/*
* 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/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);
