OSCL-LXR linux-6.0.1/​drivers/​s390/​char/​sclp_tty.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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 DEFINE_SPINLOCK(sclp_tty_lock);
 /* List of free pages that can be used for console output buffering. */
 static LIST_HEAD(sclp_tty_pages);
 /* List of full struct sclp_buffer structures ready for output. */
 static 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;
 
 #define SCLP_TTY_COLUMNS 320
 #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;
     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 unsigned int
 sclp_tty_write_room (struct tty_struct *tty)
 {
     unsigned long flags;
     struct list_head *l;
     unsigned 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 unsigned int
 sclp_tty_chars_in_buffer(struct tty_struct *tty)
 {
     unsigned long flags;
     struct sclp_buffer *t;
     unsigned int count = 0;
 
     spin_lock_irqsave(&sclp_tty_lock, flags);
     if (sclp_ttybuf != NULL)
         count = sclp_chars_in_buffer(sclp_ttybuf);
     list_for_each_entry(t, &sclp_tty_outqueue, 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 = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW);
     if (IS_ERR(driver))
         return PTR_ERR(driver);
 
     rc = sclp_rw_init();
     if (rc) {
         tty_driver_kref_put(driver);
         return rc;
     }
     /* Allocate pages for output buffering */
     for (i = 0; i < MAX_KMEM_PAGES; i++) {
         page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
         if (page == NULL) {
             tty_driver_kref_put(driver);
             return -ENOMEM;
         }
         list_add_tail((struct list_head *) page, &sclp_tty_pages);
     }
     timer_setup(&sclp_tty_timer, sclp_tty_timeout, 0);
     sclp_ttybuf = NULL;
     sclp_tty_buffer_count = 0;
     if (MACHINE_IS_VM) {
         /* case input lines to lowercase */
         sclp_tty_tolower = 1;
     }
     sclp_tty_chars_count = 0;
 
     rc = sclp_register(&sclp_input_event);
     if (rc) {
         tty_driver_kref_put(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;
     tty_set_operations(driver, &sclp_ops);
     tty_port_link_device(&sclp_port, driver, 0);
     rc = tty_register_driver(driver);
     if (rc) {
         tty_driver_kref_put(driver);
         tty_port_destroy(&sclp_port);
         return rc;
     }
     sclp_tty_driver = driver;
     return 0;
 }
 device_initcall(sclp_tty_init);

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