drivers/s390/char/sclp_con.c

Source file repositories/reference/linux-study-clean/drivers/s390/char/sclp_con.c

File Facts

System
Linux kernel
Corpus path
drivers/s390/char/sclp_con.c
Extension
.c
Size
7950 bytes
Lines
315
Domain
Driver Families
Bucket
drivers/s390
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (!buffer) {
			sclp_con_queue_running = 0;
			spin_unlock_irqrestore(&sclp_con_lock, flags);
			break;
		}
		spin_unlock_irqrestore(&sclp_con_lock, flags);
	} while (sclp_emit_buffer(buffer, sclp_conbuf_callback));
}

/*
 * Finalize and emit first pending buffer.
 */
static void sclp_conbuf_emit(void)
{
	struct sclp_buffer* buffer;
	unsigned long flags;
	int rc;

	spin_lock_irqsave(&sclp_con_lock, flags);
	if (sclp_conbuf)
		list_add_tail(&sclp_conbuf->list, &sclp_con_outqueue);
	sclp_conbuf = NULL;
	if (sclp_con_queue_running)
		goto out_unlock;
	if (list_empty(&sclp_con_outqueue))
		goto out_unlock;
	buffer = list_first_entry(&sclp_con_outqueue, struct sclp_buffer,
				  list);
	sclp_con_queue_running = 1;
	spin_unlock_irqrestore(&sclp_con_lock, flags);

	rc = sclp_emit_buffer(buffer, sclp_conbuf_callback);
	if (rc)
		sclp_conbuf_callback(buffer, rc);
	return;
out_unlock:
	spin_unlock_irqrestore(&sclp_con_lock, flags);
}

/*
 * Wait until out queue is empty
 */
static void sclp_console_sync_queue(void)
{
	unsigned long flags;

	spin_lock_irqsave(&sclp_con_lock, flags);
	timer_delete(&sclp_con_timer);
	while (sclp_con_queue_running) {
		spin_unlock_irqrestore(&sclp_con_lock, flags);
		sclp_sync_wait();
		spin_lock_irqsave(&sclp_con_lock, flags);
	}
	spin_unlock_irqrestore(&sclp_con_lock, flags);
}

/*
 * 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(struct timer_list *unused)
{
	sclp_conbuf_emit();
}

/*
 * Drop oldest console buffer if sclp_con_drop is set
 */
static int
sclp_console_drop_buffer(void)
{
	struct list_head *list;
	struct sclp_buffer *buffer;
	void *page;

	if (!sclp_console_drop)
		return 0;
	list = sclp_con_outqueue.next;
	if (sclp_con_queue_running)
		/* The first element is in I/O */
		list = list->next;
	if (list == &sclp_con_outqueue)
		return 0;
	list_del(list);
	buffer = list_entry(list, struct sclp_buffer, list);
	page = sclp_unmake_buffer(buffer);
	list_add_tail((struct list_head *) page, &sclp_con_pages);
	return 1;
}

Annotation

Implementation Notes