diff options
Diffstat (limited to 'drivers/s390/char/sclp_tty.c')
| -rw-r--r-- | drivers/s390/char/sclp_tty.c | 575 |
1 files changed, 575 insertions, 0 deletions
diff --git a/drivers/s390/char/sclp_tty.c b/drivers/s390/char/sclp_tty.c new file mode 100644 index 000000000..5aff8b684 --- /dev/null +++ b/drivers/s390/char/sclp_tty.c @@ -0,0 +1,575 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * SCLP line mode terminal driver. + * + * S390 version + * Copyright IBM Corp. 1999 + * Author(s): Martin Peschke <mpeschke@de.ibm.com> + * Martin Schwidefsky <schwidefsky@de.ibm.com> + */ + +#include <linux/kmod.h> +#include <linux/tty.h> +#include <linux/tty_driver.h> +#include <linux/tty_flip.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/gfp.h> +#include <linux/uaccess.h> + +#include "ctrlchar.h" +#include "sclp.h" +#include "sclp_rw.h" +#include "sclp_tty.h" + +/* + * size of a buffer that collects single characters coming in + * via sclp_tty_put_char() + */ +#define SCLP_TTY_BUF_SIZE 512 + +/* + * There is exactly one SCLP terminal, so we can keep things simple + * and allocate all variables statically. + */ + +/* Lock to guard over changes to global variables. */ +static spinlock_t sclp_tty_lock; +/* List of free pages that can be used for console output buffering. */ +static struct list_head sclp_tty_pages; +/* List of full struct sclp_buffer structures ready for output. */ +static struct list_head sclp_tty_outqueue; +/* Counter how many buffers are emitted. */ +static int sclp_tty_buffer_count; +/* Pointer to current console buffer. */ +static struct sclp_buffer *sclp_ttybuf; +/* Timer for delayed output of console messages. */ +static struct timer_list sclp_tty_timer; + +static struct tty_port sclp_port; +static unsigned char sclp_tty_chars[SCLP_TTY_BUF_SIZE]; +static unsigned short int sclp_tty_chars_count; + +struct tty_driver *sclp_tty_driver; + +static int sclp_tty_tolower; +static int sclp_tty_columns = 80; + +#define SPACES_PER_TAB 8 +#define CASE_DELIMITER 0x6c /* to separate upper and lower case (% in EBCDIC) */ + +/* This routine is called whenever we try to open a SCLP terminal. */ +static int +sclp_tty_open(struct tty_struct *tty, struct file *filp) +{ + tty_port_tty_set(&sclp_port, tty); + tty->driver_data = NULL; + sclp_port.low_latency = 0; + return 0; +} + +/* This routine is called when the SCLP terminal is closed. */ +static void +sclp_tty_close(struct tty_struct *tty, struct file *filp) +{ + if (tty->count > 1) + return; + tty_port_tty_set(&sclp_port, NULL); +} + +/* + * This routine returns the numbers of characters the tty driver + * will accept for queuing to be written. This number is subject + * to change as output buffers get emptied, or if the output flow + * control is acted. This is not an exact number because not every + * character needs the same space in the sccb. The worst case is + * a string of newlines. Every newline creates a new message which + * needs 82 bytes. + */ +static int +sclp_tty_write_room (struct tty_struct *tty) +{ + unsigned long flags; + struct list_head *l; + int count; + + spin_lock_irqsave(&sclp_tty_lock, flags); + count = 0; + if (sclp_ttybuf != NULL) + count = sclp_buffer_space(sclp_ttybuf) / sizeof(struct msg_buf); + list_for_each(l, &sclp_tty_pages) + count += NR_EMPTY_MSG_PER_SCCB; + spin_unlock_irqrestore(&sclp_tty_lock, flags); + return count; +} + +static void +sclp_ttybuf_callback(struct sclp_buffer *buffer, int rc) +{ + unsigned long flags; + void *page; + + do { + page = sclp_unmake_buffer(buffer); + spin_lock_irqsave(&sclp_tty_lock, flags); + /* Remove buffer from outqueue */ + list_del(&buffer->list); + sclp_tty_buffer_count--; + list_add_tail((struct list_head *) page, &sclp_tty_pages); + /* Check if there is a pending buffer on the out queue. */ + buffer = NULL; + if (!list_empty(&sclp_tty_outqueue)) + buffer = list_entry(sclp_tty_outqueue.next, + struct sclp_buffer, list); + spin_unlock_irqrestore(&sclp_tty_lock, flags); + } while (buffer && sclp_emit_buffer(buffer, sclp_ttybuf_callback)); + + tty_port_tty_wakeup(&sclp_port); +} + +static inline void +__sclp_ttybuf_emit(struct sclp_buffer *buffer) +{ + unsigned long flags; + int count; + int rc; + + spin_lock_irqsave(&sclp_tty_lock, flags); + list_add_tail(&buffer->list, &sclp_tty_outqueue); + count = sclp_tty_buffer_count++; + spin_unlock_irqrestore(&sclp_tty_lock, flags); + if (count) + return; + rc = sclp_emit_buffer(buffer, sclp_ttybuf_callback); + if (rc) + sclp_ttybuf_callback(buffer, rc); +} + +/* + * When this routine is called from the timer then we flush the + * temporary write buffer. + */ +static void +sclp_tty_timeout(struct timer_list *unused) +{ + unsigned long flags; + struct sclp_buffer *buf; + + spin_lock_irqsave(&sclp_tty_lock, flags); + buf = sclp_ttybuf; + sclp_ttybuf = NULL; + spin_unlock_irqrestore(&sclp_tty_lock, flags); + + if (buf != NULL) { + __sclp_ttybuf_emit(buf); + } +} + +/* + * Write a string to the sclp tty. + */ +static int sclp_tty_write_string(const unsigned char *str, int count, int may_fail) +{ + unsigned long flags; + void *page; + int written; + int overall_written; + struct sclp_buffer *buf; + + if (count <= 0) + return 0; + overall_written = 0; + spin_lock_irqsave(&sclp_tty_lock, flags); + do { + /* Create a sclp output buffer if none exists yet */ + if (sclp_ttybuf == NULL) { + while (list_empty(&sclp_tty_pages)) { + spin_unlock_irqrestore(&sclp_tty_lock, flags); + if (may_fail) + goto out; + else + sclp_sync_wait(); + spin_lock_irqsave(&sclp_tty_lock, flags); + } + page = sclp_tty_pages.next; + list_del((struct list_head *) page); + sclp_ttybuf = sclp_make_buffer(page, sclp_tty_columns, + SPACES_PER_TAB); + } + /* try to write the string to the current output buffer */ + written = sclp_write(sclp_ttybuf, str, count); + overall_written += written; + if (written == count) + break; + /* + * Not all characters could be written to the current + * output buffer. Emit the buffer, create a new buffer + * and then output the rest of the string. + */ + buf = sclp_ttybuf; + sclp_ttybuf = NULL; + spin_unlock_irqrestore(&sclp_tty_lock, flags); + __sclp_ttybuf_emit(buf); + spin_lock_irqsave(&sclp_tty_lock, flags); + str += written; + count -= written; + } while (count > 0); + /* Setup timer to output current console buffer after 1/10 second */ + if (sclp_ttybuf && sclp_chars_in_buffer(sclp_ttybuf) && + !timer_pending(&sclp_tty_timer)) { + mod_timer(&sclp_tty_timer, jiffies + HZ / 10); + } + spin_unlock_irqrestore(&sclp_tty_lock, flags); +out: + return overall_written; +} + +/* + * This routine is called by the kernel to write a series of characters to the + * tty device. The characters may come from user space or kernel space. This + * routine will return the number of characters actually accepted for writing. + */ +static int +sclp_tty_write(struct tty_struct *tty, const unsigned char *buf, int count) +{ + if (sclp_tty_chars_count > 0) { + sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0); + sclp_tty_chars_count = 0; + } + return sclp_tty_write_string(buf, count, 1); +} + +/* + * This routine is called by the kernel to write a single character to the tty + * device. If the kernel uses this routine, it must call the flush_chars() + * routine (if defined) when it is done stuffing characters into the driver. + * + * Characters provided to sclp_tty_put_char() are buffered by the SCLP driver. + * If the given character is a '\n' the contents of the SCLP write buffer + * - including previous characters from sclp_tty_put_char() and strings from + * sclp_write() without final '\n' - will be written. + */ +static int +sclp_tty_put_char(struct tty_struct *tty, unsigned char ch) +{ + sclp_tty_chars[sclp_tty_chars_count++] = ch; + if (ch == '\n' || sclp_tty_chars_count >= SCLP_TTY_BUF_SIZE) { + sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0); + sclp_tty_chars_count = 0; + } + return 1; +} + +/* + * This routine is called by the kernel after it has written a series of + * characters to the tty device using put_char(). + */ +static void +sclp_tty_flush_chars(struct tty_struct *tty) +{ + if (sclp_tty_chars_count > 0) { + sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0); + sclp_tty_chars_count = 0; + } +} + +/* + * This routine returns the number of characters in the write buffer of the + * SCLP driver. The provided number includes all characters that are stored + * in the SCCB (will be written next time the SCLP is not busy) as well as + * characters in the write buffer (will not be written as long as there is a + * final line feed missing). + */ +static int +sclp_tty_chars_in_buffer(struct tty_struct *tty) +{ + unsigned long flags; + struct list_head *l; + struct sclp_buffer *t; + int count; + + spin_lock_irqsave(&sclp_tty_lock, flags); + count = 0; + if (sclp_ttybuf != NULL) + count = sclp_chars_in_buffer(sclp_ttybuf); + list_for_each(l, &sclp_tty_outqueue) { + t = list_entry(l, struct sclp_buffer, list); + count += sclp_chars_in_buffer(t); + } + spin_unlock_irqrestore(&sclp_tty_lock, flags); + return count; +} + +/* + * removes all content from buffers of low level driver + */ +static void +sclp_tty_flush_buffer(struct tty_struct *tty) +{ + if (sclp_tty_chars_count > 0) { + sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0); + sclp_tty_chars_count = 0; + } +} + +/* + * push input to tty + */ +static void +sclp_tty_input(unsigned char* buf, unsigned int count) +{ + struct tty_struct *tty = tty_port_tty_get(&sclp_port); + unsigned int cchar; + + /* + * If this tty driver is currently closed + * then throw the received input away. + */ + if (tty == NULL) + return; + cchar = ctrlchar_handle(buf, count, tty); + switch (cchar & CTRLCHAR_MASK) { + case CTRLCHAR_SYSRQ: + break; + case CTRLCHAR_CTRL: + tty_insert_flip_char(&sclp_port, cchar, TTY_NORMAL); + tty_flip_buffer_push(&sclp_port); + break; + case CTRLCHAR_NONE: + /* send (normal) input to line discipline */ + if (count < 2 || + (strncmp((const char *) buf + count - 2, "^n", 2) && + strncmp((const char *) buf + count - 2, "\252n", 2))) { + /* add the auto \n */ + tty_insert_flip_string(&sclp_port, buf, count); + tty_insert_flip_char(&sclp_port, '\n', TTY_NORMAL); + } else + tty_insert_flip_string(&sclp_port, buf, count - 2); + tty_flip_buffer_push(&sclp_port); + break; + } + tty_kref_put(tty); +} + +/* + * get a EBCDIC string in upper/lower case, + * find out characters in lower/upper case separated by a special character, + * modifiy original string, + * returns length of resulting string + */ +static int sclp_switch_cases(unsigned char *buf, int count) +{ + unsigned char *ip, *op; + int toggle; + + /* initially changing case is off */ + toggle = 0; + ip = op = buf; + while (count-- > 0) { + /* compare with special character */ + if (*ip == CASE_DELIMITER) { + /* followed by another special character? */ + if (count && ip[1] == CASE_DELIMITER) { + /* + * ... then put a single copy of the special + * character to the output string + */ + *op++ = *ip++; + count--; + } else + /* + * ... special character follower by a normal + * character toggles the case change behaviour + */ + toggle = ~toggle; + /* skip special character */ + ip++; + } else + /* not the special character */ + if (toggle) + /* but case switching is on */ + if (sclp_tty_tolower) + /* switch to uppercase */ + *op++ = _ebc_toupper[(int) *ip++]; + else + /* switch to lowercase */ + *op++ = _ebc_tolower[(int) *ip++]; + else + /* no case switching, copy the character */ + *op++ = *ip++; + } + /* return length of reformatted string. */ + return op - buf; +} + +static void sclp_get_input(struct gds_subvector *sv) +{ + unsigned char *str; + int count; + + str = (unsigned char *) (sv + 1); + count = sv->length - sizeof(*sv); + if (sclp_tty_tolower) + EBC_TOLOWER(str, count); + count = sclp_switch_cases(str, count); + /* convert EBCDIC to ASCII (modify original input in SCCB) */ + sclp_ebcasc_str(str, count); + + /* transfer input to high level driver */ + sclp_tty_input(str, count); +} + +static inline void sclp_eval_selfdeftextmsg(struct gds_subvector *sv) +{ + void *end; + + end = (void *) sv + sv->length; + for (sv = sv + 1; (void *) sv < end; sv = (void *) sv + sv->length) + if (sv->key == 0x30) + sclp_get_input(sv); +} + +static inline void sclp_eval_textcmd(struct gds_vector *v) +{ + struct gds_subvector *sv; + void *end; + + end = (void *) v + v->length; + for (sv = (struct gds_subvector *) (v + 1); + (void *) sv < end; sv = (void *) sv + sv->length) + if (sv->key == GDS_KEY_SELFDEFTEXTMSG) + sclp_eval_selfdeftextmsg(sv); + +} + +static inline void sclp_eval_cpmsu(struct gds_vector *v) +{ + void *end; + + end = (void *) v + v->length; + for (v = v + 1; (void *) v < end; v = (void *) v + v->length) + if (v->gds_id == GDS_ID_TEXTCMD) + sclp_eval_textcmd(v); +} + + +static inline void sclp_eval_mdsmu(struct gds_vector *v) +{ + v = sclp_find_gds_vector(v + 1, (void *) v + v->length, GDS_ID_CPMSU); + if (v) + sclp_eval_cpmsu(v); +} + +static void sclp_tty_receiver(struct evbuf_header *evbuf) +{ + struct gds_vector *v; + + v = sclp_find_gds_vector(evbuf + 1, (void *) evbuf + evbuf->length, + GDS_ID_MDSMU); + if (v) + sclp_eval_mdsmu(v); +} + +static void +sclp_tty_state_change(struct sclp_register *reg) +{ +} + +static struct sclp_register sclp_input_event = +{ + .receive_mask = EVTYP_OPCMD_MASK | EVTYP_PMSGCMD_MASK, + .state_change_fn = sclp_tty_state_change, + .receiver_fn = sclp_tty_receiver +}; + +static const struct tty_operations sclp_ops = { + .open = sclp_tty_open, + .close = sclp_tty_close, + .write = sclp_tty_write, + .put_char = sclp_tty_put_char, + .flush_chars = sclp_tty_flush_chars, + .write_room = sclp_tty_write_room, + .chars_in_buffer = sclp_tty_chars_in_buffer, + .flush_buffer = sclp_tty_flush_buffer, +}; + +static int __init +sclp_tty_init(void) +{ + struct tty_driver *driver; + void *page; + int i; + int rc; + + /* z/VM multiplexes the line mode output on the 32xx screen */ + if (MACHINE_IS_VM && !CONSOLE_IS_SCLP) + return 0; + if (!sclp.has_linemode) + return 0; + driver = alloc_tty_driver(1); + if (!driver) + return -ENOMEM; + + rc = sclp_rw_init(); + if (rc) { + put_tty_driver(driver); + return rc; + } + /* Allocate pages for output buffering */ + INIT_LIST_HEAD(&sclp_tty_pages); + for (i = 0; i < MAX_KMEM_PAGES; i++) { + page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); + if (page == NULL) { + put_tty_driver(driver); + return -ENOMEM; + } + list_add_tail((struct list_head *) page, &sclp_tty_pages); + } + INIT_LIST_HEAD(&sclp_tty_outqueue); + spin_lock_init(&sclp_tty_lock); + timer_setup(&sclp_tty_timer, sclp_tty_timeout, 0); + sclp_ttybuf = NULL; + sclp_tty_buffer_count = 0; + if (MACHINE_IS_VM) { + /* + * save 4 characters for the CPU number + * written at start of each line by VM/CP + */ + sclp_tty_columns = 76; + /* case input lines to lowercase */ + sclp_tty_tolower = 1; + } + sclp_tty_chars_count = 0; + + rc = sclp_register(&sclp_input_event); + if (rc) { + put_tty_driver(driver); + return rc; + } + + tty_port_init(&sclp_port); + + driver->driver_name = "sclp_line"; + driver->name = "sclp_line"; + driver->major = TTY_MAJOR; + driver->minor_start = 64; + driver->type = TTY_DRIVER_TYPE_SYSTEM; + driver->subtype = SYSTEM_TYPE_TTY; + driver->init_termios = tty_std_termios; + driver->init_termios.c_iflag = IGNBRK | IGNPAR; + driver->init_termios.c_oflag = ONLCR; + driver->init_termios.c_lflag = ISIG | ECHO; + driver->flags = TTY_DRIVER_REAL_RAW; + tty_set_operations(driver, &sclp_ops); + tty_port_link_device(&sclp_port, driver, 0); + rc = tty_register_driver(driver); + if (rc) { + put_tty_driver(driver); + tty_port_destroy(&sclp_port); + return rc; + } + sclp_tty_driver = driver; + return 0; +} +device_initcall(sclp_tty_init); |