Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * drivers/s390/char/sclp_vt220.c |
| 3 | * SCLP VT220 terminal driver. |
| 4 | * |
| 5 | * S390 version |
| 6 | * Copyright (C) 2003 IBM Deutschland Entwicklung GmbH, IBM Corporation |
| 7 | * Author(s): Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com> |
| 8 | */ |
| 9 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 10 | #include <linux/module.h> |
| 11 | #include <linux/spinlock.h> |
| 12 | #include <linux/list.h> |
| 13 | #include <linux/wait.h> |
| 14 | #include <linux/timer.h> |
| 15 | #include <linux/kernel.h> |
| 16 | #include <linux/tty.h> |
| 17 | #include <linux/tty_driver.h> |
Alan Cox | 33f0f88 | 2006-01-09 20:54:13 -0800 | [diff] [blame] | 18 | #include <linux/tty_flip.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | #include <linux/errno.h> |
| 20 | #include <linux/mm.h> |
| 21 | #include <linux/major.h> |
| 22 | #include <linux/console.h> |
| 23 | #include <linux/kdev_t.h> |
| 24 | #include <linux/bootmem.h> |
| 25 | #include <linux/interrupt.h> |
| 26 | #include <linux/init.h> |
| 27 | #include <asm/uaccess.h> |
| 28 | #include "sclp.h" |
| 29 | |
| 30 | #define SCLP_VT220_PRINT_HEADER "sclp vt220 tty driver: " |
| 31 | #define SCLP_VT220_MAJOR TTY_MAJOR |
| 32 | #define SCLP_VT220_MINOR 65 |
| 33 | #define SCLP_VT220_DRIVER_NAME "sclp_vt220" |
| 34 | #define SCLP_VT220_DEVICE_NAME "ttysclp" |
| 35 | #define SCLP_VT220_CONSOLE_NAME "ttyS" |
| 36 | #define SCLP_VT220_CONSOLE_INDEX 1 /* console=ttyS1 */ |
| 37 | #define SCLP_VT220_BUF_SIZE 80 |
| 38 | |
| 39 | /* Representation of a single write request */ |
| 40 | struct sclp_vt220_request { |
| 41 | struct list_head list; |
| 42 | struct sclp_req sclp_req; |
| 43 | int retry_count; |
| 44 | }; |
| 45 | |
| 46 | /* VT220 SCCB */ |
| 47 | struct sclp_vt220_sccb { |
| 48 | struct sccb_header header; |
| 49 | struct evbuf_header evbuf; |
| 50 | }; |
| 51 | |
| 52 | #define SCLP_VT220_MAX_CHARS_PER_BUFFER (PAGE_SIZE - \ |
| 53 | sizeof(struct sclp_vt220_request) - \ |
| 54 | sizeof(struct sclp_vt220_sccb)) |
| 55 | |
| 56 | /* Structures and data needed to register tty driver */ |
| 57 | static struct tty_driver *sclp_vt220_driver; |
| 58 | |
| 59 | /* The tty_struct that the kernel associated with us */ |
| 60 | static struct tty_struct *sclp_vt220_tty; |
| 61 | |
| 62 | /* Lock to protect internal data from concurrent access */ |
| 63 | static spinlock_t sclp_vt220_lock; |
| 64 | |
| 65 | /* List of empty pages to be used as write request buffers */ |
| 66 | static struct list_head sclp_vt220_empty; |
| 67 | |
| 68 | /* List of pending requests */ |
| 69 | static struct list_head sclp_vt220_outqueue; |
| 70 | |
| 71 | /* Number of requests in outqueue */ |
| 72 | static int sclp_vt220_outqueue_count; |
| 73 | |
| 74 | /* Wait queue used to delay write requests while we've run out of buffers */ |
| 75 | static wait_queue_head_t sclp_vt220_waitq; |
| 76 | |
| 77 | /* Timer used for delaying write requests to merge subsequent messages into |
| 78 | * a single buffer */ |
| 79 | static struct timer_list sclp_vt220_timer; |
| 80 | |
| 81 | /* Pointer to current request buffer which has been partially filled but not |
| 82 | * yet sent */ |
| 83 | static struct sclp_vt220_request *sclp_vt220_current_request; |
| 84 | |
| 85 | /* Number of characters in current request buffer */ |
| 86 | static int sclp_vt220_buffered_chars; |
| 87 | |
| 88 | /* Flag indicating whether this driver has already been initialized */ |
| 89 | static int sclp_vt220_initialized = 0; |
| 90 | |
| 91 | /* Flag indicating that sclp_vt220_current_request should really |
| 92 | * have been already queued but wasn't because the SCLP was processing |
| 93 | * another buffer */ |
| 94 | static int sclp_vt220_flush_later; |
| 95 | |
| 96 | static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf); |
| 97 | static int __sclp_vt220_emit(struct sclp_vt220_request *request); |
| 98 | static void sclp_vt220_emit_current(void); |
| 99 | |
| 100 | /* Registration structure for our interest in SCLP event buffers */ |
| 101 | static struct sclp_register sclp_vt220_register = { |
| 102 | .send_mask = EvTyp_VT220Msg_Mask, |
| 103 | .receive_mask = EvTyp_VT220Msg_Mask, |
| 104 | .state_change_fn = NULL, |
| 105 | .receiver_fn = sclp_vt220_receiver_fn |
| 106 | }; |
| 107 | |
| 108 | |
| 109 | /* |
| 110 | * Put provided request buffer back into queue and check emit pending |
| 111 | * buffers if necessary. |
| 112 | */ |
| 113 | static void |
| 114 | sclp_vt220_process_queue(struct sclp_vt220_request *request) |
| 115 | { |
| 116 | unsigned long flags; |
| 117 | void *page; |
| 118 | |
| 119 | do { |
| 120 | /* Put buffer back to list of empty buffers */ |
| 121 | page = request->sclp_req.sccb; |
| 122 | spin_lock_irqsave(&sclp_vt220_lock, flags); |
| 123 | /* Move request from outqueue to empty queue */ |
| 124 | list_del(&request->list); |
| 125 | sclp_vt220_outqueue_count--; |
| 126 | list_add_tail((struct list_head *) page, &sclp_vt220_empty); |
| 127 | /* Check if there is a pending buffer on the out queue. */ |
| 128 | request = NULL; |
| 129 | if (!list_empty(&sclp_vt220_outqueue)) |
| 130 | request = list_entry(sclp_vt220_outqueue.next, |
| 131 | struct sclp_vt220_request, list); |
| 132 | spin_unlock_irqrestore(&sclp_vt220_lock, flags); |
| 133 | } while (request && __sclp_vt220_emit(request)); |
| 134 | if (request == NULL && sclp_vt220_flush_later) |
| 135 | sclp_vt220_emit_current(); |
| 136 | wake_up(&sclp_vt220_waitq); |
| 137 | /* Check if the tty needs a wake up call */ |
| 138 | if (sclp_vt220_tty != NULL) { |
| 139 | tty_wakeup(sclp_vt220_tty); |
| 140 | } |
| 141 | } |
| 142 | |
| 143 | #define SCLP_BUFFER_MAX_RETRY 1 |
| 144 | |
| 145 | /* |
| 146 | * Callback through which the result of a write request is reported by the |
| 147 | * SCLP. |
| 148 | */ |
| 149 | static void |
| 150 | sclp_vt220_callback(struct sclp_req *request, void *data) |
| 151 | { |
| 152 | struct sclp_vt220_request *vt220_request; |
| 153 | struct sclp_vt220_sccb *sccb; |
| 154 | |
| 155 | vt220_request = (struct sclp_vt220_request *) data; |
| 156 | if (request->status == SCLP_REQ_FAILED) { |
| 157 | sclp_vt220_process_queue(vt220_request); |
| 158 | return; |
| 159 | } |
| 160 | sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb; |
| 161 | |
| 162 | /* Check SCLP response code and choose suitable action */ |
| 163 | switch (sccb->header.response_code) { |
| 164 | case 0x0020 : |
| 165 | break; |
| 166 | |
| 167 | case 0x05f0: /* Target resource in improper state */ |
| 168 | break; |
| 169 | |
| 170 | case 0x0340: /* Contained SCLP equipment check */ |
| 171 | if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY) |
| 172 | break; |
| 173 | /* Remove processed buffers and requeue rest */ |
| 174 | if (sclp_remove_processed((struct sccb_header *) sccb) > 0) { |
| 175 | /* Not all buffers were processed */ |
| 176 | sccb->header.response_code = 0x0000; |
| 177 | vt220_request->sclp_req.status = SCLP_REQ_FILLED; |
| 178 | if (sclp_add_request(request) == 0) |
| 179 | return; |
| 180 | } |
| 181 | break; |
| 182 | |
| 183 | case 0x0040: /* SCLP equipment check */ |
| 184 | if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY) |
| 185 | break; |
| 186 | sccb->header.response_code = 0x0000; |
| 187 | vt220_request->sclp_req.status = SCLP_REQ_FILLED; |
| 188 | if (sclp_add_request(request) == 0) |
| 189 | return; |
| 190 | break; |
| 191 | |
| 192 | default: |
| 193 | break; |
| 194 | } |
| 195 | sclp_vt220_process_queue(vt220_request); |
| 196 | } |
| 197 | |
| 198 | /* |
| 199 | * Emit vt220 request buffer to SCLP. Return zero on success, non-zero |
| 200 | * otherwise. |
| 201 | */ |
| 202 | static int |
| 203 | __sclp_vt220_emit(struct sclp_vt220_request *request) |
| 204 | { |
| 205 | if (!(sclp_vt220_register.sclp_send_mask & EvTyp_VT220Msg_Mask)) { |
| 206 | request->sclp_req.status = SCLP_REQ_FAILED; |
| 207 | return -EIO; |
| 208 | } |
Heiko Carstens | ab14de6 | 2007-02-05 21:18:37 +0100 | [diff] [blame] | 209 | request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | request->sclp_req.status = SCLP_REQ_FILLED; |
| 211 | request->sclp_req.callback = sclp_vt220_callback; |
| 212 | request->sclp_req.callback_data = (void *) request; |
| 213 | |
| 214 | return sclp_add_request(&request->sclp_req); |
| 215 | } |
| 216 | |
| 217 | /* |
| 218 | * Queue and emit given request. |
| 219 | */ |
| 220 | static void |
| 221 | sclp_vt220_emit(struct sclp_vt220_request *request) |
| 222 | { |
| 223 | unsigned long flags; |
| 224 | int count; |
| 225 | |
| 226 | spin_lock_irqsave(&sclp_vt220_lock, flags); |
| 227 | list_add_tail(&request->list, &sclp_vt220_outqueue); |
| 228 | count = sclp_vt220_outqueue_count++; |
| 229 | spin_unlock_irqrestore(&sclp_vt220_lock, flags); |
| 230 | /* Emit only the first buffer immediately - callback takes care of |
| 231 | * the rest */ |
| 232 | if (count == 0 && __sclp_vt220_emit(request)) |
| 233 | sclp_vt220_process_queue(request); |
| 234 | } |
| 235 | |
| 236 | /* |
| 237 | * Queue and emit current request. Return zero on success, non-zero otherwise. |
| 238 | */ |
| 239 | static void |
| 240 | sclp_vt220_emit_current(void) |
| 241 | { |
| 242 | unsigned long flags; |
| 243 | struct sclp_vt220_request *request; |
| 244 | struct sclp_vt220_sccb *sccb; |
| 245 | |
| 246 | spin_lock_irqsave(&sclp_vt220_lock, flags); |
| 247 | request = NULL; |
| 248 | if (sclp_vt220_current_request != NULL) { |
| 249 | sccb = (struct sclp_vt220_sccb *) |
| 250 | sclp_vt220_current_request->sclp_req.sccb; |
| 251 | /* Only emit buffers with content */ |
| 252 | if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) { |
| 253 | request = sclp_vt220_current_request; |
| 254 | sclp_vt220_current_request = NULL; |
| 255 | if (timer_pending(&sclp_vt220_timer)) |
| 256 | del_timer(&sclp_vt220_timer); |
| 257 | } |
| 258 | sclp_vt220_flush_later = 0; |
| 259 | } |
| 260 | spin_unlock_irqrestore(&sclp_vt220_lock, flags); |
| 261 | if (request != NULL) |
| 262 | sclp_vt220_emit(request); |
| 263 | } |
| 264 | |
| 265 | #define SCLP_NORMAL_WRITE 0x00 |
| 266 | |
| 267 | /* |
| 268 | * Helper function to initialize a page with the sclp request structure. |
| 269 | */ |
| 270 | static struct sclp_vt220_request * |
| 271 | sclp_vt220_initialize_page(void *page) |
| 272 | { |
| 273 | struct sclp_vt220_request *request; |
| 274 | struct sclp_vt220_sccb *sccb; |
| 275 | |
| 276 | /* Place request structure at end of page */ |
| 277 | request = ((struct sclp_vt220_request *) |
| 278 | ((addr_t) page + PAGE_SIZE)) - 1; |
| 279 | request->retry_count = 0; |
| 280 | request->sclp_req.sccb = page; |
| 281 | /* SCCB goes at start of page */ |
| 282 | sccb = (struct sclp_vt220_sccb *) page; |
| 283 | memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb)); |
| 284 | sccb->header.length = sizeof(struct sclp_vt220_sccb); |
| 285 | sccb->header.function_code = SCLP_NORMAL_WRITE; |
| 286 | sccb->header.response_code = 0x0000; |
| 287 | sccb->evbuf.type = EvTyp_VT220Msg; |
| 288 | sccb->evbuf.length = sizeof(struct evbuf_header); |
| 289 | |
| 290 | return request; |
| 291 | } |
| 292 | |
| 293 | static inline unsigned int |
| 294 | sclp_vt220_space_left(struct sclp_vt220_request *request) |
| 295 | { |
| 296 | struct sclp_vt220_sccb *sccb; |
| 297 | sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb; |
| 298 | return PAGE_SIZE - sizeof(struct sclp_vt220_request) - |
| 299 | sccb->header.length; |
| 300 | } |
| 301 | |
| 302 | static inline unsigned int |
| 303 | sclp_vt220_chars_stored(struct sclp_vt220_request *request) |
| 304 | { |
| 305 | struct sclp_vt220_sccb *sccb; |
| 306 | sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb; |
| 307 | return sccb->evbuf.length - sizeof(struct evbuf_header); |
| 308 | } |
| 309 | |
| 310 | /* |
| 311 | * Add msg to buffer associated with request. Return the number of characters |
| 312 | * added. |
| 313 | */ |
| 314 | static int |
| 315 | sclp_vt220_add_msg(struct sclp_vt220_request *request, |
| 316 | const unsigned char *msg, int count, int convertlf) |
| 317 | { |
| 318 | struct sclp_vt220_sccb *sccb; |
| 319 | void *buffer; |
| 320 | unsigned char c; |
| 321 | int from; |
| 322 | int to; |
| 323 | |
| 324 | if (count > sclp_vt220_space_left(request)) |
| 325 | count = sclp_vt220_space_left(request); |
| 326 | if (count <= 0) |
| 327 | return 0; |
| 328 | |
| 329 | sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb; |
| 330 | buffer = (void *) ((addr_t) sccb + sccb->header.length); |
| 331 | |
| 332 | if (convertlf) { |
| 333 | /* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/ |
| 334 | for (from=0, to=0; |
| 335 | (from < count) && (to < sclp_vt220_space_left(request)); |
| 336 | from++) { |
| 337 | /* Retrieve character */ |
| 338 | c = msg[from]; |
| 339 | /* Perform conversion */ |
| 340 | if (c == 0x0a) { |
| 341 | if (to + 1 < sclp_vt220_space_left(request)) { |
| 342 | ((unsigned char *) buffer)[to++] = c; |
| 343 | ((unsigned char *) buffer)[to++] = 0x0d; |
| 344 | } else |
| 345 | break; |
| 346 | |
| 347 | } else |
| 348 | ((unsigned char *) buffer)[to++] = c; |
| 349 | } |
| 350 | sccb->header.length += to; |
| 351 | sccb->evbuf.length += to; |
| 352 | return from; |
| 353 | } else { |
| 354 | memcpy(buffer, (const void *) msg, count); |
| 355 | sccb->header.length += count; |
| 356 | sccb->evbuf.length += count; |
| 357 | return count; |
| 358 | } |
| 359 | } |
| 360 | |
| 361 | /* |
| 362 | * Emit buffer after having waited long enough for more data to arrive. |
| 363 | */ |
| 364 | static void |
| 365 | sclp_vt220_timeout(unsigned long data) |
| 366 | { |
| 367 | sclp_vt220_emit_current(); |
| 368 | } |
| 369 | |
| 370 | #define BUFFER_MAX_DELAY HZ/2 |
| 371 | |
| 372 | /* |
| 373 | * Internal implementation of the write function. Write COUNT bytes of data |
| 374 | * from memory at BUF |
| 375 | * to the SCLP interface. In case that the data does not fit into the current |
| 376 | * write buffer, emit the current one and allocate a new one. If there are no |
| 377 | * more empty buffers available, wait until one gets emptied. If DO_SCHEDULE |
| 378 | * is non-zero, the buffer will be scheduled for emitting after a timeout - |
| 379 | * otherwise the user has to explicitly call the flush function. |
| 380 | * A non-zero CONVERTLF parameter indicates that 0x0a characters in the message |
| 381 | * buffer should be converted to 0x0a 0x0d. After completion, return the number |
| 382 | * of bytes written. |
| 383 | */ |
| 384 | static int |
| 385 | __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule, |
| 386 | int convertlf) |
| 387 | { |
| 388 | unsigned long flags; |
| 389 | void *page; |
| 390 | int written; |
| 391 | int overall_written; |
| 392 | |
| 393 | if (count <= 0) |
| 394 | return 0; |
| 395 | overall_written = 0; |
| 396 | spin_lock_irqsave(&sclp_vt220_lock, flags); |
| 397 | do { |
| 398 | /* Create a sclp output buffer if none exists yet */ |
| 399 | if (sclp_vt220_current_request == NULL) { |
| 400 | while (list_empty(&sclp_vt220_empty)) { |
| 401 | spin_unlock_irqrestore(&sclp_vt220_lock, |
| 402 | flags); |
| 403 | if (in_interrupt()) |
| 404 | sclp_sync_wait(); |
| 405 | else |
| 406 | wait_event(sclp_vt220_waitq, |
| 407 | !list_empty(&sclp_vt220_empty)); |
| 408 | spin_lock_irqsave(&sclp_vt220_lock, flags); |
| 409 | } |
| 410 | page = (void *) sclp_vt220_empty.next; |
| 411 | list_del((struct list_head *) page); |
| 412 | sclp_vt220_current_request = |
| 413 | sclp_vt220_initialize_page(page); |
| 414 | } |
| 415 | /* Try to write the string to the current request buffer */ |
| 416 | written = sclp_vt220_add_msg(sclp_vt220_current_request, |
| 417 | buf, count, convertlf); |
| 418 | overall_written += written; |
| 419 | if (written == count) |
| 420 | break; |
| 421 | /* |
| 422 | * Not all characters could be written to the current |
| 423 | * output buffer. Emit the buffer, create a new buffer |
| 424 | * and then output the rest of the string. |
| 425 | */ |
| 426 | spin_unlock_irqrestore(&sclp_vt220_lock, flags); |
| 427 | sclp_vt220_emit_current(); |
| 428 | spin_lock_irqsave(&sclp_vt220_lock, flags); |
| 429 | buf += written; |
| 430 | count -= written; |
| 431 | } while (count > 0); |
| 432 | /* Setup timer to output current console buffer after some time */ |
| 433 | if (sclp_vt220_current_request != NULL && |
| 434 | !timer_pending(&sclp_vt220_timer) && do_schedule) { |
| 435 | sclp_vt220_timer.function = sclp_vt220_timeout; |
| 436 | sclp_vt220_timer.data = 0UL; |
| 437 | sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY; |
| 438 | add_timer(&sclp_vt220_timer); |
| 439 | } |
| 440 | spin_unlock_irqrestore(&sclp_vt220_lock, flags); |
| 441 | return overall_written; |
| 442 | } |
| 443 | |
| 444 | /* |
| 445 | * This routine is called by the kernel to write a series of |
| 446 | * characters to the tty device. The characters may come from |
| 447 | * user space or kernel space. This routine will return the |
| 448 | * number of characters actually accepted for writing. |
| 449 | */ |
| 450 | static int |
| 451 | sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count) |
| 452 | { |
| 453 | return __sclp_vt220_write(buf, count, 1, 0); |
| 454 | } |
| 455 | |
| 456 | #define SCLP_VT220_SESSION_ENDED 0x01 |
| 457 | #define SCLP_VT220_SESSION_STARTED 0x80 |
| 458 | #define SCLP_VT220_SESSION_DATA 0x00 |
| 459 | |
| 460 | /* |
| 461 | * Called by the SCLP to report incoming event buffers. |
| 462 | */ |
| 463 | static void |
| 464 | sclp_vt220_receiver_fn(struct evbuf_header *evbuf) |
| 465 | { |
| 466 | char *buffer; |
| 467 | unsigned int count; |
| 468 | |
| 469 | /* Ignore input if device is not open */ |
| 470 | if (sclp_vt220_tty == NULL) |
| 471 | return; |
| 472 | |
| 473 | buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header)); |
| 474 | count = evbuf->length - sizeof(struct evbuf_header); |
| 475 | |
| 476 | switch (*buffer) { |
| 477 | case SCLP_VT220_SESSION_ENDED: |
| 478 | case SCLP_VT220_SESSION_STARTED: |
| 479 | break; |
| 480 | case SCLP_VT220_SESSION_DATA: |
| 481 | /* Send input to line discipline */ |
| 482 | buffer++; |
| 483 | count--; |
Alan Cox | 33f0f88 | 2006-01-09 20:54:13 -0800 | [diff] [blame] | 484 | tty_insert_flip_string(sclp_vt220_tty, buffer, count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 485 | tty_flip_buffer_push(sclp_vt220_tty); |
| 486 | break; |
| 487 | } |
| 488 | } |
| 489 | |
| 490 | /* |
| 491 | * This routine is called when a particular tty device is opened. |
| 492 | */ |
| 493 | static int |
| 494 | sclp_vt220_open(struct tty_struct *tty, struct file *filp) |
| 495 | { |
| 496 | if (tty->count == 1) { |
| 497 | sclp_vt220_tty = tty; |
| 498 | tty->driver_data = kmalloc(SCLP_VT220_BUF_SIZE, GFP_KERNEL); |
| 499 | if (tty->driver_data == NULL) |
| 500 | return -ENOMEM; |
| 501 | tty->low_latency = 0; |
| 502 | } |
| 503 | return 0; |
| 504 | } |
| 505 | |
| 506 | /* |
| 507 | * This routine is called when a particular tty device is closed. |
| 508 | */ |
| 509 | static void |
| 510 | sclp_vt220_close(struct tty_struct *tty, struct file *filp) |
| 511 | { |
| 512 | if (tty->count == 1) { |
| 513 | sclp_vt220_tty = NULL; |
| 514 | kfree(tty->driver_data); |
| 515 | tty->driver_data = NULL; |
| 516 | } |
| 517 | } |
| 518 | |
| 519 | /* |
| 520 | * This routine is called by the kernel to write a single |
| 521 | * character to the tty device. If the kernel uses this routine, |
| 522 | * it must call the flush_chars() routine (if defined) when it is |
| 523 | * done stuffing characters into the driver. |
| 524 | * |
| 525 | * NOTE: include/linux/tty_driver.h specifies that a character should be |
| 526 | * ignored if there is no room in the queue. This driver implements a different |
| 527 | * semantic in that it will block when there is no more room left. |
| 528 | */ |
| 529 | static void |
| 530 | sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch) |
| 531 | { |
| 532 | __sclp_vt220_write(&ch, 1, 0, 0); |
| 533 | } |
| 534 | |
| 535 | /* |
| 536 | * This routine is called by the kernel after it has written a |
| 537 | * series of characters to the tty device using put_char(). |
| 538 | */ |
| 539 | static void |
| 540 | sclp_vt220_flush_chars(struct tty_struct *tty) |
| 541 | { |
| 542 | if (sclp_vt220_outqueue_count == 0) |
| 543 | sclp_vt220_emit_current(); |
| 544 | else |
| 545 | sclp_vt220_flush_later = 1; |
| 546 | } |
| 547 | |
| 548 | /* |
| 549 | * This routine returns the numbers of characters the tty driver |
| 550 | * will accept for queuing to be written. This number is subject |
| 551 | * to change as output buffers get emptied, or if the output flow |
| 552 | * control is acted. |
| 553 | */ |
| 554 | static int |
| 555 | sclp_vt220_write_room(struct tty_struct *tty) |
| 556 | { |
| 557 | unsigned long flags; |
| 558 | struct list_head *l; |
| 559 | int count; |
| 560 | |
| 561 | spin_lock_irqsave(&sclp_vt220_lock, flags); |
| 562 | count = 0; |
| 563 | if (sclp_vt220_current_request != NULL) |
| 564 | count = sclp_vt220_space_left(sclp_vt220_current_request); |
| 565 | list_for_each(l, &sclp_vt220_empty) |
| 566 | count += SCLP_VT220_MAX_CHARS_PER_BUFFER; |
| 567 | spin_unlock_irqrestore(&sclp_vt220_lock, flags); |
| 568 | return count; |
| 569 | } |
| 570 | |
| 571 | /* |
| 572 | * Return number of buffered chars. |
| 573 | */ |
| 574 | static int |
| 575 | sclp_vt220_chars_in_buffer(struct tty_struct *tty) |
| 576 | { |
| 577 | unsigned long flags; |
| 578 | struct list_head *l; |
| 579 | struct sclp_vt220_request *r; |
| 580 | int count; |
| 581 | |
| 582 | spin_lock_irqsave(&sclp_vt220_lock, flags); |
| 583 | count = 0; |
| 584 | if (sclp_vt220_current_request != NULL) |
| 585 | count = sclp_vt220_chars_stored(sclp_vt220_current_request); |
| 586 | list_for_each(l, &sclp_vt220_outqueue) { |
| 587 | r = list_entry(l, struct sclp_vt220_request, list); |
| 588 | count += sclp_vt220_chars_stored(r); |
| 589 | } |
| 590 | spin_unlock_irqrestore(&sclp_vt220_lock, flags); |
| 591 | return count; |
| 592 | } |
| 593 | |
| 594 | static void |
| 595 | __sclp_vt220_flush_buffer(void) |
| 596 | { |
| 597 | unsigned long flags; |
| 598 | |
| 599 | sclp_vt220_emit_current(); |
| 600 | spin_lock_irqsave(&sclp_vt220_lock, flags); |
| 601 | if (timer_pending(&sclp_vt220_timer)) |
| 602 | del_timer(&sclp_vt220_timer); |
| 603 | while (sclp_vt220_outqueue_count > 0) { |
| 604 | spin_unlock_irqrestore(&sclp_vt220_lock, flags); |
| 605 | sclp_sync_wait(); |
| 606 | spin_lock_irqsave(&sclp_vt220_lock, flags); |
| 607 | } |
| 608 | spin_unlock_irqrestore(&sclp_vt220_lock, flags); |
| 609 | } |
| 610 | |
| 611 | /* |
| 612 | * Pass on all buffers to the hardware. Return only when there are no more |
| 613 | * buffers pending. |
| 614 | */ |
| 615 | static void |
| 616 | sclp_vt220_flush_buffer(struct tty_struct *tty) |
| 617 | { |
| 618 | sclp_vt220_emit_current(); |
| 619 | } |
| 620 | |
| 621 | /* |
| 622 | * Initialize all relevant components and register driver with system. |
| 623 | */ |
| 624 | static int |
| 625 | __sclp_vt220_init(int early) |
| 626 | { |
| 627 | void *page; |
| 628 | int i; |
| 629 | |
| 630 | if (sclp_vt220_initialized) |
| 631 | return 0; |
| 632 | sclp_vt220_initialized = 1; |
| 633 | spin_lock_init(&sclp_vt220_lock); |
| 634 | INIT_LIST_HEAD(&sclp_vt220_empty); |
| 635 | INIT_LIST_HEAD(&sclp_vt220_outqueue); |
| 636 | init_waitqueue_head(&sclp_vt220_waitq); |
| 637 | init_timer(&sclp_vt220_timer); |
| 638 | sclp_vt220_current_request = NULL; |
| 639 | sclp_vt220_buffered_chars = 0; |
| 640 | sclp_vt220_outqueue_count = 0; |
| 641 | sclp_vt220_tty = NULL; |
| 642 | sclp_vt220_flush_later = 0; |
| 643 | |
| 644 | /* Allocate pages for output buffering */ |
| 645 | for (i = 0; i < (early ? MAX_CONSOLE_PAGES : MAX_KMEM_PAGES); i++) { |
| 646 | if (early) |
| 647 | page = alloc_bootmem_low_pages(PAGE_SIZE); |
| 648 | else |
| 649 | page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); |
| 650 | if (!page) |
| 651 | return -ENOMEM; |
| 652 | list_add_tail((struct list_head *) page, &sclp_vt220_empty); |
| 653 | } |
| 654 | return 0; |
| 655 | } |
| 656 | |
Jeff Dike | b68e31d | 2006-10-02 02:17:18 -0700 | [diff] [blame] | 657 | static const struct tty_operations sclp_vt220_ops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 658 | .open = sclp_vt220_open, |
| 659 | .close = sclp_vt220_close, |
| 660 | .write = sclp_vt220_write, |
| 661 | .put_char = sclp_vt220_put_char, |
| 662 | .flush_chars = sclp_vt220_flush_chars, |
| 663 | .write_room = sclp_vt220_write_room, |
| 664 | .chars_in_buffer = sclp_vt220_chars_in_buffer, |
| 665 | .flush_buffer = sclp_vt220_flush_buffer |
| 666 | }; |
| 667 | |
| 668 | /* |
| 669 | * Register driver with SCLP and Linux and initialize internal tty structures. |
| 670 | */ |
Heiko Carstens | 2b67fc4 | 2007-02-05 21:16:47 +0100 | [diff] [blame] | 671 | static int __init |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 672 | sclp_vt220_tty_init(void) |
| 673 | { |
| 674 | struct tty_driver *driver; |
| 675 | int rc; |
| 676 | |
| 677 | /* Note: we're not testing for CONSOLE_IS_SCLP here to preserve |
| 678 | * symmetry between VM and LPAR systems regarding ttyS1. */ |
| 679 | driver = alloc_tty_driver(1); |
| 680 | if (!driver) |
| 681 | return -ENOMEM; |
| 682 | rc = __sclp_vt220_init(0); |
| 683 | if (rc) { |
| 684 | put_tty_driver(driver); |
| 685 | return rc; |
| 686 | } |
| 687 | rc = sclp_register(&sclp_vt220_register); |
| 688 | if (rc) { |
| 689 | printk(KERN_ERR SCLP_VT220_PRINT_HEADER |
| 690 | "could not register tty - " |
| 691 | "sclp_register returned %d\n", rc); |
| 692 | put_tty_driver(driver); |
| 693 | return rc; |
| 694 | } |
| 695 | |
| 696 | driver->owner = THIS_MODULE; |
| 697 | driver->driver_name = SCLP_VT220_DRIVER_NAME; |
| 698 | driver->name = SCLP_VT220_DEVICE_NAME; |
| 699 | driver->major = SCLP_VT220_MAJOR; |
| 700 | driver->minor_start = SCLP_VT220_MINOR; |
| 701 | driver->type = TTY_DRIVER_TYPE_SYSTEM; |
| 702 | driver->subtype = SYSTEM_TYPE_TTY; |
| 703 | driver->init_termios = tty_std_termios; |
| 704 | driver->flags = TTY_DRIVER_REAL_RAW; |
| 705 | tty_set_operations(driver, &sclp_vt220_ops); |
| 706 | |
| 707 | rc = tty_register_driver(driver); |
| 708 | if (rc) { |
| 709 | printk(KERN_ERR SCLP_VT220_PRINT_HEADER |
| 710 | "could not register tty - " |
| 711 | "tty_register_driver returned %d\n", rc); |
| 712 | put_tty_driver(driver); |
| 713 | return rc; |
| 714 | } |
| 715 | sclp_vt220_driver = driver; |
| 716 | return 0; |
| 717 | } |
| 718 | |
| 719 | module_init(sclp_vt220_tty_init); |
| 720 | |
| 721 | #ifdef CONFIG_SCLP_VT220_CONSOLE |
| 722 | |
| 723 | static void |
| 724 | sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count) |
| 725 | { |
| 726 | __sclp_vt220_write((const unsigned char *) buf, count, 1, 1); |
| 727 | } |
| 728 | |
| 729 | static struct tty_driver * |
| 730 | sclp_vt220_con_device(struct console *c, int *index) |
| 731 | { |
| 732 | *index = 0; |
| 733 | return sclp_vt220_driver; |
| 734 | } |
| 735 | |
| 736 | /* |
| 737 | * This routine is called from panic when the kernel is going to give up. |
| 738 | * We have to make sure that all buffers will be flushed to the SCLP. |
| 739 | * Note that this function may be called from within an interrupt context. |
| 740 | */ |
| 741 | static void |
| 742 | sclp_vt220_con_unblank(void) |
| 743 | { |
| 744 | __sclp_vt220_flush_buffer(); |
| 745 | } |
| 746 | |
| 747 | /* Structure needed to register with printk */ |
| 748 | static struct console sclp_vt220_console = |
| 749 | { |
| 750 | .name = SCLP_VT220_CONSOLE_NAME, |
| 751 | .write = sclp_vt220_con_write, |
| 752 | .device = sclp_vt220_con_device, |
| 753 | .unblank = sclp_vt220_con_unblank, |
| 754 | .flags = CON_PRINTBUFFER, |
| 755 | .index = SCLP_VT220_CONSOLE_INDEX |
| 756 | }; |
| 757 | |
| 758 | static int __init |
| 759 | sclp_vt220_con_init(void) |
| 760 | { |
| 761 | int rc; |
| 762 | |
| 763 | if (!CONSOLE_IS_SCLP) |
| 764 | return 0; |
| 765 | rc = __sclp_vt220_init(1); |
| 766 | if (rc) |
| 767 | return rc; |
| 768 | /* Attach linux console */ |
| 769 | register_console(&sclp_vt220_console); |
| 770 | return 0; |
| 771 | } |
| 772 | |
| 773 | console_initcall(sclp_vt220_con_init); |
| 774 | #endif /* CONFIG_SCLP_VT220_CONSOLE */ |
| 775 | |