Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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);