* SCLP VT220 terminal driver.
*
* S390 version
- * Copyright (C) 2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ * Copyright IBM Corp. 2003,2008
* Author(s): Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>
*/
#include <asm/uaccess.h>
#include "sclp.h"
-#define SCLP_VT220_PRINT_HEADER "sclp vt220 tty driver: "
#define SCLP_VT220_MAJOR TTY_MAJOR
#define SCLP_VT220_MINOR 65
#define SCLP_VT220_DRIVER_NAME "sclp_vt220"
/* Number of requests in outqueue */
static int sclp_vt220_outqueue_count;
-/* Wait queue used to delay write requests while we've run out of buffers */
-static wait_queue_head_t sclp_vt220_waitq;
-
/* Timer used for delaying write requests to merge subsequent messages into
* a single buffer */
static struct timer_list sclp_vt220_timer;
/* Number of characters in current request buffer */
static int sclp_vt220_buffered_chars;
-/* Flag indicating whether this driver has already been initialized */
-static int sclp_vt220_initialized = 0;
+/* Counter controlling core driver initialization. */
+static int __initdata sclp_vt220_init_count;
/* Flag indicating that sclp_vt220_current_request should really
* have been already queued but wasn't because the SCLP was processing
} while (request && __sclp_vt220_emit(request));
if (request == NULL && sclp_vt220_flush_later)
sclp_vt220_emit_current();
- wake_up(&sclp_vt220_waitq);
/* Check if the tty needs a wake up call */
if (sclp_vt220_tty != NULL) {
tty_wakeup(sclp_vt220_tty);
static int
__sclp_vt220_emit(struct sclp_vt220_request *request)
{
- if (!(sclp_vt220_register.sclp_send_mask & EVTYP_VT220MSG_MASK)) {
+ if (!(sclp_vt220_register.sclp_receive_mask & EVTYP_VT220MSG_MASK)) {
request->sclp_req.status = SCLP_REQ_FAILED;
return -EIO;
}
sclp_vt220_emit_current();
}
-#define BUFFER_MAX_DELAY HZ/2
+#define BUFFER_MAX_DELAY HZ/20
/*
* Internal implementation of the write function. Write COUNT bytes of data
*/
static int
__sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
- int convertlf)
+ int convertlf, int may_fail)
{
unsigned long flags;
void *page;
overall_written = 0;
spin_lock_irqsave(&sclp_vt220_lock, flags);
do {
- /* Create a sclp output buffer if none exists yet */
+ /* Create an sclp output buffer if none exists yet */
if (sclp_vt220_current_request == NULL) {
while (list_empty(&sclp_vt220_empty)) {
- spin_unlock_irqrestore(&sclp_vt220_lock,
- flags);
- if (in_interrupt())
- sclp_sync_wait();
+ spin_unlock_irqrestore(&sclp_vt220_lock, flags);
+ if (may_fail)
+ goto out;
else
- wait_event(sclp_vt220_waitq,
- !list_empty(&sclp_vt220_empty));
+ sclp_sync_wait();
spin_lock_irqsave(&sclp_vt220_lock, flags);
}
page = (void *) sclp_vt220_empty.next;
add_timer(&sclp_vt220_timer);
}
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
+out:
return overall_written;
}
static int
sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
- return __sclp_vt220_write(buf, count, 1, 0);
+ return __sclp_vt220_write(buf, count, 1, 0, 1);
}
#define SCLP_VT220_SESSION_ENDED 0x01
* 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.
- *
- * NOTE: include/linux/tty_driver.h specifies that a character should be
- * ignored if there is no room in the queue. This driver implements a different
- * semantic in that it will block when there is no more room left.
*/
-static void
+static int
sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
{
- __sclp_vt220_write(&ch, 1, 0, 0);
+ return __sclp_vt220_write(&ch, 1, 0, 0, 1);
}
/*
sclp_vt220_emit_current();
}
-/*
- * Initialize all relevant components and register driver with system.
- */
-static void __init __sclp_vt220_cleanup(void)
+/* Release allocated pages. */
+static void __init __sclp_vt220_free_pages(void)
{
struct list_head *page, *p;
}
}
-static int __init __sclp_vt220_init(void)
+/* Release memory and unregister from sclp core. Controlled by init counting -
+ * only the last invoker will actually perform these actions. */
+static void __init __sclp_vt220_cleanup(void)
+{
+ sclp_vt220_init_count--;
+ if (sclp_vt220_init_count != 0)
+ return;
+ sclp_unregister(&sclp_vt220_register);
+ __sclp_vt220_free_pages();
+}
+
+/* Allocate buffer pages and register with sclp core. Controlled by init
+ * counting - only the first invoker will actually perform these actions. */
+static int __init __sclp_vt220_init(int num_pages)
{
void *page;
int i;
- int num_pages;
+ int rc;
- if (sclp_vt220_initialized)
+ sclp_vt220_init_count++;
+ if (sclp_vt220_init_count != 1)
return 0;
- sclp_vt220_initialized = 1;
spin_lock_init(&sclp_vt220_lock);
INIT_LIST_HEAD(&sclp_vt220_empty);
INIT_LIST_HEAD(&sclp_vt220_outqueue);
- init_waitqueue_head(&sclp_vt220_waitq);
init_timer(&sclp_vt220_timer);
sclp_vt220_current_request = NULL;
sclp_vt220_buffered_chars = 0;
sclp_vt220_flush_later = 0;
/* Allocate pages for output buffering */
- num_pages = slab_is_available() ? MAX_KMEM_PAGES : MAX_CONSOLE_PAGES;
for (i = 0; i < num_pages; i++) {
if (slab_is_available())
page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
else
page = alloc_bootmem_low_pages(PAGE_SIZE);
if (!page) {
- __sclp_vt220_cleanup();
- return -ENOMEM;
+ rc = -ENOMEM;
+ goto out;
}
list_add_tail((struct list_head *) page, &sclp_vt220_empty);
}
- return 0;
+ rc = sclp_register(&sclp_vt220_register);
+out:
+ if (rc) {
+ __sclp_vt220_free_pages();
+ sclp_vt220_init_count--;
+ }
+ return rc;
}
static const struct tty_operations sclp_vt220_ops = {
driver = alloc_tty_driver(1);
if (!driver)
return -ENOMEM;
- rc = __sclp_vt220_init();
+ rc = __sclp_vt220_init(MAX_KMEM_PAGES);
if (rc)
goto out_driver;
- rc = sclp_register(&sclp_vt220_register);
- if (rc) {
- printk(KERN_ERR SCLP_VT220_PRINT_HEADER
- "could not register tty - "
- "sclp_register returned %d\n", rc);
- goto out_init;
- }
driver->owner = THIS_MODULE;
driver->driver_name = SCLP_VT220_DRIVER_NAME;
tty_set_operations(driver, &sclp_vt220_ops);
rc = tty_register_driver(driver);
- if (rc) {
- printk(KERN_ERR SCLP_VT220_PRINT_HEADER
- "could not register tty - "
- "tty_register_driver returned %d\n", rc);
- goto out_sclp;
- }
+ if (rc)
+ goto out_init;
sclp_vt220_driver = driver;
return 0;
-out_sclp:
- sclp_unregister(&sclp_vt220_register);
out_init:
__sclp_vt220_cleanup();
out_driver:
static void
sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
{
- __sclp_vt220_write((const unsigned char *) buf, count, 1, 1);
+ __sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0);
}
static struct tty_driver *
if (!CONSOLE_IS_SCLP)
return 0;
- rc = __sclp_vt220_init();
+ rc = __sclp_vt220_init(MAX_CONSOLE_PAGES);
if (rc)
return rc;
/* Attach linux console */
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff