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