hw/char/sclpconsole.c

   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 <hw/qdev.h>
  16 #include "qemu/thread.h"
  17 #include "qemu/error-report.h"
  18
  19 #include "hw/s390x/sclp.h"
  20 #include "hw/s390x/event-facility.h"
  21 #include "sysemu/char.h"
  22
  23 typedef struct ASCIIConsoleData {
  24     EventBufferHeader ebh;
  25     char data[0];
  26 } QEMU_PACKED ASCIIConsoleData;
  27
  28 /* max size for ASCII data in 4K SCCB page */
  29 #define SIZE_BUFFER_VT220 4080
  30
  31 typedef struct SCLPConsole {
  32     SCLPEvent event;
  33     CharDriverState *chr;
  34     /* io vector                                                       */
  35     uint8_t *iov;           /* iov buffer pointer                      */
  36     uint8_t *iov_sclp;      /* pointer to SCLP read offset             */
  37     uint8_t *iov_bs;        /* pointer byte stream read offset         */
  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     qemu_irq irq_read_vt220;
  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
  50     return scon->iov ? SIZE_BUFFER_VT220 - scon->iov_data_len : 0;
  51 }
  52
  53 /* Receive n bytes from character layer, save in iov buffer,
  54  * and set event pending */
  55 static void receive_from_chr_layer(SCLPConsole *scon, const uint8_t *buf,
  56                                    int size)
  57 {
  58     assert(scon->iov);
  59
  60     /* read data must fit into current buffer */
  61     assert(size <= SIZE_BUFFER_VT220 - scon->iov_data_len);
  62
  63     /* put byte-stream from character layer into buffer */
  64     memcpy(scon->iov_bs, buf, size);
  65     scon->iov_data_len += size;
  66     scon->iov_sclp_rest += size;
  67     scon->iov_bs += size;
  68     scon->event.event_pending = true;
  69 }
  70
  71 /* Send data from a char device over to the guest */
  72 static void chr_read(void *opaque, const uint8_t *buf, int size)
  73 {
  74     SCLPConsole *scon = opaque;
  75
  76     assert(scon);
  77
  78     receive_from_chr_layer(scon, buf, size);
  79     /* trigger SCLP read operation */
  80     qemu_irq_raise(scon->irq_read_vt220);
  81 }
  82
  83 static void chr_event(void *opaque, int event)
  84 {
  85     SCLPConsole *scon = opaque;
  86
  87     switch (event) {
  88     case CHR_EVENT_OPENED:
  89         if (!scon->iov) {
  90             scon->iov = g_malloc0(SIZE_BUFFER_VT220);
  91             scon->iov_sclp = scon->iov;
  92             scon->iov_bs = scon->iov;
  93             scon->iov_data_len = 0;
  94             scon->iov_sclp_rest = 0;
  95         }
  96         break;
  97     case CHR_EVENT_CLOSED:
  98         if (scon->iov) {
  99             g_free(scon->iov);
 100             scon->iov = NULL;
 101         }
 102         break;
 103     }
 104 }
 105
 106 /* functions to be called by event facility */
 107
 108 static int event_type(void)
 109 {
 110     return SCLP_EVENT_ASCII_CONSOLE_DATA;
 111 }
 112
 113 static unsigned int send_mask(void)
 114 {
 115     return SCLP_EVENT_MASK_MSG_ASCII;
 116 }
 117
 118 static unsigned int receive_mask(void)
 119 {
 120     return SCLP_EVENT_MASK_MSG_ASCII;
 121 }
 122
 123 /* triggered by SCLP's read_event_data -
 124  * copy console data byte-stream into provided (SCLP) buffer
 125  */
 126 static void get_console_data(SCLPEvent *event, uint8_t *buf, size_t *size,
 127                              int avail)
 128 {
 129     SCLPConsole *cons = DO_UPCAST(SCLPConsole, event, event);
 130
 131     /* first byte is hex 0 saying an ascii string follows */
 132     *buf++ = '\0';
 133     avail--;
 134     /* if all data fit into provided SCLP buffer */
 135     if (avail >= cons->iov_sclp_rest) {
 136         /* copy character byte-stream to SCLP buffer */
 137         memcpy(buf, cons->iov_sclp, cons->iov_sclp_rest);
 138         *size = cons->iov_sclp_rest + 1;
 139         cons->iov_sclp = cons->iov;
 140         cons->iov_bs = cons->iov;
 141         cons->iov_data_len = 0;
 142         cons->iov_sclp_rest = 0;
 143         event->event_pending = false;
 144         /* data provided and no more data pending */
 145     } else {
 146         /* if provided buffer is too small, just copy part */
 147         memcpy(buf, cons->iov_sclp, avail);
 148         *size = avail + 1;
 149         cons->iov_sclp_rest -= avail;
 150         cons->iov_sclp += avail;
 151         /* more data pending */
 152     }
 153 }
 154
 155 static int read_event_data(SCLPEvent *event, EventBufferHeader *evt_buf_hdr,
 156                            int *slen)
 157 {
 158     int avail;
 159     size_t src_len;
 160     uint8_t *to;
 161     ASCIIConsoleData *acd = (ASCIIConsoleData *) evt_buf_hdr;
 162
 163     if (!event->event_pending) {
 164         /* no data pending */
 165         return 0;
 166     }
 167
 168     to = (uint8_t *)&acd->data;
 169     avail = *slen - sizeof(ASCIIConsoleData);
 170     get_console_data(event, to, &src_len, avail);
 171
 172     acd->ebh.length = cpu_to_be16(sizeof(ASCIIConsoleData) + src_len);
 173     acd->ebh.type = SCLP_EVENT_ASCII_CONSOLE_DATA;
 174     acd->ebh.flags |= SCLP_EVENT_BUFFER_ACCEPTED;
 175     *slen = avail - src_len;
 176
 177     return 1;
 178 }
 179
 180 /* triggered by SCLP's write_event_data
 181  *  - write console data to character layer
 182  *  returns < 0 if an error occurred
 183  */
 184 static ssize_t write_console_data(SCLPEvent *event, const uint8_t *buf,
 185                                   size_t len)
 186 {
 187     SCLPConsole *scon = DO_UPCAST(SCLPConsole, event, event);
 188
 189     if (!scon->chr) {
 190         /* If there's no backend, we can just say we consumed all data. */
 191         return len;
 192     }
 193
 194     return qemu_chr_fe_write_all(scon->chr, buf, len);
 195 }
 196
 197 static int write_event_data(SCLPEvent *event, EventBufferHeader *evt_buf_hdr)
 198 {
 199     int rc;
 200     int length;
 201     ssize_t written;
 202     ASCIIConsoleData *acd = (ASCIIConsoleData *) evt_buf_hdr;
 203
 204     length = be16_to_cpu(evt_buf_hdr->length) - sizeof(EventBufferHeader);
 205     written = write_console_data(event, (uint8_t *)acd->data, length);
 206
 207     rc = SCLP_RC_NORMAL_COMPLETION;
 208     /* set event buffer accepted flag */
 209     evt_buf_hdr->flags |= SCLP_EVENT_BUFFER_ACCEPTED;
 210
 211     /* written will be zero if a pty is not connected - don't treat as error */
 212     if (written < 0) {
 213         /* event buffer not accepted due to error in character layer */
 214         evt_buf_hdr->flags &= ~(SCLP_EVENT_BUFFER_ACCEPTED);
 215         rc = SCLP_RC_CONTAINED_EQUIPMENT_CHECK;
 216     }
 217
 218     return rc;
 219 }
 220
 221 static void trigger_ascii_console_data(void *opaque, int n, int level)
 222 {
 223     sclp_service_interrupt(0);
 224 }
 225
 226 /* qemu object creation and initialization functions */
 227
 228 /* tell character layer our call-back functions */
 229 static int console_init(SCLPEvent *event)
 230 {
 231     static bool console_available;
 232
 233     SCLPConsole *scon = DO_UPCAST(SCLPConsole, event, event);
 234
 235     if (console_available) {
 236         error_report("Multiple VT220 operator consoles are not supported");
 237         return -1;
 238     }
 239     console_available = true;
 240     event->event_type = SCLP_EVENT_ASCII_CONSOLE_DATA;
 241     if (scon->chr) {
 242         qemu_chr_add_handlers(scon->chr, chr_can_read,
 243                               chr_read, chr_event, scon);
 244     }
 245     scon->irq_read_vt220 = *qemu_allocate_irqs(trigger_ascii_console_data,
 246                                                NULL, 1);
 247
 248     return 0;
 249 }
 250
 251 static int console_exit(SCLPEvent *event)
 252 {
 253     return 0;
 254 }
 255
 256 static Property console_properties[] = {
 257     DEFINE_PROP_CHR("chardev", SCLPConsole, chr),
 258     DEFINE_PROP_END_OF_LIST(),
 259 };
 260
 261 static void console_class_init(ObjectClass *klass, void *data)
 262 {
 263     DeviceClass *dc = DEVICE_CLASS(klass);
 264     SCLPEventClass *ec = SCLP_EVENT_CLASS(klass);
 265
 266     dc->props = console_properties;
 267     ec->init = console_init;
 268     ec->exit = console_exit;
 269     ec->get_send_mask = send_mask;
 270     ec->get_receive_mask = receive_mask;
 271     ec->event_type = event_type;
 272     ec->read_event_data = read_event_data;
 273     ec->write_event_data = write_event_data;
 274 }
 275
 276 static const TypeInfo sclp_console_info = {
 277     .name          = "sclpconsole",
 278     .parent        = TYPE_SCLP_EVENT,
 279     .instance_size = sizeof(SCLPConsole),
 280     .class_init    = console_class_init,
 281     .class_size    = sizeof(SCLPEventClass),
 282 };
 283
 284 static void register_types(void)
 285 {
 286     type_register_static(&sclp_console_info);
 287 }
 288
 289 type_init(register_types)