |= SCLP_EVENT_BUFFER_ACCEPTED;
148     *slen = avail - src_len;
149 
150     return 1;
151 }
152 
153 /* triggered by SCLP's write_event_data
154  *  - write console data to character layer
155  *  returns < 0 if an error occurred
156  */
157 static ssize_t write_console_data(SCLPEvent *event, const uint8_t *buf,
158                                   size_t len)
159 {
160     SCLPConsole *scon = DO_UPCAST(SCLPConsole, event, event);
161 
162     if (!scon->chr) {
163         /* If there's no backend, we can just say we consumed all data. */
164         return len;
165     }
166 
167     return qemu_chr_fe_write_all(scon->chr, buf, len);
168 }
169 
170 static int write_event_data(SCLPEvent *event, EventBufferHeader *evt_buf_hdr)
171 {
172     int rc;
173     int length;
174     ssize_t written;
175     ASCIIConsoleData *acd = (ASCIIConsoleData *) evt_buf_hdr;
176 
177     length = be16_to_cpu(evt_buf_hdr->length) - sizeof(EventBufferHeader);
178     written = write_console_data(event, (uint8_t *)acd->data, length);
179 
180     rc = SCLP_RC_NORMAL_COMPLETION;
181     /* set event buffer accepted flag */
182     evt_buf_hdr->flags |= SCLP_EVENT_BUFFER_ACCEPTED;
183 
184     /* written will be zero if a pty is not connected - don't treat as error */
185     if (written < 0) {
186         /* event buffer not accepted due to error in character layer */
187         evt_buf_hdr->flags &= ~(SCLP_EVENT_BUFFER_ACCEPTED);
188         rc = SCLP_RC_CONTAINED_EQUIPMENT_CHECK;
189     }
190 
191     return rc;
192 }
193 
194 static const VMStateDescription vmstate_sclpconsole = {
195     .name = "sclpconsole",
196     .version_id = 0,
197     .minimum_version_id = 0,
198     .fields = (VMStateField[]) {
199         VMSTATE_BOOL(event.event_pending, SCLPConsole),
200         VMSTATE_UINT8_ARRAY(iov, SCLPConsole, SIZE_BUFFER_VT220),
201         VMSTATE_UINT32(iov_sclp, SCLPConsole),
202         VMSTATE_UINT32(iov_bs, SCLPConsole),
203         VMSTATE_UINT32(iov_data_len, SCLPConsole),
204         VMSTATE_UINT32(iov_sclp_rest, SCLPConsole),
205         VMSTATE_END_OF_LIST()
206      }
207 };
208 
209 /* qemu object creation and initialization functions */
210 
211 /* tell character layer our call-back functions */
212 
213 static int console_init(SCLPEvent *event)
214 {
215     static bool console_available;
216 
217     SCLPConsole *scon = DO_UPCAST(SCLPConsole, event, event);
218 
219     if (console_available) {
220         error_report("Multiple VT220 operator consoles are not supported");
221         return -1;
222     }
223     console_available = true;
224     if (scon->chr) {
225         qemu_chr_add_handlers(scon->chr, chr_can_read,
226                               chr_read, NULL, scon);
227     }
228 
229     return 0;
230 }
231 
232 static void console_reset(DeviceState *dev)
233 {
234    SCLPEvent *event = SCLP_EVENT(dev);
235    SCLPConsole *scon = DO_UPCAST(SCLPConsole, event, event);
236 
237    event->event_pending = false;
238    scon->iov_sclp = 0;
239    scon->iov_bs = 0;
240    scon->iov_data_len = 0;
241    scon->iov_sclp_rest = 0;
242    scon->notify = false;
243 }
244 
245 static int console_exit(SCLPEvent *event)
246 {
247     return 0;
248 }
249 
250 static Property console_properties[] = {
251     DEFINE_PROP_CHR("chardev", SCLPConsole, chr),
252     DEFINE_PROP_END_OF_LIST(),
253 };
254 
255 static void console_class_init(ObjectClass *klass, void *data)
256 {
257     DeviceClass *dc = DEVICE_CLASS(klass);
258     SCLPEventClass *ec = SCLP_EVENT_CLASS(klass);
259 
260     dc->props = console_properties;
261     dc->reset = console_reset;
262     dc->vmsd = &vmstate_sclpconsole;
263     ec->init = console_init;
264     ec->exit = console_exit;
265     ec->get_send_mask = send_mask;
266     ec->get_receive_mask = receive_mask;
267     ec->can_handle_event = can_handle_event;
268     ec->read_event_data = read_event_data;
269     ec->write_event_data = write_event_data;
270     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
271 }
272 
273 static const TypeInfo sclp_console_info = {
274     .name          = "sclpconsole",
275     .parent        = TYPE_SCLP_EVENT,
276     .instance_size = sizeof(SCLPConsole),
277     .class_init    = console_class_init,
278     .class_size    = sizeof(SCLPEventClass),
279 };
280 
281 static void register_types(void)
282 {
283     type_register_static(&sclp_console_info);
284 }
285 
286 type_init(register_types)
287