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1// SPDX-License-Identifier: GPL-2.02/*3 * SCLP line mode terminal driver.4 *5 * S390 version6 * Copyright IBM Corp. 19997 * Author(s): Martin Peschke <mpeschke@de.ibm.com>8 * Martin Schwidefsky <schwidefsky@de.ibm.com>9 */10 11#include <linux/kmod.h>12#include <linux/tty.h>13#include <linux/tty_driver.h>14#include <linux/tty_flip.h>15#include <linux/err.h>16#include <linux/init.h>17#include <linux/interrupt.h>18#include <linux/gfp.h>19#include <linux/uaccess.h>20 21#include "ctrlchar.h"22#include "sclp.h"23#include "sclp_rw.h"24#include "sclp_tty.h"25 26/*27 * size of a buffer that collects single characters coming in28 * via sclp_tty_put_char()29 */30#define SCLP_TTY_BUF_SIZE 51231 32/*33 * There is exactly one SCLP terminal, so we can keep things simple34 * and allocate all variables statically.35 */36 37/* Lock to guard over changes to global variables. */38static DEFINE_SPINLOCK(sclp_tty_lock);39/* List of free pages that can be used for console output buffering. */40static LIST_HEAD(sclp_tty_pages);41/* List of full struct sclp_buffer structures ready for output. */42static LIST_HEAD(sclp_tty_outqueue);43/* Counter how many buffers are emitted. */44static int sclp_tty_buffer_count;45/* Pointer to current console buffer. */46static struct sclp_buffer *sclp_ttybuf;47/* Timer for delayed output of console messages. */48static struct timer_list sclp_tty_timer;49 50static struct tty_port sclp_port;51static u8 sclp_tty_chars[SCLP_TTY_BUF_SIZE];52static unsigned short int sclp_tty_chars_count;53 54struct tty_driver *sclp_tty_driver;55 56static int sclp_tty_tolower;57 58#define SCLP_TTY_COLUMNS 32059#define SPACES_PER_TAB 860#define CASE_DELIMITER 0x6c /* to separate upper and lower case (% in EBCDIC) */61 62/* This routine is called whenever we try to open a SCLP terminal. */63static int64sclp_tty_open(struct tty_struct *tty, struct file *filp)65{66 tty_port_tty_set(&sclp_port, tty);67 tty->driver_data = NULL;68 return 0;69}70 71/* This routine is called when the SCLP terminal is closed. */72static void73sclp_tty_close(struct tty_struct *tty, struct file *filp)74{75 if (tty->count > 1)76 return;77 tty_port_tty_set(&sclp_port, NULL);78}79 80/*81 * This routine returns the numbers of characters the tty driver82 * will accept for queuing to be written. This number is subject83 * to change as output buffers get emptied, or if the output flow84 * control is acted. This is not an exact number because not every85 * character needs the same space in the sccb. The worst case is86 * a string of newlines. Every newline creates a new message which87 * needs 82 bytes.88 */89static unsigned int90sclp_tty_write_room (struct tty_struct *tty)91{92 unsigned long flags;93 struct list_head *l;94 unsigned int count;95 96 spin_lock_irqsave(&sclp_tty_lock, flags);97 count = 0;98 if (sclp_ttybuf != NULL)99 count = sclp_buffer_space(sclp_ttybuf) / sizeof(struct msg_buf);100 list_for_each(l, &sclp_tty_pages)101 count += NR_EMPTY_MSG_PER_SCCB;102 spin_unlock_irqrestore(&sclp_tty_lock, flags);103 return count;104}105 106static void107sclp_ttybuf_callback(struct sclp_buffer *buffer, int rc)108{109 unsigned long flags;110 void *page;111 112 do {113 page = sclp_unmake_buffer(buffer);114 spin_lock_irqsave(&sclp_tty_lock, flags);115 /* Remove buffer from outqueue */116 list_del(&buffer->list);117 sclp_tty_buffer_count--;118 list_add_tail((struct list_head *) page, &sclp_tty_pages);119 /* Check if there is a pending buffer on the out queue. */120 buffer = NULL;121 if (!list_empty(&sclp_tty_outqueue))122 buffer = list_entry(sclp_tty_outqueue.next,123 struct sclp_buffer, list);124 spin_unlock_irqrestore(&sclp_tty_lock, flags);125 } while (buffer && sclp_emit_buffer(buffer, sclp_ttybuf_callback));126 127 tty_port_tty_wakeup(&sclp_port);128}129 130static inline void131__sclp_ttybuf_emit(struct sclp_buffer *buffer)132{133 unsigned long flags;134 int count;135 int rc;136 137 spin_lock_irqsave(&sclp_tty_lock, flags);138 list_add_tail(&buffer->list, &sclp_tty_outqueue);139 count = sclp_tty_buffer_count++;140 spin_unlock_irqrestore(&sclp_tty_lock, flags);141 if (count)142 return;143 rc = sclp_emit_buffer(buffer, sclp_ttybuf_callback);144 if (rc)145 sclp_ttybuf_callback(buffer, rc);146}147 148/*149 * When this routine is called from the timer then we flush the150 * temporary write buffer.151 */152static void153sclp_tty_timeout(struct timer_list *unused)154{155 unsigned long flags;156 struct sclp_buffer *buf;157 158 spin_lock_irqsave(&sclp_tty_lock, flags);159 buf = sclp_ttybuf;160 sclp_ttybuf = NULL;161 spin_unlock_irqrestore(&sclp_tty_lock, flags);162 163 if (buf != NULL) {164 __sclp_ttybuf_emit(buf);165 }166}167 168/*169 * Write a string to the sclp tty.170 */171static int sclp_tty_write_string(const u8 *str, int count, int may_fail)172{173 unsigned long flags;174 void *page;175 int written;176 int overall_written;177 struct sclp_buffer *buf;178 179 if (count <= 0)180 return 0;181 overall_written = 0;182 spin_lock_irqsave(&sclp_tty_lock, flags);183 do {184 /* Create a sclp output buffer if none exists yet */185 if (sclp_ttybuf == NULL) {186 while (list_empty(&sclp_tty_pages)) {187 spin_unlock_irqrestore(&sclp_tty_lock, flags);188 if (may_fail)189 goto out;190 else191 sclp_sync_wait();192 spin_lock_irqsave(&sclp_tty_lock, flags);193 }194 page = sclp_tty_pages.next;195 list_del((struct list_head *) page);196 sclp_ttybuf = sclp_make_buffer(page, SCLP_TTY_COLUMNS,197 SPACES_PER_TAB);198 }199 /* try to write the string to the current output buffer */200 written = sclp_write(sclp_ttybuf, str, count);201 overall_written += written;202 if (written == count)203 break;204 /*205 * Not all characters could be written to the current206 * output buffer. Emit the buffer, create a new buffer207 * and then output the rest of the string.208 */209 buf = sclp_ttybuf;210 sclp_ttybuf = NULL;211 spin_unlock_irqrestore(&sclp_tty_lock, flags);212 __sclp_ttybuf_emit(buf);213 spin_lock_irqsave(&sclp_tty_lock, flags);214 str += written;215 count -= written;216 } while (count > 0);217 /* Setup timer to output current console buffer after 1/10 second */218 if (sclp_ttybuf && sclp_chars_in_buffer(sclp_ttybuf) &&219 !timer_pending(&sclp_tty_timer)) {220 mod_timer(&sclp_tty_timer, jiffies + HZ / 10);221 }222 spin_unlock_irqrestore(&sclp_tty_lock, flags);223out:224 return overall_written;225}226 227/*228 * This routine is called by the kernel to write a series of characters to the229 * tty device. The characters may come from user space or kernel space. This230 * routine will return the number of characters actually accepted for writing.231 */232static ssize_t233sclp_tty_write(struct tty_struct *tty, const u8 *buf, size_t count)234{235 if (sclp_tty_chars_count > 0) {236 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0);237 sclp_tty_chars_count = 0;238 }239 return sclp_tty_write_string(buf, count, 1);240}241 242/*243 * This routine is called by the kernel to write a single character to the tty244 * device. If the kernel uses this routine, it must call the flush_chars()245 * routine (if defined) when it is done stuffing characters into the driver.246 *247 * Characters provided to sclp_tty_put_char() are buffered by the SCLP driver.248 * If the given character is a '\n' the contents of the SCLP write buffer249 * - including previous characters from sclp_tty_put_char() and strings from250 * sclp_write() without final '\n' - will be written.251 */252static int253sclp_tty_put_char(struct tty_struct *tty, u8 ch)254{255 sclp_tty_chars[sclp_tty_chars_count++] = ch;256 if (ch == '\n' || sclp_tty_chars_count >= SCLP_TTY_BUF_SIZE) {257 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0);258 sclp_tty_chars_count = 0;259 }260 return 1;261}262 263/*264 * This routine is called by the kernel after it has written a series of265 * characters to the tty device using put_char().266 */267static void268sclp_tty_flush_chars(struct tty_struct *tty)269{270 if (sclp_tty_chars_count > 0) {271 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0);272 sclp_tty_chars_count = 0;273 }274}275 276/*277 * This routine returns the number of characters in the write buffer of the278 * SCLP driver. The provided number includes all characters that are stored279 * in the SCCB (will be written next time the SCLP is not busy) as well as280 * characters in the write buffer (will not be written as long as there is a281 * final line feed missing).282 */283static unsigned int284sclp_tty_chars_in_buffer(struct tty_struct *tty)285{286 unsigned long flags;287 struct sclp_buffer *t;288 unsigned int count = 0;289 290 spin_lock_irqsave(&sclp_tty_lock, flags);291 if (sclp_ttybuf != NULL)292 count = sclp_chars_in_buffer(sclp_ttybuf);293 list_for_each_entry(t, &sclp_tty_outqueue, list) {294 count += sclp_chars_in_buffer(t);295 }296 spin_unlock_irqrestore(&sclp_tty_lock, flags);297 return count;298}299 300/*301 * removes all content from buffers of low level driver302 */303static void304sclp_tty_flush_buffer(struct tty_struct *tty)305{306 if (sclp_tty_chars_count > 0) {307 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0);308 sclp_tty_chars_count = 0;309 }310}311 312/*313 * push input to tty314 */315static void316sclp_tty_input(unsigned char* buf, unsigned int count)317{318 struct tty_struct *tty = tty_port_tty_get(&sclp_port);319 unsigned int cchar;320 321 /*322 * If this tty driver is currently closed323 * then throw the received input away.324 */325 if (tty == NULL)326 return;327 cchar = ctrlchar_handle(buf, count, tty);328 switch (cchar & CTRLCHAR_MASK) {329 case CTRLCHAR_SYSRQ:330 break;331 case CTRLCHAR_CTRL:332 tty_insert_flip_char(&sclp_port, cchar, TTY_NORMAL);333 tty_flip_buffer_push(&sclp_port);334 break;335 case CTRLCHAR_NONE:336 /* send (normal) input to line discipline */337 if (count < 2 ||338 (strncmp((const char *) buf + count - 2, "^n", 2) &&339 strncmp((const char *) buf + count - 2, "\252n", 2))) {340 /* add the auto \n */341 tty_insert_flip_string(&sclp_port, buf, count);342 tty_insert_flip_char(&sclp_port, '\n', TTY_NORMAL);343 } else344 tty_insert_flip_string(&sclp_port, buf, count - 2);345 tty_flip_buffer_push(&sclp_port);346 break;347 }348 tty_kref_put(tty);349}350 351/*352 * get a EBCDIC string in upper/lower case,353 * find out characters in lower/upper case separated by a special character,354 * modifiy original string,355 * returns length of resulting string356 */357static int sclp_switch_cases(unsigned char *buf, int count)358{359 unsigned char *ip, *op;360 int toggle;361 362 /* initially changing case is off */363 toggle = 0;364 ip = op = buf;365 while (count-- > 0) {366 /* compare with special character */367 if (*ip == CASE_DELIMITER) {368 /* followed by another special character? */369 if (count && ip[1] == CASE_DELIMITER) {370 /*371 * ... then put a single copy of the special372 * character to the output string373 */374 *op++ = *ip++;375 count--;376 } else377 /*378 * ... special character follower by a normal379 * character toggles the case change behaviour380 */381 toggle = ~toggle;382 /* skip special character */383 ip++;384 } else385 /* not the special character */386 if (toggle)387 /* but case switching is on */388 if (sclp_tty_tolower)389 /* switch to uppercase */390 *op++ = _ebc_toupper[(int) *ip++];391 else392 /* switch to lowercase */393 *op++ = _ebc_tolower[(int) *ip++];394 else395 /* no case switching, copy the character */396 *op++ = *ip++;397 }398 /* return length of reformatted string. */399 return op - buf;400}401 402static void sclp_get_input(struct gds_subvector *sv)403{404 unsigned char *str;405 int count;406 407 str = (unsigned char *) (sv + 1);408 count = sv->length - sizeof(*sv);409 if (sclp_tty_tolower)410 EBC_TOLOWER(str, count);411 count = sclp_switch_cases(str, count);412 /* convert EBCDIC to ASCII (modify original input in SCCB) */413 sclp_ebcasc_str(str, count);414 415 /* transfer input to high level driver */416 sclp_tty_input(str, count);417}418 419static inline void sclp_eval_selfdeftextmsg(struct gds_subvector *sv)420{421 void *end;422 423 end = (void *) sv + sv->length;424 for (sv = sv + 1; (void *) sv < end; sv = (void *) sv + sv->length)425 if (sv->key == 0x30)426 sclp_get_input(sv);427}428 429static inline void sclp_eval_textcmd(struct gds_vector *v)430{431 struct gds_subvector *sv;432 void *end;433 434 end = (void *) v + v->length;435 for (sv = (struct gds_subvector *) (v + 1);436 (void *) sv < end; sv = (void *) sv + sv->length)437 if (sv->key == GDS_KEY_SELFDEFTEXTMSG)438 sclp_eval_selfdeftextmsg(sv);439 440}441 442static inline void sclp_eval_cpmsu(struct gds_vector *v)443{444 void *end;445 446 end = (void *) v + v->length;447 for (v = v + 1; (void *) v < end; v = (void *) v + v->length)448 if (v->gds_id == GDS_ID_TEXTCMD)449 sclp_eval_textcmd(v);450}451 452 453static inline void sclp_eval_mdsmu(struct gds_vector *v)454{455 v = sclp_find_gds_vector(v + 1, (void *) v + v->length, GDS_ID_CPMSU);456 if (v)457 sclp_eval_cpmsu(v);458}459 460static void sclp_tty_receiver(struct evbuf_header *evbuf)461{462 struct gds_vector *v;463 464 v = sclp_find_gds_vector(evbuf + 1, (void *) evbuf + evbuf->length,465 GDS_ID_MDSMU);466 if (v)467 sclp_eval_mdsmu(v);468}469 470static void471sclp_tty_state_change(struct sclp_register *reg)472{473}474 475static struct sclp_register sclp_input_event =476{477 .receive_mask = EVTYP_OPCMD_MASK | EVTYP_PMSGCMD_MASK,478 .state_change_fn = sclp_tty_state_change,479 .receiver_fn = sclp_tty_receiver480};481 482static const struct tty_operations sclp_ops = {483 .open = sclp_tty_open,484 .close = sclp_tty_close,485 .write = sclp_tty_write,486 .put_char = sclp_tty_put_char,487 .flush_chars = sclp_tty_flush_chars,488 .write_room = sclp_tty_write_room,489 .chars_in_buffer = sclp_tty_chars_in_buffer,490 .flush_buffer = sclp_tty_flush_buffer,491};492 493static int __init494sclp_tty_init(void)495{496 struct tty_driver *driver;497 void *page;498 int i;499 int rc;500 501 /* z/VM multiplexes the line mode output on the 32xx screen */502 if (MACHINE_IS_VM && !CONSOLE_IS_SCLP)503 return 0;504 if (!sclp.has_linemode)505 return 0;506 driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW);507 if (IS_ERR(driver))508 return PTR_ERR(driver);509 510 rc = sclp_rw_init();511 if (rc) {512 tty_driver_kref_put(driver);513 return rc;514 }515 /* Allocate pages for output buffering */516 for (i = 0; i < MAX_KMEM_PAGES; i++) {517 page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);518 if (page == NULL) {519 tty_driver_kref_put(driver);520 return -ENOMEM;521 }522 list_add_tail((struct list_head *) page, &sclp_tty_pages);523 }524 timer_setup(&sclp_tty_timer, sclp_tty_timeout, 0);525 sclp_ttybuf = NULL;526 sclp_tty_buffer_count = 0;527 if (MACHINE_IS_VM) {528 /* case input lines to lowercase */529 sclp_tty_tolower = 1;530 }531 sclp_tty_chars_count = 0;532 533 rc = sclp_register(&sclp_input_event);534 if (rc) {535 tty_driver_kref_put(driver);536 return rc;537 }538 539 tty_port_init(&sclp_port);540 541 driver->driver_name = "sclp_line";542 driver->name = "sclp_line";543 driver->major = TTY_MAJOR;544 driver->minor_start = 64;545 driver->type = TTY_DRIVER_TYPE_SYSTEM;546 driver->subtype = SYSTEM_TYPE_TTY;547 driver->init_termios = tty_std_termios;548 driver->init_termios.c_iflag = IGNBRK | IGNPAR;549 driver->init_termios.c_oflag = ONLCR;550 driver->init_termios.c_lflag = ISIG | ECHO;551 tty_set_operations(driver, &sclp_ops);552 tty_port_link_device(&sclp_port, driver, 0);553 rc = tty_register_driver(driver);554 if (rc) {555 tty_driver_kref_put(driver);556 tty_port_destroy(&sclp_port);557 return rc;558 }559 sclp_tty_driver = driver;560 return 0;561}562device_initcall(sclp_tty_init);563