1 files changed, 252 insertions, 0 deletions
diff --git a/drivers/s390/char/sclp_con.c b/drivers/s390/char/sclp_con.c
new file mode 100644
index 000000000000..10ef22f13541
--- /dev/null
+++ b/drivers/s390/char/sclp_con.c
@@ -0,0 +1,252 @@
+/*
+ *  drivers/s390/char/sclp_con.c
+ *    SCLP line mode console driver
+ *
+ *  S390 version
+ *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *    Author(s): Martin Peschke <mpeschke@de.ibm.com>
+ *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <linux/config.h>
+#include <linux/kmod.h>
+#include <linux/console.h>
+#include <linux/init.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
+#include <linux/bootmem.h>
+#include <linux/err.h>
+
+#include "sclp.h"
+#include "sclp_rw.h"
+#include "sclp_tty.h"
+
+#define SCLP_CON_PRINT_HEADER "sclp console driver: "
+
+#define sclp_console_major 4		/* TTYAUX_MAJOR */
+#define sclp_console_minor 64
+#define sclp_console_name  "ttyS"
+
+/* Lock to guard over changes to global variables */
+static spinlock_t sclp_con_lock;
+/* List of free pages that can be used for console output buffering */
+static struct list_head sclp_con_pages;
+/* List of full struct sclp_buffer structures ready for output */
+static struct list_head sclp_con_outqueue;
+/* Counter how many buffers are emitted (max 1) and how many */
+/* are on the output queue. */
+static int sclp_con_buffer_count;
+/* Pointer to current console buffer */
+static struct sclp_buffer *sclp_conbuf;
+/* Timer for delayed output of console messages */
+static struct timer_list sclp_con_timer;
+
+/* Output format for console messages */
+static unsigned short sclp_con_columns;
+static unsigned short sclp_con_width_htab;
+
+static void
+sclp_conbuf_callback(struct sclp_buffer *buffer, int rc)
+{
+	unsigned long flags;
+	void *page;
+
+	do {
+		page = sclp_unmake_buffer(buffer);
+		spin_lock_irqsave(&sclp_con_lock, flags);
+		/* Remove buffer from outqueue */
+		list_del(&buffer->list);
+		sclp_con_buffer_count--;
+		list_add_tail((struct list_head *) page, &sclp_con_pages);
+		/* Check if there is a pending buffer on the out queue. */
+		buffer = NULL;
+		if (!list_empty(&sclp_con_outqueue))
+			buffer = list_entry(sclp_con_outqueue.next,
+					    struct sclp_buffer, list);
+		spin_unlock_irqrestore(&sclp_con_lock, flags);
+	} while (buffer && sclp_emit_buffer(buffer, sclp_conbuf_callback));
+}
+
+static inline void
+sclp_conbuf_emit(void)
+{
+	struct sclp_buffer* buffer;
+	unsigned long flags;
+	int count;
+	int rc;
+
+	spin_lock_irqsave(&sclp_con_lock, flags);
+	buffer = sclp_conbuf;
+	sclp_conbuf = NULL;
+	if (buffer == NULL) {
+		spin_unlock_irqrestore(&sclp_con_lock, flags);
+		return;
+	}
+	list_add_tail(&buffer->list, &sclp_con_outqueue);
+	count = sclp_con_buffer_count++;
+	spin_unlock_irqrestore(&sclp_con_lock, flags);
+	if (count)
+		return;
+	rc = sclp_emit_buffer(buffer, sclp_conbuf_callback);
+	if (rc)
+		sclp_conbuf_callback(buffer, rc);
+}
+
+/*
+ * When this routine is called from the timer then we flush the
+ * temporary write buffer without further waiting on a final new line.
+ */
+static void
+sclp_console_timeout(unsigned long data)
+{
+	sclp_conbuf_emit();
+}
+
+/*
+ * Writes the given message to S390 system console
+ */
+static void
+sclp_console_write(struct console *console, const char *message,
+		   unsigned int count)
+{
+	unsigned long flags;
+	void *page;
+	int written;
+
+	if (count == 0)
+		return;
+	spin_lock_irqsave(&sclp_con_lock, flags);
+	/*
+	 * process escape characters, write message into buffer,
+	 * send buffer to SCLP
+	 */
+	do {
+		/* make sure we have a console output buffer */
+		if (sclp_conbuf == NULL) {
+			while (list_empty(&sclp_con_pages)) {
+				spin_unlock_irqrestore(&sclp_con_lock, flags);
+				sclp_sync_wait();
+				spin_lock_irqsave(&sclp_con_lock, flags);
+			}
+			page = sclp_con_pages.next;
+			list_del((struct list_head *) page);
+			sclp_conbuf = sclp_make_buffer(page, sclp_con_columns,
+						       sclp_con_width_htab);
+		}
+		/* try to write the string to the current output buffer */
+		written = sclp_write(sclp_conbuf, (const unsigned char *)
+				     message, count);
+		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.
+		 */
+		spin_unlock_irqrestore(&sclp_con_lock, flags);
+		sclp_conbuf_emit();
+		spin_lock_irqsave(&sclp_con_lock, flags);
+		message += written;
+		count -= written;
+	} while (count > 0);
+	/* Setup timer to output current console buffer after 1/10 second */
+	if (sclp_conbuf != NULL && sclp_chars_in_buffer(sclp_conbuf) != 0 &&
+	    !timer_pending(&sclp_con_timer)) {
+		init_timer(&sclp_con_timer);
+		sclp_con_timer.function = sclp_console_timeout;
+		sclp_con_timer.data = 0UL;
+		sclp_con_timer.expires = jiffies + HZ/10;
+		add_timer(&sclp_con_timer);
+	}
+	spin_unlock_irqrestore(&sclp_con_lock, flags);
+}
+
+static struct tty_driver *
+sclp_console_device(struct console *c, int *index)
+{
+	*index = c->index;
+	return sclp_tty_driver;
+}
+
+/*
+ * This routine is called from panic when the kernel
+ * is going to give up. We have to make sure that all buffers
+ * will be flushed to the SCLP.
+ */
+static void
+sclp_console_unblank(void)
+{
+	unsigned long flags;
+
+	sclp_conbuf_emit();
+	spin_lock_irqsave(&sclp_con_lock, flags);
+	if (timer_pending(&sclp_con_timer))
+		del_timer(&sclp_con_timer);
+	while (sclp_con_buffer_count > 0) {
+		spin_unlock_irqrestore(&sclp_con_lock, flags);
+		sclp_sync_wait();
+		spin_lock_irqsave(&sclp_con_lock, flags);
+	}
+	spin_unlock_irqrestore(&sclp_con_lock, flags);
+}
+
+/*
+ * used to register the SCLP console to the kernel and to
+ * give printk necessary information
+ */
+static struct console sclp_console =
+{
+	.name = sclp_console_name,
+	.write = sclp_console_write,
+	.device = sclp_console_device,
+	.unblank = sclp_console_unblank,
+	.flags = CON_PRINTBUFFER,
+	.index = 0 /* ttyS0 */
+};
+
+/*
+ * called by console_init() in drivers/char/tty_io.c at boot-time.
+ */
+static int __init
+sclp_console_init(void)
+{
+	void *page;
+	int i;
+	int rc;
+
+	if (!CONSOLE_IS_SCLP)
+		return 0;
+	rc = sclp_rw_init();
+	if (rc)
+		return rc;
+	/* Allocate pages for output buffering */
+	INIT_LIST_HEAD(&sclp_con_pages);
+	for (i = 0; i < MAX_CONSOLE_PAGES; i++) {
+		page = alloc_bootmem_low_pages(PAGE_SIZE);
+		if (page == NULL)
+			return -ENOMEM;
+		list_add_tail((struct list_head *) page, &sclp_con_pages);
+	}
+	INIT_LIST_HEAD(&sclp_con_outqueue);
+	spin_lock_init(&sclp_con_lock);
+	sclp_con_buffer_count = 0;
+	sclp_conbuf = NULL;
+	init_timer(&sclp_con_timer);
+
+	/* Set output format */
+	if (MACHINE_IS_VM)
+		/*
+		 * save 4 characters for the CPU number
+		 * written at start of each line by VM/CP
+		 */
+		sclp_con_columns = 76;
+	else
+		sclp_con_columns = 80;
+	sclp_con_width_htab = 8;
+
+	/* enable printk-access to this driver */
+	register_console(&sclp_console);
+	return 0;
+}
+
+console_initcall(sclp_console_init);